Pure tone hearing thresholds and speech recognition scores in Dutch patients carrying mutations in the USH2A gene.

OBJECTIVE

To establish the audiometric profile and speech recognition characteristics in 36 Usher IIa patients, carrying one (A) or two (B) pathogenic mutations in the gene.

STUDY

DESIGN

Family study.

SETTING

Tertiary referral center.

PATIENTS: Thirty six Usher IIa patients from 21 Dutch families.

METHODS

Ophthalmologic, vestibular, and audiometric examinations were performed on all patients. Cross-sectional analysis was performed on pure tone threshold data at 0.25 to 8 kHz and on speech phoneme recognition scores. Progression was evaluated using linear regression analysis on raw and presbyacusis corrected data.

RESULTS

A downsloping audiogram was found, with a mean threshold slope of -9 dB per octave, that was mildly progressive, i.e., by approximately 0.5 dB per year. Individual monaural maximum phoneme recognition scores (% correct) were analyzed in 30 patients in relation to the patient's age and level of hearing impairment characterized by a pure tone average (PTA(1-4 kHz)). The speech recognition score started to deteriorate from a score of 90% at 38 years at a rate of 0.4% per year. The 90% level was attained at 69 dB hearing level (PTA(1-4 kHz)); at higher levels of impairment, the score deteriorated at a slope of 0.6% per dB hearing level. There was no significant difference between group A and B in pure tone threshold, with or without presbyacusis correction, or phoneme recognition score as related to age or PTA(1-4 kHz).

CONCLUSIONS

Patients with various mutations in have moderate to severe hearing impairment showing mild progression at approximately 0.5 dB hearing level per year.