Standard Technology 

A standard/analog hearing aid contains a linear or compression circuit with a set prescription level. Today, compression circuits are most commonly used because they can amplify soft sounds while keeping the loud sounds from being uncomfortably loud. Linear circuits amplify all sounds equally and are sometimes too loud in noisy environments. Most standard aids come with a volume control wheel and a telecoil (telephone) switch. 

Programmable Technology 

Programmable hearing aids have an analog circuit; however, unlike standard aids they are programmed by a computer. Therefore, the sound of the hearing aid can be modified to accommodate the listener's needs. Programmable hearing aids can often times store more than one setting so they are comfortable to wear in a variety of listening environments. These hearing aids have much more flexibility than the standard aids, but not as much as the digital aids. 

Digital Technology 

Digital hearing aids offer the latest technology on the market. Some of these aids can automatically adjust to the changing acoustic environments by analyzing different sounds and reproducing those signals at a loudness level that is comfortable for the patient. Therefore, soft sounds are made audible and loud sounds are made comfortable. The digital aid can offer a more comfortable listening environment by reducing steady state noises; however, this does not always equate to better speech understanding. Additionally, it has feedback (whistling or ringing) reduction capabilities which means the aid can detect and reduce feedback before it is ever audible to even a normal hearing person. There are some companies that reduce the occlusion effect (barrel effect). Some digital aids are completely automatic and need no remote control, but there are some hearing aids that do offer the use of a remote (handheld or watch) that can override the decision made by the hearing aid. Additionally, a digital hearing aid can always be connected to the computer to allow for changes to be made with changes in hearing loss.