- Email: [email protected]
Laboratory and clinical tests of spatial working memory
208
for age and pre-morbid IQ, on a battery of tests compiled to assess verbal short term and long term memory. Despite normal performance on conventional tests of verbal short-term memory (Digit Span Forwards/Backwards) implying a sparing of this aspect, short term memory process as measured by the recent performance of the serial position curve, was found to be impaired. Investigation of the effects of priming on recall using Graf's free and cued recall paradigms indicated that, although schizophrenics were impaired on free recall, performance on the cued condition was normal. This indicated that the long term verbal memory deficit in schizophrenia may reflect impaired access rather than a defect in encoding.
XIII.B.5 R E T E N T I O N IN SCHIZOPHRENIA PATIENTS O N TWO W O R K I N G M E M O R Y TASKS R. Hijman, H.E. H u l s h o f f P o l , W.F.C. Baar6, H. Talma, J. van der Linden and R.S. K a h n
Depts. of Psychiatry, UniversityHospital Utrecht, Utrecht, The Netherlands, Rudolf Magnus Institutefor Neuroscience, University Utrecht, P.O.B. 85500, 3508 GA, The Netherlands Background, In schizophrenic patients deficits in working memory are found. The present studies examine working memory in schizophrenics using the Subjective Ordering Paradigm and a visuospatial working memory task (DOT test). Methods. Two tasks relying on short-term retention, i.e. digit span, missing item scan, and two tasks on working memory, i.e. randomization span, self-ordered pointing were presented to schizophrenic patients (n = 12) and normal controls (n = 12) matched for age, education and sex. The DOT test was administered to another group of schizophrenic patients (n = 12) and normal controls (n= 12). Diagnosis was made using the CASH interview according to DSM-IV criteria. Results. The schizophrenic patients performed significantly worse on a short-term retention tasks (missing item scan: t = 3.70, df= 11, p < .004), while also significant differences were found on a working memory task (the randomization span task, p<.05). The DOT test showed a significant difference between the delayed recall and the immediate recall version (t=7.31, df=21, p <.05). Conclusion. These data suggest that the schizophrenic patients show deficits in short-term retention and deficits in selforganization in working memory on verbal and visuospatial tasks.
XIII.B.6 VISUOSPATIAL M E M O R Y IN FIRST EPISODE SCHIZOPHRENIA S.B. Hutton, B.K. Puri, T.R.E. Barnes, T.W. Robbins* and E.M. Joyce
Academic Dept. P~ychiatry, Charing Cross and Westminster Medical School St Dunstan's Road, London W6 8RP, U.K. *Dept Experimental Psychology, Universityof Cambridge, Downing Street, Cambridge, U.I~ Eighteen first-episode schizophrenic patients were compared with 18 controls, matched for age and NART IQ, on CANTAB computerised tests of visuospatial memory. Schizophrenic patients were unimpaired on a two-choice recognition test of spatial memory. On a version of Corsi's block tapping test, schizophrenic patients demonstrated normal spatial span. They were, however, impaired on a test of spatial working memory. Here subjects were asked to search for 'tokens' hidden inside 'boxes' and were told that, on any trial, each box would be used only once to hide a token. Schizophrenic subjects returned to boxes in which a token had already been found more often than controls (F= 9.0, p < 0.01 ). A measure of search strategy was also deficient in the schizophrenic group (t = 2.74, p < 0.02) and this was related to search errors (schizophrenic: r=0.55, p < 0.05; control: r = 0.70, p < 0.001 ). These results suggest that deficits in spatial working memory were due to an inefficient search strategy rather than memory impairment. In this respect schizophrenic patients resemble patients with frontal lobe resections but not Parkinson's disease or temporal lobe resections (Owen et al. 1990, Neuropsychologia, 28:1021; 1992, Brain, 115:1727; 1995 Neuropsychologia, 33:1) thus providing evidence for a specific deficit in frontal lobe function early in the course of schizophrenia.
XIII.B.7 LABORATORY AND CLINICAL TESTS OF SPATIAL W O R K I N G M E M O R Y R.S.E. Keefe, S.E. Lees R o i t m a n , R.L. D u p r e and P.D. Harvey
Department of Psychiatry, Duke University Medical Center, Durham NC, US.A, VAMC, Bronx, NY, ~ZS.A. Results from neuropsychological tests purporting to measure the functioning of the prefrontal cortex (PFC) are often misinterpreted in psychiatric patients. Since many of these tests highly complex, they are vulnerable to factors such as amotivation, uncooperativeness and anergia. Simple, easily administered tests sensitive to dysfunction of the PFC are needed. Simple working memory functions can be measured by tests
209
that activate a neural network that includes the PFC. Twentyfour schizophrenics and 11 normal controls were examined to compare a computerized version of a visual working memory test that determines performance by measuring eye position data when a subject recalls where a stimulus had previously been presented, and a version that requires subjects simply to indicate visuospatial recall with a pen on paper. In the laboratory version only, eye position data from 11 schizophrenics could not be analyzed due to head movement, restlessness, and excessive blinking. Schizophrenics were significantly less accurate than controls on both working memory tasks. Performance on the pen-and-paper version of the task was correlated with performance determined by eye position data (r = 0.59, p < .05). An easily administered pen-and-paper working memory task may be useful as a clinical tool for measuring working memory functions in schizophrenics and other psychiatric patients.
XIII.B.8 RELATIONSHIP OF ATTENTIONAL ORGANIZATIONAL CAPACITY TO RECENT MEMORY PERFORMANCE SCHIZOPHRENIA AND OTHER PSYCHOTIC DISORDERS
AND IN
G.P. Lee, S.L. H a v e r s t o c k a n d A.S. K i t c h e n s
Departments of Psychiatry and Surgery ( Neurosurgery), Medical College of Georgia and VA Medical Center, Augusta, GA 30912, U.S.A. Relating recent memory performance in schizophrenia to dysfunction of mesial temporal lobe structures has been criticized because other cognitive functions important for recent memory are also frequently impaired in schizophrenia. To help determine the contribution of attentional and executive functions to the memory deficit seen in schizophrenia, we compared the cognitive performance of chronic schizophrenics to patients with other, more acute, psychotic disorders (e.g., bipolar, schizoaffective). Although chronic schizophrenics performed worse than normals, and better than other psychotic disorders, on tests of attention, memory, and executive functions, most of these differences were not statistically significant. The single exception was schizophrenics performed significantly worse than normals (but not other psychotics) on a verbal learning test. Significant correlations were obtained between attentional and executive tests and memory measures in other psychotic disorders but not in schizophrenia. Because attentional and organizational measures were correlated with memory performance in the more acute psychotic disorders but not in schizophrenia, memory tests may be more sensitive to attentional and organizational influences in acute psychosis than in chronic schizophrenia. Thus, it appears that certain verbal learning measures may accurately assess recent memory in chronic schizophrenia, and therefore, cerebral anatomical correlations may be made with more assurance.
XIII.B.9 MEMORY AND INTELLECTUAL FUNCTIONING IN FAMILIAL AND NON FAMILIAL SCHIZOPHRENIC SUBJECTS D.M. Mockler, R.M. M u r r a y , S. F r a n g o u , T. Sigmunsson a n d T. S h a r m a
Department of Psychological Medicine, Institute of PsychhTtry, London, U.K. Familial schizophrenic (FS) (n = 23) and non familial schizophrenic (NFS) (n= 12) subjects were compared for neuropsychological differences using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), Rivermead Behavioural Memory Test (RBMT) and the National Adult Reading Test (NART). The two subject groups were compared to controls with no history of neurological or psychiatric disorder. Both FS and NFS subjects showed impaired current intellectual (WAIS-R) and memory (RBMT) functioning compared to matched controis. Each subject group displayed general working memory impairment, however, the FS subject group was more generally impaired on verbal memory tasks and less impaired using visual memory. The NFS subjects were more generally impaired on visual memory tasks. There was no significant variation in estimated IQ (NART) between both FS and NFS subjects compared to their matched controls. The findings indicate that there is current intellectual and memory impairment in both FS and NFS subjects compared to controls. However, the distinguishing characteristics of memory impairment in familial/non familial schizophrenic subjects is that familial schizophrenics are more impaired on verbal aspects of memory functioning and NFS subjects on visual memory performance.
X I I I . B . 10 MEMORY AND INTELLECTUAL IMPAIRMENT IN FAMILIAL SCHIZOPHRENIA D . M . Mockler, R.M. M u r r a y , T. Sigmunsson a n d T. S h a r m a
Department of Psychological Medicine, Institute of Psychiatry, London, U.K. The Study investigates neuropsychological differences between family members of multiplex schizophrenic families. The family subjects were divided into two groups; schizophrenic family members (SFM; n = 2 3 ) and non-schizophrenic family members (NSFM; n = 50) and then compared to controls with no history of neurological or psychiatric disorder. Each subject was administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R), Rivermead Behavioural Memory Test (RBMT)
for age and pre-morbid IQ, on a battery of tests compiled to assess verbal short term and long term memory. Despite normal performance on conventional tests of verbal short-term memory (Digit Span Forwards/Backwards) implying a sparing of this aspect, short term memory process as measured by the recent performance of the serial position curve, was found to be impaired. Investigation of the effects of priming on recall using Graf's free and cued recall paradigms indicated that, although schizophrenics were impaired on free recall, performance on the cued condition was normal. This indicated that the long term verbal memory deficit in schizophrenia may reflect impaired access rather than a defect in encoding.
XIII.B.5 R E T E N T I O N IN SCHIZOPHRENIA PATIENTS O N TWO W O R K I N G M E M O R Y TASKS R. Hijman, H.E. H u l s h o f f P o l , W.F.C. Baar6, H. Talma, J. van der Linden and R.S. K a h n
Depts. of Psychiatry, UniversityHospital Utrecht, Utrecht, The Netherlands, Rudolf Magnus Institutefor Neuroscience, University Utrecht, P.O.B. 85500, 3508 GA, The Netherlands Background, In schizophrenic patients deficits in working memory are found. The present studies examine working memory in schizophrenics using the Subjective Ordering Paradigm and a visuospatial working memory task (DOT test). Methods. Two tasks relying on short-term retention, i.e. digit span, missing item scan, and two tasks on working memory, i.e. randomization span, self-ordered pointing were presented to schizophrenic patients (n = 12) and normal controls (n = 12) matched for age, education and sex. The DOT test was administered to another group of schizophrenic patients (n = 12) and normal controls (n= 12). Diagnosis was made using the CASH interview according to DSM-IV criteria. Results. The schizophrenic patients performed significantly worse on a short-term retention tasks (missing item scan: t = 3.70, df= 11, p < .004), while also significant differences were found on a working memory task (the randomization span task, p<.05). The DOT test showed a significant difference between the delayed recall and the immediate recall version (t=7.31, df=21, p <.05). Conclusion. These data suggest that the schizophrenic patients show deficits in short-term retention and deficits in selforganization in working memory on verbal and visuospatial tasks.
XIII.B.6 VISUOSPATIAL M E M O R Y IN FIRST EPISODE SCHIZOPHRENIA S.B. Hutton, B.K. Puri, T.R.E. Barnes, T.W. Robbins* and E.M. Joyce
Academic Dept. P~ychiatry, Charing Cross and Westminster Medical School St Dunstan's Road, London W6 8RP, U.K. *Dept Experimental Psychology, Universityof Cambridge, Downing Street, Cambridge, U.I~ Eighteen first-episode schizophrenic patients were compared with 18 controls, matched for age and NART IQ, on CANTAB computerised tests of visuospatial memory. Schizophrenic patients were unimpaired on a two-choice recognition test of spatial memory. On a version of Corsi's block tapping test, schizophrenic patients demonstrated normal spatial span. They were, however, impaired on a test of spatial working memory. Here subjects were asked to search for 'tokens' hidden inside 'boxes' and were told that, on any trial, each box would be used only once to hide a token. Schizophrenic subjects returned to boxes in which a token had already been found more often than controls (F= 9.0, p < 0.01 ). A measure of search strategy was also deficient in the schizophrenic group (t = 2.74, p < 0.02) and this was related to search errors (schizophrenic: r=0.55, p < 0.05; control: r = 0.70, p < 0.001 ). These results suggest that deficits in spatial working memory were due to an inefficient search strategy rather than memory impairment. In this respect schizophrenic patients resemble patients with frontal lobe resections but not Parkinson's disease or temporal lobe resections (Owen et al. 1990, Neuropsychologia, 28:1021; 1992, Brain, 115:1727; 1995 Neuropsychologia, 33:1) thus providing evidence for a specific deficit in frontal lobe function early in the course of schizophrenia.
XIII.B.7 LABORATORY AND CLINICAL TESTS OF SPATIAL W O R K I N G M E M O R Y R.S.E. Keefe, S.E. Lees R o i t m a n , R.L. D u p r e and P.D. Harvey
Department of Psychiatry, Duke University Medical Center, Durham NC, US.A, VAMC, Bronx, NY, ~ZS.A. Results from neuropsychological tests purporting to measure the functioning of the prefrontal cortex (PFC) are often misinterpreted in psychiatric patients. Since many of these tests highly complex, they are vulnerable to factors such as amotivation, uncooperativeness and anergia. Simple, easily administered tests sensitive to dysfunction of the PFC are needed. Simple working memory functions can be measured by tests
209
that activate a neural network that includes the PFC. Twentyfour schizophrenics and 11 normal controls were examined to compare a computerized version of a visual working memory test that determines performance by measuring eye position data when a subject recalls where a stimulus had previously been presented, and a version that requires subjects simply to indicate visuospatial recall with a pen on paper. In the laboratory version only, eye position data from 11 schizophrenics could not be analyzed due to head movement, restlessness, and excessive blinking. Schizophrenics were significantly less accurate than controls on both working memory tasks. Performance on the pen-and-paper version of the task was correlated with performance determined by eye position data (r = 0.59, p < .05). An easily administered pen-and-paper working memory task may be useful as a clinical tool for measuring working memory functions in schizophrenics and other psychiatric patients.
XIII.B.8 RELATIONSHIP OF ATTENTIONAL ORGANIZATIONAL CAPACITY TO RECENT MEMORY PERFORMANCE SCHIZOPHRENIA AND OTHER PSYCHOTIC DISORDERS
AND IN
G.P. Lee, S.L. H a v e r s t o c k a n d A.S. K i t c h e n s
Departments of Psychiatry and Surgery ( Neurosurgery), Medical College of Georgia and VA Medical Center, Augusta, GA 30912, U.S.A. Relating recent memory performance in schizophrenia to dysfunction of mesial temporal lobe structures has been criticized because other cognitive functions important for recent memory are also frequently impaired in schizophrenia. To help determine the contribution of attentional and executive functions to the memory deficit seen in schizophrenia, we compared the cognitive performance of chronic schizophrenics to patients with other, more acute, psychotic disorders (e.g., bipolar, schizoaffective). Although chronic schizophrenics performed worse than normals, and better than other psychotic disorders, on tests of attention, memory, and executive functions, most of these differences were not statistically significant. The single exception was schizophrenics performed significantly worse than normals (but not other psychotics) on a verbal learning test. Significant correlations were obtained between attentional and executive tests and memory measures in other psychotic disorders but not in schizophrenia. Because attentional and organizational measures were correlated with memory performance in the more acute psychotic disorders but not in schizophrenia, memory tests may be more sensitive to attentional and organizational influences in acute psychosis than in chronic schizophrenia. Thus, it appears that certain verbal learning measures may accurately assess recent memory in chronic schizophrenia, and therefore, cerebral anatomical correlations may be made with more assurance.
XIII.B.9 MEMORY AND INTELLECTUAL FUNCTIONING IN FAMILIAL AND NON FAMILIAL SCHIZOPHRENIC SUBJECTS D.M. Mockler, R.M. M u r r a y , S. F r a n g o u , T. Sigmunsson a n d T. S h a r m a
Department of Psychological Medicine, Institute of PsychhTtry, London, U.K. Familial schizophrenic (FS) (n = 23) and non familial schizophrenic (NFS) (n= 12) subjects were compared for neuropsychological differences using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), Rivermead Behavioural Memory Test (RBMT) and the National Adult Reading Test (NART). The two subject groups were compared to controls with no history of neurological or psychiatric disorder. Both FS and NFS subjects showed impaired current intellectual (WAIS-R) and memory (RBMT) functioning compared to matched controis. Each subject group displayed general working memory impairment, however, the FS subject group was more generally impaired on verbal memory tasks and less impaired using visual memory. The NFS subjects were more generally impaired on visual memory tasks. There was no significant variation in estimated IQ (NART) between both FS and NFS subjects compared to their matched controls. The findings indicate that there is current intellectual and memory impairment in both FS and NFS subjects compared to controls. However, the distinguishing characteristics of memory impairment in familial/non familial schizophrenic subjects is that familial schizophrenics are more impaired on verbal aspects of memory functioning and NFS subjects on visual memory performance.
X I I I . B . 10 MEMORY AND INTELLECTUAL IMPAIRMENT IN FAMILIAL SCHIZOPHRENIA D . M . Mockler, R.M. M u r r a y , T. Sigmunsson a n d T. S h a r m a
Department of Psychological Medicine, Institute of Psychiatry, London, U.K. The Study investigates neuropsychological differences between family members of multiplex schizophrenic families. The family subjects were divided into two groups; schizophrenic family members (SFM; n = 2 3 ) and non-schizophrenic family members (NSFM; n = 50) and then compared to controls with no history of neurological or psychiatric disorder. Each subject was administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R), Rivermead Behavioural Memory Test (RBMT)