Assessing aspects of auditory handicap by means of pupil dilatation.

The demand on extra effort and concentration during listening are notorious handicapping effects of hearing impairment as is shown by self-assessment studies. In an attempt to explore new ways of assessing hearing handicap, the present study focuses on an objective measure of mental effort during listening. Pupil dilatation is used as the index of mental effort. Results for 14 hearing-impaired and 14 normal hearing listeners show a relation between pupil dilatation and difficulty in speech reception in noise, as manipulated by the speech-to-noise ratio. In addition the study shows that, with regard to effort and concentration, hearing-impaired subjects benefit less than normals from easier listening situations (e.g. at 5 dB above the individual speech-reception threshold). The results show a significant correlation between self-rated handicap and pupil dilatation.