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PubMed2000

[Neuropsychological deficits in depressive disorders].

Neuropsychological deficits are considered a significant feature of depression both for their differential value in the diagnostics and the underlying pathophysiology of depressive disorders. The studies reviewed in the present paper predominantly focus on memory disorders as well as frontal-lobe associated dysfunctions such as deficits of attentional performance and executive functions. Despite heterogeneous results in the literature, there is emerging evidence that executive functions and anterograde memory performance are those domains predominantly affected in depressive disorders. The fact that not all depressive patients display neuropsychological deficits rather indicates a dominant role of moderating variables. We discuss the following variables possibly intervening with type and degree of neuropsychological dysfunction: [1] severity and remission of depressive disorders, [2] age of patients and age at the first manifestation of a depressive disorder, [3] psychological factors such as motivation and coping with failure, [4] type and efficacy of antidepressive drug treatment, [5] duration of the stay as inpatients, [6] number of depressive episodes, and [7] gender. Furthermore, we discuss the theory of a dysfunction of fronto-striatal circuits as an underlying mechanism of depressive disorders. The majority of neuropsychological findings seem to support this theory.

Attention↗

PubMed2006

Consistent resting-state networks across healthy subjects.

Functional MRI (fMRI) can be applied to study the functional connectivity of the human brain. It has been suggested that fluctuations in the blood oxygenation level-dependent (BOLD) signal during rest reflect the neuronal baseline activity of the brain, representing the state of the human brain in the absence of goal-directed neuronal action and external input, and that these slow fluctuations correspond to functionally relevant resting-state networks. Several studies on resting fMRI have been conducted, reporting an apparent similarity between the identified patterns. The spatial consistency of these resting patterns, however, has not yet been evaluated and quantified. In this study, we apply a data analysis approach called tensor probabilistic independent component analysis to resting-state fMRI data to find coherencies that are consistent across subjects and sessions. We characterize and quantify the consistency of these effects by using a bootstrapping approach, and we estimate the BOLD amplitude modulation as well as the voxel-wise cross-subject variation. The analysis found 10 patterns with potential functional relevance, consisting of regions known to be involved in motor function, visual processing, executive functioning, auditory processing, memory, and the so-called default-mode network, each with BOLD signal changes up to 3%. In general, areas with a high mean percentage BOLD signal are consistent and show the least variation around the mean. These findings show that the baseline activity of the brain is consistent across subjects exhibiting significant temporal dynamics, with percentage BOLD signal change comparable with the signal changes found in task-related experiments.

Brain↗

PubMed2006

What about theory of mind after severe brain injury?

BACKGROUND: Behavioural changes are often reported after a severe traumatic brain injury (TBI). These changes are usually a greater burden for relatives than physical or cognitive impairments. This study investigated social cognition in TBI patients using two theory of mind (TOM) tasks. METHOD: The performances of 17 patients with severe TBI and 17 matched controls were compared on two tasks designed to investigate understanding of other people's mental states: The 'Reading the Mind in the Eyes' test (RME) and the 'Character Intention Task' (CIT). TBI patients and controls were also given several executive function tasks. RESULTS: Compared to healthy controls, patients were impaired in most executive tests and in both TOM tasks. No relationship was found between TOM and executive measures. This is consistent with Rowe's position, who suggested an independence between executive functioning and social cognition. These data suggest that TBI patients may have specific social intelligence disturbances. CONCLUSION: Future work should employ additional tests of TOM and behavioural ratings and recruit more patients in order to complete analysis.

Adolescent↗

PubMed2004

Investigation of factors related to employment outcome following traumatic brain injury: a critical review and conceptual model.

PURPOSE: The purpose of this article is to critically review the literature to examine factors that are most consistently related to employment outcome following traumatic brain injury (TBI), with a particular focus on metacognitive skills. It also aims to develop a conceptual model of factors related to employment outcome. METHOD: The first stage of the review considered 85 studies published between 1980 and December 2003 which investigated factors associated with employment outcome following TBI. English-language studies were identified through searches of Medline and PsycINFO, as well as manual searches of journals and reference lists. The studies were evaluated and rated by two independent raters (Kappa=0.835) according to the quality of their methodology based upon nine criteria. Fifty studies met the criteria for inclusion in the second stage of the review, which examined the relationship between a broad range of variables and employment outcome. RESULTS: The factors most consistently associated with employment outcome included pre-injury occupational status, functional status at discharge, global cognitive functioning, perceptual ability, executive functioning, involvement in vocational rehabilitation services and emotional status. CONCLUSIONS: A conceptual model is presented which emphasises the importance of metacognitive, emotional and social environment factors for improving employment outcome.

Brain Injuries↗

PubMed2006

Perceptual anomalies in schizophrenia: integrating phenomenology and cognitive neuroscience.

From phenomenological and experimental perspectives, research in schizophrenia has emphasized deficits in "higher" cognitive functions, including attention, executive function, as well as memory. In contrast, general consensus has viewed dysfunctions in basic perceptual processes to be relatively unimportant in the explanation of more complex aspects of the disorder, including changes in self-experience and the development of symptoms such as delusions. We present evidence from phenomenology and cognitive neuroscience that changes in the perceptual field in schizophrenia may represent a core impairment. After introducing the phenomenological approach to perception (Husserl, the Gestalt School), we discuss the views of Paul Matussek, Klaus Conrad, Ludwig Binswanger, and Wolfgang Blankenburg on perception in schizophrenia. These 4 psychiatrists describe changes in perception and automatic processes that are related to the altered experience of self. The altered self-experience, in turn, may be responsible for the emergence of delusions. The phenomenological data are compatible with current research that conceptualizes dysfunctions in perceptual processing as a deficit in the ability to combine stimulus elements into coherent object representations. Relationships of deficits in perceptual organization to cognitive and social dysfunction as well as the possible neurobiological mechanisms are discussed.

Attention↗

PubMed1996

Neuropsychological features of early Alzheimer's disease: preclinical and clinical stages.

In the preclinical stage of Alzheimer's disease (AD), studies of asymptomatic mutation carriers have identified impairments in episodic memory. Other cognitive functions show no or slight impairment suggesting that preclinical AD is a unifunctional cognitive syndrome; the brain is affected selectively and predominantly in the medial temporal structures. In the early clinical stage, deficits occur in episodic memory, verbal abilities, visuospatial functions, attention, and executive functions. AD becomes a multifunctional cognitive syndrome and the brain's association cortices are affected. Nevertheless, sensory-motor performance and procedural memory seem to be intact and only slight impairment may be seen in primary memory. In advanced AD, cognitive dysfunction including deficits is global in primary memory, although sensory-motor performance may be well preserved. The brain's association cortices are severely affected. The sequence of cognitive decline; from unifunctional to global deficits, conforms to the three-stage development of neurofibrillary tangles described by Braak and Braak.

Alzheimer Disease↗

PubMed2000

Neuropsychological outcome after unilateral pallidotomy for the treatment of Parkinson's disease.

OBJECTIVE: To assess the long term cognitive outcome of unilateral posteroventral pallidotomy (PVP) and the overall efficacy of the surgery. METHODS: Forty two (29 left and 13 right PVP) patients with Parkinson's disease underwent neurological and neuropsychological testing before PVP and at 3 and 12 months after PVP. The neuropsychological testing battery emphasised measures of verbal learning and memory, visuospatial abilities, speed of information processing, executive functioning, and affective functioning. RESULTS: All patients demonstrated motor improvements after surgery during their off state, and 86% of patients also showed improvements in motor functioning in their on state. Repeated measures ANOVA showed significant improvements in confrontational naming, visuospatial organisation, and affective functioning 3 months and 12 months after surgery, with inconsistent improvements in executive functioning 12 months post-PVP. Patients demonstrated a transient impairment in verbal memory, with verbal learning performance returning to baseline 12 months post-PVP after a significant decline 3 months after PVP. When three patients with lesions extending outside of the PVP were excluded from the analysis, a decline in verbal fluency performance after PVP was not found to be significant. Differences due to side of lesion placement were not found on any of the cognitive measures. CONCLUSIONS: In the largest long term follow up study reported to date, the cognitive changes found up to a year after PVP are minimal compared with the robust improvements in motor function. The findings highlight the need to investigate the relation between the specific fibre tracts affected by the lesions and cognitive outcome.

Activities of Daily Living↗

PubMed2006

Executive performance on the Wisconsin Card Sorting Test in mesial temporal lobe epilepsy.

Executive dysfunction assessed by the Wisconsin Card Sorting Test has been observed in patients with mesial temporal lobe epilepsy (TLE); however, the mechanism of executive impairment is unclear. We therefore investigated the potential contribution of the hippocampus toward executive dysfunction in 85 mesial TLE patients, and in a control group of 34 patients with neocortical TLE. Standardized regression-based methodology was used for correcting test-retest bias. We found that 56% of mesial TLE patients had impaired sorting performance, with 30% showing severe impairment. A lower full-scale intelligence quotient, older age, longer duration, and preoperative use of topiramate were significantly correlated with poorer preoperative sorting abilities. However, neither these variables nor postoperative discontinuation/reduction of topiramate were related to postoperative changes in sorting abilities. Only preoperative sorting abilities were negatively correlated with postoperative changes in executive performance. That is, patients with better preoperative executive ability showed greater postoperative deterioration in executive function, whereas those with poorer preoperative sorting ability had greater improvement in executive function after mesial temporal resection. There were no differences in card sorting ability between the mesial and neocortical TLE groups. In conclusion, our results suggest that impairment of card sorting performance in the mesial TLE group cannot be explained only by hippocampal dysfunction, but that other processes (possibly epileptic discharges propagated to the extratemporal area) must play a predominant role.

Adult↗

PubMed2004

[Is it possible to improve social functioning of schizophrenia with cognitive rehabilitation?].

Social dysfunction of schizophrenia is observed in many domains including social skills, ability to conduct tasks, attention/durability, volition/motivation, stability of social life, and insight of dysfunction. These dysfunctions have been found to relate to non-social cognitive functioning to some extent. Social skills may have a strong relationship with social cognition. The intervention technique of cognitive functioning of schizophrenia, known as cognitive rehabilitation or cognitive remediation, has its main target as non-social cognition. Cognitive behavior therapy focuses on the contents of the cognitive process, while cognitive rehabilitation focuses on the cognitive process (information process) or thinking skills. Which cognitive functioning should be targeted was revealed as were theoretical models of cognitive rehabilitation, and various intervention techniques and their usefulness. It has been found that some elements of cognitive functioning, such as executive functioning, could be improved in experimental settings in efficacy studies. However, comprehensive rehabilitation including cognitive rehabilitation should be used in order to relieve social dysfunctioning or psychiatric symptoms. Some experts insisted that an individualized program with several steps, along with cognitive abilities, is required to enhance usefulness and effectiveness. Other experts said more complex cognitive functioning profoundly associated with social life should be targeted, rather than elementary cognitive functioning. The conclusions of meta-analyses of randomized controlled trails were not consistent until now, because inclusion criteria of meta-analysis was different. Finally, it was discussed how the theory and techniques of cognitive rehabilitation should be implemented in traditional rehabilitation.

Cognition↗

PubMedDate not supplied

[The neurocognitive profile of non-verbal learning disorder].

INTRODUCTION: Non-verbal learning disorder is a specific type of learning disorder that is characterised by difficulties in social skills, in visuospatial and visual-constructional capabilities, and in motor skills. AIM: To observe the cognitive profile characterising these children. PATIENTS AND METHODS: We evaluated the intelligence, memory, visuospatial functions, instrumental and executive functions of 13 children between 8 and 14 years of age diagnosed with non-verbal learning disorder. RESULTS: All the children displayed an overall intelligence quotient within a range considered to be normal, with a marked difference between the verbal and manipulative intelligence quotients. They all had a good verbal memory. In contrast, they had difficulties in any tasks requiring spatial organisation and sequencing. Spontaneous language was fluent and aprosodic, with poor non-verbal communication. CONCLUSIONS: Good verbal skills and marked deficits in visuospatial skills are the characteristic pattern that has been described in the literature and this coincides with the observations made in the 13 children under study.

Adolescent↗

PubMed2002

Does cognitive function improve with quetiapine in comparison to haloperidol?

Recent evidence suggests that schizophrenia patients taking atypical antipsychotic medications may perform better on some tests of cognitive function than those treated with older antipsychotics. The current study compared the effects of quetiapine and haloperidol on measures of executive function, memory and attention. Subjects were 58 stable outpatients with schizophrenia (DSM III-R) who received a battery of cognitive tests as part of a randomized, double-blind, multi-site clinical efficacy study conducted by AstraZeneca Pharmaceuticals. Cognitive assessments were conducted prior to randomization when patients were receiving < or =30 mg haloperidol or equivalent (mean: 9.2mg/day haloperidol equivalents), and again after 24 weeks of fixed-dose treatment with either quetiapine 600 or 300 mg/day or haloperidol 12 mg/day. Analyses of covariance with planned comparisons were used to compare scores on cognitive measures at the end of 24 weeks by treatment group with baseline cognitive function scores used as covariates. Patients receiving quetiapine 600 mg/day improved to a greater extent than patients receiving haloperidol on overall cognitive function (p<0.02). Specific differences were found for executive function (Verbal Fluency Test, p<0.04), attention (Stroop Color Word Test, p<.03) and verbal memory (Paragraph Recall Test, p<0.02). Treatment group differences were not solely due to benztropine use, medication side effects, or changes in symptomatology. Treatment with quetiapine at higher doses (600 mg/day) relative to haloperidol appears to have a positive impact on important domains of cognitive performance that have been found to predict role function and community outcomes in patients with schizophrenia.

Antipsychotic Agents↗

PubMed2006

A cross-sectional study to investigate long-term cognitive function in people with treated pituitary Cushing's disease.

INTRODUCTION: It has been proposed that exposure to high levels of endogenous steroids in untreated pituitary Cushing's disease damages hippocampal structures leading to impairment in learning and memory processes. We hypothesised that patients with treated pituitary Cushing's disease would perform significantly worse on tests of cognitive ability than those with nonfunctioning pituitary adenomas. DESIGN: Sixteen adults with pituitary Cushing's disease (PCD) and 16 adults with non-functioning pituitary adenomas (NFA) undertook the following comprehensive neuropsychological assessments: National Adult Reading Test (NART: premorbid abilities), California Verbal Learning Test (CVLT 2 UK: learning and recall), Stroop (executive functioning), Trail-Making Test (TMT: executive functioning and attention), Adult Memory and Information Processing Battery (AMIPB: Information Processing Speed and Story Recall subtests). RESULTS: There was no significant difference in premorbid IQ scores (NFA mean=101 SD=13; PCD mean=102, SD=13), in verbal learning nor any significant difference in the percentage of verbal material retained in story recall (AMIPB). Performance on higher executive tasks Stroop and TMT and on measures of information processing was similar. However, there were significant decrements between some mean scores for both groups and published normative data with a clear association between higher HADS depression scores and impaired objective memory and attention which was not specific to PCD. CONCLUSIONS: We found no difference in cognitive function between patients with PCD and NFA. The results suggest a discrepancy between patients' subjective perception of functional cognitive impairments and objective findings on psychometric testing and point to the influence of affective symptoms on cognitive performance, particularly in Cushing's disease.

Adult↗

PubMed2004

Patterns of obsessive-compulsive symptoms and social function in schizophrenia.

Research has alternately found that obsessive and compulsive (OC) symptoms in schizophrenia are associated with graver and lesser levels of negative symptoms. One possible explanation is that there are two distinct groups of persons with OC symptoms: those with cognitive deficits and high levels of negative symptoms and those who generally function well and have low levels of negative symptoms. To examine this question, we performed a cluster analysis on 66 persons with schizophrenia spectrum disorders on the basis of their level of obsessive-compulsive phenomena and global psychosocial function. Four groups were found: high OC/good function (n=9), non-OC/poor function (n=25), non-OC/moderate function (n=20), and high OC/poor function (n=12). A MANCOVA controlling for age found significant group differences on assessments of negative symptoms, executive function and attention among groups. As predicted, the high OC/poor function group had significantly poorer attention than any other group and poorer executive function than either non-OC group. The high OC/good function had lower levels of negative symptoms than either non-OC group. Implications for research and rehabilitation are discussed.

Cluster Analysis↗

PubMed2002

Neurobehavioural functioning in neonatal intensive care unit graduates in late childhood and early adolescence.

The current study examined memory and executive functioning in a sample of children who were hospital ized in a neonatal intensive care unit (NICU) after birth. Thirty-two children born prematurely and/or with medical complications (NICU children) and 25 control children born at term were assessed with the Cambridge Neuropsychological Testing Automated Battery (CANTAB), a multi-dimensional computer-based measure of memory and executive functioning. Comparisons between the NICU and control groups on the CANTAB subscales indicated that the NICU children had a shorter spatial memory span length and committed more forgetting errors on a spatial working memory task. Correlational analyses demonstrated that the number and extent of medical complications at birth was negatively associated with spatial memory span, planning and spatial recognition memory. Multiple regression models suggested that gestational age was of primary importance in predicting spatial memory span, while neurobiological risk was primary in the prediction of spatial working memory errors. Overall, the current results showed fewer deficits in this group of children than were found in a previous neuropsychological assessment of this cohort. The implications of this finding for discerning the effects of neural plasticity over and above normal brain maturational processes are discussed.

Adolescent↗

PubMed2000

Prediction of functional status from neuropsychological tests in community-dwelling elderly individuals.

Age-related dysfunction of frontal systems can result in deficits in planning, organization, self-control, and awareness of problems, which are likely to affect the ability to care for one's self. The purpose of this study was to determine the relationship between age-related frontal/executive deficits and impairment in instrumental activities of daily living (IADLs) in elderly individuals. Twenty-seven community-dwelling individuals were administered a comprehensive battery of neuropsychological tests and a performance-based evaluation of IADLs. Multiple regression analyses indicated that executive function and depression severity accounted for a significant proportion of variance in IADLs, with executive function making the greatest contribution. Tests measuring other cognitive functions, such as memory, language, and spatial skills, did not contribute significantly to the prediction of functional status. Furthermore, executive measures accounted for more variance than other demographic characteristics such as general health status, age, and educational level. The results of this study indicate that executive dysfunction in normal aging may be the best predictor of functional decline. A better understanding of the mechanisms that underlie IADL skills will ultimately aid in the development of compensatory and intervention strategies designed to delay the onset of assisted living and nursing home placement.

Activities of Daily Living↗

PubMed2001

Functional neuroanatomy of visuo-spatial working memory in Turner syndrome.

Turner syndrome (TS), a genetic disorder characterized by the absence of an X chromosome in females, has been associated with cognitive and visuo-spatial processing impairments. We utilized functional MRI (fMRI) to investigate the neural substrates that underlie observed deficits in executive functioning and visuo-spatial processing. Eleven females with TS and 14 typically developing females (ages 7-20) underwent fMRI scanning while performing 1-back and 2-back versions of a standard visuo-spatial working memory (WM) task. On both tasks, TS subjects performed worse than control subjects. Compared with controls, TS subjects showed increased activation in the left and right supramarginal gyrus (SMG) during the 1-back task and decreased activation in these regions during the 2-back task. In addition, decreased activation in the left and right dorsolateral prefrontal cortex (DLPFC) and caudate nucleus was observed during the 2-back task in TS subjects. Activation differences localized to the SMG, in the inferior parietal lobe, may reflect deficits in visuo-spatial encoding and WM storage mechanisms in TS. In addition, deficits in the DLPFC and caudate may be related to deficits in executive function during WM performance. Together these findings point to deficits in frontal-striatal and frontal-parietal circuits subserving multiple WM functions in TS.

Adolescent↗

PubMed1998

Are there sex differences in neuropsychological functions among patients with schizophrenia?

OBJECTIVE: Studies of sex differences in neuropsychological performance in schizophrenia report inconsistent results, due in part to methodological artifacts. The study presented here was specifically designed to examine sex differences in neuropsychological performance. It was hypothesized that schizophrenic women would exhibit fewer neuropsychological deficits than schizophrenic men and that their performance would be more similar to that of normal women than schizophrenic men's performance would be to that of normal men. METHOD: Thirty-one outpatients with DSM-III-R-defined schizophrenia were systematically sampled from an extensive service network serving a large urban catchment area for seriously mentally ill persons. Twenty-seven normal comparison subjects were matched within sex on the basis of age, parental socioeconomic status, ethnicity, and handedness. An extensive neuropsychological test battery was administered, and multivariate analysis of variance was used to test for the effects of sex and group and sex-by-group interactions. RESULTS: Male patients were significantly impaired across all functions in comparison with normal male subjects and on tests of attention, verbal memory, and executive functions in comparison with female patients. Female patients performed significantly worse than female normal comparison subjects only on tests of attention, executive functions, visual memory, and motor functions. CONCLUSIONS: The findings suggest that women with schizophrenia may be less vulnerable to particular cognitive deficits, especially those involving verbal processing, than schizophrenic men.

Adult↗

PubMedDate not supplied

Frontal lobe and cognitive development.

In phylogeny as in ontogeny, the association cortex of the frontal lobe, also known as the prefrontal cortex, is a late-developing region of the neocortex. It is also one of the cortical regions to undergo the greatest expansion in the course of both evolution and individual maturation. In the human adult, the prefrontal cortex constitutes as much as nearly one-third of the totality of the neocortex. The protracted, relatively large, development of the prefrontal cortex is manifest in gross morphology as well as fine structure. In the developing individual, its late maturation is made most apparent by the late myelination of its axonal connections. This and other indices of morphological development of the prefrontal cortex correlate with the development of cognitive functions that neuropsychological studies in animals and humans have ascribed to this cortex. In broad outline, the ventromedial areas of the prefrontal cortex, which with respect to other prefrontal areas develop relatively early, are involved in the expression and control of emotional and instinctual behaviors. On the other hand, the late maturing areas of the lateral prefrontal convexity are principally involved in higher executive functions. The most general executive function of the lateral prefrontal cortex is the temporal organization of goal-directed actions in the domains of behavior, cognition, and language. In all three domains, that global function is supported by a fundamental role of the lateral prefrontal cortex in temporal integration, that is, the integration of temporally discontinuous percepts and neural inputs into coherent structures of action. Temporal integration is in turn served by at least three cognitive functions of somewhat different prefrontal topography: working memory, preparatory set, and inhibitory control. These functions engage the prefrontal cortex in interactive cooperation with other neocortical regions. The development of language epitomizes the development of temporal integrative cognitive functions and their underlying neural substrate, notably the lateral prefrontal cortex and other late-developing cortical regions.

Animals↗