Rehabilitation of speech disorders following glossectomy based on ultrasound visual feedback

Inaccurate positioning or modified shape of speech articulators due to intraoral surgery can induce persistent speech disorders. The literature emphasises the importance of the link between speech perception and production, and in particular of auditory and proprioceptive feedback, both for language acquisition and maintenance. Some theories postulate the existence of speech internal models-or representations-coding the relations between the articulatory movements, their proprioception and their acoustic outcome. Therefore, we hypothesise that part of articulatory disorders may be ascribed to some degradation of the efficiency of the sensory channels, especially the proprioceptive ones, or an erroneous speaker's internal representation. Since many studies have revealed that subjects are somehow able of articulatory awareness and of tongue reading, using the vision of articulators can be assumed to enhance sensory feedback channels and constitute a promising perspective for the remediation of articulation disorders. In the article, we describe a clinical study on the efficiency of speech therapy based on the visualization of tongue movements captured by ultrasound imaging for the rehabilitation of patients who underwent intraoral surgery subsequent to tongue cancer. We explored two rehabilitation paradigms: visual illustration, which consists in providing the patient with pre-recorded ultrasound image sequences showing the target tongue movement, and visual feedback, that is the visualization in real-time by the patient of his/her own tongue. Based on a cohort of 10 patients, we demonstrate the benefit of complementing the illustration paradigm with visual feedback.