Cognitive impairments in cerebellar infarcts.

The effects of the cerebellum on cognitive functions (CF) are poorly known and inadequately studied. Neurological, neuropsychological, and neuroimaging studies were performed on 25 non-random patients (14 female, 11 male, mean age 51.8 +/- 18.0 years) with isolated cerebellar infarcts. Cognitive impairments (CI) were seen in 22 patients (88%). These included impairments of attention, planning, control, abstract thought, memory, and speech disturbances (naming difficulties, irregularity of speech, agrammatism, dysprosodia), visuospatial and quasispatial disturbances, and counting impairments, demonstrating dysfunction of the anterior and posterior associative areas of the cortex. The extent of CI varied: 16 patients (64%) showed impairments only in neuropsychological tests, while six (24%) had clinically apparent impairments. Clinically significant CI developed in lesions of particular areas (posteroinferolateral and posteromedial/median) of the cerebellar cortex associated with the dominant hemisphere of the brain. The existence of clinically significant CI was independent of infarct size: infarcts were smaller (mean 5.65 cm3) in patients with marked impairments than in others (mean 12.8 cm3). The typical signs of cerebellar infarcts (ataxia, vertigo, vomiting) were seen in all patients with clinically insignificant and in only two of six patients with clinically significant CI. The present studies demonstrated the involvement of the cerebellum in the modulation of CF. The extent of CI in cerebellar infarcts depended on infarct location. The topical localizations of cerebellar zones controlling CF and movement are different.

[Cognitive disturbances in cerebellum infarctions]. / Kognitivnye narusheniia pri infarktakh mozzhechka.

The influence of the cerebellum on cognitive functions (CF) is poorly known and understudied so far. Neurological, neuropsychological and neuroimaging non-randomized study was carried out in 25 patients (14 women, 11 men, mean age 51.8 +/- 18.0 years) with isolated cerebellum infarctions. Cognitive disturbances (CD) were detected in 22 (88%) patients. They included impairment of attention, planning, control, abstract reasoning, memory; speech (naming, fluency, agrammatism, dysprosodia), special visual, quasi-spatial and counting disorders that indicated dysfunction of the anterior and posterior associative areas of the brain cortex. The expression of CD was different: being clinically obvious in 6 patients (24%), they were found only by neuropsychological methods in 16 patients (64%). Clinically significant CD developed in the lesions of certain areas (posterior-lower- lateral and posterior-medial) of the cerebellum hemisphere related to the dominant brain hemisphere. The presence of these CD did not depend on infarctions size: in expressed CD it was smaller (mean 5.65 cm3) than in other cases (mean 12.8 cm3). Typical appearances of cerebellum infarction (ataxia, vertigo, vomiting) were observed in all the patients with clinically non-significant CD and only in 2 out of 6 with clinically significant CD. The study demonstrated a role of the cerebellum in CF modulation. The expression of CD in cerebellum infarctions depends on their localization. Topic localization of the cerebellum areas, controlling CD and movement, is different.