Cognitive aspects of Down
syndrome across the lifespan
Dr Gaye Powell
Head of Speech &
Language Services
Plymouth Teaching
PCT ( DDREG member)
Down syndrome
 Profiles
 Plateaus
 Prophecies
 And
Why the interest?
lifespan expectancy
(reproduced from Glasson and Bittles, 2004)
Table I: Life expectancies of individuals with Down
syndrome, from selected population-based studies
Year of
publication
Average life
expectancy (y)
Country
Reference
1929,1949
9, 12
England
26
1963
18
Australia
79
1973
30
USA
80
1982
35
Transnational*
35
1991
56
USA
81
2002
60
Australia
27
* Australian, US, Canadian, and European estimates
Lifespan (reproduced from Glasson and Bittles, 2004)
Profiles
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Models: genetic, medical, neurobiological,
psychological and developmental
Are findings from early intervention valid?
(Wishart, 1996)
Variables of better medical care and general
health, a home environment and access to
educational toys and stimulation
Influence of gender
Infancy

early gains between 1.5 months and 6 months
(Carr, 1988)


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in line with TD children in contingency learning
6 months (Ohr and Fagen 1991, 1993)
then decline (Ohr and Fagen 1994)
steep drop in IQ between 1 and 3 years up to
13 years (Carr review 1985; Wishart & Duffy, 1990;
Wishart 1995)
Efficacy of early intervention?

effects upon cognition relatively short lived
(Hines & Bennett, 1996; Spiker & Hopman 1997)

display greater decline in cognitive scores than
children with Autism, or developmental delay
after 8 years (Sigman & Ruskin 1999)

Launonen (1996, 1998, 2003) highlighted impact
of early manual signing
Why? processes involved in
acquisition and maintenance
3 neurobehavioral phenotypes (Capone 2004)
1. no spoken language despite adequate
cognitive skills and language comprehension
2. PDD + history of ‘regression’, in addition to
cognitive and speech difficulties
3. those who do progress - intact neural
machinery to process, organize, store and
recall
Programmes to match deficit profile?
Launonen (1996, 1998, 2003)

early signing group advanced on all measures (social,
academic,cognitive) at all points up to 8yrs compared
to controls

shared attention, reciprocal and active engagement in
interaction, symbolic representation, and initiation of
interactions
delay versus difference
difference
 strengths - social and visuo-spatial skills
 difficulties - verbal-linguistic development,
auditory processing (Bellugi, 1994; Chapman,
Seung, Schwartz and Kay-Raining Bird, 1998; Fowler,
1990; Hodapp, 1996)
delay
 sequence of acquisition are in line (Fowler,
Gelman and Gleitman, 1994)
Late childhood and Adolescence
What changes?



No significant change (Carr 2000)
language ability not always appear to be
directly related to nonverbal IQ (Rondal, 1995)
reading and language ‘bootstrap’ other areas
(Buckley et al 1996; Carr 2000)

educational inclusion for adolescents – gains
communication & academic skills (Cunningham
et al 1998).
Adulthood
Dementia a reality?

neuropathology associated with AD – at risk
(Wisneiwski, Wisneiwski and Wen, 1985)

‘biological age’ exceeds CA up to 20 years
(Olson and Shaw, 1969)

However, majority of individuals do not exhibit
clinical signs (see Silverman et al, 1998; Devenny et
al 1992; Burt et al 1995 )
Plateaus


Anecdotal - develop more slowly, longer periods of
consolidation ‘plateauing’ between ‘developmental
spurts’
How do children learn, develop and fail to retain skills?
(Wishart,1990, 1991, 1993a, 1993b ; Wishart & Duffy 1990)


Reliability of responses?
Lack of engagement, motivation, avoidance
behaviours.
Influencing factors (Wishart 1996)

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early experiences of failure
lower expectations of carers
the use of avoidance strategies when faced with
cognitive challenges
poor use of existing problem solving skills
failure to assimilate & consolidate newly-acquired
cognitive skills
increasing reluctance to take the initiative learning
process
Plateau due to



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genetic predisposition and programming
neurophysiology
health
psychological
environmental factors
some skills acquired – greater difference over
time
Prophecies for 21st century?
Programmes of intervention?

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truly effective programmes of intervention?
exploiting areas of strength
visual channel – signing, reading systems
learning environments
continued intervention to protect vulnerable
areas
integration of pharmacological treatments
Significant impact on cognitive profile?

integration of methodologies and packages of care

With individuals & families at centre of the process