Objectives: To determine whether the assessment of orofacial praxis is useful for the differential diagnosis of parkinsonian syndromes and to understand the neural mechanisms underlying OFA, searching for the respective roles of cortical and subcortical structures.
Methods: Forty-four patients were assessed: 12 with idiopathic Parkinson's disease (IPD), 8 with multiple system atrophy (MSA), 12 with progressive supranuclear palsy (PSP) and 12 with corticobasal degeneration (CBD). An easy bedside scale was used, exploring single gestures, gestures with noise production and multiple sequential gestures. We searched for group and task effects.
Results: Patients with CBD were significantly more impaired than those with IPD, MSA or PSP (p<0.001). Our assessment was unable to distinguish between the IPD, MSA and PSP groups. There was a clear task effect in CBD with a major impairment in multiple sequential gestures (p<0.0001).
Conclusion: Assessment of orofacial praxis helps in the clinical diagnosis of CBD. Patients with IPD, MSA and PSP did not present with OFA. We suggest that the deficit in multiple sequential gestures in CBD is related to simultaneous lesions of the parietal lobule and the supplementary motor area.