The progress and development of hearing aids is an amazing procedure worth studying! Right from its beginning of its evolution starting with horns, down to the modern day digital hearing aids, hearing devices have been continuously been incorporated with innovations and technological advancements. While the past few decades saw the use of analog hearing aids, the past few years have being seeing a wonderful evolution of the technologically advanced digital hearing aids that have proved themselves to be absolutely indispensable in the present generation.

 

What is Directionality?

First let us understand what are directional systems. We, as the listeners, are surrounded by various kinds of sounds throughout the day - even during sleep! It is just that while we are asleep, our brain simply ignores any incoming sounds, and hence let’s us have a ‘sound’ sleep! We get to hear sounds coming from every direction, and our brain is clever enough to understand and identify which sound is coming from which direction! Thus, we can understand whether a speeding car is approaching from the left backside or the right while we are on the roads!

But among these hundreds and thousands of sounds that we get to hear every single day, some are soothing to us, some are important to us, while some are absolutely unwanted to us. Our brain again does the job of filtering each of these sounds - it helps us stay focussed on the important and soothing sounds that we actually want to hear, by preventing all the unwanted and disturbing sounds (termed as noises) from diverting us.

This same mechanism is adapted by the digital hearing aids of our generation. The term ‘directionality’, therefore, refers to a hearing aid’s sensitivity to the different kinds of sounds coming from various directions. This feature of directionality is now incorporated in the digital hearing aids of today, which help us to stay focussed on some particular sounds which are important for us - by leaving out the unwanted noises; such as the ones coming from front of us like speech sounds, while the background noises are diminished or are cancelled out altogether.

 

What are the types of Directionality?

  • Omni-directionality

Omni-directionality refers to the phenomenon in which the hearing aid amplifies each and every sound coming from all the directions. If we imagine ourselves standing at the centre of a circle, the sounds which are coming from the centre as well as from the further distance on or near the circumference, are all amplified equally.

Omni- Directional Systems in Hearing Aids

  • Fixed Directionality

This feature is found today in most of the digital hearing aids, which enables them to amplify those sounds which are coming from your front, such as the speech sounds coming from the speaker you are conversing with and who is sitting in front of you. Suppose you are sitting at a dinner table and you want to listen to a particular person speaking with you, and hence do not want to listen to what the other persons sitting at the sides or at the back of you are saying. The Fixed Directionality feature present in digital hearing aids is capable of distinguishing between speech and noise, and hence reduces or cancels out the background sounds, and amplifies and makes you stay focussed only on the important sounds in front.

Fixed Directional Systems in Hearing Aids

  • Adaptive Directionality

But what if the source of the sound keeps changing? It means that the direction of sound is also changing, thus constantly shifting your point of attention. What if you want to listen to people speaking from various directions around you - such as from the front, back and the sides? In such a case, the Adaptive Directionality feature found in almost all the advanced and updated digital hearing aids, comes at your rescue! This system has a remarkable speed of analyzing the loudest sounds which enables you listen to all the important sounds coming from all the directions around you. The feature is also advanced enough to take into account different sound frequency ranges and analyzes and adjusts the amplification in each of them. Accordingly it enables us to hear only specific ones, which we want to hear - by cancelling out the unwanted ones.

Adaptive Directional Systems in Hearing Aids

  • Hybrid Adaptive Directionality

This feature performs exactly like a healthy, open ear canal. It is much more advanced due to its capability to help the person wearing digital hearing aids actually listen clearly to important sounds even in challenging situations - such as the wind, or at environments which have a echo - such as at a wide hilly region. The Hybrid Adaptive Directionality feature combines two patterns - the Adaptive and the Omni Directionality ones. It maintains the important sounds by “fixing” or adjusting the amplification on the low frequency ranges and constantly adapts to the higher ones so as to help reduce the unwanted noises.

 

In a nutshell, it is always advised by certified Audiologists to go for the advanced and the more updated digital hearing aids, as they would not only make you hear better, but would also enable you to enjoy what you hear!