Compromised memory function in schizophrenia and temporal lobe epilepsy.
The purpose of this study was to investigate compromised memory function of schizophrenia patients in comparison with temporal lobe epilepsy patients, whose memory impairments result from a clear lesion. The authors hypothesized that schizophrenia patients would show poorer immediate and delayed recall performances in verbal and visual memory tasks. The study sample consisted of a healthy comparison group of 30 subjects and three patient groups comprising 76 schizophrenia patients, 93 left temporal lobe epilepsy patients, and 72 right temporal lobe epilepsy patients. The authors assessed immediate recall, delayed recall, and delayed retention. Tasks were subdivided into two categories (easy and difficult), and then patient memory dysfunction was compared among the memory tests. The authors observed material-specific memory impairment, where the left temporal lobe epilepsy group showed severe verbal memory impairment and the right temporal lobe epilepsy group showed severe visual memory impairment. A moderate impairment was found in immediate and delayed verbal memory in schizophrenia patients, and the impairment of visual memory was amplified with delayed recall. Such a result can be interpreted not only as a generalized cognitive deficit, but also as an integrative dysfunction involving the mesial temporal and frontal lobes in the left and right hemispheres, whereby the lesion site cannot be determined selectively. Our results show that the selection of a memory task that cannot be influenced by verbal mediation is very important for analyzing memory dysfunction in schizophrenia patients.
Yoo
Hee J
HJ
Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Songpa-gu, Seoul, Korea. junhkl@hanafos.com
Lee
Sang A
SA
Kim
Seong Y
SY
Kang
Joong G
JG
Lee
Jung G
JG
D000328:Adult; D004292:Dominance, Cerebral / Q000502:physiology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D008570:Memory, Short-Term / Q000502:physiology; D011939:Mental Recall / Q000502:physiology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010153:Paired-Associate Learning / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011594:Psychometrics; D012016:Reference Values; D012153:Retention, Psychology / Q000502:physiology; D012563:Schizophrenia, Paranoid / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000503:physiopathology