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Regular Article   |    
Cognitive Abnormalities in Schizophrenia and Schizophrenia-Like Psychosis of Epilepsy
David A. Nathaniel-James, Ph.D.; Richard G. Brown, Ph.D.; Michael Maier, M.R.C.Psych., Ph.D.; John Mellers, M.R.C.Psych.; Brian Toone, F.R.C.Psych.; Maria A. Ron, F.R.C.Psych., Ph.D.
The Journal of Neuropsychiatry and Clinical Neurosciences 2004;16:472-479. doi:10.1176/appi.neuropsych.16.4.472
View Author and Article Information

Received August 8, 2002; revised March 31, 2003, accepted April 15, 2003. From the Department of Psychology, Institute of Psychiatry, King’s College, London Department of Psychiatry, Imperial College Faculty of Medicine, Charing Cross Campus, London; the Department of Psychological Medicine, King’s College Hospital, London; the Institute of Neurology, University College London, Queen Square, London. Address correspondence to Professor Ron, Institute of Neurology, Queen Square, London WC1N 3BG, UK; m.ron@ion.ucl.ac.uk (E-mail).

Twenty-six patients with schizophrenia and 12 patients with schizophrenia-like psychosis of epilepsy (SLPE) were compared to 38 healthy volunteers and 12 nonpsychotic patients with epilepsy to determine the contribution of psychosis to the pattern of cognition. Tests of memory and executive function were used. The schizophrenic group was more cognitively impaired than the SLPE and comparison groups. The profile of neuropsychological impairment in SLPE resembled that of schizophrenia and is unlikely to be explained solely by temporal lobe dysfunction. These results do not support the concept of SLPE as an independent nosological entity.

Abstract Teaser
Figures in this Article

The prevalence of schizophrenia is approximately 1%, and a chronic schizophrenia-like psychosis occurs in 3%—7%1 among patients with epilepsy, particularly those with partial seizures arising from mesial temporal structures (temporal lobe epilepsy [TLE]). The phenomenology,2 course, treatment response, and outcome of these two forms of chronic psychosis are not readily distinguishable. The schizophrenia-like psychosis of epilepsy (SLPE) offers a model of schizophrenia that is seemingly driven by temporal lobe pathology.3 However, the similarities in structural4 and spectroscopic5 brain abnormalities should not be overemphasized. While these abnormalities are focal in TLE, they appear to be global in schizophrenia.6 A comparison of the two disorders may make it possible to disaggregate those features of schizophrenia that are associated with temporal lobe pathology and those attributable to extratemporal abnormalities, most notably in the frontal regions.

A recent study from our group7 compared cognitive performance in patients with schizophrenia and SLPE, nonpsychotic patients with epilepsy, and healthy comparison subjects. Patients with schizophrenia and SLPE had almost identical profiles. Impaired attention, executive function, and episodic—particularly verbal—memory characterized both groups. The nonpsychotic comparison subjects with epilepsy showed similar, though less marked, deficits. These findings did not support the concept of a separate SLPE syndrome.

Verbal811 and visual12 memory deficits, unrelated to specific symptoms or chronicity, have been reported in schizophrenia, but opinions are divided as to the precise pattern and underlying mechanisms. For some (e.g., McKenna et al.,8 Saykin et al.,13 and Duffy and O’Carrroll14), the sparing of immediate recall relative to delayed recall points to a classic temporal amnesia. For others (e.g., Beatty et al.,15 Paulsen et al.,16 and Nathaniel-James et al.17), the relative sparing of recognition memory with impaired immediate free recall suggests a pattern akin to that seen in patients with frontal lobe lesions. However, this dissociation between recall and recognition has not been consistently identified (e.g., Seidenberg et al.,18 Blaxton and Theodore,19 Helmstaedter et al.,20 and Gleissner et al.21). Only two studies22,23 have compared the cognitive deficits of schizophrenia and TLE, although neither looked specifically at SLPE. Gold et al.22 found that schizophrenic patients were impaired on tests of attention, motor speed, and executive function, while TLE patients performed worse on tests of memory and semantic knowledge. They concluded that temporal lobe dysfunction alone did not provide a satisfactory model for the deficits observed in schizophrenia. Seidman et al.,23 on the other hand, reported greater similarities between the two groups, although schizophrenic subjects performed better on paired associate learning tests and benefited from retrieval cues, a pattern similar to that observed in patients with frontal lesions.

In this study, we aimed to elucidate further the differences and similarities in the cognitive performance of patients with SLPE, nonpsychotic patients with epilepsy, schizophrenic patients, and healthy comparison subjects. Subjects in the SLPE group and the nonpsychotic patients with epilepsy group participated in one of our previous studies,7 but all were retested using a different range of neuropsychological tests that allowed us to explore the relationship between executive impairment and the pattern of memory deficits. In addition, recognition memory tests, not employed in the earlier study, were used in this study, which was intended to separate the contributions of psychosis and TLE to the pattern of cognitive deficits.

+

Subjects

Four groups of subjects were examined, 12 patients with epilepsy (11 with TLE and 1 with primary generalized epilepsy) and psychosis (SLPE); 12 patients with epilepsy (11 with TLE and one with primary generalized epilepsy) without psychosis; 26 patients with schizophrenia, fulfilling RDC criteria; and 38 healthy comparison subjects. All subjects in the psychotic groups had taken part in our earlier studies.5,7,17

The diagnosis of TLE was based on the semiology of seizure description. When possible, the laterality of the focus in the 24 epileptic patients was determined by pooling data from EEG studies performed as part of their clinical assessment. The subjects in the two epileptic groups were matched for side of focus, gender, and age. The seizure frequency in the 12 months prior to entry was also matched in the two groups and ranged from 0 to 120 seizures per month. All had complex partial seizures, apart from one subject in each group who had primary generalized epilepsy. The overall mix of right- and left-sided abnormalities as detected by EEG was similar in the two groups. In the SLPE group, four had bilateral epileptiform activity (generalized and/or nonspecific) with no focal abnormalities; two had bilateral focal temporal lobe abnormalities with no clear left/right predominance; five had bilateral abnormalities, four with a left-sided and one with a right-sided predominance; five of the nonpsychotic patients with epilepsy had bilateral epileptic activity with no detectable foci; the remaining seven had bilateral abnormalities, four with a left-sided and three with a right-sided predominance. The age at onset of epilepsy was similar in the two groups: 11.3 years (SD=5.8) in patients with SLPE and 13.9 years (SD=12.6) in the nonpsychotic patients with epilepsy. All SLPE patients had chronic interictal psychosis with onset many years after the epilepsy (mean age at onset of psychosis=26.8 years, SD=6.4). Patients with epilepsy were on long-term anticonvulsants, and those with schizophrenia and SLPE were receiving neuroleptics.

Healthy comparison subjects were recruited from various sources and matched to the other groups for premorbid intelligence quotient (IQ) and gender. All subjects were right handed as assessed by the Annett Handedness Questionnaire.24 Those drinking more than 80 gr of alcohol per week or regularly using recreational drugs were excluded, as were those with head injury leading to unconsciousness or with other neurological or systemic illness. Comparison subjects with past or present psychiatric disorders were also excluded. Informed consent was obtained from all participants.

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Neuropsychological Assessment

Premorbid and current intellectual functioning were estimated using the National Adult Reading Test25 and the Raven’s Progressive Matrices (advanced set 1),26 respectively. Verbal learning and memory were assessed using the California Verbal Learning Test.27 Subjects were required to recall a list of 16 words (list A), which consisted of four words from each of four semantic categories, over five trials. Following an interference list presented for one trial, subjects were tested for free recall (short-delay free recall) and category-cued recall (short-delay cued recall) of list A. Following a 20-minute break, during which some of the executive function tests were administered, free and cued recall (long-delay free and cued recall) and recognition of list A were assessed. Semantic and serial clustering scores were also calculated for initial learning.

Executive function was assessed using a range of measures. First, the Verbal Fluency Test was conducted to determine fluency for the letters F, A, and S.28 The score was the sum of all valid words within 60 seconds per trial and was corrected for gender, age, and education according to existing norms.29 Next, subjects completed the Modified Card Sorting Test,30 in which they were required to sort 48 cards on the basis of three categories (color, number, and shape). The total number of errors, categories achieved, and perseverative errors were recorded. The percentage of perseverative errors was also calculated. Finally, they performed the Hayling Sentence Completion Test,31 which is a response initiation and suppression test consisting of two stimulus conditions of 15 sentences each. In the response initiation condition (condition 1), 15 sentences were read omitting the last word. Subjects were required to give a word that would plausibly complete the sentence. In the response suppression condition (condition 2), subjects were asked to produce a word unrelated to each sentence. The sum of response latencies in condition 1 and an error score based on the quality of responses in condition 2 were scored. A "correct" completion response received an error score of 3. A word semantically related to a word in the sentence received a score of 1 and a related word a score of 0.

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Statistical Analyses

Analysis of variance using general factorial or repeated measures approaches appropriately was used. For simplicity, only the main effects and interactions involving the group variable are reported in detail. Age and current intellectual status, as measured by the Raven’s Matrices, were used as constant covariates in all analyses. These variables, which differed significantly between the groups (see below), might either mask or accentuate group differences in the memory and executive measures that were the focus of this study. Although the unadjusted group mean data are provided in the tables, estimated adjusted means are shown in the figures as these provide a more meaningful illustration of the results. In interpreting significant group and interaction effects, post hoc tests were performed using Bonferroni correction throughout.

The groups did not differ in gender ratio or estimated premorbid IQ. There were significant differences between the groups in age (F=12.5, df=3, 72, p<0.001) and current level of intellectual functioning (F=4.3, df=3, 72, p<0.01) (t1).

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Learning and Memory (t2, F1, F2, and F3)

Analysis of recall over the five learning trials indicated a significant group-by-trial interaction (F=2.8, df=12, 268, p<0.005), arising from impaired performance of the two psychotic groups over the initial trials. Group differences during learning were found for both the semantic cluster score (F=6.9, df=3, 66, p<0.001) and the serial cluster score (F=6.9, df=3, 66, p<0.001). The healthy comparison subjects and the nonpsychotic patients with epilepsy tended to use more semantic than serial strategies, while the two psychotic groups tended to use more serial strategies (F2). However, these differences were significant (p<0.05) for the paired comparisons of nonpsychotic patients with epilepsy and patients with schizophrenia only.

Free recall was unaffected by a short delay (F<1, df=1, 67), while cueing led to differential improvement in recall (F=4.0, df=3, 67, p<0.05), with the greatest gains seen in the schizophrenia group. A differential effect was also observed in the effect of longer delays on free recall (F=5.6, df=3, 67, p<0.01) (F3), where a significant deterioration was observed in the schizophrenic group (p<0.001) but not for the other groups. However, as before, the schizophrenia group was able to benefit from cueing to improve their performance relative to the other groups.

Finally, there was no significant difference between recognition memory performance in the four groups (F=1.7, df=3, 67, p>0.10) (t2).

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Executive Function (t3)

The groups differed in their performance on the Verbal Fluency Test (F=6.57, df=3, 66, p<0.01), with the schizophrenic group performing worse than the healthy comparison subjects and the nonpsychotic patients with epilepsy. On the Modified Card Sorting Test, no difference was found in the total number of categories or the total number of errors (F<1, df=3, 66). The groups differed in the number of perseverative errors (F=3.3, df=3, 66, p<0.05), with the two psychotic groups tending to perform worse, although post hoc paired comparisons failed to reveal any significant paired differences. Similar results were found with percentage of perseverative errors.

A highly significant difference was found between groups for errors on the Hayling Response Suppression Test (F=7.6, df=3, 66, p<0.001) (t3). Post hoc tests revealed a significant impairment in the schizophrenic group that was relative to all other groups. The other three groups did not differ significantly.

The results of this study suggest a consistent pattern of cognitive deficits in the groups with schizophrenia and SLPE, with patients with schizophrenia showing the greatest impairment on executive and memory tasks. Patients with schizophrenia performed poorly on tasks of verbal learning and short and long delayed retention and benefited more from cued recall. The performance of the SLPE group on verbal learning was intermediate, between the schizophrenia group and the other groups. Both psychotic groups used serial in preference to semantic strategies, while the reverse was true for the nonpsychotic groups. All groups scored within the normal range on tests of recognition. Schizophrenic subjects scored worse on executive tasks, while the SLPE group occupied an intermediate position between patients with schizophrenia and the comparison groups.

Cognitive impairment in schizophrenia is now widely accepted, with memory and executive functions bearing the brunt.32,33 A metaanalysis34 has reported verbal and nonverbal memory deficits, with recall more severely impaired than recognition, suggesting poor retrieval. Furthermore, others35 have reported a dissociation between impaired declarative and preserved nondeclarative memory, a pattern found in patients with frontosubcortical pathology. There is also recent evidence indicating deficits in working memory36 and aberrant activation of prefrontal cortex during working memory performance.37 These observations suggest that some aspects of memory impairment in schizophrenia may be due to deficits in executive function. The findings of this study are broadly in agreement. Schizophrenic subjects performed poorly on recall tasks and less so on recognition, and although this difference may be explained partially by differences in task difficulty, the improvement with cueing suggests a failure of retrieval mechanisms. The failure to make use of semantic strategies would also favor a dysexecutive component.

Few studies22,23,38 have directly compared memory function in schizophrenia and TLE. Gold et al.22,38 examined the contribution of left and right temporal pathology. Their schizophrenic group performed better on tasks of verbal memory than epileptics with left temporal lobe pathology. In these studies, as in Mellers et al.,7 TLE subjects with and without psychosis performed better than schizophrenic subjects on tests of new verbal learning. This may reflect the fact that the TLE groups contained as many right-sided as left-sided patients in these studies. The conclusion of the study by Mellers et al.,7 as of this study, was that temporal lobe dysfunction alone does not provide an adequate explanation for the cognitive impairment of schizophrenia. Seidman et al.23 reported mildly impaired verbal and nonverbal memory in schizophrenic patients, as compared with those with TLE and normal control groups. Schizophrenic subjects performed best on cued verbal tests such as the paired associate learning, in which new information was nonsupraspan.

Some limitations to this study must be considered. Patients with SLPE and nonpsychotic patients with epilepsy were well matched for laterality of EEG abnormalities, but a more accurate lesion and language lateralization would have required more invasive procedures (e.g., those used in presurgical assessment) not warranted in our patients. The small size of the SLPE group, determined by the rarity of these patients, requires caution in the interpretation of the results. Similarly, the high estimated premorbid IQ of all our subjects might make our results less applicable to other populations. In addition, the small number of nonpsychotic patients with epilepsy may have obscured potential differences between patients and comparison subjects.

In conclusion, our findings support the view that cognitive decline in schizophrenia is characterized by memory impairment and executive dysfunction. The profile of cognitive impairment in SLPE resembles that of schizophrenia, but it is less pronounced. This finding does not support the concept of SLPE as a nosological entity sui generis. Rather, it argues for epilepsy as a risk factor for the development of an exogenous and relatively benign form of schizophrenia.

The authors thank Professor Michael Trimble for allowing them to approach some of his patients. Dr. D.A. Nathaniel-James was supported by a grant from the Rayne Foundation and Professor M.A. Ron was partly supported by the Scarfe Trust. Finally, the authors thank all the patients and healthy volunteers for their time and effort in helping to carry out this work.

   
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TABLE 2. Performance on the California Verbal Learning Test
   
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FIGURE 1.

 Adjusted Mean Scores, Controlling for Age and Raven’s Progressive Matrices Score, Across the Five Learning Trials of the California Verbal Learning Test in the Four Subject Groups

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

 
Anchor for JumpAnchor for JumpAnchor for Jump
FIGURE 2.

 Adjusted Mean Scores, Controlling for Age and Raven’s Progressive Matrices Score, for the Final Learning Trial of the California Verbal Learning Test and the Subsequent Free and Cued Recall Trials After Short and Long Delays in the Four Subject Groupsa

aThe error bars indicate standard errors of the mean.

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

 
Anchor for JumpAnchor for JumpAnchor for Jump
FIGURE 3.

 Adjusted Mean California Verbal Learning Test Semantic and Serial Scores, Controlling for Age and Raven’s Progressive Matrices Score, in the Four Subject Groupsa

aThe error bars indicate standard errors of the mean.

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

Toone B: The psychoses of epilepsy (editorial). J Neurol Neurosurg Psychiatry  2000; 69:1—4
[CrossRef] | [PubMed]
 
Toone BK, Garralda ME, Ron MA: The psychoses of epilepsy and the functional psychoses: a clinical and phenomenological comparison. Br J Psychiatry  1982; 141:256—261
[CrossRef] | [PubMed]
 
Roberts GW, Done DJ, Brunton C, et al.: A mock up of schizophrenia: temporal lobe epilepsy and schizophrenia-like psychosis. Biol Psychiatry  1990; 28:127—143
[CrossRef] | [PubMed]
 
Barr WB, Ashtari M, Bilder RM, et al.: Brain morphometry comparison of first-episode schizophrenia and temporal lobe epilepsy. Br J Psychiatry  1997; 170:515—519
[CrossRef] | [PubMed]
 
Maier M, Ron MA, Barker GJ, et al.: Proton magnetic resonance spectroscopy: an in vivo method of estimating hippocampal neuronal depletion in schizophrenia. Psychol Med 1995; 25:1201—1209; correction,  1996; 26:877
 
Harrison P: The neuropathology of schizophrenia: a critical review of the data and their interpretation. Brain  1999; 122:593—624
[CrossRef] | [PubMed]
 
Mellers J, Toone BK, Lishman WA: A neuropsychological comparison of schizophrenia and schizophrenia-like psychosis of epilepsy. Psychol Med  2000; 30:325—335
[CrossRef] | [PubMed]
 
McKenna P, Tamlyn D, Lund CE, et al.: Amnesic syndrome in schizophrenia. Psychol Med  1990; 20:967—972
[CrossRef] | [PubMed]
 
Tamlyn D, McKenna PJ, Mortimer AM, et al.: Memory impairment in schizophrenia: its extent, affiliations and neuropsychological character. Psychol Med  1992; 22:101—115
[CrossRef] | [PubMed]
 
Brebion G, Amador X, Smith MJ, et al.: Memory impairment in schizophrenia: the role of processing speed. Schizophr Res  1998; 30:31—39
[CrossRef] | [PubMed]
 
Wexler BE, Stevens AA, Bowers AA, et al.: Word and tone working memory deficits in schizophrenia. Arch Gen Psychiatry  1998; 55:1093—1096
[CrossRef] | [PubMed]
 
Silverstein SM, Osborn LM, Palumbo DR: Rey-Osterrieth Complex Figure Test performance in acute, chronic, and remitted schizophrenia patients. J Clin Psychol  1998; 54:985—994
[CrossRef] | [PubMed]
 
Saykin AJ, Gur RC, Gur RE, et al.: Neuropsychological function in schizophrenia: selective impairment in memory and learning. Arch Gen Psychiatry  1991; 48:618—624
[PubMed]
 
Duffy L, O’Carroll R: Memory impairment in schizophrenia—a comparison with that observed in the alcoholic Korsakoff syndrome. Psychol Med  1994; 24:155—165
[CrossRef] | [PubMed]
 
Beatty WW, Jocic Z, Monson N, et al.: Memory and frontal lobe dysfunction in schizophrenia and schizoaffective disorder. J Ment Dis  1993; 181:448—453
[CrossRef]
 
Paulsen JS, Heaton RK, Sadek JR, et al.: The nature of learning and memory impairments in schizophrenia. J Int Neuropsychol Soc  1995; 1:88—99
[CrossRef] | [PubMed]
 
Nathaniel-James DA, Brown R, Ron MA: Memory impairment in schizophrenia: its relationship to executive function. Schizophr Res 1996:21:85—96
 
Seidenberg M, Hermann B, Haltiner A, et al.: Verbal recognition memory performance in unilateral temporal lobe epilepsy. Brain Lang  1993; 44:191—200
[CrossRef] | [PubMed]
 
Blaxton TA, Theodore WH: The role of the temporal lobes in recognizing visuospatial materials: remembering versus knowing. Brain Cogn  1997; 35:5—25
[CrossRef] | [PubMed]
 
Helmstaedter C, Gleissner U, Di-Perna M, et al.: Relational verbal memory processing in patients with temporal lobe epilepsy. Cortex  1997; 33:667—678
[CrossRef] | [PubMed]
 
Gleissner U, Helmstaedter C, Elger CE: Right hippocampal contribution to visual memory: a pre-surgical and post-surgical study in patients with temporal lobe epilepsy. J Neurol Neurosurg Psychiatry  1998; 65:665—669
[CrossRef] | [PubMed]
 
Gold JM, Hermann BP, Randolph C, et al.: Schizophrenia and temporal lobe epilepsy: a neuropsychological analysis. Arch Gen Psychiatry  1994; 51:265—272
[PubMed]
 
Seidman LJ, Stone WS, Jones R, et al.: Comparative effects of schizophrenia and temporal lobe epilepsy on memory. J Int Neuropsychol Soc  1998; 4:342—352
[PubMed]
 
Annett M: Classification of hand preference by association analysis. Br J Psychol  1970; 61:303—321
[CrossRef] | [PubMed]
 
Nelson H, Willison J: The National Adult Reading Test, 2nd ed. Windsor, Berkshire, UK, National Foundation for Educational Research-Nelson, 1991
 
Raven JC: Advanced Progressive Matrices (Set 1): Manual. London, HK Lewis, 1958
 
Delis DC, Kramer JH, Kaplan E, et al.: The California Verbal Learning Test Manual. New York, Psychological Corp, 1987
 
Benton AL, Hamsher K, Varney NR, et al.: Contributions to Neuropsychological Assessment. New York, Oxford University Press, 1983
 
Benton AL, Hamsher K: Multilingual Aphasia Examination. Iowa City, University of Iowa Press, 1976
 
Nelson HE: A modified card-sorting test sensitive to frontal lobe defects. Cortex  1976; 12:313—324
[PubMed]
 
Burgess P, Shallice T: The Hayling and Brixton Tests. Bury St Edmunds, UK, Thames Valley Test Company, 1997
 
Weickert TW, Goldberg TE, Gold JM, et al.: Cognitive impairment in patients with schizophrenia displaying preserved and compromised intellect. Arch Gen Psychiatry  2000; 57:907—913; correction, 57:1122
[CrossRef] | [PubMed]
 
Bryson G, Whelahan HA, Bell M: Memory and executive function impairments in deficit syndrome in schizophrenia. Psychiatry Res  2001; 102:29—37
[CrossRef] | [PubMed]
 
Aleman A, Hijman R, de Haan EHF, et al.: Memory impairment in schizophrenia: a meta-analysis. Am J Psychiatry 1999; 156:1358—  1366
 
Perry W, Light GA, Davis H, et al.: Schizophrenia patients demonstrate a dissociation on declarative and non-declarative memory tests. Schizophr Res  2000; 46:167—174
[CrossRef] | [PubMed]
 
Pantelis C, Stuart GW, Nelson HE, et al.: Spatial working memory deficits in schizophrenia: relationship with tardive dyskinesia and negative symptoms. Am J Psychiatry  2001; 158:1276—1285
[CrossRef] | [PubMed]
 
Perlstein WM, Carter CS, Noll DC, et al.: Relation of prefrontal cortex dysfunction to working memory and symptoms in schizophrenia. Am J Psychiatry  2001; 158:1105—1113
[CrossRef] | [PubMed]
 
Gold JM, Blaxton TA, Hermann BP, et al.: Memory and intelligence in lateralized temporal lobe epilepsy and schizophrenia. Schizophr Res  1995; 17:59—65
[CrossRef] | [PubMed]
 

FIGURE 1.

 Adjusted Mean Scores, Controlling for Age and Raven’s Progressive Matrices Score, Across the Five Learning Trials of the California Verbal Learning Test in the Four Subject Groups

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

FIGURE 2.

 Adjusted Mean Scores, Controlling for Age and Raven’s Progressive Matrices Score, for the Final Learning Trial of the California Verbal Learning Test and the Subsequent Free and Cued Recall Trials After Short and Long Delays in the Four Subject Groupsa

aThe error bars indicate standard errors of the mean.

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

FIGURE 3.

 Adjusted Mean California Verbal Learning Test Semantic and Serial Scores, Controlling for Age and Raven’s Progressive Matrices Score, in the Four Subject Groupsa

aThe error bars indicate standard errors of the mean.

ENP=nonpsychotic patients with epilepsy

SLPE=schizophrenia-like psychosis of epilepsy

+

References

Toone B: The psychoses of epilepsy (editorial). J Neurol Neurosurg Psychiatry  2000; 69:1—4
[CrossRef] | [PubMed]
 
Toone BK, Garralda ME, Ron MA: The psychoses of epilepsy and the functional psychoses: a clinical and phenomenological comparison. Br J Psychiatry  1982; 141:256—261
[CrossRef] | [PubMed]
 
Roberts GW, Done DJ, Brunton C, et al.: A mock up of schizophrenia: temporal lobe epilepsy and schizophrenia-like psychosis. Biol Psychiatry  1990; 28:127—143
[CrossRef] | [PubMed]
 
Barr WB, Ashtari M, Bilder RM, et al.: Brain morphometry comparison of first-episode schizophrenia and temporal lobe epilepsy. Br J Psychiatry  1997; 170:515—519
[CrossRef] | [PubMed]
 
Maier M, Ron MA, Barker GJ, et al.: Proton magnetic resonance spectroscopy: an in vivo method of estimating hippocampal neuronal depletion in schizophrenia. Psychol Med 1995; 25:1201—1209; correction,  1996; 26:877
 
Harrison P: The neuropathology of schizophrenia: a critical review of the data and their interpretation. Brain  1999; 122:593—624
[CrossRef] | [PubMed]
 
Mellers J, Toone BK, Lishman WA: A neuropsychological comparison of schizophrenia and schizophrenia-like psychosis of epilepsy. Psychol Med  2000; 30:325—335
[CrossRef] | [PubMed]
 
McKenna P, Tamlyn D, Lund CE, et al.: Amnesic syndrome in schizophrenia. Psychol Med  1990; 20:967—972
[CrossRef] | [PubMed]
 
Tamlyn D, McKenna PJ, Mortimer AM, et al.: Memory impairment in schizophrenia: its extent, affiliations and neuropsychological character. Psychol Med  1992; 22:101—115
[CrossRef] | [PubMed]
 
Brebion G, Amador X, Smith MJ, et al.: Memory impairment in schizophrenia: the role of processing speed. Schizophr Res  1998; 30:31—39
[CrossRef] | [PubMed]
 
Wexler BE, Stevens AA, Bowers AA, et al.: Word and tone working memory deficits in schizophrenia. Arch Gen Psychiatry  1998; 55:1093—1096
[CrossRef] | [PubMed]
 
Silverstein SM, Osborn LM, Palumbo DR: Rey-Osterrieth Complex Figure Test performance in acute, chronic, and remitted schizophrenia patients. J Clin Psychol  1998; 54:985—994
[CrossRef] | [PubMed]
 
Saykin AJ, Gur RC, Gur RE, et al.: Neuropsychological function in schizophrenia: selective impairment in memory and learning. Arch Gen Psychiatry  1991; 48:618—624
[PubMed]
 
Duffy L, O’Carroll R: Memory impairment in schizophrenia—a comparison with that observed in the alcoholic Korsakoff syndrome. Psychol Med  1994; 24:155—165
[CrossRef] | [PubMed]
 
Beatty WW, Jocic Z, Monson N, et al.: Memory and frontal lobe dysfunction in schizophrenia and schizoaffective disorder. J Ment Dis  1993; 181:448—453
[CrossRef]
 
Paulsen JS, Heaton RK, Sadek JR, et al.: The nature of learning and memory impairments in schizophrenia. J Int Neuropsychol Soc  1995; 1:88—99
[CrossRef] | [PubMed]
 
Nathaniel-James DA, Brown R, Ron MA: Memory impairment in schizophrenia: its relationship to executive function. Schizophr Res 1996:21:85—96
 
Seidenberg M, Hermann B, Haltiner A, et al.: Verbal recognition memory performance in unilateral temporal lobe epilepsy. Brain Lang  1993; 44:191—200
[CrossRef] | [PubMed]
 
Blaxton TA, Theodore WH: The role of the temporal lobes in recognizing visuospatial materials: remembering versus knowing. Brain Cogn  1997; 35:5—25
[CrossRef] | [PubMed]
 
Helmstaedter C, Gleissner U, Di-Perna M, et al.: Relational verbal memory processing in patients with temporal lobe epilepsy. Cortex  1997; 33:667—678
[CrossRef] | [PubMed]
 
Gleissner U, Helmstaedter C, Elger CE: Right hippocampal contribution to visual memory: a pre-surgical and post-surgical study in patients with temporal lobe epilepsy. J Neurol Neurosurg Psychiatry  1998; 65:665—669
[CrossRef] | [PubMed]
 
Gold JM, Hermann BP, Randolph C, et al.: Schizophrenia and temporal lobe epilepsy: a neuropsychological analysis. Arch Gen Psychiatry  1994; 51:265—272
[PubMed]
 
Seidman LJ, Stone WS, Jones R, et al.: Comparative effects of schizophrenia and temporal lobe epilepsy on memory. J Int Neuropsychol Soc  1998; 4:342—352
[PubMed]
 
Annett M: Classification of hand preference by association analysis. Br J Psychol  1970; 61:303—321
[CrossRef] | [PubMed]
 
Nelson H, Willison J: The National Adult Reading Test, 2nd ed. Windsor, Berkshire, UK, National Foundation for Educational Research-Nelson, 1991
 
Raven JC: Advanced Progressive Matrices (Set 1): Manual. London, HK Lewis, 1958
 
Delis DC, Kramer JH, Kaplan E, et al.: The California Verbal Learning Test Manual. New York, Psychological Corp, 1987
 
Benton AL, Hamsher K, Varney NR, et al.: Contributions to Neuropsychological Assessment. New York, Oxford University Press, 1983
 
Benton AL, Hamsher K: Multilingual Aphasia Examination. Iowa City, University of Iowa Press, 1976
 
Nelson HE: A modified card-sorting test sensitive to frontal lobe defects. Cortex  1976; 12:313—324
[PubMed]
 
Burgess P, Shallice T: The Hayling and Brixton Tests. Bury St Edmunds, UK, Thames Valley Test Company, 1997
 
Weickert TW, Goldberg TE, Gold JM, et al.: Cognitive impairment in patients with schizophrenia displaying preserved and compromised intellect. Arch Gen Psychiatry  2000; 57:907—913; correction, 57:1122
[CrossRef] | [PubMed]
 
Bryson G, Whelahan HA, Bell M: Memory and executive function impairments in deficit syndrome in schizophrenia. Psychiatry Res  2001; 102:29—37
[CrossRef] | [PubMed]
 
Aleman A, Hijman R, de Haan EHF, et al.: Memory impairment in schizophrenia: a meta-analysis. Am J Psychiatry 1999; 156:1358—  1366
 
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