Speech recognition with BAHA simulator in subjects with acquired unilateral sensorineural hearing loss

We question the justification for the cost of a surgically implanted device for the restoration of limited circumstances of audible communication, although we understand that the decision is taken depending on the social relevance of communication or personal criteria.

The purpose of this study was to evaluate the effect of the BAHA simulator (BAHAS) system in subjects with acquired unilateral sensorineural hearing loss. In particular we tested the changes of speech reception threshold (SRT) in relation to different speech source positions, with a background of diffuse noise.

The primary message consisting of lists of Italian sentences was delivered from a loudspeaker placed at horizontal azimuths of 0°, 90°, 180° and 270°; the interference consisted of uncorrelated speech-shaped noise simultaneously delivered by four loudspeakers at a fixed intensity. The speech recognition tests were administered to 11 patients with BAHAS either on or off; hence each patient underwent 8 acoustic conditions (4 primary message directions × 2 BAHAS conditions). The SRT (50% correct responses) was measured by a simple 2 dB step adaptive procedure. Ten normal-hearing subjects served as the control group.

Our data demonstrated that even for the acoustic condition where BAHAS should be more useful (i.e. lateral speech toward the impaired side), it was definitely ineffective in the study conditions.