jeudi 8 septembre 2016

How Hearing Aids Are Evaluated

By Brenda Murphy


Another name for a hearing aid is a deaf aid. This is a gadget designed for use by deaf people to improve the ability to hear. In most countries, these devices are categorized as mechanical devices subject to regulation. A lot of evolution has occurred in hearing aids from being simple sound amplification devices that directed external sounds to ear canals to being computerized electroacoustic systems.

Sound is made more comfortable and intelligible by modern gadgets since they are computerized electroacoustic systems. The sound processing ability in them enable them to cancel wind and noise, highlight voice and partial region, and to shift frequencies. For the device to match the lifestyle, physical feature, and the degree of hearing loss in a person, it must be configured.

The devices need to be configured to match various aspects. The configuration is referred to as fitting and it is done by an audiologist. The quality of fitting done in the gadget often determines how beneficial the user finds it to be. It is vital to understand that deafness cannot be truly rectified by a deaf aid. The most the devices does it to increase accessibility to sound.

The level of efficiency of these gadgets in undermined by two key factors. The first factor is related to loss of cells of the brain responsible for sound processing. The loss of these cells is triggered by prolonged absence of stimulation to primary auditory cortex. As the degree of deafness rises in an individual so does the loss in these brain cells. Factor number two is related to the damage of hair cells in inner ear due to sensorineural hearing loss. The patient becomes incapable of discriminating sounds as the hair cells are continuously lost.

The effectiveness of a device in compensating for lost ability to hear can be evaluated using various methods. Audiometry is of the methods used for the evaluation. Audiometry is performed in a lab environment to measure hearing levels in a subject. Audiometric tests resemble real-world conditions as much as possible. However, subjects still have different daily experiences with the gadgets.

Three main dimensions are available for representing the outcome of the device. These dimensions are hearing aid usage, satisfaction, and aided speech recognition. The correctness of the adjustments done to the device can be measured through a method called real ear measurement, which is also called probe microphone measurements. This method uses a silicone probe tube microphone to assess the characteristics of amplification by the device near the eardrum.

Different types of these instruments have been invented. The devices vary in their size, circuitry, and power among other factors. Major modern types today include body worn aid, receiver in the canal aid, BTE cross system, behind the ear aid, and on-the-ear aid. Other types are BTE Bi cross system, extended wear deaf aid, earmolds, open-fit gadgets, disosable deaf aid, invisible in canal deaf aid, stethoscope deaf aids, and bone anchored devices.

In most cases, modern gadgets run on button cell zinc-air batteries. These batteries come in five key standards. Mercury batteries used to be common in older models. There are also manufacturers who make modern devices that run on rechargeable of long-life disposable batteries.




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