Corticobasal Syndrome: Are There Central or Peripheral Triggers?

Corticobasal syndrome (CBS) is a complex of symptoms and signs comprising limb rigidity, bradykinesia, dystonia, myoclonus, apraxia, cortical sensory loss, and a variety of cognitive and language impairments. CBS is commonly seen in tauopathies. Striking asymmetry in clinical and imaging findings in CBS raises questions about potential triggers initiating neurodegeneration. The objective of this study was to investigate potential central or peripheral triggers preceding CBS symptoms.

In this retrospective observational study, we reviewed medical records of patients with CBS at our Parkinson's Disease Center and Movement Disorders Clinic, focusing on evidence of possible central or peripheral "trigger" occurring within a year before the onset of CBS. We also reviewed records of patients with Parkinson disease (PD) for comparison.

Of the 72 patients with CBS, 15 (20.8%) reported potential focal triggers before the onset of CBS-related neurologic symptoms. By contrast, only 1 of 72 patients with PD (1.4%) had a documented trigger before the onset of PD-related symptoms (p < 0.001). Of potential triggers, 13 were peripheral (related to hand or shoulder surgeries or trauma) and 2 were central (stroke and head trauma). Patients with CBS with triggers were younger, had earlier symptom onset, comprised a higher proportion of men, and had a higher likelihood of limb onset of symptoms than those without.

Our finding of relatively high frequency of focal triggers in CBS compared with PD suggests potential central or peripheral triggers initiating neurodegeneration, possibly explaining asymmetric clinical and imaging features in CBS. Further research is necessary to validate and explore this observation's implications for CBS pathogenesis.