Alteration in auditory threshold during auditory rehabilitation.

The average hearing thresholds centred on Fc were measured in all subjects before and during hearing-aid fitting. A 2-way repeated-measures ANOVA (on frequency and rehabilitation time course) showed a significant effect for frequency (F(9,216)=42.921; p<0.001), with higher auditory thresholds for higher frequencies, whereas no overall effect was found for rehabilitation time course (F(3,216)=1.210, p=0.327). Nevertheless, a significant interaction between some of the frequencies and stages of hearing-aid fitting was observed (F(27,216)=2.087; p=0.002). Post-hoc tests revealed that, at Fc+1/8 and Fc+1/4 octave, auditory thresholds were significantly worse 6 months after auditory rehabilitation than before (at Fc+1/8, p=0.006; at Fc+1/4, p=0.01). No significant difference was found for any of the other frequencies.