Impaired motor speech performance in Huntington's disease.

Dysarthria is a common symptom of Huntington's disease and has been reported, besides other features, to be characterized by alterations of speech rate and regularity. However, data on the specific pattern of motor speech impairment and their relationship to other motor and neuropsychological symptoms are sparse. Therefore, the aim of the present study was to describe and objectively analyse different speech parameters with special emphasis on the aspect of speech timing of connected speech and non-speech verbal utterances. 21 patients with manifest Huntington's disease and 21 age- and gender-matched healthy controls had to perform a reading task and several syllable repetition tasks. Computerized acoustic analysis of different variables for the measurement of speech rate and regularity generated a typical pattern of impaired motor speech performance with a reduction of speech rate, an increase of pauses and a marked disability to steadily repeat single syllables. Abnormalities of speech parameters were more pronounced in the subgroup of patients with Huntington's disease receiving antidopaminergic medication, but were also present in the drug-naïve patients. Speech rate related to connected speech and parameters of syllable repetition showed correlations to overall motor impairment, capacity of tapping in a quantitative motor assessment and some score of cognitive function. After these preliminary data, further investigations on patients in different stages of disease are warranted to survey if the analysis of speech and non-speech verbal utterances might be a helpful additional tool for the monitoring of functional disability in Huntington's disease.