Cognitive and behavioral involvement in spinal and bulbar muscular atrophy (SBMA): a systematic review

This study aimed at reviewing currently available evidence on cognitive and behavioral involvement in spinal and bulbar muscular atrophy (SBMA).

This review was performed in accordance with the 2020 PRISMA guidelines. We included case reports/series and group studies reporting data on the neuropsychological features of SBMA patients.

Out of 123 unique records identified, 11 studies were included (N = 5 case reports/series; N = 6 group studies), comprising 151 SBMA patients. Among case reports and series, 6 out of 10 patients were reported to exhibit some degree of neuropsychological involvement, with two being diagnosed with a dementia condition resembling the characteristics of behavioral variant-frontotemporal dementia. Three of the 6 case-control studies found no cognitive differences between SBMA patients and healthy controls. Cognitive deficits reported in group studies mostly involved the executive, attentional, memory and visuo-spatial/-constructive domains.

The available evidence on cognitive and behavioral involvement in SBMA is scarce and conflicting. However, it is conceivable that at least some patients may exhibit dysexecutive-type changes, possibly reflecting a frontal system involvement.