Is it really necessary to wear two hearing aids, or can I get by with just one?

In the past, Audiologists have always stressed that "Two ears are better than one", promoting binaural listening and hearing.  This is, indeed, USUALLY the case. However, more recent studies have linked auditory processing and auditory memory with auditory capability.  Dr.  George A. Gates, M.D. of the University of Washington, Seattle, has been studying the connection between Executive Function (which effects short term memory, decision making, and attention) and Auditory Processing.  Neuropsychological considerations have to be considered when fitting amplification.  Due to some of these newer findings, Advanced is now able to screen for Auditory Processing deficits for all age groups, in addition to standard audiometric testing, to determine if a unilateral fitting (wearing an amplification device on one ear only) would be worth considering or be more beneficial for some of our patients with significant processing difficulties or single-ear weaknesses.

http://www.medicalnewstoday.com/articles/115659.php

http://yourtotalhealth.ivillage.com/memory-problems-tied-sound-processing-disorder.html

There are four main reasons why binaural (two eared) listening is superior to monaural (one eared) listening for most individuals with hearing loss. They include:

1. Better Hearing in Noise: An individual's hearing in noise can be improved if the signal reaching each ear arrives at a slightly different moment in time. This is technically referred to as phase. When the brain receives slightly different, yet still audible signals at the two ears, it has the ability to cross-correlate and process the primary signal (usually speech) better than if the signal is received monaurally.
2. Improved Signal versus Noise Level from Optimizing Position: Sound loses intensity (loudness) when it travels across the head. This occurs mostly for the high frequencies which are the most important for understanding of consonants, such as /s/, /t/, /f/, and /sh/. If you have a hearing aid on only one ear, say the left one, and the person you wish to hear is speaking to you from the right side, the consonants may be decreased by nearly 20 decibels by the time it gets to your aided ear. Unfortunately, noise in the room may occur from any or all directions, so while the noise level is not decreased, the speech level is. Wearing two hearing aids ensures that the speech sounds will not be diminished any more than necessary because of your position in the room.
3. Improved Localization Ability: We determine where a sound is coming from on the basis of 1) the relative time in which the sound arrives at each ear, 2) the relative difference in loudness at the two ears, and 3) the relative difference in the pitch of the sound at the two ears. When there is a large difference in hearing between two ears (as might occur when a person with similar hearing in both ears only wears one hearing aid) the brain cannot make use of these subtle relative differences and their ability to locate sounds may suffer.
4. Possible Deterioration of the Unaided Ear: We hear in our brain, not in our ears. The ultimate goal of hearing aids is not just to send sound into the ear. It is also essential to retrain the central auditory system in the brain. While it is uncertain whether hearing sensitivity (ability to hear soft sounds) will decrease if your ear is not stimulated adequately, research now suggests that there can be changes in the way in which your brain processes sound when it is "starved." Thus, providing stimulation may be important in preserving your auditory potential.

Reference:
http://www.audiology.org/aboutaudiology/consumered/guides/hearingaids.htm

Binaural Hearing Aids: The Fitting Choice for Bilateral Loss Subjects

• Binaural amplification results in higher consumer satisfaction, benefit and wearer performance over monaural amplification in various listening situations
• Structural point of view: the auditory system is binaural in nature
• Binaural loudness summation: sound is greater when it is presented to both ears simultaneously than when it is presented to one ear alone
• Better intensity and frequency discrimination ability than the monaural system= better sound quality and speech understanding
• Less gain required (loudness summation) which decreases the chance of feedback
• Masking Level Difference: ability to utilize interaural time and intensity differences between ears to extract a signal from the noise background= better speech intelligibility
• Improve Localization ability based on a difference of intensity and phase of the same sound arriving at 2 ears, important in daily communication situations and localizing source of potential danger e.g. traffic
• Preservation of integrity of the sensory system which depends on external stimulation (minimize deprivation)-to reduce the functional deterioration of the central processing ability and dexterity (relative with age)
• Beneficial for Bilateral tinnitus reduction
• Ease of listening comfort

Synopsis of the Advantages of Wearing Two Hearing Aids

1. Better understanding of speech
2. Better understanding in group and in noisy situations
3. Better ability to tell the direction of sound - localization
4. Better sound quality - hearing range from 180 deg. to 360 deg.
5. Smoother tone quality- less distortion, less volume
6. Wider hearing range
7. Better sound identification
8. Keeps both ears active resulting in less hearing loss deterioration (auditory deprivation effect)
9. Hearing is less tiring and listening more pleasant- conversation more enjoyable and less strain to hear, more relaxing
10. Feeling of balanced hearing
11. Greater comfort when loud noises occur- better tolerance of loud sounds
12. Reduced feedback and whistling- lower volume control setting
13. Tinnitus masking
14. Consumer preference
15. Customer satisfaction

Reference:
http://www.betterhearing.org/pdfs/MR45.pdf#search=%22binaural%20hearing%20aids%3A%20The%20fitting%20of%20choice%20for%20Bilateral%20Loss%20Subjects%22