Many people in India use only monoaural ( only in one ear ) hearing aids. The main factor for the use of monoaural hearing aid use is due to the cost associated with the hearing aids.
Apart from this dis-advantage there are various plus points for using the binaural amplification namely :-
Firstly binaural summation when a person uses hearing aids in both ears he / she gets additional gain of 6 dB i.e. the speech is perceived much clearer and there is less need for concentrating on speaker.
Secondly one gets the sense of directionality, one would be able to track down the side from which the speech / sound is coming, where as with one hearing aid, would have the person confused. He perceives all sounds coming from only one side i.e. aided ear.
Thirdly binaural hearing helps in understanding speech better in group situations. Our brain is able to decide more appropriately to suppress background noise naturally when signal is from both the ears.