Caudate infarcts

Much of what is known about the function of different regions of the human brain has been learned from pathological conditions. The caudate nucleus, a region of the basal ganglia which is located below the brain's cortex, is involved in involuntary movement. Although the caudate nucleus is affected in diseases like Huntington's disease, attributing specific symptoms to the caudate nucleus is difficult because most degenerative diseases affect more than one brain area. In contrast, strokes often affect particular areas of the brain with some precision and leave other regions unaffected, and consequently provide a better opportunity for the study of function. A study of 18 patients with stroke-related focal lesions in the caudate area were studied, and a range of motor, behavioral, and cognitive disturbances were observed. Five of the patients had no motor symptoms, and 11 had only slight symptoms. Two patients had a moderately severe muscular weakness. Eleven patients had speech difficulties due to muscle weakness; six of these patients had right-side caudate lesions and five had left-side lesions. Four patients did not seem to have any noticeable behavioral or cognitive disturbances. Ten of the 18 patients had a problem consisting of profound disinterest, decreased spontaneous activity, prolonged latency in response to questions of stimuli, and decreased ability to persist in a task. This state of 'no will' has been termed 'abulia'. Seven patients were confused, restless, or hyperactive during their acute stroke; in three patients these states alternated with abulia. Three patients with right-side lesions ignored objects on their left-hand side. Other symptoms observed in some of the patients included mumbling, echolalia, and poor drawing and copying. The small number of patients reviewed cannot lead to a definitive discussion about the function of the caudate nucleus, but it is clear that the important motor functions previously attributed to the caudate are only a portion of the total picture. (Consumer Summary produced by Reliance Medical Information, Inc.)