Behavioral audiometry: validity of audiometric measurements obtained using the "Delaroche protocol" in babies aged 4--18 months suffering from bilateral sensorineural hearing loss

Abstract

Objective: Evaluation of the validity of the audiometric measurements obtained in babies aged from 4 to 18 months suffering from bilateral sensorineural hearing loss (SNHL) using an original behavioral audiometry (BA) protocol called the "Delaroche protocol" [IJPORL 68 (2004) 1233-1243].

Methods: (1) We compared the auditory brainstem (ABR) threshold in the better ear with the mean of the BA thresholds obtained, bilaterally, at 2000 and 4000 Hz, both measurements being performed in the diagnostic phase. (2) We compared the BA thresholds obtained prior to the age of 18 months, bilaterally, at the frequencies of 500,1000, 2000 and 4000 Hz, with the thresholds of the better ear obtained at the same frequencies at the age of 3--4 years by BA.

Results: (1) Cross- sectional study (78 children). When there was no ABR at 100 db, there was no BA response at 100 dB in 84.2% of cases, resulting in a kappa coefficient of 0.72. When there were ABR, the difference between the ABR and the BA thresholds was equal to or less than 10 dB in 67% of cases and equal to or less than 20 dB in 95% of cases. (2) Longitudinal study (50 children). The difference between the behavioral thresholds obtained within 4 and 18 months (median age=12 months) and those obtained at 3 or 4 years old in the same children (median age=39 months) was equal to or less than 10 dB in 94% of cases at the frequencies of 1000, 2000 and 4000 Hz and in 78% of cases at 500 Hz.

Conclusion: The two analysis evidence the validity of the behavioral measurements obtained at an early age using the protocol described.