Cognitive impairment before changes appear on [18F]-fluoro-D-glucose positron emission tomography images in a patient with possible early-stage cerebellar-predominant multiple system atrophy.

Multiple system atrophy (MSA) is a sporadic, rapidly progressive neurodegenerative disorder characterized by autonomic dysfunction combined with parkinsonism or cerebellar ataxia. Patients with MSA typically suffer from cognitive disorders and rapid eye movement sleep behaviour disorder. 18 F-fluorodeoxyglucose-positron emission tomography is used to assess MSA. However, the relationship between the clinical features and findings on 18 F-fluorodeoxyglucose-positron emission tomography in patients with MSA has not yet been investigated. Here we report a case of possible early-stage cerebellar-type MSA. We concluded that cerebellar-type MSA or other factors, such as rapid eye movement sleep behaviour disorder or obstructive sleep apnoea cognitive impairment, could appear before changes are visible on 18 F-fluorodeoxyglucose-positron emission tomography images. Additionally, we concluded that the cognitive impairment could derive from cerebellar-type MSA itself, not from other factors such as rapid eye movement sleep behaviour disorder or sleep apnoea syndrome.