Cognitive deficits in elderly bipolar patients may herald dementia
medwireNews: Elderly patients with bipolar disorder have persistent cognitive dysfunction, prospective study findings suggest.
Therefore "clinicians should be especially attentive to early signs of cognitive decline, which may herald the dementia outcome," say researchers.
Orestes Forlenza (University of San Paulo, Brazil) and colleagues found that, compared with older individuals without bipolar disorder, similarly aged euthymic adults with bipolar disorder had worse global cognitive performance as shown by lower scores on the Mini-Mental State Examination (MMSE).
Bipolar disorder patients also performed worse on the Verbal Fluency Test (VFT) and the Clock Drawing Test (CDT) than individuals without the condition.
"Cognitive impairment is a common feature of bipolar disorder, with increased risk of developing dementia in later life," explain Aprahamian and team in TheAmerican Journal of Geriatric Psychiatry.
The team compared cognitive function in a cross section of 86 adults with and 100 adults without bipolar disorder. The latter group included 30 healthy patients, 40 patients with cognitive impairment but no dementia (CIND), and 30 patients with probable Alzheimer's disease.
The mean age of the study cohort was 69.2 years. Thirty-five of the 86 patients with bipolar disorder had no cognitive impairments, with 25 showing signs of CIND and 26 with dementia.
"Patients with BD [bipolar disorder] performed slightly worse, although not always significantly, than non-BD subjects in most cognitive screening tests in the same level of global cognitive function," the researchers report.
MMSE (27.8 vs 28.8) and VFT (15.9 vs 20.0) scores were lower, suggesting worse performance, in bipolar patients than in non-bipolar patients who had no cognitive impairments.
MMSE scores were also lower in patients with bipolar disorder than in in non-bipolar patients with CIND (25.8 vs 27.2).
Even patients with dementia due to possible Alzheimer's disease fared better than bipolar patients on the VFT (10.8 vs 7.8) and CDT (2.7 vs 1.8).
Medication for bipolar disorder did not affect the results; with the exception that demented patients taking valproate had a worse performance on the VFT than those who were not taking this drug.
"Bearing in mind that BD patients may have persistent cognitive impairments and may be at an increased risk for dementia, the correct use of screening tests is important in clinical practice," the researchers observe.
"The MMSE cutoff score to discriminate CIND from normal cognition was two points lower among BD patients as compared with their non-BD counterparts," they write.
"This finding may be clinically relevant given that the MMSE is widely used in the screening for cognitive deficits."
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By Sara Freeman, medwireNews Reporter