In-the-ear (ITE) hearing aids are custom made for each individual ear and are appropriate for individuals with mild to moderately severe hearing loss.  This style may also be more appropriate than the smaller hearing aids, for those with manual dexterity problems such as arthritis.  Depending on an individual’s ear size, this style may be less desirable for those with moderately severe hearing loss.  They are available in all types of circuits.

In-the-canal (ITC) hearing aids are custom-designed for individual ears.  They fit deeper into the ear canal and are smaller in overall size.  The ITC is most appropriate for milder to moderate hearing loss.  All types of circuits are available in this size hearing aid.  Because they are smaller than ITE aids, certain special features and options may not be available due to size limitations.

Among the smallest of hearing aids are the completely-in-the-canal (CIC) hearing aids, which fit deeply in the ear canal.  Individuals with mild to moderate hearing loss can be fit with  CIC hearing aids.  The shape and size of the individual ear canal assists in determining if this style is appropriate.  Although they have removal wires that are used to remove them from the ear canal, their size is quite small and may pose problems for individuals with hand dexterity problems such as arthritis.

There are primarily two type of circuits:  a. Analog (conventional non-programmable) and b. Digital (programmable).

Analog or “conventional” circuits were among the first types of electronic circuits used in hearing aids.  They have some controls that are built into the hearing aids, which can be used to make certain adjustments.  Although there are controls (potentiometers), which can be used to improve the incoming signals, these aids have limited flexibility and are not programmable.  Some circuit adjustments must be made by the manufacturer.  Analog hearing aids are the least expensive but vary in cost depending on the style, circuitry, and controls.

Digital (programmable) hearing aids are programmed using computer software and offer a wide range of listening options to users.  Most digital hearing aids have individual memories that can be activated by small user-operated controls buttons.  For instance, one memory might be used for everyday conversation, another for listening when there are high levels of background noise, and possibly another for listening to music or telephone use.  Individuals who were formerly analog hearing aid users frequently report that digital circuits offer a more “natural” sound quality.  Depending on the programming done, they may also provide improved speech understanding.  Because they are programmable and use digital technology, digital hearing aids can be adjusted over several visits to meet the needs of an individual who has to listen in a variety of conditions.   If a patient has changes in hearing ability, programmable hearing aids can be adjusted to help meet many of those needs.

With the advancements in hearing aid research, and the need to help individuals with varying degrees of hearing loss, there are several features to consider, such as whether to include a telephone coil; whether to use omni directional, directional or multiple microphones; and whether the individual needs couplers that enable the use of assistive listening devices. 

Microphones vary in their function.  Omni directional microphones are those which pick up sounds that originate in almost any direction around the individual.  Directional microphones are those that are specifically designed to amplify signals that are in front of the individual and are often enabled by a user push-button.  This can improve listening in noisy settings.  Some more sophisticated hearing aids use more than one microphone that can better help differentiate speech from surrounding noise.  While one sees advertisements of hearing aids that “block background noise”, these are misleading and have become the target of the Food and Drug Administration scrutiny.  Microphone technology and digital circuitry such as described above may help enhance speech understanding in noise, but results may vary depending on the type and degree of hearing loss.