Hypernasality in dysarthric speakers following severe closed head injury: a perceptual and instrumental analysis.

Hypernasality in the dysarthric speech of 20 severely closed-head-injured (CHI) subjects was investigated using both perceptual and instrumental techniques. A perceptual analysis of the speech of the CHI subjects was performed using a four-point rating scale for hypernasality. Instrumental assessment was carried out using a computerized accelerometric technique yielding a nasal coupling index. Results revealed a high incidence of perceived hypernasality (95%) in the speech of subjects in the CHI group. More than half of these subjects exhibited hypernasality of speech to a moderate to severe degree. When compared with a control group matched for age and sex the severely CHI subjects were perceived as being significantly more hypernasal. Instrumental assessment revealed that the functioning of the velopharyngeal valve in the group of CHI subjects was significantly impaired compared to the control group. The study highlighted the need to evaluate the perceptual and instrumental assessment results for the severely CHI subjects on an individual basis. The clinical implications of these findings are discussed.