Researchers in the Department of Psychology, University of Rome, Italy, retrospectively analyzed charts from patients in the Ataxia Lab of Santa Lucia Foundation between 1997 and 2007, focusing on the role of the cerebellum in cognition. Of 223 charts of cerebellar patients, mostly adults, 67 were excluded because the pathology was not restricted to the cerebellum; 156 comprising 84 males and 72 females were selected for analysis. Patients with focal or atrophic damage were grouped by etiology or location of the lesion. Focal lesions were ischemic or hemorrhagic stroke or surgical ablation for AV malformation or tumor. MRI was used to identify the lobular distribution of the lesion. Twelve different cerebellar atrophic lesions were represented by 16 cases of olivo-ponto-cerebellar atrophy, 15 idiopathic, 11 Friedreich's ataxia and the remainder as 1-5 cases each. In the clinical focal subgroup of 118 cases, 64 involved cerebellar deep nuclei, 25 the distribution of the posterior inferior cerebellar artery, and 12 the superior cerebellar artery.

Subjects with cerebellar damage had below average z-scores for all cognitive domains. Language, executive function, visuospatial abilities and sequencing are most severely affected functions. Subjects with lesions in the posterior inferior cerebellar artery territory exhibit the worst cognitive patterns, especially affecting sequencing, similar to those with lesions of the deep cerebellar nuclei. Vascular topography and involvement of deep cerebellar nuclei are the chief factors that determine the cerebellar cognitive profile. The findings support a model in which sequencing is the basic function of the cerebellum. [1]

COMMENT. The cerebellar cognitive affective syndrome includes impairments in executive functions, spatial cognition, language and personality changes in patients with cerebellar pathologies. In addition to executive function impairments, visuospatial functions, working memory, verbal memory, linguistic processing, verbal fluency, attention, sequencing and emotion are involved. This study including a large number of patients with cerebellar pathology provides a more comprehensive description of the variety and localization of cerebellar lesions and the specific type of cognition affected, especially sequencing. Subjects with lesions in the posterior inferior cerebellar artery territory and lesions in the deep cerebellar nuclei of the posterior lobe (dentate, emboliform, fastigial, globose nuclei) exhibit the worst cognitive patterns. Cerebellar lesions do not eliminate cognitive function, but they impair motor and mental task performance, causing a “dysmetria of thought.” [2]