If both of your ears have hearing loss, both of your ears should be receiving stimulation from amplification, such as hearing aids! Because of financial reasons or poorer hearing in one ear versus the other, some patients question the recommendation of two hearing aids. However, research has proven that bilateral amplification is preferable for those with aidable hearing loss in both ears. Researchers, such as Kobler & Rosenhall (2002), have examined speech intelligibility under conditions that simulate conversational speech in real-world scenarios. They have done so by using multiple noise sources and sentence-based materials rather than monosyllabic words in quiet. Their findings showed that bilateral amplification improved speech intelligibility and localization performance over unilateral fittings and unaided conditions.
Sound localization is beneficial in order to hear environmental sounds as well as speech perception. While hearing birds chirping is a beautiful part of nature, what is most important for many hearing aid users is understanding conversation in complex environments. Localization, provided by wearing two hearing aids rather than one, aids in identifying speech first and separating it from competing sound sources before higher level auditory processing in the brain can occur (Stevens, 1996). Therefore, the effect of bilateral hearing aids on localization impacts your overall ability to hear and understand conversation speech in a noisy environment, while a unilateral fitting may not be successful at doing so. Furthermore, someone with a moderate to severe hearing loss, for example, who wears only one hearing aid may hear only on the aided side. With a binaural fitting, time and intensity cues are preserved!
Auditory deprivation is a major reason why the consensus among clinicians is the recommendation of bilateral hearing aids. First described in 1984 by Silman, Gelfand and Silverman, it was reported that individuals who had bilateral hearing impairment, but were unilaterally fit, experienced a reduced speech discrimination in the unaided ear relative to the aided ear. Studies thereafter showed that subjects who experienced the phenomenon of auditory deprivation due to a unilateral fitting who were later fit with a second hearing aid experienced improved word recognition (Silverman & Silman, 1990; Silverman & Emmer, 1993; Silman, et al., 1992). With that being said, the best way to treat auditory deprivation is to avoid it, with bilateral amplification as part of the solution!
