Dysarthria and orofacial apraxia in corticobasal degeneration.

The authors evaluated dysarthria and orofacial apraxia (OFA) in 10 patients with a clinical diagnosis of corticobasal degeneration (CBD). Nine patients were slightly dysarthric according to the French version of the Frenchay Dysarthria Assessment, which evaluates the motricity of the components of the vocal tract. The severity of dysarthria assessed by an intelligibility score was correlated to the global severity of the disease, but not to the duration of the disease. Voluntary movements of the tongue and the lips were impaired in all patients. OFA, evaluated with simple and sequential gestures, was present in nine patients. Sequential gestures were more frequently impaired. The score of OFA was not correlated to the severity of dysarthria, suggesting independent underlying mechanisms. Thus, when specifically assessed, dysarthria and OFA are more frequent in CBD than usually reported. We propose that the underlying pathophysiology is the result of a deficit in programming and execution of repetitive movements.