Cognitive impairment and stroke

There are numerous studies which have demonstrated cognitive impairment associated with of specific regions of cerebral infarction (Gazzaniga 2000). Although the focus of this chapter will be on the relationship between depression and cognitive impairment, it is worthwhile to review some of the recent studies which have documented the frequency and severity of cognitive impairment associated with stroke. Perhaps the most well-designed study is the one involving the Framingham cohort (Kase et al. 1998). They prospectively studied a group of 74 subjects who had suffered a stroke during a 13-year follow-up and compared them with 74 control subjects who had not suffered a stroke, but were matched for age and sex. The patients who suffered a stroke were noted to have a significantly lower mini-mental state exam (MMSE) score at prestroke baseline (i.e., 27.3 ± 0.3, stroke and 28.1 ± 0.2, control). Following the stroke, however, the mean MMSE in the affected group was 23.6 ± 0.9 compared with a mean mini-mental score of 28.3 ± 0.2 (p < 0.001) in the control patients. The decline in cognitive function was correlated with large left-sided strokes as documented on CT scan. The Framingham Study also found that the Center for Epidemiological Studies – depression scale (CES-D) scores indicated significantly more depressive symptoms in the patients with stroke compared with controls.