Biomedical subjects

Vivienne A Curtis

Publications and source records attributed to Vivienne A Curtis.

3 recordsLinked to original sources

PubMed2004

A functional MRI study of working memory task in euthymic bipolar disorder: evidence for task-specific dysfunction.

OBJECTIVES: Even when euthymic bipolar disorder patients can have persistent deficits in working memory, but the neural basis of this deficit remains unclear. We undertook an functional magnetic resonance imaging investigation of euthymic bipolar disorder patients performing two working memory paradigms; the two-back and Sternberg tasks, selected to examine the central executive and the phonological loop respectively. We hypothesized that neuronal dysfunction would be specific to the network underlying the executive rather than the phonological loop component of working memory. METHODS: Twelve right-handed euthymic bipolar I males receiving lithium carbonate monotherapy were matched with 12 controls. The two-back task comprised a single working memory load contrasted with baseline vigilance condition. The Sternberg paradigm used a parametric design incorporating variable working memory load with fixed delay between presentation of an array of items to be remembered and a target item. Functional activation data were acquired during performance of the tasks and were analysed to produce brain activation maps representing significant group differences in activation (ANOVA). Load-response curves were derived from the Sternberg task data set. RESULTS: There were no significant between-group differences (t-test) in performance of the two-back task, or in 2 x 5 group by memory load ANOVA for the performance data from Sternberg task. In the two-back task, compared with controls bipolar disorder patients showed reductions in bilateral frontal, temporal and parietal activation, and increased activations with the left precentral, right medial frontal and left supramarginal gyri. No between-group differences were observed in the Sternberg task at any working memory load. CONCLUSIONS: Our findings support the notion that, in euthymic bipolar disorder, failure to engage fronto-executive function underpins the core neuropsychological deficits.

Bipolar Disorder↗

PubMed2004

The bipolar spectrum: diagnostic and pharmacologic considerations.

Bipolar disorder represents a clinically challenging, episodic, lifelong medical illness that is both disabling and dangerous to the patient and is associated with a high risk of suicide. The prognosis for bipolar patients is likely to worsen with delays in accurate diagnosis and treatment as time is allowed for more extensive complications and morbidity to accrue and for alcohol or other substance use comorbidity to complicate the course of the illness. Physicians face several challenges when diagnosing bipolar disorder, including overlapping symptomatology and comorbidity with other disorders, as well as the somewhat restrictive and categorical approach taken by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) and the International Statistical Classification of Diseases, 10th Revision (ICD-10) diagnostic criteria. As a result, bipolar disorder is frequently unrecognized and misdiagnosed with considerable clinical and prognostic consequences for the patient. The accuracy of diagnosis of bipolar disorder could be improved through the introduction of a refined procedure for the identification and evaluation of a broader range of symptoms, and by careful attention to the presence of subthreshold symptomatology. A conceptual shift toward acceptance of a 'spectrum' model of bipolar disorder and the development of appropriate clinical diagnostic tools should assist physicians in differentiating bipolar disorder from other Axis I, Axis II, and personality disorders, as well as ensuring early diagnosis and therapeutic intervention.

Bipolar Disorder↗

PubMed2002

D-fenfluramine-evoked serotonergic responses in olanzapine-treated schizophrenic patients.

Antagonist activity at the 5-HT(2) receptor may contribute to the therapeutic efficacy of atypical antipsychotics in schizophrenia. This neuroendocrine study examined the in vivo functional serotonergic (5-HT) activity of the atypical antipsychotic olanzapine. We examined central 5-HT(2) responses by measuring the serum prolactin (PRL) over 5 h in response to 30 mg of D-fenfluramine (DFEN) in two groups of male schizophrenic patients. Blunted PRL responses to DFEN indicate functional 5-HT(2) receptor antagonism. Seven patients treated with olanzapine at a mean (S.D.) dose of 13.1 (4.6) for a mean of 28 weeks were compared with a matched group of eight patients who had received no antipsychotic treatment for at least 2 weeks. Baseline PRL levels did not differ significantly in the two patient groups and were within the normal range. The olanzapine-treated patients showed a significantly lower maximal DFEN-evoked PRL response and a significantly lower group x time overall PRL release compared with the untreated patient group. We have previously demonstrated a similar degree of functional in vivo 5-HT(2) antagonism with the atypical antipsychotic clozapine. This study thus suggests that this activity may not contribute to the unique clinical efficacy of clozapine.

Adult↗