Hearing aids worn in both ears are called binaural hearing aids. There are a number of advantages to having a hearing aid in each ear.
Binaural fitting will usually allow a patient to have balanced hearing, with speech perceived of equal volume in the two ears – this will permit localisation of sound. The most important advantage, however, is that most hearing aid users are able to understand speech in a noisy situation much better than when an aid is used only in one ear.
Furthermore, using two aids results in a significant increase in sound volume due to binaural summation. This means the volume control may be reduced for each ear, which in turn will lessen the impact of background noise.
Each individual reacts differently to the use of a hearing aid. One’s age, the severity of the hearing impairment and the acceptance of the need for the aid, may all strongly influence the reaction to supplementing hearing with amplified sound.
The type and degree of hearing impairment may affect the benefits to be gained from a hearing aid. Generally speaking, those with hearing impairment have a dual problem – reduction in the intensity of sound, in which every day noises, including speech, are not perceived at their normal volume; and usually an accompanying reduction in discrimination, which is one’s ability to distinguish among the sounds of speech, leading to a reduction in understanding.
If a person has an impairment of the conductive type, they can expect maximum benefits from a hearing aid because discrimination ability has not been greatly affected. Most people with this type of impairment adjust to using a hearing aid with very little difficultly.
If the hearing impairment is of the sensorineural or nerve type, there may be more difficulty adjusting to a hearing aid. Often, people who have this type of hearing loss can hear speech sounds if they are loud enough but cannot always understand what is being said. It is true that speech must be loud enough to permit the listener to understand to their full capability, but making speech increasingly louder will not necessarily lead to a corresponding improvement in discrimination because the hearing nerve has become less sensitive to the acoustic differences of speech sounds.
A hearing impaired person will often say, “I hear but I can’t always understand what I hear.” The major problem for a new hearing aid user is to adjust to hearing over background noise. Innovations in hearing aid fitting have made hearing in noisy situations more comfortable. Changes in circuitry of the hearing aid, specially designed ear moulds and highly adjustable aids have greatly eased the initial learning process for many patients.