Uncomfortable loudness levels in experienced unilateral and bilateral hearing aid users: evidence of adaptive plasticity following asymmetrical sensory input?
Munro and Trotter [Inter J Audiol 45, 684-688, 2006] reported an asymmetry in uncomfortable loudness levels (ULLs) in a preliminary study using 12 experienced unilateral hearing aids users. The aim of the present study was to investigate ULLs in a larger sample of listeners with unilateral and bilateral hearing aid experience. Participants were adults with symmetrical high-frequency hearing impairment. There were 48 listeners with unilateral experience, 13 listeners with bilateral experience and a control group of 47 listeners with no hearing aid experience. The minimum duration of hearing aid experience was 2 years. ULLs were measured at 0.5, 1, 2 and 4 kHz. The unilateral group showed a statistically significant inter-aural asymmetry of 3-5 dB. Compared to the controls, there was a non-significant trend of higher ULLs in the fitted ear and lower ULLs in the not-fitted ear. ULLs in the bilateral group were symmetrical and similar to the control group. The findings suggest that changes in ULL may be a feature of asymmetrical sensory input and are consistent with a central gain mechanism.
Hamilton
Ann-Marie
AM
School of Psychological Sciences, University of Manchester, Manchester, UK.
Munro
Kevin J
KJ
D000161:Acoustic Stimulation; D000223:Adaptation, Psychological; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D016022:Case-Control Studies; D012048:Correction of Hearing Impairment; D056228:Feedback, Sensory; D005260:Female; D006310:Hearing Aids; D006312:Hearing Loss, Bilateral / Q000523:psychology / Q000534:rehabilitation*; D046088:Hearing Loss, Unilateral / Q000523:psychology / Q000534:rehabilitation*; D006801:Humans; D008144:Loudness Perception; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*