McArdle et al (2012) reviewed the debate and literature regarding amplifying one versus two ears. They conducted two experiments involving 20 veterans (aged 59 to 85 years with mild to moderately-severe symmetric SNHL) to explore which fitting protocol provide the best results for speech-in-noise. The authors report 80 percent of all hearing aid fittings in the United States are binaural (per Kochkin, 2010).
In brief, 20 percent (4 of 20 veterans) performed better with a monaural fitting. However for 80 percent of the participants, their best speech recognition in noise was obtained with binaural amplification. McArdle et al note that "not only is the use of two ears better than one ear…but the availability of binaural cues further improves speech recognition in noise performance." Further, the authors stated, "The fact that two ears listening to one signal performed better than either ear alone, and two ears listening to binaural cues performed even better, provided further support for the belief that two aids are most often better than one."
For More Information, Resources, and Recommendations
McArdle RA, Killion M, Mennite MA, Chisolm TH. (2012) Are Two Ears Not Better Than One? Journal of the American Academy of Audiology. 23:171-181.