Prognostic factors of survival in corticobasal syndrome and corticobasal degeneration: A scoping review.

backgroundCorticobasal syndrome (CBS) and corticobasal degeneration (CBD) are rare, progressive neurodegenerative disorders characterized by significant clinical and pathological heterogeneity. Although considerable research has addressed their diagnostic challenges, survival outcomes and prognostic factors remain poorly understood.

objectiveTo synthesize existing evidence on survival duration, mortality outcomes, and prognostic indicators in CBS and CBD.

methodsA scoping review was conducted following PRISMA-ScR guidelines across five databases, resulting in 36 studies meeting inclusion criteria. Data were extracted on demographics, disease duration, age at death, cause of death, clinical presentation, imaging biomarkers, genetic findings, and treatment-related outcomes.

resultsThe average disease duration for CBS and CBD ranged from 4 to 8 years, with age at death typically between 68 and 73 years. Pneumonia was the most common cause of death. Early presence of motor features, such as dystonia, apraxia, myoclonus, and alien limb, was consistently associated with shorter survival. On the other hand, cognitive impairment, age at onset, and sex were not reliably linked to prognosis. Imaging and biomarker findings were mixed, though recent studies suggest functional connectivity and midbrain atrophy may hold predictive value. The presence of dysphagia, earlier tube feeding, and bedridden state were associated with worse outcomes. Palliative interventions, including gastrostomy, may prolong survival when applied early.

conclusionPrognosis in CBS and CBD is shaped by specific motor and functional features, but many presumed indicators show inconsistent associations with survival. Future prospective studies are needed to improve prognostic accuracy and optimize care strategies, including timely palliative support.