Acoustical Analysis of Speech in Progressive Supranuclear Palsy

Background

Dysarthria often is an early and prominent clinical feature of progressive supranuclear palsy (PSP). Based on perceptual analyses, speech impairment in PSP reportedly consists of prominent hypokinetic and spastic components with occasional ataxic features.

Objective

To measure objectively and quantitatively different speech parameters in PSP as compared with Parkinson's disease (PD) by acoustical analysis and to correlate these parameters with disease duration, global motor, and speech impairment and with the subtype of disease (Richardson's syndrome [RS] vs parkinsonian type of PSP [PSP-P]).

Patients and Methods

Twenty-six patients with clinical diagnosis of PSP (n = 14 classified as RS and n = 12 classified as PSP-P) and 30 age- and gender-matched patients with clinical diagnosis of PD were tested. Speech examination was based on the acoustical analysis of a standardized four-sentence reading task. Several speech variables were measured to assess phonation, intonation variability, speech velocity, and articulatory precision. All participants were tested according to Unified Parkinson's Disease Rating Scale/Motor Score (UPDRS-III) and staged according to Hoehn and Yahr stages. Global speech intelligibility was evaluated on the basis of the UPDRS-III speech item.

Results

In the PSP group, speech velocity, intonation variability, and the fraction of intraword pauses as a measure of articulatory precision were significantly reduced, whereas the percentage of speech pauses was prolonged as compared with the PD group. Only in the male PSP patients, vowel articulation was found to be impaired. Global speech performance was worse in the PSP group in comparison with the PD group and showed a correlation to some distinct speech dimensions. No differences of speech variables were seen between RS and PSP-P patients.

Conclusions

PSP patients feature a mixed type of dysarthria with hypokinetic and spastic components that differ significantly from the speech performance of PD speakers. This probably reflects the widespread neuropathological changes in PSP comprising basal ganglia as well as pontine and further brainstem regions.