Lip, tongue and forefinger force control in Parkinson's disease

Abstract

This study examined the production of isometric force in Parkinson's disease. The relationship among several parameters of the ramp-and-hold force contraction and target force level was quantified for the upper lip, lower lip, tongue, right and left forefingers, in 14 patients (seven males, seven females) with a diagnosis of idiopathic Parkinson's disease, and 14 age-and-sex matched control subjects. All patients were evaluated in off drug conditions and their speech was classified at stage 2 on item 18 of the Unified Parkinson's disease rating scale (UPDRS). The target force level used in the present study included 0.25 N, 0.5 N, 1 N and 2 N corresponding to fine forces presumably involved in speech production. Parkinsonian patients showed force production impairments: slower rate of force development, difficulties in maintaining a given contraction and increased variability. Moreover, the disorders of orofacial and forefinger force control did not resemble each other in Parkinson's disease, and differences were noted between the articulatory organs.

• Parkinson Force Motor Control Dysarthria