This chapter presents an overview and practical approach to conceptualize manifestations of cerebellar lesions and outlines the principles that govern the cerebellar contribution to cognition and emotion as well as to sensorimotor function. Lesions of the cerebellum have been regarded as producing motor impairments. The cerebellar motor syndrome is characterized by wide-based and unsteady, or ataxic, gait; incoordination, or dysmetria, of the arms and legs; articulation impairment, or dysarthria; and eye movement abnormalities that disturb vision. The cerebellar cognitive affective syndrome (CCAS) results from lesions of the posterior lobe, characterized by clinically relevant deficits in executive function, visual spatial performance, linguistic processing, and dysregulation of affect. The connections of the cerebellum with brain circuits are implicated in psychiatric illness. Applying repetitive transcranial magnetic stimulation (TMS) to the limbic cerebellum in the vermis improves psychiatric disorders such as schizophrenia by upregulating cerebellar modulation of cerebrocerebellar circuits engaged in cognition and emotion.

This chapter presents a brief background on the rationale for how the cerebellum is engaged in non-motor functions. It discusses the relationship of the cerebellar motor syndrome to the higher order aspects of cerebellar dysfunction. The chapter analyzes the nature of the neuro-behavioral deficits and their relationship to cerebellar structure and vascular anatomy. It examines the clinical relevance of the cognitive and behavioral manifestations of cerebellar stroke in the diagnosis and management of patients with posterior circulation ischemia. In stroke neurology, the natural and appropriate tendency is to consider stroke syndromes as manifestations of occlusions of specific blood vessels. Bedside and office-based tests that the neurologist can administer to detect the cerebellar cognitive affective syndrome (CCAS) should focus on the domains known to be affected, namely, disorders of executive function, visuospatial cognition, language-based tests, and assessment of affect and other neuropsychiatric domains.