Age-related effects on sensorimotor control of speech production

The current study investigates the effect of aging on the speech motor control, more specifically the labial and lingual system. We provide an acoustic and articulatory analysis comparing younger (20-30 years old) and older speakers (70-80 years old) of German, all of them recorded with electromagnetic articulography. We analyzed target words in contrastive focus condition. In the acoustic domain, target syllables were not prolonged in the productions of the older speakers. However, when looking at the articulatory domain, we found systematic modifications: Especially vocalic gestures, requiring movements of the lingual system, showed slower peak velocities for older subjects. Furthermore, we found age-related effects on the symmetry of articulatory gestures. Older subjects produce longer deceleration and shorter acceleration phases leading to a strong asymmetry of the movement components. Variability between and across speakers were considerably higher in the group of older speakers compared to younger ones. Our results on age-related effects on speech motor control are comparable with those from general motor control, where e.g. prolonged deceleration phases are an indicator for a decrease in sensory feedback control.