Frontal lobe dysfunction in unilateral lenticulostriate infarcts. Prominent role of cortical lesions.

Most studies on frontal lobe dysfunction (FLD) in patients with striatal lesions did not consider possible associated cortical lesions not seen on computed tomographic scans. To determine the possible role of such cortical lesions, we assessed FLD in 10 patients with unilateral lenticulostriate infarct on computed tomographic scans. Magnetic resonance imaging revealed an associated cortical infarct not seen on computed tomographic scans in four patients. Using a battery of neuropsychological tests sensitive to FLD, we found that (1) the crossed tapping test was the only FLD test significantly disturbed in patients with pure unilateral lenticulostriate infarcts, (2) FLD was only present in patients with associated cortical infarct, and (3) caudate lesions only account for the number of echopraxic errors in the crossed tapping test. We conclude that unilateral isolated lenticulostriate infarcts might not lead to FLD, even though they may disturb the development of strategies involved in motor procedural learning.