Effect of low frequency on speech performance with bimodal hearing in bilateral severe hearing loss

Unilateral cochlear implantation has emerged as a widely accepted procedure to treat severe to profound hearing loss, but many studies have reported benefits in terms of speech comprehension when listeners with residual low-frequency hearing in the nonimplanted ear use a hearing aid.

Retrospective study.

In this study, we analyzed the speech performance and satisfaction of bimodal hearing according to the residual low-frequency hearing level in the nonimplanted ear. Based on low-frequency pure-tone audiometry (average of 250 Hz and 500 Hz) in the nonimplanted ear, we classified individuals into three groups as follows: group A (under 70 dB), group B (71-90 dB), and group C (over 91 dB). Listeners were tested using the Word Recognition Score, the Korea-Central Institute for Deaf sentence recognition test, and the Korean version of the Hearing Handicap Inventory for the Elderly questionnaire.

We observed a bimodal benefit when the residual low-frequency threshold was less than 70 dB HL and a greater satisfaction with bimodal hearing compared to cochlear implant alone, when the residual low-frequency threshold was less than 70 dB HL.

This study supports the benefits of bimodal hearing in listeners with bilateral severe to profound sensorineural hearing loss as standard clinical practice, when the residual low-frequency hearing threshold is under 70 dB in the nonimplanted ear.

4 Laryngoscope, 126:2817-2822, 2016.