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Título

“Dysmetria of thought”: cerebellar stroke as a possible cause of strategic infarct dementia

RESUMO

Case presentation: A 71-years-old woman, 8 years of schooling, presented to hospital with intense vertigo, vomiting and headache. Brain CT showed cerebellar (CB) infarct in vermis and CB right hemisphere, diagnosed CB stroke. After discharge, the patient developed a non-progressive cognitive decline with amnestic complaints, with executive, attention and social cognition declines. After 9 months, she presented to our service to cognitive investigation. The neurological examination showed right skew deviation and horizontal nystagmus, besides right dysmetria and dysdiadochokinesia. In cognitive tests, she scored 22/30 in the Mini Mental State Examination; 19/30 in the Montreal Cognitive Assessment, with Clinical Dementia Rating Scale (CDR) score equal to 1 and Frontal Assessment Battery scale score of 14/18. In the Schmahmann Syndrome Scale, a specific office to evaluation of cognitive impairment in CB lesions, the patient scored 52/120 points, with fail in 9/10 tests. Laboratory tests were unremarkable. Brain MRI showed increased T2/FLAIR signal in area of previous CB stroke. A diagnosis of probable cerebellar vascular cognitive decline was made.
Discussion: The cerebellar cognitive affective syndrome (CCAS), was described first in 1998, also named Schmahmann's syndrome, is characterized by declines in executive functions, linguistic processing, spatial cognition, and affect regulation. The “dysmetria of thought hypothesis” attributes the cerebellar-related cognitive declines to changes in pathways connecting the CB with the limbic circuitry, prefrontal and parietal association cortices. Part of patients with CB lesions and cognitive complaints present normal ranges in tests as MoCA and MMSE. Thus, in 2018 was published the CCAS Scale, that recently in 2022 was translate and validated to Portuguese. In our case, we used the validated version of CCAS scale and we detected significant decline in CB functions associated to a related subtle decline in functional daily activity, based on CDR scale, indicating probable dementia. In addition, symptoms were reported to have started soon after acute CB injury and there was no significant report of progressive worsening of these symptoms.

Final comments: Cerebellar stroke can be a cause of vascular cognitive impairment, which in this case fulfills the criteria for the diagnosis of a dementia syndrome, thus also fulfilling the criteria for the diagnosis of dementia due to strategic infarctions.

Palavras Chave

dementia; cerebellar stroke; cerebellar cognitive affective syndrome