Neurocase
2003, Vol. 9, No. 2, pp. 140–155
1355-4794/03/0902–140$16.00
# Swets & Zeitlinger
Nothing to Say, Something to Sing:
Primary Progressive Dynamic Aphasia
Jason D. Warren1,2, Jane E. Warren3, Nick C. Fox1 and Elizabeth K. Warrington1
1
Dementia Research Group, Institute of Neurology, Queen Square, London, UK, 2Auditory Group, University
of Newcastle Medical School, Newcastle-upon-Tyne, UK and 3MRC Clinical Sciences Centre, Cyclotron Unit,
Hammersmith Hospital, London, UK
Abstract
We describe a 76-year-old man (ADY) with dynamic aphasia in the setting of a degenerative frontal lobe dementia:
primary progressive dynamic aphasia. He displayed a striking paucity of propositional speech despite intact speech
production, and preserved singing and prosody. Vocal expression in the verbal and musical domains was
investigated in a series of neuropsychological experiments based on novel language and musical tasks that were
designed to establish the nature and specificity of the verbal output deficit. The features of the language disorder
indicated that the speech output pathway was disrupted at the early stage of generation of a new pre-verbal
message. In contrast, tests of musical output demonstrated that the generation of new musical ideas was unimpaired.
The domain-specificity of dynamic aphasia may result from the disruption of specific cognitive processes necessary
for the creation of verbal messages, as well as selective damage of brain regions involved in language production.
Introduction
For all its apparent banality, conversational speech remains an
enigmatic process. Theoretical models of speech production
(reviewed by Nickels, 2002) generally postulate an early stage
of lexical-semantic preparation and a later stage at which the
phonological output is organised (Levelt, 1999; Levelt et al.,
1999; Nickels, 2002). At the level of single word production,
the early stage of lexical-semantic retrieval is generally considered to involve pre-linguistic concepts that may activate
semantic, phonological and syntactic information required in
order to achieve verbal expression (Levelt, 1999; Nickels,
2002). In Levelt’s formulation, an initial stage of conceptual
preparation leads to the generation of a pre-verbal message
(Levelt, 1999). In the case of a novel sentence, this message is
typically an extended semantic structure requiring retrieval
and linking together of several pre-linguistic concepts. Encoding of the pre-verbal message in the form of a sentence
requires a linguistic scheme that brings words corresponding
to pre-linguistic concepts into grammatical relation with one
another. This scheme is used to generate a phonological
programme for the delivery of the spoken sentence.
The syndrome of dynamic aphasia, first described by
Lichtheim (1885), is characterised by a severe reduction in
spontaneous propositional speech despite the preserved ability to produce speech in specific contexts such as naming,
repetition or reading. Dynamic aphasia is of considerable
theoretical importance as a window on the mechanisms by
which normal propositional speech is generated. However,
previous detailed neuropsychological case studies of dynamic
aphasia (summarised in Table 1) have led to divergent
accounts of the syndrome.
Luria (1970) maintained that dynamic aphasia results from
disruption of a transitional stage of language output, interposed between the generation of a preliminary idea and the
delivery of the extended verbal proposition. According to this
formulation, ‘inner speech’ is disturbed such that the linear
scheme of the sentence cannot be constructed. Kleist (1934)
and Luria (1970) observed the syndrome in association with
post-traumatic left inferior frontal damage that spared Broca’s
area.
Costello and Warrington (1989) described dynamic aphasia
in a patient, ROH, with a left posterior frontal astrocytoma.
Although ROH’s propositional speech was gravely impaired,
the short sentences he did produce (in response to simple
conversational questions) had normal syntax, prosody and
articulation and no paraphasic errors were observed. Luria’s
model of defective sentence schema formation would predict
errors in sentence construction and word order. Since ROH
made no such errors, Costello and Warrington proposed that
dynamic aphasia in this case resulted from a defect at the early
stage of verbal planning corresponding to the ‘idea’ of a
Correspondence to: Prof. E. K. Warrington, Dementia Research Group, Institute of Neurology, Queen Square, London WC1N 3BG, UK.
Tel: þ44 207 829 8773; Fax: þ44 870 132 0447; e-mail: [email protected]
Table 1. Comparison of language disturbance features and lesion location in current study (ADY) and in previously reported cases of dynamic aphasia. Key: BA, Brodmann area; L, left; PSP, progressive
supranuclear palsy; R, right
Study
Spontaneous propositional speech Naming
Luria cases (Luria,
1970)
Reduced;
grammatical
errors (word
order)
ROH (Costello and Reduced;
Warrington, 1989)
grammatically
correct
2 cases (Esmonde
Reduced;
et al., 1996)
syntactic
errors
Sentence completion
Sentence generation from context
Single word
Phrase
Single word Picture
Topic
Intact
?
Usually
intact
Impaired
Intact for
simple
scenes
Impaired
?
Linear
scheme of
sentence
L inferior
premotor
(trauma)
Intact
Slow (high
probability
only)
Impaired
Impaired Impaired
Intact
Impaired
Impaired
Verbal
planning
Impaired ?
Impaired
Impaired in ?
one case;
normal in
other
Impaired
Impaired
(oral
better)
L posterior
frontal
(tumour)
PSP
Intact
Sentence anagram task Putative deficit Lesion
KC (Snowden
et al., 1996)
Reduced;
syntactic
errors
Intact
Intact (high
probability
only)
Intact
Intact
Impaired
CO (Gold et al.,
1997)
Reduced;
grammatically
correct
Reduced;
grammatically
correct
Intact
?
?
?
?
Impaired
?
Intact
Impaired
Intact
Intact
Impaired
(simple
actions)
Intact
ANG (Robinson
et al., 1998)
ADY (present
study)
Reduced;
grammatically
correct
Intact
Poor for low
Impaired Impaired
probability,
(except
better for
proper
high
nouns)
probability
Mildly
Poor for low
Impaired Impaired
impaired
probability;
intact for high
probability
Frontalsubcortical
dysfunction
Temporal
organisation
of verbal
output
Semantic
strategy
formation
Selection
between
competing
verbal
responses
Creation of
pre-verbal
message
L > R frontal
(degeneration)
Bilateral
striatocapsular
(infarcts)
L parafalcine
and L inferiorfrontal
(BA 45) meningiomas
L > R frontal
(degeneration)
Primary progressive dynamic aphasia
141
142
J. D. Warren et al.
sentence, rather than the subsequent implementation of a
sentence schema to express that idea. In support of this
model, ROH was able to produce single words to complete
sentences where the target word was clearly established by the
context (for example, ‘Most cats see well at . . . ’) and to
produce sentences describing a simple picture. He had difficulty, however, in completing sentences requiring a
phrase (for example, ‘The black cat . . . ’) and in producing
whole sentences to incorporate a common stimulus word. In
addition, ROH was unable to rearrange a set of words to
form a short sentence. In contrast, he was able to order
pictures to form a meaningful sequence, suggesting a dissociation between the ability to plan in the verbal and non-verbal
(e.g. visual) domains. In terms of contemporary models
of speech production (Levelt, 1999; Nickels, 2002), Costello
and Warrington’s stage of verbal planning would correspond
to the generation of a pre-verbal message.
Snowden et al. (1996) described a patient, KC, with a
frontal degeneration, who had impaired propositional language evident even in simple conversational exchanges. She
could generate sentence completions, but made errors of
organisation (e.g. temporal ordering), leading Snowden et al.
to localise the deficit at Luria’s transitional stage of sentence
scheme formation. Esmonde et al. (1996) reported three
patients with progressive supranuclear palsy who displayed
impoverished propositional speech with preserved naming
and comprehension. These authors postulated that interruption of frontostriatal feedback loops might lead to breakdown
of monitoring of verbal responses with resulting insertion of
inappropriate sentence completions. Gold et al. (1997) studied a patient, CO, with frontal dysfunction and impaired
propositional speech due to bilateral striatocapsular infarcts:
CO had particular difficulty in describing familiar procedures
and in semantic categorisation, attributed to a defect in generating concepts and semantic strategies that was not specific
to language.
Robinson et al. (1998) carried out a detailed analysis of
dynamic aphasia exhibited by a patient, ANG, with a
malignant left frontoparietal parafalcine meningioma. Like
Costello and Warrington’s patient, ROH, ANG had sparse
propositional speech with normal prosody and syntax. She
exhibited a similar difficulty in generating a phrase to
complete a sentence, and in generating a sentence from
a single common word. Although she was able to generate
single words to complete a sentence, her performance
deteriorated when the range of possible completions was
wide. Unlike ROH, ANG had no difficulty in rearranging
single words to construct a meaningful sentence. She was
also able to generate a sentence incorporating a familiar
proper noun (for example, ‘Hitler’), to generate phrases to
complete a sentence when the phrase was highly predictable (for example, ‘‘The man sat in the dentist’s
chair . . . ’’) and to construct sentences containing highly
associated word pairs (for example, ‘giraffe-neck’).
Robinson et al. proposed that this pattern of deficits was
the result of an inability to select between competing verbal
responses, under circumstances where the number of responses was unconstrained.
Several unresolved theoretical issues emerge from this
review of the literature on dynamic aphasia. What is the core
defect in this syndrome? Can it be reconciled with contemporary theoretical models of normal speech production? To
what extent is the defect specific for verbal material? We
recently had the opportunity to address these issues in a
patient with dynamic aphasia due to a frontal degeneration
who was bilingual and had achieved a high level of musical
competence. This patient displayed a profound reduction in
spontaneous propositional speech despite intact speech production, and preserved singing and prosody. We designed a
series of neuropsychological experiments in order to define
the nature of his language disorder and to assess its specificity
for verbal (in contrast to musical) material.
Fig. 1. Magnetic resonance images of the brain of ADY at the time of the experimental investigations. Representative coronal (left), axial (middle) and sagittal
(right) sections are presented in radiological convention (left hemisphere on the right). Levels of the respective sections are indicated by intersecting white lines.
Bilateral frontal atrophy is evident, including the corpus callosum, anterior cingulate gyri, dorsolateral convexities, inferior frontal gyri and frontal opercula, more
severe on the left. The temporal lobes are relatively spared.
Primary progressive dynamic aphasia
Case report
ADY, a 76-year-old, right-handed man, presented with a four
year history of progressive impairment of conversational
speech. His first language was German, however, he had
spoken English fluently since age 14, and had used it exclusively in his occupation as an engineer. Initially, he experienced difficulty finding the names of everyday objects in
conversation. Gradually the quantity of his speech output
diminished, until he rarely initiated or participated in conversations. Comprehension was unaffected. His memory for
appointments and dates deteriorated, and he developed intermittent dysphagia. He became somewhat more rigid in his
daily routines, but retained interest and proficiency in his
hobbies, which included chess, bridge and singing. Despite
his language impairment, he continued to take part in a
weekly amateur group singing traditional Yiddish songs,
and read the Hebrew liturgy regularly at his local synagogue;
according to his wife, there had been no deterioration in either
of these abilities. He listened to a range of music (classical,
Broadway musicals and Gilbert and Sullivan operettas), and
had played the piano regularly from an early age, attaining
sufficient proficiency to play some of the Beethoven sonatas.
His wife reported that he was still able to play competently,
and to read and write music.
The general neurological examination was normal.
Standard investigations for reversible causes of cognitive
impairment were normal.
Serial volumetric magnetic resonance imaging (MRI) of
ADY’s brain on three occasions during an eighteen month
period demonstrated progressive bi-frontal atrophy, more
marked on the left, involving the corpus callosum and anterior
cingulate gyri, the dorsolateral convexities, inferior frontal
gyri and frontal opercula. The temporal lobes were relatively
spared. Representative images at the time of the neuropsychological experiments are shown in Fig. 1.
Although the imaging findings supported the clinical picture of a primary degenerative dementia, the nature of the
underlying degenerative process remains unknown.
General neuropsychological assessment
ADY underwent a general neuropsychological assessment
(Table 2), conducted in English (his preferred language). Verbal IQ was 97 (a decline from estimated premorbid levels), and
performance IQ 114. Premorbid literacy skills were estimated
to have been in the superior range. Phonemic and category
fluency were severely reduced. Digit span was superior (9
forward, 8 backward). Verbal and visual recognition memory
were mildly impaired. Praxis, motor sequencing, calculation
and visual perceptual functions were normal.
Language
Although ADY’s conversation was grossly impoverished,
the few sentences he produced were grammatically correct
without paraphasic errors. He was unable to construct a
143
narrative around a simple topic (e.g. what he had eaten for
breakfast). Description of a visual scene (the Boston Cookie
Theft Picture) was disjointed, hesitant and incomplete. Verbal
comprehension on word-picture matching tests, and repetition
of sentences (ranging from six to ten words in length) were
normal (Table 2). He read a passage aloud fluently, without
phonemic or semantic errors. Picture naming was mildly
impaired (Table 2); however, he was able to recognise objects
and to indicate their uses and attributes. ADY’s errors on the
naming task were all omissions; there were no misidentifications or circumlocutions. Written language output was
severely impaired: although he wrote a sentence to dictation
without errors, he was unable to generate a spontaneous
written sentence.
Table 2. Summary of general neuropsychological assessment in ADY. Agescaled score, otherwise raw scores given; RMT, Recognition Memory Test;
NART, National Adult Reading Test; WAIS-R, Wechsler Adult Intelligence
Scale – Revised; WCST, Wisconsin Card Sorting Test
Test
Score
Language tasks
NART
British Picture Vocabulary Test
WAIS-R Comprehension
WAIS-R Similarities
Test for Reception of Grammara
Boston Naming Test: nounsb
Graded Naming Testc
Naming: nounsd
Naming: actionsd
Repetition: sentences
7 errors
27/32
3 (2 )
10 (8 )
70/80
31/60
10/30
27/40
29/40
10/10
Frontal executive tasks
WCST (number of categories)
Verbal fluency: animals in 1 minute
Verbal fluency: letter c in 1 minute
Other cognitive tasks
WAIS-R Arithmetic
WAIS-R Picture Completion
WAIS-R Picture Arrangement
WAIS-R Block Design
RMT wordse
RMT facese
Camden Topographicalf
Synonyms Test (Concrete)g
A Cancellation
Incomplete Letters Testh
Position Discrimination Testh
a
6
3
2
13
14
7
13
34/50
30/50
15/30
19/25
24 seconds
20/20
20/20
Bishop D, Test for Reception of Grammar, MRC: Chapel Press, England,
1990.
b
Kaplan EF et al. The Boston Naming Test, 2nd edn, Lea & Febiger:
Philadelphia, 1983.
c
McKenna & Warrington, The Graded Naming Test, NFER-Nelson: Windsor,
1983.
d
Orpwood L & Warrington EK, Cortex 1995; 31: 239–65.
e
Warrington EK, Recognition Memory Test Manual, NFER-Nelson: Windsor,
1984.
f
Warrington EK, The Camden Memory Tests Manual. Psychology Press: East
Sussex, 1996.
g
Warrington et al. Neuropsych Rehab 1998; 8: 143–54.
h
Warrington & James, The Visual Object and Space Perception Battery,
Thames Valley Test Co: Bury St Edmunds, 1991.
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J. D. Warren et al.
Prosody
ADY’s intonation when reading and in his few spontaneous
utterances was normal. He was able to attribute a nominated
emotional tone (surprised, angry, sad) to an emotionally
neutral sentence (‘All cats are grey at night’). Semantic
prosody was also intact: he was able to place stress on
nominated words within the sentence, and to turn a statement
into a question. He was also able to attribute affective or
semantic prosody to a meaningless syllable string (‘Ba ba ba
ba ba’). He mimicked accents (Yiddish or an exaggerated
German accent) convincingly. He was able to read a passage
chosen at random from the Torah using the heightened intonation (distinct from both singing and ordinary reading)
normally reserved for reading aloud in synagogue.
Music
ADY’s general musical abilities were well preserved. For
testing purposes, melodies were presented in wavefile format
using the sound card of a personal computer. ADY was able to
hum familiar melodies from a range of musical genres (nursery and folk songs, show tunes, classical), either from memory
or after the first few bars were played to him (Appendix 2).
However, he was able to supply accompanying lyrics for only
a few songs, and he was unable to name any of the melodies
despite recognising they were familiar. He did not benefit
from cueing with the first few words of the lyrics; nor was he
able to ‘sing’ novel propositional sentences, although he
seemed to understand the task. He was able to sight-read
unfamiliar songs from a score, to name and copy notes written
in the treble clef, and to notate short melodies with only
occasional errors.
Experimental investigations
The experimental investigations were administered in four
testing sessions each lasting approximately two hours, conducted over the course of two months. Experiments were
conducted with ADY’s informed consent in accord with the
guidelines of the Declaration of Helsinki and approved by the
local Ethics Committee. Findings for language and music will
be described in turn.
Language
The language experiments were designed to analyse the
properties of ADY’s language disorder in detail and to establish its cognitive neuropsychological basis.
Experiment 1. Sentence completion: high and low probability single words
It has been shown (Costello and Warrington, 1989; Esmonde
et al., 1996; Snowden et al., 1996; Robinson et al., 1998) that
patients with dynamic aphasia are able to complete sentences
when a single target word is required. Robinson et al. (1998)
found that performance on a sentence completion task is
better when the choice of terminal word is limited than when
it is wide. The probability that a particular terminal word will
be generated defines ‘high probability’ (for example, ‘The
boat passed easily under the . . . ’) and ‘low probability’
(‘Helen reached up to dust the . . . ’) sentence completions
(Breen and Warrington, 1994; Manning and Warrington,
1996). We first tested whether ADY’s performance on a sentence completion task was affected by the range of choice of
terminal noun, i.e. the probability of a particular completion.
Thirty sentences requiring high probability and 30 requiring
low probability single terminal nouns for completion were
selected from the list devised by Breen and Warrington (1994).
Sentences were presented in interleaved order.
Results. ADY completed 22/30 sentences requiring high
probability nouns. In contrast, he completed only 8/30 sentences requiring low probability nouns (Table 3): in most low
probability cases, he offered no verbal response at all. This
difference in performance was statistically highly significant
(2 ¼ 11.3, p < 0.001).
Comment. ADY’s performance was significantly better for
high than for low probability sentence completions, consistent
with the pattern reported in a previous case of dynamic
aphasia (Robinson et al., 1998). It could be argued that the
high probability completion is already implied by the context
of the sentence that has gone before it; whereas in the ‘openended’ sentences, selection of a low probability terminal noun
requires the generation of a new verbal message for the
complete sentence. Accordingly, the dissociation between
high and low probability completions in dynamic aphasia
could result from defective generation of a pre-verbal message, equivalent to Costello and Warrington’s (1989) postulated verbal planning defect.
Experiment 2. ‘Restricted alternative’ single words
Although ADY’s superior performance for high than for low
probability sentence completions is consistent with a defect of
pre-verbal message generation, other interpretations are possible. In particular, Robinson et al. (1998) have proposed that
this pattern results from an inability to select between competing potential verbal responses. We therefore devised a task
that would test these two models, defective message generation
and impaired response selection. In designing this task, we
exploited a sentence completion condition not previously
tested explicitly: namely, ‘restricted alternative’ completions,
for which several equally plausible words exist (Appendix 1).
For example, the sentence ‘Cats, unlike dogs, see very well
at . . . . ’ has ‘night’ as its only sensible conclusion; whereas in
the sentence, ‘Mother peeled John another . . . . ’, ‘apple’,
‘banana’ or ‘orange’ would be equally suitable. The message
generation model would predict a superior performance for
restricted alternative than for open-ended (low probability)
sentence completions, since the former establish a context
which suggests plausible single words to complete the sentence. In contrast, the competing-responses model would
predict disproportionate difficulty for restricted alternative
Primary progressive dynamic aphasia
145
Table 3. Summary of language experiment findings in ADY. NR: not recorded
Test
Score correct (%)
Reaction time: mean (range) (seconds)
Experiment 1. Sentence completion:
High and low probability single words
High probability
Low probability
22/30 (73)
8/30 (27)
NR
Experiment 2. Sentence completion: High probability,
low probability and restricted alternative single words
High probability
Low probability
Restricted alternatives
20/20 (100)
9/20 (45)
19/20 (95)
0.20 (0–4)
6.9 (0–22)
1.6 (0–16)
Experiment 3. Sentence completion:
Unconstrained and constrained phrases
Unconstrained
Constrained
4/10 (40)
8/20 (40)
2.5 (0–10)
2.4 (0–19)
Experiment 4. Sentence elaboration
Elaboration of nuclear sentences
2/15 (13)
NR
Experiment 5. Facilitated sentence generation
Single words
Pictured action description
Sentence formula
Reporter’s Test
Sentence anagram task
4/10 (40)
10/13 (77)
10/10 (100)
8/10 (80)
5/5 (100)
NR
Experiment 6. German to English translation
Same word order
Altered word order
Altered word order and content
Idiom
4/5 (80)
3/5 (60)
0/5
0/5
completions, since according to such a model, this situation
brings equally valid, potential verbal responses into direct
conflict.
The test material in this experiment comprised three new
sets of sentences (not previously presented in Experiment 1)
requiring completion with high probability, low probability
and restricted alternative terminal nouns, respectively. Each
set of sentences contained 20 examples (Appendix 1) and
sentences requiring each type of completion were interleaved
and presented in fixed order (High-Low-Restricted). Reaction
times were measured in each case, with an arbitrary ‘No
response’ cut-off period of 30 seconds.
Results. ADY had no difficulty with either the high probability or restricted alternative examples (Table 3), and his
performance on the two sets (high probability 20/20, restricted alternatives 19/20) did not differ significantly. His mean
reaction times on both these sets (Table 3) were comparable to
reaction times for high probability completions obtained
previously in normal subjects (Costello and Warrington,
1989). In contrast, he again experienced difficulty with the
low probability set, reflected in both his low score (9/20) and
prolonged mean reaction time (6.9 seconds). As in Experiment 1, he made no verbal response at all in the majority of the
low probability cases. In addition, in the low probability
condition some responses (Appendix 1, Table 5), though
context-appropriate, were rather unlikely (for example, ‘For
dinner the children all asked for . . . . ’ produced ‘fruit juice’).
NR
Performance was significantly worse for the low probability
condition compared with both the high probability condition
(2 ¼ 12.5, p < 0.001) and the restricted alternative condition
(2 ¼ 9.64, p < 0.01).
Comment. In contrast to his difficulty in selecting a low
probability terminal noun, ADY had no difficulty when the
context demanded a small number of equally plausible alternatives. His responses in the restricted alternative completions
(Appendix 1) were not influenced by the number of available
alternatives for each sentence (ranging between two, and
approximately eight, equally highly probable nouns), and
included a number of unusual items (for example, ‘appendix’,
‘toboggan’, ‘quintet’), arguing against a word frequency effect. We propose that noun generation in both the high
probability and restricted alternative sentence completions
is facilitated because the message of the sentence is indicated
by the context. Such facilitation should not occur for restricted
alternative completions if inability to choose between potential completions were defective. The pattern of ADY’s responses in this experiment therefore supports the message
generation model of dynamic aphasia.
Experiment 3. Unconstrained and constrained phrases
The arguments presented above for sentence completions
using single words can be extended to the completion of
sentences using a phrase. Previous patients with dynamic
aphasia have shown impaired performance on tasks requiring
146
J. D. Warren et al.
the generation of a phrase in response to a given open-ended
phrase, in order to form a complete sentence: for example,
‘The old lady . . . . ’ (Costello and Warrington, 1989). However, performance may improve if the completing phrase is
predictable: for example, ‘She took the hair-dryer and . . . ’
(Robinson et al., 1998). As in the case of single word sentence
completions, this pattern on phrase completions could reflect
an incapacity to generate a new message embodied in a
completing phrase or an inability to select between possible
alternative endings.
Our objectives in this experiment were therefore twofold:
first, to determine whether ADY’s performance on a phrase
completion task conformed to the previously reported pattern;
and second, to establish which of the above models could best
account for the pattern observed. In order to address the
second question, we designed a novel phrase completion
task: phrases for completion were presented with or without
a ‘keyword’, which ‘constrained’ the phrase that could be
used to complete the sentence. Thus, ‘Although he was
crippled . . . ’ is an example of an unconstrained phrase, since
the sentence could be completed in many different ways;
whereas ‘Although he was crippled . . . [violin]’ is an example
of a constrained phrase, since the keyword ‘violin’ here
suggests the completion . . . . ‘he was still able to play the
violin.’ (Appendix 1). In contrast to the pattern predicted in
the single word completion experiments, a message generation defect should not be substantially improved by the provision of the keyword, since it is still necessary to formulate
an idea for a phrase containing that word. On the other hand,
selection between alternative endings should be facilitated by
provision of a keyword, since the ideational content of the
phrase to be used is constrained by the keyword.
Accordingly, ADY was presented with two sets of phrases,
each requiring the addition of a second phrase in order to
generate a complete sentence. Twenty ‘constrained’ phrases
were devised, each followed by a single word which ADY was
required to incorporate in the completing phrase (Appendix
1); and in addition, 10 ‘unconstrained’ phrases, drawn from
the set used by Costello and Warrington (1989), were presented without any guidance as to how the sentence should be
completed. Phrases in each category were presented as a block
(unconstrained-constrained). Reaction times were measured
in each case, with an arbitrary ‘No response’ cut-off period of
30 seconds.
Results. ADY had difficulty completing ‘unconstrained’
(open-ended) sentences when a phrase was required, managing only 4/10 (40%) responses (Table 3). His performance was
identical (8/20, 40%) when a single word acting as a contextual constraint was provided. Reaction times for successful
attempts were very similar in both cases (mean 2.5 and 2.4
seconds, respectively). The sentences he did produce were
always grammatical: for example, ‘The carpenter swore loudly because of the hammer blow on his knee’.
Comment. ADY’s similar performance on both constrained
and unconstrained phrase completions complements the findings in Experiment 2 for single word completions. The provi-
sion of a keyword should have reduced any conflict engendered
by competing possible endings: since performance did not
improve in this situation, sentence generation itself must be
defective. The few sentences ADY did produce were free of
grammatical errors, suggesting that the primary defect lay at the
early stage of pre-verbal message creation, prior to formation of
the linguistic sentence schema.
Experiment 4. Elaboration of nuclear sentences
The observation that patients with dynamic aphasia may
occasionally elaborate spontaneously on basic sentence formulas when describing simple pictures (Costello and
Warrington, 1989) led us to test this ability formally in
ADY. A set of 15 ‘nuclear’ sentences was devised (Appendix
1) which ADY was asked to elaborate in any manner he
wished. An example was first given to illustrate the task (‘The
children listened to the story’ was elaborated to ‘The children
were listening intently to the exciting story’).
Results. ADY was able to provide a meaningful elaboration (either an adjective or a short adjectival clause) in only
2/15 cases (Table 3). In several instances, he inserted the
context-inappropriate adjective, ‘silly’, a perseverative response (Appendix 1).
Comment. ADY’s inability to elaborate on basic sentence
structures was further evidence of a profound impairment in
the generation of novel verbal output: even the provision of a
verbal ‘nucleus’ did not facilitate this process.
Experiment 5. Facilitated sentence generation
Grammatical and syntactical impairments of variable severity
have been described in patients with dynamic aphasia (Luria,
1970). A variety of tasks have been employed in previous
studies of dynamic aphasia in order to ‘assist’ patients’ verbal
production by providing a prompt or framework for both the
semantic and linguistic structure of a spoken sentence (Table
1). Such tasks have included the provision of a word around
which the sentence is to be structured, showing a pictorial
scene, asking the patient to describe a sequence of pictures,
having the patient describe the examiner’s actions (Reporter’s
Test), or providing sentence fragments for rearrangement to
reconstitute a coherent whole (sentence anagram test). In
order to establish that ADY’s impoverished propositional
speech was indeed free of grammatical errors, we provided
several types of framework to facilitate sentence production
(Table 3).
Single words. Ten common concrete nouns were presented, around which ADY was required to construct a sentence. Although he managed only 4/10 responses, these
responses were grammatically correct: for example, the word
‘garage’ elicited ‘The motor car is in the garage’.
Description of simple pictures. Thirteen simple pictures
containing a single action (for example, a man chopping
wood) were selected from a variety of picture vocabulary
tests. ADY produced short, syntactically correct sentences
describing 10 of the 13 pictures presented.
Primary progressive dynamic aphasia
Application of a sentence formula. Following a procedure
devised by Manning and Warrington (1996), ADY was required to produce a novel sentence given a model verbal
framework. In this test, 10 simple action pictures (not
previously presented to ADY) were first described by the
examiner using a simple formula (for example, ‘The boys are
playing with the ball’): in each case, ADY was then required
to apply this formula to describe another picture (for example,
a cat with a ball of yarn). He was able to apply this type of
framework correctly in all cases. On one occasion, he spontaneously produced the passive voice where this was not
required by the task (‘The brown horse is being chased by
the girl’). In another example, he spontaneously altered a
preposition (‘beside’ became ‘next to’).
Reporter’s Test. ADY also performed well on an adapted
version of the Reporter’s Test (De Renzi and Ferrari, 1978) in
which he was required to describe 10 simple procedures
performed by the examiner, scoring 8/10 correct. On one
occasion, he again provided a more elaborate construction
than required by the task (‘You took the yellow circle and the
blue square and put them together’).
Sentence anagram task. ADY was tested on a sentence
anagram task, requiring rearrangement of five cut-up sentences to reconstitute the originals (see Appendix 1). The
number of fragments for each sentence ranged from five to
eight. He made no errors on this task.
Comment. ADY’s performance in the tests of facilitated
sentence generation was determined by the completeness of
the conceptual framework provided. In the case of single
words, this framework was minimal, and performance was
poor. In the picture description, sentence formula and Reporter’s tests, the conceptual content was implied (since these
simple pictures and actions could be described in essentially
only one way), and in these tests, ADY performed well. His
excellent performance on the sentence anagram task further
indicates that he was able to manipulate syntactical rules:
however, here again the conceptual content of the sentence
(though not its syntactic structure) was supplied, removing the
need to generate a pre-verbal message de novo. Taken together, therefore, the tests of facilitated sentence generation
complement the first four experiments: all suggest that the
verbal output deficit in ADY is pre-linguistic.
Experiment 6. Translation from German to English
ADY retained excellent comprehension of spoken German
at the time of testing. Translation between German and
English frequently involves reorganisation of syntax or vocabulary in order to express the equivalent idea. This feature allowed us to explore the recoding of verbal thought
between languages. Twenty sentences, divided into four
sets each with five examples, were prepared for translation
from German into English (Appendix 1). All sentences used
only common German vocabulary and constructions with
which a native speaker would be highly familiar. Each sentence set tested a different level of translation: (i) sentences with literal correspondence of word order and
147
vocabulary between the German sentence and the ‘target’
English sentence (set one); (ii) sentences with literal correspondence in vocabulary but requiring an alteration in word
order (set two); (iii) sentences requiring alteration of both
word order and vocabulary (set three); and (iv) idiomatic
expressions, which cannot be rendered by a literal translation
(set four).
Results. ADY’s ability to translate the sentences declined
as the degree of similarity in vocabulary between the German
and ‘target’ English sentences diminished (Table 3 and
Appendix 1). He performed well on sentences that could
be translated literally, producing 4/5 correct sentences in set
one and 3/5 in set two. In contrast, in sets three and four, where
literal translation was not possible and new vocabulary had to
be selected, he produced only fragmentary responses.
Comment. ADY’s superior performance on sentences
closely matched in word order and vocabulary between the
two languages is analogous to the facilitation of sentence
production by provision of a frame: in this situation, the
‘frame’ in one language can be used to generate the corresponding sentence in the other language directly, with minimal requirement for the creation of novel conceptual
structures. However, as the ‘mapping’ between the two languages becomes progressively less explicit (requiring a
change in vocabulary or expression), the message for the
corresponding target sentence must be actively derived: it is
no longer present in the original sentence. This type of
translation might be viewed as analogous to ‘low probability’
or ‘unconstrained’ sentence completions, where the ‘completion’ must occur in a different language: a number of valid
responses are possible, but conceptual reorganisation is required in order to arrive at an equivalent idea in the new
language. The pattern of ADY’s performance on the graded
translation test was therefore in accord with his earlier failure
to generate English sentences de novo: verbal output suffered
as the demand for novel message generation increased.
Music
In order to assess the specificity of ADY’s language disorder
for verbal material, we performed a detailed assessment of
vocal output in another domain, namely music. In comparing
ADY’s musical with his verbal output, however, it was not
sufficient to test familiar musical material alone: this depends
on access to stored musical memories (Peretz, 2001), but does
not require novel musical output, whereas sentence production routinely demands the generation of a novel verbal
output, however banal. Accordingly, in order to compare
ADY’s musical vocal expression as directly as possible with
his propositional speech, we devised two tests that demanded
a novel musical response. These tasks were designed as
analogues to the high and low probability sentence completion (Experiment 1) and the sentence elaboration (Experiment
4) tasks used to assess ADY’s language. In each of the musical
experiments, short note sequences were composed and then
translated into wavefile format in Matlab6ß for presentation
148
J. D. Warren et al.
Fig. 2. Examples of musical tests with ADY’s responses. Grey boxes enclose new material generated by ADY (not present in the original sequence). A. High
probability continuations. In these examples, ADY completes the test sequence by adding a terminal note (here the dominant or fifth note of the scale) that creates a
finished melody. B. Low probability continuations. In each example, ADY modifies the test sequence to create a variant melody that leads to a clear conclusion. C.
Similarity of melodic contour between test and response sequences. Examples correspond to the sequences shown in (B). For purposes of illustration, musical notes
in each sequence have been replaced by square markers, linked to indicate the shape of the melodic contour of the sequence. The melody contour of ADY’s
response closely resembles the test melody; however, the exact pitch intervals differ between the two sequences. D. Elaboration of note sequences. In each case,
ADY extends the short note sequence to create a novel melody.
using the soundcard of a personal computer. ADY sang his
responses using the syllable ‘da’. Responses were recorded on
audiotape and later transcribed offline with the aid of an
electronic piano keyboard into standard musical notation for
detailed analysis. When he gave more than one response to a
given test sequence, the longest response sequence was used.
Although assessment of ADY’s performance on the musical tasks was based in part on objective criteria, unlike
assessment of the language tasks, a degree of subjec-
tivity in assessing musicality was unavoidable. A more
detailed explanation of the musical tasks is presented in
Appendix 2.
Experiment 7. Continuation of musical sequences
Twenty short musical tone sequences were composed as
musical analogues of the sentence completion tasks in Experiment 1, using the standard chromatic eight-note Western
scale. Since these sequences did not necessarily have a single
Primary progressive dynamic aphasia
correct terminal note, they should be regarded as ‘continuations’ rather than completions in the same sense as the single
word sentence completions. The musical sequences comprised 10 high probability and 10 low probability melodic
continuations (Fig. 2 and Appendix 2).
ADY was instructed simply to continue the melodies.
Examples of musical sequences and possible continuations
(not subsequently used in the test set) were first played to
ensure that he understood the task. Sequences were presented
in random order without constraints on response time.
Results. In contrast to his frequent failures on the language
completion tasks, ADY was able to generate a continuation for
every musical test sequence (Fig. 2). For 6/10 high probability
and 10/10 low probability sequences, he responded with a
variation of the test sequence rather than reproducing it exactly
(Fig. 2B). In these cases, ADY repeated the initial portion
(typically the first three to six notes) of the test sequence, then
continued with a new but melodically congruent series of
notes: these we termed ‘variant’ responses. Of these variant
responses, almost all (5/6 high probability, 9/10 low probability), were equal in length or longer than the test sequence
and ended on a ‘correct’ (i.e. musically appropriate) terminal
note (Fig. 2A). In six of the variant low probability responses,
he produced a new series of notes which led towards a clear
conclusion that was not implied by the original test sequence,
effectively converting low probability into high probability
sequences (Fig. 2B): linguistically this would be analogous to
changing the sentence ‘‘John went to town to buy a . . . . ’’ into
‘‘John went to town to post a letter’’. In 4/10 high probability
sequences, ADY repeated the test sequence exactly, then
added a single musically appropriate terminal note (Fig.
2A). A striking feature of ADY’s musical responses was that,
although the precise pitch intervals between successive notes
differed in the test and response sequences, the melody contour of the response sequence closely resembled that of the
test sequence in all but one (high probability) instance
(Fig. 2C).
Experiment 8. Elaboration of simple tone sequences
Five simple tone sequences were composed as musical analogues to the ‘nuclear’ sentences used in the sentence elaboration task of Experiment 4 (Fig. 2D and Appendix 2). An
example of a musical sequence elaboration (not subsequently
used in the test set) was first played to illustrate the task,
following which ADY was asked to elaborate the test sequences in any manner he wished.
Results. In every case, ADY repeated the test sequence
then continued with a novel series of notes that created a
tuneful melody (Fig. 2D). ADY expanded the test sequences
of three to five notes into sequences ranging from eight to
twenty notes in length.
Comment. ADY’s performance in the two musical experiments contrasts sharply with the language experiments. In
both the musical continuation and elaboration tasks, he demonstrated a capacity to generate novel musical output. Moreover, he was able to do this even in the musical low probability
149
continuations and elaborations, when the musical context did
not provide a strong indication of how the melody should
develop: he performed equally well on low probability musical continuations and musical elaborations as on high probability musical continuations. These results are in striking
contrast to his performance on the language tests: ADY
performed satisfactorily on the high probability sentence
completions, but was unable to generate any response at all
in the majority of low probability sentence completions and
sentence elaborations. It should also be emphasised that, on
the majority of the musical continuations, ADY did not
merely supply a single terminal note: rather, he produced a
new, melodically congruent sequence of notes (a musical
phrase). In none of the language tests did he show a capacity
for novel verbal production at the level of phrases. This
disparity between his capacity for novel output in the musical
and verbal domains indicates that ADY’s deficit is specific for
verbal material.
Discussion
The cognitive basis for dynamic aphasia
ADY displayed grossly reduced propositional speech, however his few spontaneous sentences had normal form, content
and prosody. Comprehension, repetition and reading aloud
were well preserved. Although verbal fluency was markedly
reduced, ADY’s naming to visual confrontation was only
mildly impaired, suggesting that word retrieval per se was
not the primary defect. His retained ability for novel expression in non-verbal (notably musical) tasks argues that his
language deficit was a specific disorder of propositional
speech, rather than simply a manifestation of abulia, akinesia
or executive dysfunction per se. The features of ADY’s
language disorder fulfil the criteria for dynamic aphasia, as
originally described by Lichtheim (1885) and later formalised
by Luria (1970). The present case is a rare example of primary
progressive aphasia manifesting as dynamic aphasia.
In the language experiments, we investigated the cognitive
neuropsychological basis for ADY’s dynamic aphasia. The
two most fully developed contemporary accounts of the
syndrome have been given by Costello and Warrington
(1989), who proposed a defect of verbal planning (corresponding to the generation of pre-verbal messages) and
Robinson et al. (1998), who proposed an inability to select
between competing verbal responses. Accordingly, the sentence completion tasks (Experiments 1, 2 and 3) were designed firstly to determine which of these alternative models
could best account for the language deficit in ADY.
In Experiment 1, ADY had no difficulty completing high
probability sentences (e.g. ‘Absentmindedly, he sent the letter
without a . . . ’). In Experiment 2, he had no difficulty completing sentences in which alternative completions were restricted by the context (e.g. ‘‘You should eat more fruit’’
said mother, peeling Tom another . . . ). In both experiments,
he performed poorly on open-ended sentences requiring
150
J. D. Warren et al.
selection of low probability single words (e.g. ‘Jack went into
the electrical store in search of a . . . . ’). ADY also performed
poorly in Experiment 3, in which he was required to generate a
phrase, rather than a single word, to complete a sentence (e.g.
‘John just managed to . . . ’). The competing responses model
of dynamic aphasia (Robinson et al., 1998), in contrast to the
message generation model (Costello and Warrington, 1989),
would predict that performance on a single word sentence
completion task should be impaired by the availability of a
small number of equally plausible alternative completions;
whereas performance on a sentence completion task requiring
the selection of a phrase should be improved by the provision
of a keyword constraining the choice of phrase. It is clear that
ADY’s, performance was neither impaired by the availability
of alternatives (Experiment 2) nor improved by a phrase
constraint (Experiment 3): this is the pattern predicted by
the message generation model of dynamic aphasia.
Experiments 4 to 6 were designed as complementary tests
of the message generation account of dynamic aphasia. In
Experiment 4, ADY was unable to generate new verbal material spontaneously when provided with only the nucleus of a
sentence such as ‘The girl collected shells’: here, no guidance
was available as to what form the elaboration (the new
message) should take. In Experiment 5, ADY displayed an
ability to use an external framework for a sentence when this
was provided via the visual (picture of a simple action, or
examiner’s action) or verbal (sentence formula) route. In these
tests, a pre-verbal message for the corresponding sentence
was either provided or strongly implied. ADY’s improved
performance in Experiment 5 therefore complements the
results of Experiments 1 to 4. His excellent performance
on the sentence anagram task demonstrates that he was able
to manipulate supplied verbal material (sentence fragments)
syntactically. Both his performance on the sentence anagram
task and his grammatically correct (though sparse) propositional speech suggest that ADY remained able to follow and
manipulate grammatical rules. Indeed, he occasionally generated sophisticated syntactical constructions (such as the
passive voice). However, these syntactic manipulations did
not demand the generation of a novel message. In contrast, he
had difficulty in generating a sentence containing a nominated
noun such as ‘book’ or ‘hammer’: here, the external framework was minimal, effectively demanding the generation of a
new message to incorporate the nominated word, but giving
no guidance as to what form that message should take. Finally,
in the German to English translations of Experiment 6, ADY
was able to translate sentences requiring a direct ‘mapping’
between languages or a change in word order, but not sentences demanding a change of vocabulary to express the
equivalent idea. In the last situation, reformulation of the
conceptual content between languages is required.
Taken together, the results of all the language experiments
suggest that the core language output defect in ADY occurs at
the early pre-linguistic stage of sentence production: namely,
defective generation of new pre-verbal messages. By extension from current models of single word production (Levelt,
1999; Levelt et al., 1999; Nickels, 2002), we propose that the
creation of a new sentence requires the formation of a novel
sequence of pre-linguistic concepts corresponding to the individual content words in the sentence. This linked sequence
of concepts could be regarded as the pre-verbal message of the
sentence. In the case of high probability completions, or
descriptions of simple actions or pictures, the conceptual
content of the sentence is established by the context. In
contrast, the selection of a low probability terminal word,
the elaboration of a phrase or sentence and many forms of
translation between languages all require the generation of a
novel pre-verbal message corresponding to the completed
sentence. Since the stage of pre-verbal message generation
precedes the organisation of the sentence schema, the application of grammatical rules is unaffected.
Considering the previously reported case studies of dynamic aphasia (Table 1), ADY’s language disorder closely
resembles that of Costello and Warrington’s (1989) patient,
ROH. It is difficult to assess whether our message generation
model could account for other cases described in the literature
(Table 1), since in most the crucial language experiments
were not performed. Nevertheless, the available information
does suggest a number of differences between ADY and these
earlier cases. Unlike some patients described by Luria
(1970), ADY did not make errors of word order: the preserved
syntax and phonemic structure of his propositional speech
indicate that he retained the capacity to assemble a normal
sentence schema. ADY did not produce any bizarre sentence
completions, arguing against a defect of response monitoring
due to fronto-subcortical dysfunction similar to that proposed
in the two cases of Esmonde et al. (1996). Patient KC of
Snowden et al. (1996) was able to complete sentences with
phrases but was unable to perform a written sentence anagram
task; ADY displayed the converse pattern. Patient CO described by Gold et al. (1997) had difficulty in describing how
he would perform common sequential procedures and in
sorting closely semantically related items, interpreted as a
defect of semantic strategy formation: however, comparison
of CO’s language disorder with ADY’s is difficult since
sentence completion was not assessed in CO.
The heterogeneity of clinical, neuropsychological and imaging findings described in the literature on dynamic aphasia
(Table 1) makes it likely that the syndrome does not have a
single mechanism, but rather represents a ‘final common
pathway’ of disorders affecting different cognitive operations
in the production of propositional speech.
Music: a non-verbal mode of vocal expression
We now consider the evidence that ADY’s defect was specific
for the verbal domain. Experiments 7 and 8 were designed to
mirror the language tasks that demanded generation of a novel
verbal output by requiring ADY to generate new musical
ideas: novel musical continuations or elaborations that did not
merely access stored musical memories. The tests incorporated musical analogues to the low probability sentence completions and sentence elaborations. ADY generated novel
Primary progressive dynamic aphasia
musical output successfully in both situations. He produced a
melodic continuation for every test sequence: furthermore,
these continuations generally consisted of note sequences
rather than single notes, and led toward a conclusion that
was congruent with the rest of the melody (Fig. 2). For a
number of ‘low probability’ musical sequences, ADY did not
merely continue the sequence with a novel series of notes, but
spontaneously modified the sequence so that it led to a
musical conclusion (Fig. 2B). These observations suggest
that ADY was not simply producing notes at random: rather,
he produced melodic phrases that were both novel and musically meaningful. This is in striking contrast to his performance in the corresponding language tasks, in which he had
great difficulty completing low probability sentences with a
single word and was unable to complete sentences using a
phrase (a novel word sequence). At no time in any of
the language tests did ADY produce a new, alternative continuation for any of the sentences. We would argue that the
extended, musically meaningful structures sung here by ADY
represent musical ‘messages’, the musical equivalent of the
verbal messages instantiated in spoken sentences.
The basis for domain specificity in dynamic aphasia
The cognitive processes involved in creating verbal and
musical messages share the basic similarity that both are
governed by implicit combinatorial ‘rules’. In the case of
language, these rules are embodied in verbal semantics,
grammar and syntax (Nowak et al., 2002). In the case of
music, generation of a tuneful note sequence is governed by
musical rules at several levels. Firstly, the repertoire of notes
available is necessarily limited by the structures of musical
scales and the pitch ranges of instruments and voices.
Secondly, the succession of pitch intervals in a melody is
constrained: a sequence of notes will tend to sound more
musically congruent (tuneful) when the intervals between
successive notes are small. Finally, the individual’s past
experience of music will provide melodic frameworks that
influence the overall shape or global structure of musical
phrases (Peretz, 2001). This last type of constraint may
account for ADY’s tendency both to produce a melodic
contour very similar to the test sequence (Fig. 2C), and to
supply a conclusion for musically incomplete phrases (Figs.
2B and 2D). ADY demonstrated preserved capacity to
utilise a variety of rule systems in addition to that of music.
He was able to manipulate grammatical constructions in
English and when translating from German, and he could
correctly apply intonational templates to convey prosody. He
could also utilise the explicit rule systems of chess and bridge.
However, whereas ADY’s ability to create novel musical
output was intact, his ability to create novel verbal output
was grossly impaired. How should we account for this
striking dissociation? A process akin to sentence completion
is required in everyday conversation, whereas the musical
continuation tasks were novel experimental tests: it is therefore implausible that the musical tests were intrinsically less
difficult than the language tests. Although the number of
151
ways in which a given musical phrase can be extended is
limited, this is also the case for the vocabulary used in
ordinary conversational sentences such as the examples
here: in completing such sentences, one searches and selects
from a relatively small body of candidate words (rather than
the vast number of possible nouns in the language). It is
unlikely that the dissociation observed in ADY arose solely
from the different sizes of the potential ‘search spaces’ in
language and music.
We propose a qualitative, rather than quantitative distinction between verbal and musical expression. Although both
involve the application of rule systems, a crucial difference
between the two is that language, in contrast to music, refers
to independent concepts in the external world. For a verbal
message to be meaningful, the referential meanings of each of
the constituent words must be linked; this imposes a semantic
constraint in addition to the grammatical rules of the particular language. This dimension of the verbal domain is not
present in music: the elements of a musical message do not
possess an independent meaning analogous to that of
words. Evidence for the existence of a musical semantic
system independent of the mode of musical expression has
been obtained in human lesion studies (Peretz, 2001); however, the nature of ‘pre-vocal musical messages’ remains
speculative. Although music may acquire external semantic
associations, these associations do not determine how a melody is constructed. In contrast, construction of a sentence to
convey a particular message always depends on the meaning
of the constituent words. We therefore suggest that the verbal
and musical modes of vocal expression dissociate because
cognitive operations specific to the generation of verbal semantic content are selectively impaired. A model of vocal output that draws on Luria’s (1970), Costello and Warrington’s
(1989) and Levelt’s (1999) verbal models and incorporates
the domain of musical vocal expression is presented in Fig. 3.
Neuroanatomical considerations
Propositional speech production in normal subjects involves
the left superior frontal gyrus, left frontal operculum, rostral
left temporal cortex (Blank et al., 2002) and posterior areas in
both hemispheres (Braun et al., 2001). The left inferior prefrontal cortex is specifically engaged in tasks requiring controlled semantic retrieval (Wagner et al., 2001). Translation
between languages engages anterior cingulate as well as
supplementary motor area and insula (Price et al., 1999).
The extent to which singing and speaking have independent
neuroanatomical substrates remains unresolved (Perry et al.,
1999; Riecker et al., 2000; Maess et al., 2001). In patients
with dynamic aphasia, brain imaging has implicated the
anterior left frontal lobe (Table 1); however, more specific
localisation is difficult. It is well recognised that the ability
to sing may be retained despite aphasia in acute stroke
(Yamadori et al., 1977); however, musical expression has
been studied only infrequently in degenerative brain diseases
(Confavreux et al., 1992; Polk and Kertesz, 1993). The degenerative process in ADY involved a number of brain areas in
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J. D. Warren et al.
Fig. 3. Model of the stages involved in formulation of verbal and musical vocal output. The defect that gave rise to dynamic aphasia in the present case lies at the
initial pre-linguistic stage of the verbal output pathway, corresponding to generation of the pre-verbal message. The generation of pre-verbal and pre-vocal musical
messages is domain specific: the domain specificity of subsequent stages in the verbal and musical vocal output pathways remains unresolved.
both hemispheres that may participate in both verbal and
musical vocal production: it is therefore not possible to draw
firm conclusions regarding their respective neuroanatomical
substrates in the present case.
Conclusions
Our patient’s dynamic aphasia arose from a defect in the
generation of new pre-verbal messages. This deficit was
specific for language: the generation of new musical ideas
was unaffected. We propose that the domain specificity of
dynamic aphasia may result from disruption of specific cognitive operations in the creation of verbal output, as well
as selective damage of brain regions involved in language
production.
Acknowledgements
We thank ADY for his participation, and Professor Martin
Rossor for allowing us to study this patient under his care. We
are grateful to Dr. John Stevens for reviewing the brain
imaging and James Friswell for performing the general
neuropsychological assessment. JDW is supported by the
Wellcome Trust, NCF is supported by the Medical Research
Council.
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Appendix 1. Language tests
Received on 4 September, 2002; resubmitted on 3 January, 2003;
accepted on 3 January, 2003
Sentence
Response
The small row boat passed easily under the . . .
Absentmindedly, he sent the letter without a . . .
Cats, unlike dogs, see very well at . . .
It was starting to rain, so he quickly opened his . . . .
Bears have a sweet tooth and like eating . . .
bridge
stamp
night
umbrella
honey
Examples of sentence completion, sentence elaboration, sentence anagram and
translation tests
Experiment 1. Sentence completions using single words
High probability
Low probability
Sentence
Response
Jack went into the electrical store in search of a . . . .
Since it was sunny, Jill walked to the . . .
For dinner, the children all asked for . . .
Just outside the window he could see the big . . .
Patiently, the old man stood in line at the . . .
None
None
fruit juice
None
None
Experiment 2. Sentence completions using restricted alternative single words
(complete set)
Sentence
Response
Mrs. Smith hurried out
of the kitchen because she heard the ring of the . . .
That night, John took his
telescope outside to look at the . . .
The African explorer became ill after
he was bitten by the . . .
‘You should eat more fruit’ said mother,
peeling Tom another . . .
Before setting off for work, Mr. Jones
washed his face and brushed his . . .
Poor little Jane had to have an
operation to take out her . . .
Driving his huskies through the storm,
the Eskimo could hear the howling of the . . .
After a long wait, the ambassador was
finally granted an audience with the . . .
The tenant was warned that unless he paid
his bill the company would cut off the . . .
After the fresh fall of snow, the
children excitedly got out their . . .
After much thought, the grandmaster
took his opponent’s pawn with his . . .
The music lover bought the latest
record of the Beethoven piano . . .
The wind player blew a false note on his . . .
My dog likes nothing better than to retrieve a . . .
Tim rode down the country lane on his . . .
When dressing for the ring, the clown put
on his big red . . .
In the wild, stripes are perfect camouflage for the . . .
The teacher made the pupils wait until
they had all said: ‘Good . . . . . ’
The children’s mother took them to the
park to feed the . . .
To have something to read while waiting
for the dentist, Mr. Brown picked up a . . . .
bell
moon
snake
tomato
teeth
appendix
wind
Pope
electricity
toboggan
king
quintet
horn
None
bike
hat
bear
morning
ducks
magazine
154
J. D. Warren et al.
Experiment 3. Sentence completions using a phrase
Unconstrained phrases
Die Kinder sagten der Mutter die Wahrheit, wie der Unfall passierte.
[The children told their mother the truth about how the accident happened]
Phrase
Response
The woman on the beach . . .
He went to the factory, where . . .
John just managed to . . .
The black cat . . .
As the tree came crashing down . . .
None
None
None
None
the hewer of wood . . .
Wenn sie hinausgehen wollen, sollten sie bestimmt die Mäntel anziehen.
[If they want to go out, they should certainly put their coats on]
Ich brauche einen Schlüssel, um die Tür zu öffnen.
[I need a key in order to open the door]
III. Alteration of word order and vocabulary
Der kluger Mann konnte mehrere Sprachen.
[The clever man could speak several languages]
Ich höre der Klaviermusik gern zu.
[I like listening to piano music]
Constrained phrases
Phrase [constraint]
Response
When the ugly frog . . . [prince]
The magician . . . [rabbit]
She told him not to stand . . . [a cold]
Due to popular demand, . . . [musical]
Because of the fog . . . [iceberg]
. . . becomes a prince . . .
None
None
None
None
Der junger Student machte sich um die Prüfungen keine Sorgen.
[The young student was not worried about his exams]
Der Vater führt ein Gespräch mit seinem Sohn.
[The father is having a talk to his son]
Ich bin auf dem Ergebnis gespannt.
[I’m curious about the result]
IV. Idiomatic expressions
Punkt zwei Uhr wird die Königin das Wort ergreifen.
[At two o’clock sharp the Queen will commence speaking]
Experiment 4. Nuclear sentences and elaborations
Der Reisende irrt sich im Weg.
[The traveller is going the wrong way]
Sentence
Response
Ich halte ihn zum Narren; er hat einen Vogel!
[I make fun of him; he’s crazy!]
The girl listens to the story.
The lady was pushing
the pram.
The girl collected shells.
My brother is eating
ice-cream.
The lion saw the boy.
None
The silly lady was pushing the pram.
Zuerst muss ich diesen Brief ins reine schreiben
[First I need to make a fair copy of this letter]
The silly girl collected shells which can . . .
My silly brother is eating silly ice-cream.
Dieses Lied kommt mir nicht aus dem Sinn.
[I can’t get that song out of my mind]
The mangy lion saw the boy who was . . .
Appendix 2. Musical tests
Experiment 5. Sentence anagrams
Anagram
Rearrangement
start/the/would/car/not
decided/having/bus/
the/to walk/missed/home/we
The car would not start
Having decided to walk
home we missed the bus
Experiment 6. Sentences for German to English translation (complete set)
I. Direct correspondence of word order and vocabulary
Das neues Gebäude war unglaublich hoch.
[The new building was unbelievably tall]
Das Messer, die Gabel und der Löffel sind nebeneinander.
[The knife, the fork and the spoon are next to one another]
Der kleiner Junge benimmt sich unerwartet gut.
[The small boy is behaving himself unexpectedly well]
Der Geschäftsmann verkaufte die Fabrik mit Gewinn.
[The businessman sold the factory at a profit]
Diese Blumen von dem Garten sind wunderbar frisch und farbig.
[These flowers from the garden are wonderfully fresh and colourful]
II. Alteration of word order
Weil es bald dunkel wird, müssen wir ein Licht anzünden
[Because it will be dark soon, we must light a candle]
Der grosser Hund jagt die schwarze Katze, die die Maus gefressen hat.
[The big dog is chasing the black cat that has eaten the mouse]
High probability musical continuations were composed so that the musical
phrase could be completed using one of a small number of notes. This was
achieved by ending the incomplete test phrase with the 2nd, 3rd, 5th or 7th notes of
the melody’s key scale; the tendency of these notes to ‘lead towards’ the tonic
(1st) note of the melody’s key imparted a ‘finished’ sound to the phrase when the
tonic note was added (Fig. 2A). Although the phrases were constructed with the
tonic note in mind as the ‘correct’ completion, other notes from the major triad
(i.e. the 3rd or 5th) would also serve as musically congruent completing notes. In
composing the low probability musical continuations, note sequences which
‘led towards’ the tonic note of the key scale were deliberately avoided (Fig. 2B).
Without a sense of evolution toward finality, ADY was effectively presented
with a wider range of possibilities to continue the note sequence. All sequences
were written in a major key utilising simple rhythmic structures. High probability test phrases consisted of 8–15 notes (average 10.8); it proved difficult to
devise shorter sequences that fulfilled the conditions necessary to create a high
probability continuation. Low probability test phrases contained 9–12 notes
(average 10.3).
In addition, five sequences ranging from three to five notes in length were
composed as musical analogues to the ‘nuclear’ sentences used in the sentence
elaboration task (Fig. 2D). These sequences were not derived from existing
melodies and had no rhythmic variation.
Familiar melodies sung by ADY
From memory
Baa, Baa Black Sheep
Happy Birthday
God Save the Queen
Danny Boy
Brahms’ Lullaby
Summertime
Somewhere over the Rainbow
Take a Pair of Sparkling Eyes
A Wand’ring Minstrel
Primary progressive dynamic aphasia
Che Gelida Manina
Celeste Aida
Non Piu Andrai
Two Yiddish folksongs
After introduction
Three Blind Mice
The Entertainer
Greensleeves
When I was a Lad
Tit Willow
Le Cygne
Jesu, Joy of Man’s Desiring
Ständchen
Chanukah, Chanukah
155
Nothing to say, something to sing:
primary progressive dynamic aphasia
J. D. Warren, J. E. Warren, N. C. Fox
and E. K. Warrington
Abstract
We describe a 76 year old man (ADY) with dynamic aphasia in the setting of a
degenerative frontal lobe dementia: primary progressive dynamic aphasia. He
displayed a striking paucity of propositional speech despite intact speech
production, and preserved singing and prosody. Vocal expression in the verbal
and musical domains was investigated in a series of neuropsychological experiments based on novel language and musical tasks that were designed to
establish the nature and specificity of the verbal output deficit. The features of
the language disorder indicated that the speech output pathway was disrupted at
the early stage of generation of a new pre-verbal message. In contrast, tests of
musical output demonstrated that the generation of new musical ideas was
unimpaired. The domain-specificity of dynamic aphasia may result from the
disruption of specific cognitive processes necessary for the creation of verbal
messages, as well as selective damage of brain regions involved in language
production.
Journal
Neurocase 2003; 9: 140–155
Neurocase Reference Number
548/02
Primary diagnosis of interest
Dynamic aphasia
Author’s designation of case
ADY
Key theoretical issue
* Primary progressive dynamic aphasia
* Propositional speech production
Key words: dynamic aphasia; speech production; music; singing; frontotemporal dementia
Scan, EEG and related measures
Volumetric MRI brain; standard investigations for reversible dementia
Standardized assessment
NART, BPVT, WAIS-R, WCST, TROG, GNT, Boston Naming, RMT,
Synonyms, VOSP
Other assessment
Sentence completion tasks
Musical continuation tasks
Lesion location
* Bilateral frontal lobes
Lesion type
Degeneration
Language
English