Cognitive functioning in patients with a small infarct in the brainstem.

Earlier findings in patients with a small supratentorial white matter infarct demonstrated subtle impairments of cognition. This is in line with reported difficulties in regaining premorbid level of functioning in daily life activities, even though any physical neurological deficits are no longer present. Either a "bystander effect" of adjoining gray matter or a long distance effect through hypometabolism or other neurochemical changes might underlie these impairments. To find the best explanation, a group of 17 patients with a lacunar infarct in the brainstem was neuropsychologically evaluated and compared with a closely matched control group. The patients demonstrated significantly impaired task performance on a constellation of neuropsychological tasks that was very similar to the findings previously found in patients with a supratentorial lacunar infarct (Boston Naming Test, TEA visual elevator, category fluency, Trailmaking Test). We conclude that a small white-matter infarct may affect cognitive functioning in a nonspecific way independently of its location.