A hearing aid is designed and tested such that it produces the required amount of amplification of existing sound such that a person hard of hearing will be able to make out the speech and noises around him clearly. There are various types of hearing aids like behind the ear hearing aids, in-the-ear hearing aids, in the canal hearing aids etc, which are named according to the place they are fitted into. Patients with mild to severe loss of hearing are usually advised to wear in-the-ear hearing aids which consist of small plastic devices which are fitted outside the ear.
The specialist takes into consideration the patient’s level of hearing whether mild or moderate, the size and shape of the ear, the volume or size of the ear canal and the other medical conditions that they might possess before setting out to select which type of hearing aid should be suitable for the patient. Tele coils, which are usually used in telephones to improve sound quality, are sometimes incorporated in the hearing aids as amplifiers. These plastic cases with the batteries are easy to fit in-the-ear rather than extended wear hearing aids which is inserted into the ear canal less than a few millimeter within-the-ear drum. This hard plastic case houses the microphone to capture the sound, an amplifier to increase the volume of the sound, and a receiver to receive the signals from the amplifier and transmits it to the ear.
These hearing aids can be coupled with zinc batteries, which perform by mixing zinc with the air outside. Rechargeable hearing aid batteries are also available in the market which last for a whole two years is properly maintained. They cost higher than the zinc batteries but the overall cost for two years would cost out lesser than zinc batteries. The shelf life of a hearing aid battery is approximately three years. 5 to 7 days is the typical working life of a single battery. It is better to dispose unused batteries immediately due to problems which might arise on the use of drained batteries on a good in-the-ear hearing aid.
The disadvantage of such a hearing aid is that it can be easily damaged by ear wax and other conditions and is usually not prescribed for children as their ear canal keeps growing. Due to the close placement of microphone and amplifier feedback is possible which can cause the wearer some discomfort.
Siemens hearing aids are a very reliable brand of hearing aid and are readily available at various different outlets.