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Contribution of working memory to the performance of Tower of Hanoi in chronic schizophrenia
11. Psychology, NeuroCONTRIBUTION
129
OF WORKING
THE PERFORMANCE
MEMORY
TO
OF TOWER OF HANOI IN
INDIRECT SEMANTIC SCHIZOPHRENIC
PRIMING IN
PATIENTS
CHRONIC SCHIZOPHRENIA
C. Chiu,* S. A. Gruber, N. Simpson, D. A. Yurgelun-Todd
R. C. Chan,* E. Y. Chen, H. K. Cheung
Harvard Medical School, Boston, MA, USA
Psychiatry, The University of Hong Kong, Hong Kong, nil, Hong Kong
A semantic priming task using a lexical decision paradigm with indirectly related word pairs was applied to investigate the characteristics of the spread of activation in semantic networks in 15 schizophrenic patients with thought disorder and 16 normal controls. In addition, backward masking and spatial uncertainty of primes were employed to determine whether patients and controls relied differentially on strategic, such as expectancy and semantic matching, versus automatic, the spreading of activation, processes during the lexical decision paradigm. Two stimulus onset asynchronies (SOAs) were used: 250 ms and 950ms. In the short SOA conditions (with or without masking), both groups showed significant indirect priming effects: patients had priming effects of 49.47_+45.23 ms (mean _+ S.D.) (P =0.00083) and 70.67 _+96.27 ms (P = 0.013) with and without masking, respectively; and controls showed priming effects of 19.69 -+28.41 ms (P = 0.014) and 33.19 _+32.61 ms (P = 0.00t) with and without masking, respectively. Furthermore, in the short SOA with masking condition, patients showed a significantly greater indirect priming effect than controls (P = 0.0035). However, this group difference did not survive correction for longer reaction times (RTs) (P >0.1). In the long S OA conditions, neither group showed significant indirect priming effects (Ps > 0.1). Regarding the effects of masking and spatial uncertainty of primes, during the short SOA conditions, RTs for the word/non-word pairs were influenced by masking in the control group (P = 0.012) but not in the patient group (P = 0.328). The fact that patients' RTs on word/non-word pairs were not affected by backward masking, which would eliminate the semantic matching strategy, suggests that schizophrenic patients employed less strategic processes during this task. Our findings also indicate that patients have larger indirect priming effects when most of the strategic processes are eliminated. This can be interpreted as the effect of a hyper-activation or disinhibition of the spreading of activation in patients' semantic network. However, it is also possible that the "hyper-priming" condition might be due to the effect of longer RTs. Preliminary functional MRI studies will also be presented to fnrther explore the indirect priming effect in schizophrenic patients.
The current study investigated executive thnction measure emphasizing Tower of Hanoi (TOH) to understand relationships among executive and non-executive tasks. A total of 90 (74 males; 16 females) patients with chronic schizophrenia received a comprehensive cognitive assessment. Background cognition was assessed by information and block design subscales of WAIS-III. Working memory was assessed by Letter-Number Span Test (LN Span), Visual Pattern Test (VP), N-Back Working Memory Test (N-Back). Executive function was assessed by TOH. The sample reported a mean illness duration of 22.2 years (SD = 9.7). The mean age and number of education year was 46.5 years (SD = 9.7) and 7.5 years (SD = 3.2) respectively. Stepwise multiple linear regression was performed including age, education, duration of illness and all cognitive functions. The results show that only visual reproduction, visual pattern, and WCST category scores retained in the final equation, accounting for 30.8% of variance. These findings suggest the importance of working memory components when conceptualizing the performance of TOH in schizophrenia.
MOTOR SOFT NEUROLOGICAL
SIGNS IN
FIRST EPISODE SCHIZOPHRENIA: YEAR LONGITUDINAL
A TWO-
STUDY
E. Y. Chen,* R. C. Chan, E. L. Dunn, W. E Chan, W. S. Yeung, Y. K. Miao, C. K. Wong, R. Y. Chen, K. E Chung, W. N. Tang
Psychiatry, Universityof Hong Kong, Hong Kong, S.A.R., China The present study aimed to investigate the prevalence of motor neurological soft signs (SNS) in patients with first episode schizophrenia (FES). Sixty-eight patients FES (30 males; 38 females) were recruited. The motor SNS subscale of Cambridge Neurological Inventory was implemented to all participants. The prevalence of motor neurological signs was compared with 68 healthy controls and t00 chronic schizophrenic patients matched for age and education. The FES patients (mean = 19.28, SD = 22.19) exhibited a significantly higher prevalence of motor soft signs than the matched controls (mean = 9.48, SD = 14.78) (p<0.003), Further analysis indicated a significant increase of motor soft signs in medication naive (mean 18.63, SD = 22.84) than normal controls (p<0.05). When compared with chronic schizophrenic patients (mean = 13.56, SD = 18.66), no significant difference was found. Since the level of soft neurological sign in FES patients might be enhanced by the psychotic state, a further comparison between the chronic patients and first episode patients after clinical stabilization was carried out. No significant difference was found between patients with FES (mean = 15.52, SD = 21.9) and those with chronic schizophrenia. There is also no significant longitudinal change in SNS level in the 2-year period. However, despite the stability in the quantity of motor soft signs, the clinical correlates of signs appear to evolve with time. In summary, the data suggests that (1) motor soft signs are increased in medication-naive first-episode patients. (2) the level of SNS is comparable to that in chronic patients (3) the level of SNS remained stable in the first 2 years of the illness, and (4) the association of SNS with clinical features evolved with time.
PROFILE OF COGNITIVE
FUNCTIONING
PATIENTS WITH SCHIZOPHRENIA SPECIALIZED
IN
IN
CLASSES
S. Chouinard,* E. Stip, G. Comtois, M. Corbiere, R Bo16, L. Lamontagne, M. Lecavaliel; R Lalonde, E Beauregard
Centre de RechercheJ~rnand-Seguin, HopitalLouis-H-Lafontaine, Montreal, QC, Canada The cognitive deficits are largely recognized in schizophrenia. Specialized classes are necessary since the institution of regular classes is unable to deal with the needs of patients with schizophrenia. Cognitive deficits are strongly associated with psychosocial dysfunc tioning. Accordingly a program aiming to facilitate the reinsertion of patients was established as a pilot project. Specialized classes, restricted to fifteen patients per class were assigned to two teachers. Patients were taught French and mathematics, which were accredited by regular academic system. Furthermore, techniques to develop their learning abilities were presented in class. Thirteen patients with schizophrenia enrolled in this specialized class were evaluated with Repeatable Battery for assessment of Neuropsychological Status
International Congress on Schizophrenia Research 2003
129
OF WORKING
THE PERFORMANCE
MEMORY
TO
OF TOWER OF HANOI IN
INDIRECT SEMANTIC SCHIZOPHRENIC
PRIMING IN
PATIENTS
CHRONIC SCHIZOPHRENIA
C. Chiu,* S. A. Gruber, N. Simpson, D. A. Yurgelun-Todd
R. C. Chan,* E. Y. Chen, H. K. Cheung
Harvard Medical School, Boston, MA, USA
Psychiatry, The University of Hong Kong, Hong Kong, nil, Hong Kong
A semantic priming task using a lexical decision paradigm with indirectly related word pairs was applied to investigate the characteristics of the spread of activation in semantic networks in 15 schizophrenic patients with thought disorder and 16 normal controls. In addition, backward masking and spatial uncertainty of primes were employed to determine whether patients and controls relied differentially on strategic, such as expectancy and semantic matching, versus automatic, the spreading of activation, processes during the lexical decision paradigm. Two stimulus onset asynchronies (SOAs) were used: 250 ms and 950ms. In the short SOA conditions (with or without masking), both groups showed significant indirect priming effects: patients had priming effects of 49.47_+45.23 ms (mean _+ S.D.) (P =0.00083) and 70.67 _+96.27 ms (P = 0.013) with and without masking, respectively; and controls showed priming effects of 19.69 -+28.41 ms (P = 0.014) and 33.19 _+32.61 ms (P = 0.00t) with and without masking, respectively. Furthermore, in the short SOA with masking condition, patients showed a significantly greater indirect priming effect than controls (P = 0.0035). However, this group difference did not survive correction for longer reaction times (RTs) (P >0.1). In the long S OA conditions, neither group showed significant indirect priming effects (Ps > 0.1). Regarding the effects of masking and spatial uncertainty of primes, during the short SOA conditions, RTs for the word/non-word pairs were influenced by masking in the control group (P = 0.012) but not in the patient group (P = 0.328). The fact that patients' RTs on word/non-word pairs were not affected by backward masking, which would eliminate the semantic matching strategy, suggests that schizophrenic patients employed less strategic processes during this task. Our findings also indicate that patients have larger indirect priming effects when most of the strategic processes are eliminated. This can be interpreted as the effect of a hyper-activation or disinhibition of the spreading of activation in patients' semantic network. However, it is also possible that the "hyper-priming" condition might be due to the effect of longer RTs. Preliminary functional MRI studies will also be presented to fnrther explore the indirect priming effect in schizophrenic patients.
The current study investigated executive thnction measure emphasizing Tower of Hanoi (TOH) to understand relationships among executive and non-executive tasks. A total of 90 (74 males; 16 females) patients with chronic schizophrenia received a comprehensive cognitive assessment. Background cognition was assessed by information and block design subscales of WAIS-III. Working memory was assessed by Letter-Number Span Test (LN Span), Visual Pattern Test (VP), N-Back Working Memory Test (N-Back). Executive function was assessed by TOH. The sample reported a mean illness duration of 22.2 years (SD = 9.7). The mean age and number of education year was 46.5 years (SD = 9.7) and 7.5 years (SD = 3.2) respectively. Stepwise multiple linear regression was performed including age, education, duration of illness and all cognitive functions. The results show that only visual reproduction, visual pattern, and WCST category scores retained in the final equation, accounting for 30.8% of variance. These findings suggest the importance of working memory components when conceptualizing the performance of TOH in schizophrenia.
MOTOR SOFT NEUROLOGICAL
SIGNS IN
FIRST EPISODE SCHIZOPHRENIA: YEAR LONGITUDINAL
A TWO-
STUDY
E. Y. Chen,* R. C. Chan, E. L. Dunn, W. E Chan, W. S. Yeung, Y. K. Miao, C. K. Wong, R. Y. Chen, K. E Chung, W. N. Tang
Psychiatry, Universityof Hong Kong, Hong Kong, S.A.R., China The present study aimed to investigate the prevalence of motor neurological soft signs (SNS) in patients with first episode schizophrenia (FES). Sixty-eight patients FES (30 males; 38 females) were recruited. The motor SNS subscale of Cambridge Neurological Inventory was implemented to all participants. The prevalence of motor neurological signs was compared with 68 healthy controls and t00 chronic schizophrenic patients matched for age and education. The FES patients (mean = 19.28, SD = 22.19) exhibited a significantly higher prevalence of motor soft signs than the matched controls (mean = 9.48, SD = 14.78) (p<0.003), Further analysis indicated a significant increase of motor soft signs in medication naive (mean 18.63, SD = 22.84) than normal controls (p<0.05). When compared with chronic schizophrenic patients (mean = 13.56, SD = 18.66), no significant difference was found. Since the level of soft neurological sign in FES patients might be enhanced by the psychotic state, a further comparison between the chronic patients and first episode patients after clinical stabilization was carried out. No significant difference was found between patients with FES (mean = 15.52, SD = 21.9) and those with chronic schizophrenia. There is also no significant longitudinal change in SNS level in the 2-year period. However, despite the stability in the quantity of motor soft signs, the clinical correlates of signs appear to evolve with time. In summary, the data suggests that (1) motor soft signs are increased in medication-naive first-episode patients. (2) the level of SNS is comparable to that in chronic patients (3) the level of SNS remained stable in the first 2 years of the illness, and (4) the association of SNS with clinical features evolved with time.
PROFILE OF COGNITIVE
FUNCTIONING
PATIENTS WITH SCHIZOPHRENIA SPECIALIZED
IN
IN
CLASSES
S. Chouinard,* E. Stip, G. Comtois, M. Corbiere, R Bo16, L. Lamontagne, M. Lecavaliel; R Lalonde, E Beauregard
Centre de RechercheJ~rnand-Seguin, HopitalLouis-H-Lafontaine, Montreal, QC, Canada The cognitive deficits are largely recognized in schizophrenia. Specialized classes are necessary since the institution of regular classes is unable to deal with the needs of patients with schizophrenia. Cognitive deficits are strongly associated with psychosocial dysfunc tioning. Accordingly a program aiming to facilitate the reinsertion of patients was established as a pilot project. Specialized classes, restricted to fifteen patients per class were assigned to two teachers. Patients were taught French and mathematics, which were accredited by regular academic system. Furthermore, techniques to develop their learning abilities were presented in class. Thirteen patients with schizophrenia enrolled in this specialized class were evaluated with Repeatable Battery for assessment of Neuropsychological Status
International Congress on Schizophrenia Research 2003