Contact: 0674-2558059/2362059 , 9338261670 , 7381656666, 9861148010
What is a digital hearing aid
What are digital hearing aids?

Digital hearing aids came to the market in the mid 1990s.A digital hearing aid is a hearing aid device that receives sound and digitizes it. Digitization of sound waves basically means to break down sound waves up into very small, discrete units prior to amplification. A traditional analog hearing aid simply makes the sound wave larger to amplify sounds.

Analog hearing aids make continuous sound waves louder. These hearing aids essentially amplify all sounds in the same way. Digital hearing aids have all the features of analog programmable aids, but they convert sound waves into digital signals and produce an exact duplicate of sound. Digital hearing aids are programmed using computers. Various hearing aids manufacturing companies have respective computer software to program these hearing aids. Once the digital hearing aid is programmed the hearing instrument performs to cater to the needs of the hearing impaired or deaf person for his better hearing. A digital hearing aid converts an analog signal to digital signal by two operations. One is “SAMPLING” and the other one is “QUANTIZATION” to replicate the analog signal exactly. “Sampling” refers to the process of measuring the instantaneous values of continuous time signal in a discrete form. It also means number of analog sound waves taken per second for analysis. ” Sample” is a piece of data which is continuous in the time domain. Therefore, higher the sampling rate more accurate is the signal replication. If we want the sampled signal to be a good representation of the original signal, these samples must be obtained very often. Sampling rate should be greater than twice the highest frequency component present in a complex signal. Thus, if a hearing aid is to faithfully amplify signal up to, say, 10 kHz, the sampling frequency has to be at least 20 kHz. “Quantization” is the process of approximating a continuous signal by a set of discreet symbols or integer values.

Digital hearing aids make soft sounds louder and loud sounds softer automatically. One doesn’t have to fiddle with the volume control. It is also adaptive which means, in an intelligent way the amplification and other features in the hearing aid varies when the wearer changes from one situation to another situation. Digital hearing aids are smaller in size compared to the analog hearing aids.

Most importantly, the background noise is very less with digital hearing aids. This is done with the help of “Directional Microphones”. A conventional electret microphone has one inlet port through which the sound waves enter and get converted into electrical signals. In contrast to this a ‘directional microphone’ has two ports and this can be made to have a sensitivity that depends on direction of arrival by feeding sounds to both sides of the diaphragm from two separate inlet ports by using acoustic dampers.

Digital hearing aids also have memory chips; so that their electroacoustic performances can be programmed to suit particular aid wearers for different situations consisting of programme1, programme2, so on and so forth.

so that their electroacoustic performances can be programmed to suit particular aid wearers for different situations consisting of programme1, programme2, so on and so forth.

Remote programming is also possible in digital hearing aids. It is not always possible to go to the dispensing audiologist for further adjustments or reprogramming. Online programming is warranted at times and in those situations the client’s hearing aids can be programmed or reprogrammed irrespective of the distance. Programming is also possible if the client is as far as U.S.A. or Australia and the audiologist is in India. In current pandemic this is an important feature.

Digital hearing aids can be paired with other assistive listening devices in competing speech environments for better discrimination of speech sounds.

In a nutshell, with digital hearing aids the discomfort and distortion experienced by the wearer compared to analog hearing aids are very less and the speech discrimination ability is far beyond analog hearing aids.