Articulation difficulties following maxillofacial surgery: A single case study

Hypernasality and inaccurate tongue placement are common causes of poor speech intelligibility. The velum controls nasal coupling and hence resonance, and forms an

essential seal, allowing the build up of intra-oral pressure required for obstruent sounds. Velopharyngeal insufficiency (VPI), the inability to make adequate velopharyngeal closure, may result from either structural or neurological abnormalities (Albery & Russell, 1990).

The tongue is the most versatile of the articulators, being involved in the production of all vowels and the majority of consonants. By altering tongue position and shape, the size of the oral cavity, and hence its resonating characteristic, changes, and different sounds are created. In order to speak, these complex movements must be coordinated with the controlled movement of the other articulators. Any errors in coordination, speed of movement, shape, or place of tongue contact will cause distortion and speech intelligibility will be affected.

Objective measurement of these parameters can be difficult. Two new systems have been developed by the University of Kent Medical Electronics Research Team, Kent & Canterbury Hospital Speech & Language Therapy Department and Canterbury & Thanet Community Dental Department. SNORS (Super Nasal Oral Ratiometry System) measures both nasal and oral airflow during speech, allowing the very rapid movement of the velum to be inferred. Linguagraph is a clinical electropalatography system, which measures tongue-palate contact. A single case study is presented on a patient with whom both systems have been used.