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Biomedical subjects

Barbara Sahakian

Publications and source records attributed to Barbara Sahakian.

4 recordsLinked to original sources
PubMed2006

A pilot study of positive mood induction in euthymic bipolar subjects compared with healthy controls.

BACKGROUND: Demonstrating differences between euthymic bipolar subjects and healthy controls in response to positive (happy) mood induction may help elucidate how mania evolves. This pilot study evaluates the Go task in a reward paradigm as a method for inducing a happy mood state and compares the response of euthymic bipolar subjects and healthy controls. METHOD: The Sense of Hyperpositive Self Scale, the Tellegen positive and negative adjectives, the Global-Local task and a visual analogue scale for measuring positive affect were administered to 15 euthymic bipolar subjects and 19 age-and-sex-matched healthy control subjects before and after they had performed the Go task in a reward paradigm. RESULTS: Significant differences were found between subjects and controls on several measures at each time-point but there were no differences across the groups across time except for the visual analogue scales, where subjects had a more sustained duration in self-reported happiness compared with controls. CONCLUSIONS: This pilot study has shown that a positive affect can be induced in bipolar subjects and controls which can be demonstrated by changes in scores on several tasks. However, only the visual analogue scales showed a significant difference between cases and controls over time. Such tests may prove valuable in furthering understanding about the evolution of manic mood states.

Adult↗
PubMed2002

Decision-making processes following damage to the prefrontal cortex.

Recent work has suggested an association between the orbitofrontal cortex in humans and practical decision making. The aim of this study was to investigate the profile of cognitive deficits, with particular emphasis on decision-making processes, following damage to different sectors of the human prefrontal cortex. Patients with discrete orbitofrontal (OBF) lesions, dorsolateral (DL) lesions, dorsomedial (DM) lesions and large frontal lesions (Large) were compared with matched controls on three different decision-making tasks: the Iowa Gambling Task and two recently developed tasks that attempt to fractionate some of the cognitive components of the Iowa task. A comprehensive battery including the assessment of recognition memory, working memory, planning ability and attentional set-shifting was also administered. Whilst combined frontal patients were impaired on several of the tasks employed, distinct profiles emerged for each patient group. In contrast to previous data, patients with focal OBF lesions performed at control levels on the three decision-making tasks (and the executive tasks), but showed some evidence of prolonged deliberation. DL patients showed pronounced impairment on working memory, planning, attentional shifting and the Iowa Gambling Task. DM patients were impaired at the Iowa Gambling Task and also at planning. The Large group displayed diffuse impairment, but were the only group to exhibit risky decision making. Methodological differences from previous studies of OBF patient groups are discussed, with particular attention to lesion laterality, lesion size and psychiatric presentation. Ventral and dorsal aspects of prefrontal cortex must interact in the maintenance of rational and 'non-risky' decision making.

Adult↗
PubMedDate not supplied

Impulsivity in patients with borderline personality disorder.

This study investigated features of impulsivity in patients with borderline personality disorder (BPD) using the self-report Attention-Deficit Scales for Adults (ADSA) and computer-administered neurocognitive tasks. Forty-one patients with DSM-III-R BPD and 35 nonclinical control subjects were assessed by the ADSA, the National Adult Reading Test, and two computerized tasks mediated by the frontal lobes. Mean scores for seven ADSA scales (six of which relate to aspects of impulsivity) were significantly higher in the patient group compared with the control group. Also, the ADSA ratings for impaired coordination were increased in the BPD patients. The findings indicate that a range of aspects of impulsivity, as well as impaired coordination, are associated with patients selected on the basis of BPD. Also, in the patient group, but not in the control group, associations of the neurocognitive tasks indicated that, first, performance on a planning task related to dorsolateral frontal lobe functioning is correlated with aspects of impulsivity reflected by ADSA scale III ratings (involving disorganisation and lack of perseverance) and, second, performance on a decision-making task related to orbitofrontal functioning is correlated with ratings of impaired coordination. Further work is needed to establish the specificity of the findings.

Adolescent↗