Further delineation of the DFNA5 phenotype: results of speech recognition tests

Speech recognition scores were analyzed in 34 carriers of a DFNA5 mutation. Cross-sectional linear regression analysis (last visit, maximum recognition score in %Correct on age or PTA1,2,4 kHz) established onset age (score 90%) at 16 years and onset PTA1,2,4 kHz level (score 90%) at 41 dB hearing level. The deterioration rate was 0.7%/y in the plot of maximum score against age, whereas the deterioration gradient was 0.4%/dB in the plot of maximum score against PTA1,2,4 kHz. Given the previously demonstrated rapid progression of hearing impairment, speech recognition was relatively good: at age 70, the score was still >50%.