Abstract:
Background: Corticobasal syndrome (CBS) is a rare, clinically heterogeneous form of atypical Parkinsonism. Hyperkinetic movements, aside from myoclonus and dystonia, have rarely been reported in CBS.
Cases: We present two patients with CBS, one with pathologically confirmed corticobasal degeneration (CBD) and generalized chorea, and another with probable CBS and Levodopa-induced dyskinesia (LID). Case 1 exhibited late-onset generalized chorea, which was preceded by several years of dystonia, rigidity and apraxia affecting the right upper limb. Case 2 presented with dystonia, cortical sensory loss, and apraxia in the left upper limb, while LID affected the face and the right side of the body.
Literature review: A systematic review of published cases of chorea or levodopa-induced dyskinesia (LID) in CBS was performed. The literature search was executed in PubMed from its inception for cases of chorea or LID associated with CBS. Twelve patients were identified across eight studies. Only five cases of pathologically confirmed CBD with chorea were found; chorea developed after 4 years of disease progression.
Conclusions: Chorea and LID are rare but may represent late manifestations of CBS. The exact mechanisms are unclear; they may relate to variability in anatomical involvement, particularly relative sparing of the GPi. Greater understanding of topographical disease progression may improve diagnostic precision and phenotypic classification in CBS and related tauopathies.
