Adaptation to a physical alteration of the vocal apparatus: The effect of visual self-perception on speech motor plasticity

Adapting speech movements to novel or perturbed conditions relies critically on the processing of self-produced sensory information. In the context of a physical alteration of the vocal apparatus (e.g., palatal prosthesis), talkers have been shown to adapt following 10–15 min of practice to produce improved acoustic output. It is possible that additional information, such as ultrasound imaging of the tongue, may help talkers adapt even more effectively to such perturbations. Providing visual feedback of the tongue surface in real-time has shown promise in the treatment of speech-sound disorders. However, it remains unclear whether the addition of such visual information will influence speech plasticity on the timescale examined in experimental studies of speech adaptation. Here, we examine how neurotypical talkers adapt to a palatal prosthesis, relying on auditory and somatosensory feedback alone (n = 15), or with the addition of ultrasound feedback of the tongue, either in the mid-sagittal (n = 15) or coronal plane (n = 15). Differences in adaptation performance between the three feedback conditions were observed, both in the patterns of speech adaptation and the learning after-effects. The results indicate that talkers will rapidly integrate visual articulatory information into their control of oral speech movements in order to guide productions towards improved acoustic outcomes.Adapting speech movements to novel or perturbed conditions relies critically on the processing of self-produced sensory information. In the context of a physical alteration of the vocal apparatus (e.g., palatal prosthesis), talkers have been shown to adapt following 10–15 min of practice to produce improved acoustic output. It is possible that additional information, such as ultrasound imaging of the tongue, may help talkers adapt even more effectively to such perturbations. Providing visual feedback of the tongue surface in real-time has shown promise in the treatment of speech-sound disorders. However, it remains unclear whether the addition of such visual information will influence speech plasticity on the timescale examined in experimental studies of speech adaptation. Here, we examine how neurotypical talkers adapt to a palatal prosthesis, relying on auditory and somatosensory feedback alone (n = 15), or with the addition of ultrasound feedback of the tongue, either in the mid-sagittal (n = 15) or co...