Abnormal rhythms of speech in patients with idiopathic Parkinson's disease

Parkinson's disease (PD) involves impairments of voice an speech (hypokinetic dysarthria). Dysprosody is one of the most common features of PD speech, that includes alterations of rhythm and velocity of articulation. The aim of this study is the evaluation of rhythm alterations of speech in Parkinsonian patients during a sentence repetition task. 13 PD patients (9 male and 4 female) and 9 healthy controls (4 male and 5 female) were tested. Results show significant differences between the two groups as far as parameters Tinter (time interval between two consecutive sentences) and D (percent of speech time with respect to sentence duration) are concerned. In particular, Tinter is larger in PD patients while D is higher in the control group. These preliminary results show that PD patients may exhibit longer pauses between adjacent sentences and a lower percentage of "speech time" during a whole repetition period. Thus, the decrease of D leads to an increase of NSR (Net Speech Rate, defined as the number of syllables per second). This study confirms that speech in PD patients is characterized by short rushes followed by inappropriate pauses.