Dysarthria is a motor speech disorder leading to imprecise articulation of speech. Acoustic analysis capable of detecting and assessing articulation errors is use-ful in dysarthria diagnosis and therapy. Since speakers with dysarthria expe-rience diﬃculty in producing rhotics due to complex articulatory gestures of these sounds, the hypothesis of the present study is that duration of the rhotic approximant /ô/ distinguishes dysarthric speech of diﬀerent severity levels. Du-ration measurements were conducted using the third formant (F3) trajectories estimated from quasi-closed-phase (QCP) spectrograms. Results indicate that the severity level of spastic dysarthria has a signiﬁcant eﬀect on duration of /ô/. In addition, the phonetic context has a signiﬁcant eﬀect on duration of /ô/, the I-r-E context showing the largest diﬀerence in /ô/ duration between dysarthric speech of the highest severity levels and healthy speech. The results of this preliminary study can be used in the future to develop signal processing and machine learning methods to automatically predict the severity level of spastic dysarthria from speech signals.
- Rhotic approximant
- Quasi-closed-phase analysis