The Evaluation of Negative Symptoms by
Videoconferencing in a Clinical Trial
Williams, JBW 1,2 Popp, D1 Osman, DA1 Cohen, EA1 Detke, MJ 1,3
1MedAvante, Inc. 2Department of Psychiatry, Columbia University 3Indiana University School of Medicine
RESULTS
BACKGROUND
• Negative symptoms in Schizophrenia are of increasing
interest because they are not adequately treated by available
medications.
• Assessment instruments include the Negative Symptom
Assessment (NSA-16), (Alphs et al, 1989), the PANSS negative
symptom subscale, and the PANSS Marder negative symptoms
factor. Assessment of patients with Schizophrenia by video
conferencing has been shown to yield results equivalent to
those obtained when the scale is administered face-to-face
(Zarate et al, 1997; Yoshino et al, 2001; Sharp et al, 2011).
• Videoconferencing facilitates the use of independent
remote raters.
• Advantages of independent remote raters may include
blinding to protocol details and visit number, which may
eliminate enrollment and expectation biases.
• A smaller cohort of raters can be continuously calibrated with
trainers observing interviews live by 3-way videoconferencing.
• This poster addresses how well negative symptoms can be
assessed by videoconferencing.
METHODS
• Mean duration of PANSS = 36 min (SD = 15); mean duration NSA-16 = 16 min (SD = 7).
• All total and subscale scores were normally distributed at screening (all skewness < +/-.34; all kurtosis < +/- .91).
Variable
Internal Consistency Reliability
Cronbach’s alpha is an indicator of scale reliability in that it
examines the correlations among different items in a scale to see to
what extent they measure the same construct. Cronbach’s alpha
ranges from 0-1.0, with .7-.8 indicating acceptable to good internal
consistency.
• All scales showed acceptable to good internal consistency.
Cronbach’s alpha was higher for the NSA-16 than for the
PANSS Negative or PANSS Marder subscales.
Interrater Reliability
One measure of the reliability of a scale is the degree to which
different raters can assign similar scores to the same phenomena
using the same scale. ICCs range from 0-1.0, with .9 or above
being excellent.
• All scales showed excellent interrater reliability between
raters and trainers.
• 225 subjects with
Schizophrenia in a randomized clinical trial.
• All subjects were interviewed by live two-way
videoconferencing at
screen, baseline, 11 more visits over 36 weeks, and at end
point or 1 year (14 visits altogether).
• PANSS and NSA-16 were administered at all visits (n=1122).
NSA immediately followed PANSS.
• 17 blinded independent central raters.
• Central raters were uniformly trained according to training
and calibration plans which involved thorough initial didactic
and applied training and ongoing monitoring to ensure
standardization and to prevent drift.
• 65 NSA-16 and 68 PANSS interviews were observed and
independently rated by a senior clinician as a quality control
measure.
Negative Symptom Items Across Scales
PANSS Negative Scale
NSA-16 Items
PANSS Marder Negative
Symptoms Factor
N1. Blunted affect
1. Prolonged time to respond
N1. Blunted affect
N2. Emotional withdrawal
2. Restricted speech quantity
N2. Emotional withdrawal
N3. Poor rapport
3. Impoverished speech quantity
N3. Poor rapport
N4. Passive/apathetic social withdrawal
4. Inarticulate speech
N4. Passive/apathetic social withdrawal
N5. Difficulty in abstract thinking
5. Emotion: reduced range
N6. Lack of spontaneity
N6. Lack of spontaneity
6. Affect: reduced modulation
G7. Motor retardation
N7. Stereotyped thinking
7. Affect: reduced display
G16. Active social avoidance
8. Reduced social drive
11. Poor grooming/hygiene
12. Reduced sense of purpose
13. Reduced hobbies/interests
14. Reduced daily activity
PANSS Positive
PANSS General
.88
.76
.71
.84
.72
.76
Variable
NSA
ICC
.99
PANSS Marder PANSS Negative
.97
.97
PANSS Total
.98
.95
.98
N = 65 pairs
Convergent and Discriminant Validity – Subscale Correlations
To be useful, a scale must have convergent validity (high
correlation with other scales that measure the same construct)
and divergent validity (relatively low correlations with other scales
that measure different constructs).
• As expected, the NSA-16 correlates highest with the PANSS
Marder and PANSS negative subscales, and is negatively
correlated with the PANSS positive subscale.
Variable
Correlations
PANSS Marder .84***
PANSS Negative
.85***
PANSS Total .43***
PANSS Positive - .020
PANSS General .232**
***p < .001, **p <.01
Inter-item Correlations for the PANSS Negative Scale,
NSA-16 Scale, and PANSS Marder Negative Symptoms Factor *
PANSS Negative
Subscale Item
NSA-16 Item
Correlations
Affect - Reduced Modulation of
Intensity (6)
Affect - Reduced Display on Demand (7)
Reduced Expressive Gestures (15)
.87***
Emotional Withdrawal (N2)
Reduced Social Drive (8)
Reduced Hobbies and Interest (13)
Reduced Daily Activity (14)
.56***
.43***
.43***
Poor Rapport (N3)
Poor Rapport with Interviewer (9)
.86***
Passive/Apathetic Social
Withdrawal (N4)
Reduced Social Drive (8)
Reduced Daily Activity (14)
.55***
.42***
Lack of Spontaneity and Flow
of Conversation (N6)
Prolonged Time to Respond (1)
Restricted Speech Quantity (2)
Impoverished Speech Content (3)
.46***
.88***
.49***
Additional PANSS
Marder Negative
Symptoms Factor Items
NSA-16 Item
Correlations
Motor Retardation (PANSS G7)
Slowed Movements (16)
.83***
Active Social Avoidance
(PANSS G16)
Reduced Social Drive (8)
Reduced Daily Activity (14)
.32***
.25***
Blunted Affect (N1)
.53***
.80***
15. Reduced expressive gestures
16. Slow movements
NSA
PANSS Marder
PANSS Negative
PANSS Total PANSS Positive
PANSS General
9. Poor rapport w/interviewer
10. Reduced sexual interest
Cronbach’s Alpha
*PANSS Negative Symptom scale items N5. Difficulty in Abstract Thinking and N7. Stereotyped Thinking are not
included because they did not correlate significantly with any NSA item.
***p < .001
DISCUSSION AND CONCLUSIONS
The high total and item-level ICCs,
good internal consistency of each
of the scales, and the high inter-item
correlations across scales, suggest
that negative symptoms can be
rated very reliably by videoconferencing using well-calibrated
blinded independent raters. In
addition, the high convergent and
discriminant validity suggest that
negative symptoms can be validly
rated by videoconferencing using
well-calibrated raters. This facilitates
the use of blinded independent
raters in clinical trials. The PANSS
and NSA-16 in this study were not
administered totally independent
of one another, and this puts a
limit on a comparison of the
PANSS-Negative and Marder
subscales and the NSA-16.
References
Alphs LD, Summerfelt A, Lann H, Muller RJ. 1989. The negative symptom assessment: A new instrument to assess negative symptoms of schizophrenia. Psychopharmacol Bull; 25(2):159-63. Sharp IR, Kobak KA, Osman DA. 2011. The use of videoconferencing with patients with psychosis: a review of the literature.
Ann Gen Psychiatry; 10(14). Yoshino A, Shigemura J, Kobayashi Y, Nomura S, Shishikura K, Den R, Wakisaka H, Kamata S, Ashida H. 2001. Telepsychiatry: Assessment of televideo psychiatric interview reliability with present- and next-generation internet infrastructures. Acta Psychiatr Scand; 104:223–226.
Zarate CA Jr, Weinstock L, Cukor P, Morabito C, Leahy L, Burns C, Baer L. 1997. Applicability of telemedicine for assessing patients with schizophrenia: Acceptance and reliability. J Clin Psychiatry; 58:1, 22–25. One or more authors report potential conflicts which are described in the program.
©2013 MedAvante Inc.
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