Revisiting the case of a man with near total absence of the cerebellum identified at age 70: a case report with detailed neurologic and cognitive assessment

In addition to coordination of sensorimotor functions, the cerebellum plays a role in the regulation of affective and cognitive functions. The latter include a variety of cognitive abilities including attention, executive, visuospatial, and language abilities. Acquired damage to the cerebellum, neurodegenerative or otherwise, can result in a characteristic pattern of cognitive and behavioural changes referred to as the cerebellar cognitive affective syndrome (CCAS). Cerebellar agenesis, a term used variably to describe total or near total absence of the cerebellum, is a very rare disorder that typically presents with motor and cognitive impairments, and relatively few cases have been described. We aim to present a case report that sheds light on the non-motor functions of the cerebellum and the strength of cerebellar reserve. Because of rarity of this condition, we revisit a previously described case of a 72-year-old man with near total absence of the cerebellum to provide additional pertinent details of his presentation, including a new detailed neurologic assessment and cognitive testing. This man had a prior lifelong diagnosis of “cerebral palsy” and presented to our hospital for assessment of headache and worsening balance at age 70. He had dysarthric and ataxic speech and mild dysmetria and ataxia. Cognitive testing showed impairment affecting abstract reasoning, verbal fluency, and visuospatial ability. He was unable to read or write. Prior cognitive testing permitted comparison of his cognitive functioning at ages 38–44 and 72. Updated neuroimaging confirmed near total absence of the cerebellum. This report provides a detailed cognitive profile of an elderly adult living with near total absence of the cerebellum and provides novel documentation of the stability of cognitive impairments over several decades in such a patient.