• Do not distinguish different sounds and therefore amplify all sounds equally, which means some sounds, are too loud while others may be difficult to hear. This is rectified when the hearing aid user adjusts the volume
• Programmable analogue hearing aids are equipped with different programs that are saved in the aid. The programs are then switched depending on the listening environment. As an example, one program will work during a conversation, while the other may work best while in the theatre.

• Translate sound to digital code, change it and re-transmit it back by using mathematical calculations.
• Duplicates sound transmission.
• Produces a high quality sound that is extremely accurate.

Many believe that the digital system has revolutionized hearing by accurately duplicating sound transmission. Digital hearing aids have many benefits and lots of automatic features, although some still believe that programmable analogue aids possess great sound quality and functionality and are great in that they are more affordable.

People who use traditional analogue hearing aids often complain that they find it difficult or impossible to follow conversations in noisy places.

Many digital aids are designed to reduce steady kinds of background noise, such as the rumble of traffic or the whirr of a fan. This can make listening more comfortable. But it does not necessarily help you to pick out a single voice from everything else going on, especially when several people are talking at once.

Two things have been shown to improve hearing in noisy situations more than anything else - wearing hearing aids in both ears, and using hearing aids that have directional microphones.

Directional microphone systems amplify sounds that come from in front of you more than sounds to the side or behind you. This makes it easier for you to focus on what you want to listen to in a noisy place. Most digital hearing aids have microphones that can be set to operate like this. This means you can switch between directional and all-round sound, depending on what you need to hear at the time. Some digital aids will detect where the noise is coming from and automatically adjust to reduce the noise selectively. However, a hearing aid cannot know what you want to listen to and so the reduction of unwanted sound can never be perfect.

Yes. Some digital hearing aids have feedback management systems. This means that they can automatically detect any feedback and try to reduce the whistling that bothers many people who use hearing aids.

• More comfortable listening

  Most digital hearing aids have some form of loudness compression system. This means the hearing aid can manage sounds of different volumes and only amplify them as much as you need. It means the aid can be programmed to suit your particular hearing loss and ensures that you always hear different sounds at levels that are comfortable for you. This type of aid is often completely self-adjusting.

  It will only work well for you if the person who fits it also adjusts the settings carefully to suit you, when you first have it. You may need to have your aid fine-tuned again, when you get used to it.

• What is the ' T ' setting?

  It is usually possible to switch to the ' T ' (telecoil) setting with a digital hearing aid, as it is with an analogue aid. The telecoil is a small component in the aid that picks up signals from a loop system or hearing aid compatible telephone. But your audiologist will need to programme the ' T ' setting and show you how to switch over. If you choose a very small style of hearing aid that fits into your ear canal, there might not be room for a telecoil, so you won ' t have the ' T ' option.