Articulation disorders and duration, severity and L-dopa dosage in idiopathic Parkinson's disease

Abstract

Background: Parkinson's disease (PD) is one of the most common diseases of the central nervous system (CNS). It is frequently heralded by speech disturbances, which are one of its first symptoms.

Aim: The aim of this paper is to share our own experience concerning the correlation between the severity of speech disorders and the PD duration, its severity and the intake of L-dopa.

Material and methods: The research included 93 patients with idiopathic PD, aged 26-86 years (mean age 65.1 years). Participants were examined neurologically according to the Unified Parkinson's Disease Rating Scale (UPDRS) and the Hoehn and Yahr Scale. They were also assessed by Frenchay Dysarthria Assessment.

Results: Considerable and severe disorders were concurrent with impairments in the mobility of the tongue, lips, the jaw as well as the pitch and loudness of the voice. The strongest correlation but at a moderate level was found to exist between the severity of labial impairment, voice loudness and the length of the disease. There was also a positive correlation between lip movement while the motions were being diversified, lip arrangement while speaking and the intake of L-dopa.

Conclusions: As PD progresses a significant decline in vocal articulation can be observed, which is due to reduced mobility within the lips and the jaw. Exacerbation of articulation disorders resulting from progression of the disease does not materially influence the UPDRSS scores. L-dopa has been found to positively affect the mobility of the lips while the patient is speaking and their arrangement at rest.

Keywords: Dysarthria; Parkinson disease; Speech disturbances; Speech therapy.