1 Hearing Aid or 2 ?

Bilateral hearing aids fully stimulate your brain
One of the best ways to keep your body healthy and in good working order is to use it – that means getting regular exercise, taking the stairs instead of the elevator and getting your steps in for the day. Conversely, when we don't move and use our muscles, they tend to weaken and can even atrophy over time.
 
Even though your ears aren't muscles, depriving them of sound can make the auditory nerve pathways and the associated centers in the brain less effective at decoding the sound around you. Understanding speech, particularly in the presence of noise gets more difficult even when the sound is loud enough for you to hear it. This is called auditory deprivation. Wearing two hearing aids means each ear picks up sound and gets the stimulus it needs to stay at peak performance.  
 
A study published in the Journal of the American Academy of Audiology looked at the word recognition abilities of people fitted with one hearing aid versus two. The researchers found that a significantly higher number of the study subjects wearing only one hearing aid experienced a decline in their word recognition compared to those who had two hearing aids.  
 
Advantages of wearing Hearing Aids in Both Ears
Better Speech Understanding - With normal hearing, sound signals from both ears are comparable in strength. The brain can pick out the important signals, like voices, when they’re louder than the background noise. When you wear two hearing aids, you can take better advantage of the way the brain processes sound through what’s known as binaural hearing. But if you’re wearing just one hearing aid and someone talks into your unaided ear in a noisy room, the voice may sound softer than the background noise. As a result, it’s harder for your brain to give it preferential status.
 
Better Sound Directionality
It may also be harder for the brain to identify the location of particular sounds if you’re wearing a single hearing aid. The brain normally does this by comparing the qualities of the sound signals that come through each ear—their relative loudness, their frequencies, and the time it takes them to travel through the ears. But the brain can’t locate a sound as well if sound signals are always louder through one ear.