Improved verbal learning in the semantic variant of primary progressive aphasia when using semantic cues

The semantic variant of primary progressive aphasia (PPA-S) is characterized by impairments in confrontation naming and single word comprehension. Although episodic memory may be relatively spared, there can be impairment in verbal learning tasks. We report a patient with PPA-S and impaired verbal learning who was tested to learn if when provided with semantic categories, her learning would improve. A 70-year-old right-handed woman with a 2-year history of progressive difficulties with word finding, naming, and memory was tested for language and memory deficits using the Hopkins Verbal Learning Test-Revised (HVLT-R). She was then retested with the HVLT-R after being provided with the three semantic categories to which these words belonged. Confrontation naming was impaired on the Boston Naming Test. Sentence repetition was normal. Comprehension testing with word picture matching and sentence comprehension was normal. On a test of semantic associations, Pyramids and Palm Trees, she was impaired. She was also impaired on tests of verbal learning (HVLT-R) (total: 13) but not recall. When a different version of the HVLT-R was given with the semantic categories of the words given beforehand, her scores improved (total: 26). This patient with PPA-S had an impairment of verbal learning, but not delayed recall. When given a semantic category cue beforehand, her verbal learning performance improved. This observation suggests that this patient did not spontaneously use semantic encoding. Using a semantic cueing strategy may help other patients with PPA-S improve their capacity for verbal learning.     

The effect of impaired verbal memory retrieval on autobiographical memory across different life periods in schizophrenia

ObjectivesAutobiographical memory (AM) involves recollection of personal events and facts about one's life. Αim of the present study was to investigate AM in schizophrenia patients, and, in particular, patients' ability to recall autobiographical memories after controlling for verbal memory and verbal fluency deficits.MethodParticipants included 40 schizophrenia patients (23 male) and 40 healthy controls (23 male), matched for age, gender, educational level, and premorbid intellectual functioning. Participants' verbal memory (list learning and story recall) and verbal fluency were assessed. AM was evaluated by the Questionnaire of Autobiographical Memory, consisting of the Personal Semantic Memory scale and the Autobiographical Incidents scale. Furthermore, personal incidents' specificity was examined.ResultsSchizophrenia patients showed deficits in verbal memory and verbal fluency, as well as in both semantic and episodic AM compared with healthy controls. Deficits were shown in episodic and semantic memories of events and facts dating to three different life periods (childhood, early adulthood and recent life). Regarding specificity of recalled events, patients reported fewer specific autobiographical incidents than controls. After controlling AM deficits for patients' verbal memory and verbal fluency impairment, it was shown that schizophrenia patients recalled fewer memories of autobiographical incidents dating only to recent life, compared with healthy controls.ConclusionsSchizophrenia patients showed impaired AM after controlling for verbal memory and verbal fluency impairment only in regard with personal episodic memories from recent life. Current findings raise the important issue of cognitive remediation therapy in schizophrenia.     

Differential pattern of semantic memory organization between bipolar I and II disorders

Semantic cognition is one of the key factors in psychosocial functioning. The aim of this study was to explore the differences in pattern of semantic memory organization between euthymic patients with bipolar I and II disorders using the category fluency task. Study participants included 23 euthymic subjects with bipolar I disorder, 23 matched euthymic subjects with bipolar II disorder and 23 matched control subjects. All participants were assessed for verbal learning, recall, learning strategies, and fluency. The combined methods of hierarchical clustering and multidimensional scaling were used to compare the pattern of semantic memory organization among the three groups. Quantitative measures of verbal learning, recall, learning strategies, and fluency did not differ between the three groups. A two-cluster structure of semantic memory organization was identified for the three groups. Semantic structure was more disorganized in the bipolar I disorder group compared to the bipolar II disorder. In addition, patients with bipolar II disorder used less elaborate strategies of semantic memory organization than those of controls. Compared to healthy controls, strategies for categorization in semantic memory appear to be less knowledge-based in patients with bipolar disorders. A differential pattern of semantic memory organization between bipolar I and II disorders indicates a higher risk of cognitive abnormalities in patients with bipolar I disorder compared to patients with bipolar II disorder. Exploring qualitative nature of neuropsychological domains may provide an explanatory insight into the characteristic behaviors of patients with bipolar disorders.     

Cognitive deficits in early-onset schizophrenia spectrum patients and their non-psychotic siblings: a comparison with ADHD

BACKGROUND: Previous research has shown cognitive deficits in patients with schizophrenia spectrum disorders in the areas of executive function, verbal memory and attention. Subtle deficits have been shown in healthy first-degree relatives of patients, suggesting that they may be trait markers. The specificity of these markers for schizophrenia compared with another neurodevelopmental disorder, Attention Deficit Hyperactivity Disorder (ADHD) has not been reliably established. METHODS: The Rey Auditory Verbal Learning Test (RAVLT), Hayling Sentence Completion Test (HSCT), FAS Test of orthographic verbal fluency (FAS) and Continuous Performance Test-Identical Pairs (CPT-IP) were administered to adolescent schizophrenia spectrum patients (SZ; n=30), adolescent siblings of schizophrenia spectrum patients (SZ-SIB; n=36), healthy control participants (HC; n=72); a neurodevelopmental comparison group of adolescents with ADHD (n=27). RESULTS: The SZ group were impaired on all measures. The SZ-SIB group were impaired on IQ, immediate recall (RAVLT), target sensitivity (CPT-IP), response initiation (HSCT); error rates for the FAS and HSCT. There were no significant differences between the SZ-SIB and ADHD groups on individual measures of cognitive function. Principal Components Analysis revealed four factors on which further analyses were conducted. The SZ-SIB and ADHD groups showed different profiles of impairment on components related to response initiation and sustained attention/vigilance when each was compared with the HC group. CONCLUSIONS: Deficits in intellectual function, verbal memory and response initiation/inhibition were found in the SZ-SIB group indicating that these are markers of risk for schizophrenia. Subtle differences in profiles of impairment in the SZ-SIB and ADHD groups on composite measures of attention and response initiation require further investigation.     

Fonctions cognitives sous-jacentes aux déficits de fluence verbale dans la schizophrénie : revue de la littérature

Individuals with schizophrenia usually show impairment on various cognitive functions, including long-term memory, executive functions and language. Compared to healthy controls, their performance is impaired in verbal fluency tests. These tests require participants to generate in a given time as many words as they can, belonging to a given category (semantic fluency), or beginning with a specific letter (orthographic fluency). Various cognitive functions are involved in verbal fluency tests: psychomotor speed, executive functions, language, long-term verbal memory and semantic memory. The purpose of the present study was to clarify the functional origin of verbal fluency deficits in schizophrenia through a literature review. Nineteen articles were selected in Pubmed and PsycINFO after initial screening and detailed review. They were formally analyzed with regard to general performance, cognitive strategies used in semantic and orthographic fluency tests and, underlying cognitive origin of deficits. Results show that individuals with schizophrenia produce fewer words than healthy controls in both types of fluency tests. Their impairment is more apparent in semantic than in orthographic fluency tests. Results of studies reviewed also show that individuals with schizophrenia adopt the same clustering (i.e. production of related words within a subcategory) and switching (i.e. ability to shift between clusters when a subcategory is exhausted) strategies than healthy controls, but less efficiently. Several hypotheses, such as the impairment of executive functions, semantic memory or speed of information processing, were put forward to account for this finding. Interestingly, the few studies in which researchers performed an analysis of the semantic relationships between words produced in fluency tests showed a less semantic coherence among people with schizophrenia than in healthy controls. Such a difference could be explained by disorganization of semantic memory or impairment in the activation of conceptual representations in semantic memory. Studies in which correlations and regression analyzes were performed allow for clarifying the cognitive origin underlying verbal fluency deficits in schizophrenia. The links between these deficits and information processing speed as well as working memory are well established. These two cognitive domains also appear to be strong predictors of performance in semantic and orthographic fluency tasks in schizophrenia. Individuals with schizophrenia usually present with a significant slowdown in the speed of information processing. Such a slowdown is likely to account for their poor performance in verbal fluency tests, which require the independent and rapid production of words. Working memory disorders are also core cognitive symptoms of schizophrenia. Working memory is involved in verbal fluency tests since they involve “strategic” activation of verbal information in long-term memory, inhibition of inappropriate words, switching between clusters, etc. However, the concept of working memory also partially encompasses the notion of executive functions so that the results reported in the present literature review, according to which impairment of verbal fluency in schizophrenia results from working memory deficits but not from executive functions deficits, are difficult to interpret. Results are also less clear-cut in regard to verbal long-term memory and to language abilities. Finally, numerous studies had shown that individuals with schizophrenia present specific deficits in the organization of semantic memory. However, the impact of this deficit on verbal fluency was explored in one study only. To conclude, verbal fluency tests are sensitive to various neurocognitive conditions and are helpful for differential diagnosis. Further studies are still needed to clarify the functional origin of verbal fluency deficits in schizophrenia, in particular the differential role of executive functions and working memory as well as the impact of semantic memory impairment.     

Cognitive functioning in siblings discordant for schizophrenia

OBJECTIVE: The objective of this study was to investigate neuropsychological impairment as a genetically mediated risk indicator for schizophrenia while accounting for prevalence of schizotypy signs/symptoms in siblings. METHOD: Cognitive functioning in 25 individuals with schizophrenia, 25 unaffected siblings and 25 unrelated healthy controls, was assessed using neuropsychological tests of sustained attention, memory and learning, executive function, visual-spatial ability and psychomotor performance. RESULTS: Unaffected siblings demonstrated better performance than patients on some measures of memory and learning and executive function. Patients and siblings demonstrated impaired Full Scale IQ and verbal fluency, otherwise siblings performed similarly to healthy controls. Controlling for differences in IQ, the shared deficit in verbal fluency disappeared. CONCLUSION: Patients with schizophrenia and unaffected siblings (without schizotypy personality disorder) shared a neuropsychological deficit in verbal fluency. This deficit appeared to be mediated by IQ. Deficits, which differentiated patients from controls, may not be inherited and perhaps are related to the manifestation or treatment of schizophrenia.     

Executive and amnestic functions of a group of first-degree relatives of schizophrenic patients

Several lines of evidence seem to indicate that some neurocognitive measures could be phenotypic markers of predisposition to schizophrenia. The aim of this study was to investigate 21 patients with schizophrenia, 51 of their first-degree relatives and 46 nonpsychiatric controls, with a series of tests known to be sensitive to prefrontal cortical damage--the Trail Making Test, part B (TMT B), the Wisconsin Card Sorting Test (WCST) and a verbal fluency test (VFT)- and/or sensitive to temporo-hippocampic dysfunctions: verbal and visual memory and verbal learning tests from the Wechsler Memory Scale-Revised (Wechsler, 1987). Since parents and siblings share on average 50% of their genes with the schizophrenic proband, firstly we predicted that the first-degree relatives' performance would be at an intermediate level between patients and control subjects and secondly, we expected that a higher proportion of relatives than of control subjects would be impaired. The patients demonstrated deviant patterns of neuropsychological performance on the three tests sensitive to frontal dysfunctions and on most of the memory and learning tests. In the relative group, performance on the TMT B, VFT, immediate verbal recall and verbal learning was at an intermediate level between both other groups and significantly impaired compared to control subjects. However, the relative group did not differ from the control group on the WCST, immediate visual recall, and delayed verbal and visual recalls. Furthermore, compared to the control group, the percentages of patients and relatives who scored one standard deviation below the mean control group were significantly higher for the VFT and immediate verbal recall scores. Among all the tests studied, the verbal fluency and the immediate verbal recall appeared to be valuable phenotypic markers of schizophrenia since: (i) their mean scores were poorer in the patient and in the relative groups, (ii) the percentages of patients and relatives with poor performance were higher than the percentage of controls, (iii) these deficits were not due to poorer general intellectual abilities in the relative group, (iv) these deficits did not correlate with anxiety or depression scores.     

Executive dysfunction in patients with spinocerebellar ataxia type 3

The aim of this study was to assess the cognitive functions of patients with spinocerebellar ataxia type 3(SCA3). We examined 15 patients with genetically confirmed SCA3 and 15 healthy control subjects matched for age, years of education, and intellectual ability. We administered verbal memory (word recall and word recognition) and executive function tasks (word fluency test, forward and backward digit and visual span tests, Kana Pick-out Test, Trail Making Test, and conflicting instructions and a Go/NoGo task from the Frontal Assessment Battery). We found that patients with SCA3 had significantly lower scores than the healthy control subjects on the word recall, semantic, and letter fluency, and backward digit span tests, while word recognition was well preserved. The other executive function tests showed preserved functions in the SCA3 group, indicating that visual working memory, and attention and inhibition control were not affected. The patients with SCA3 showed impaired word recall and intact word recognition, and accordingly, episodic memory encoding and storage processes in short-term memory were preserved. In category and letter-fluency tests, impairment was attributable to word-retrieval from semantic memory. Impaired verbal working memory may be involved in the retrieval of verbal information from phonological storage by means of continuous subvocal rehearsal, rather than a deficit in initial phonological encoding. Essential executive dysfunction in patients with SCA3 may be due to damage in the cerebellar cortex–ventral dentate nucleus–thalamus–prefrontal cortex circuits, which are involved in strategic retrieval of verbal information from different modes of memory storage.     

抑郁症和早期阿尔茨海默病的记忆和执行功能

目的 研究抑郁症和早期阿尔茨海默病(AD)的神经心理学特征,试图运用神经心理学评估对两者进行鉴别。方法 对32例单相抑郁症、38例早期AD和34例对照进行WHO-UCLA词语学习、词语流畅、复杂图形和逻辑记忆的评估。结果 早期AD组神经心理学测验得分最低,抑郁症组次之,对照组最高,3组之间有显著性差异(P<0.01);抑郁症组仅表现为词语学习和逻辑记忆的自由回忆以及语义流畅的损害(P<0.05),而早期AD组表现为全面的认知功能损害(P<0.01);逐步判别分析提示,复杂图形延迟自由回忆、词语学习长时延迟自由回忆和语义流畅是区分抑郁症组和早期AD组的重要指标。结论 抑郁症和早期AD认知功能损害的特征不同,长时延迟自由回忆、再认和语义流畅能够区分早期AD和抑郁症。     

Hippocampal dysfunction during free word association in male patients with schizophrenia

In schizophrenia, speech production deficits in patients with positive formal thought disorder (FTD e.g. loosening of associations and derailment) have been attributed to impairments in the semantic network. The brain area implicated in the retrieval of associated (i.e. relational) concepts is the hippocampus, a key region in the psychopathology of schizophrenia. However, its role in schizophrenic speech production and FTD in particular is yet little understood.

To investigate the neural correlates of associative verbal retrieval, twelve patients with schizophrenia with varying degrees of FTD and twelve matched healthy control subjects underwent a free verbal association (FVA), a semantic (SVF) and a phonological verbal fluency (PVF) task while brain activity was measured with fMRI. The tasks varied in the relational binding operations needed for linking the stimulus to the respective response.

Compared to control subjects, patients revealed attenuated left hippocampal activity during both semantic word generation tasks (FVA, SVF). Contrasting verbal fluency with FVA, a failure in recruiting the anterior cingulate gyrus emerged in the patient group. A negative correlation was found between right middle temporal activity and the severity of FTD during FVA.

The hippocampus seems to play a major role in word generation. In schizophrenia, attenuated hippocampal activity during semantic tasks strengthens the hypothesis of impaired relational memory processes, affecting thought and language.     

Semantic fluency is impaired but phonemic and design fluency are preserved in early-onset schizophrenia

Impairments of verbal fluency are recognised in adult-onset schizophrenia but their presence in early-onset schizophrenia is not well established. This study investigated the extent and character of verbal fluency disturbance in young patients close to illness onset. Thirty-three adolescents with DSM-IV schizophrenia and 33 controls completed phonemic and semantic fluency tests and a free design fluency test. Patients had significantly impaired semantic fluency compared to controls but no impairment on phonemic or design fluency. The difference between patients and controls for semantic fluency remained significant when corrected for age and IQ. These results lend support to the hypothesis that impaired semantic fluency may be an early trait marker of schizophrenia that is potentially related to a failure of lateralisation of language.     

Deficits in memory strategy use are related to verbal memory impairments in adolescents with schizophrenia-spectrum disorders

OBJECTIVE: To assess the nature of learning and verbal memory deficits in adolescents with schizophrenia-spectrum disorders (SzS) (i.e., schizophrenia, schizoaffective disorder, and schizophreniform disorder). METHOD: Sixty patients with SzS (mean age=16.1 years, S.D. = 2.2) and 60 age- and gender-matched diagnosis-free healthy volunteers were assessed using the California Verbal Learning Test (CVLT). Planned analyses were conducted to assess the following aspects of memory: span of apprehension, verbal learning, short-term and long-term memory, rate of forgetting, interference, and organizational strategies. Adolescents with schizophrenia (Sz) were compared to those with schizoaffective disorder (SzA). Second, patients' test profiles were compared to those of controls. Relationships between initial learning and overall verbal learning with organizational strategy were explored. RESULTS: Neurocognitive profiles did not significantly differ between Sz and SzA participants. Patients performed significantly worse than healthy comparison subjects on measures of span of apprehension, verbal learning, short- and long-term memory, and organizational strategies after adjusting for differences in premorbid intelligence. No group differences were found in rate of forgetting or susceptibility to proactive or retroactive interference. CONCLUSIONS: Adolescents with SzS are characterized by significant verbal memory dysfunction similar to what has been observed in adults with first-episode schizophrenia. Deficits in consistency of learning over several trials, as well as a strong relationship between semantic organizational strategies and reduced learning capacity, implicate dysfunction of the dorsolateral prefrontal cortex as a contributor to verbal memory deficits in adolescents with SzS.     

Verbal short‐term memory in Down's syndrome: An articulatory loop deficit?

Background Verbal short‐term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age‐matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub‐components is at the base of the deficient maintenance and recall of phonological representations in individuals with DS. Methods Two experiments were carried out in a group of adolescents with DS and in typically developing children matched for mental age. In the first experiment, the authors explored the reliance of these subjects on the subvocal rehearsal mechanism during a word‐span task and the effects produced by varying the frequency of occurrence of the words on the extension of the word span. In the second experiment, they investigated the functioning of the phonological store component of the articulatory loop in more detail. Results A reduced verbal span in DS was confirmed. Neither individuals with DS nor controls engaged in spontaneous subvocal rehearsal. Moreover, the data provide little support for defective functioning of the phonological store in DS. Conclusions No evidence was found suggesting that a dysfunction of the articulatory loop and lexical‐semantic competence significantly contributed to verbal span reduction in subjects with DS. Alternative explanations of defective verbal short‐term memory in DS, such as a central executive system impairment, must be considered.     

Neurocognition and cognitive biases in schizophrenia

ABSTRACT: Individuals with schizophrenia have been found to exhibit a number of information processing biases that may play a role in the development and exacerbation of symptoms and may impair overall functioning. However, little is known about the factors that are associated with these cognitive biases. Recently, researchers have begun to consider whether neurocognitive deficits, common in schizophrenia, may be risk factors for the development of cognitive biases. In the present study, we assessed neurocognition (verbal learning, delayed verbal recall memory, and verbal recognition memory) and cognitive biases (knowledge corruption and impaired cognitive insight) in 72 individuals with schizophrenia or schizoaffective disorder. As hypothesized, poorer delayed verbal recall memory was associated with increased knowledge corruption. Contrary to expectations, verbal learning and verbal memory were not associated with cognitive insight. These findings suggest that an inadequate recall memory system may put patients with schizophrenia at greater risk for cognitive distortions.     

Implicit and explicit memory functioning in children with heavy prenatal alcohol exposure.

Prenatal alcohol exposure is associated with widespread and devastating neurodevelopmental deficits. Numerous reports have suggested memory deficits in both humans and animals exposed prenatally to alcohol. However, the nature of these memory deficits remains to be characterized. Recently children with fetal alcohol syndrome were shown to have learning and memory deficits on a verbal learning and memory measure that involved free recall and recognition memory. The current study seeks to further characterize memory functioning in children with heavy prenatal alcohol exposure by evaluating priming performance. The choice of task is also relevant given previous studies of memory performance in patient groups with and without involvement of the basal ganglia, a group of structures known to be affected in fetal alcohol syndrome. Three groups were evaluated for lexical priming, free recall, recognition memory, and verbal fluency: (1) children with heavy prenatal alcohol exposure; (2) children with Down syndrome; and (3) nonexposed controls. The children with Down syndrome showed significantly less priming than alcohol-exposed children, who did not differ from controls. In addition, the alcohol-exposed children were impaired on the free recall task but not on the recognition memory task, whereas the children with Down syndrome performed significantly worse than the alcohol-exposed group on both tasks. Finally, on the verbal fluency task, children with heavy prenatal alcohol exposure were impaired on both category and letter fluency, but the degree of impairment was greater for letter fluency. These results further characterize the memory deficits in children with heavy prenatal alcohol exposure suggesting that in spite of learning and memory deficits, they are able to benefit from priming of verbal information.     

Cognitive consequences of early phase of literacy.

The effect of the degree of illiteracy (complete or incomplete) on phonological skills, verbal and visual memory and visuospatial skills is examined in 97 normal Brazilian adults who considered themselves illiterate, and 41 Brazilian school children aged 7 to 8 years, either nonreaders or beginning readers. Similar literacy effects were observed in children and in adults. Tasks involving phonological awareness and visual recognition memory of nonsense figures distinguish the best nonreaders and beginning readers. Children performed better than adults at oral repetition of short items and figure recall, and adults better than children at semantic verbal fluency, digit span, and word list recall. A principal component analysis of the correlations between tasks showed that phonological awareness/reading, phonological memory/oral repetition, and semantic verbal memory/fluency tasks, generated different components. The respective role of culturally based preschool activities and literacy on the cognitive functions that are explored in this study is discussed.     

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.     

Prose memory deficits associated with schizophrenia

Memory of contextual information is essential to one's quality of living. This study investigated if the different components of prose memory, across three recall conditions: first learning trial immediate recall, fifth learning trial immediate recall, and 30-min delayed recall, are differentially impaired in people with schizophrenia, relative to healthy controls. A total of 39 patients with schizophrenia and 39 matched healthy controls were recruited. Their prose memory, in terms of recall accuracy, temporal sequence, recognition accuracy and false positives, commission of distortions, and rates of learning, forgetting, and retention were tested and compared. After controlling for the level of intelligence and depression, the patients with schizophrenia were found to commit more distortions. Furthermore, they performed poorer on recall accuracy and temporal sequence accuracy only during the first initial immediate recall. On the other hand, the rates of forgetting/retention and recognition accuracy were comparable between the two groups. These findings suggest that people with schizophrenia could be benefited by repeated exposure to the materials to be remembered. These results may have important implications for rehabilitation of verbal declarative memory deficits in schizophrenia.     

The episodic buffer in children with intellectual disabilities: An exploratory study

Performance on three verbal measures (story recall, paired associated learning, category fluency) designed to assess the integration of long-term semantic and linguistic knowledge, phonological working memory and executive resources within the proposed ‘episodic buffer’ of working memory (Baddeley, 2007) was assessed in children with intellectual disabilities (ID). It was hypothesised that children with ID would show equivalent performance to typically developing children of the same mental age. This prediction was based on the hypothesis that, despite poorer phonological short-term memory than mental age matched peers, those with ID may benefit from more elaborate long-term memory representations, because of greater life experience. Children with ID were as able as mental age matched peers to remember stories, associate pairs of words together and generate appropriate items in a category fluency task. Performance did not, however, reach chronological age level on any of the tasks. The results suggest children with ID perform at mental age level on verbal ‘episodic buffer’ tasks, which require integration of information from difference sources, supporting a ‘delayed’ rather than ‘different’ view of their development.     

Cognitive functioning in young people with first episode psychosis: relationship to diagnosis and clinical characteristics

OBJECTIVE: To examine the extent and nature of neuropsychological deficits in adolescents and young people with first episode psychosis (FEP), and to determine whether the pattern and extent of neuropsychological deficits varied according to diagnosis. METHOD: A total of 83 FEP subjects aged 13-25 years, and 31 healthy controls completed a comprehensive battery of neuropsychological tests, grouped into 10 cognitive domains. First episode psychosis subjects were stratified into three diagnostic groups (schizophrenia, affective disorders, substance-induced psychosis) and differences in cognitive profiles were examined. The contribution of demographic and clinical characteristics to cognitive performance was also explored. RESULTS: The schizophrenia group demonstrated significantly worse performance on tasks of verbal learning and memory than the affective disorders group. Compared to healthy controls, the schizophrenia group also demonstrated global impairment across the majority of cognitive domains. The substance-induced group's performance lay between that of the schizophrenia and affective disorders groups. Analyses of differential deficits revealed that verbal learning, verbal memory and current intellectual functioning were selectively impaired in the schizophrenia group, whereas the affective disorders group demonstrated a selective deficit in speeded processing. Premorbid intellectual functioning, negative symptomatology and medication levels were the strongest predictors of cognitive performance in FEP subjects. CONCLUSIONS: Verbal memory deficits differentiate individuals with schizophrenia from those with psychotic affective disorders. Although significant cognitive deficits are evident across all diagnostic FEP groups, individuals with schizophrenia appear to have more generalized impairment across a broad array of cognitive functions than other psychotic diagnoses. Lower premorbid intellectual functioning does not appear to contribute to greater cognitive deterioration following onset of psychosis, but severity of illness may be a more important factor than levels of mood disturbance.