Cochlear implants glossary

Terms related to cochlear implants

Acoustic stimulation

This is the "normal" auditory process by which pressurewaves are perceived as sound when the waves are passed through theouter, middle and inner ear, eventually stimulating the auditorynerve.

Action potentials of the auditory nerve

Action potentials are the electrical responses of theauditory nerve. This is typically measured by the electrophysiology team.

Appropriate expectations post-implantation

There is a common assumption that cochlear implants allow people to "hear normally." This is not the case and should not be expected. It is appropriate to expect to have some degree, however great or small, of adjustment to a cochlear implant. This adjustment period may last from a few months to a year or beyond. Adjusting to listening with a cochlear implant can be just as difficult if not more so than adjusting to hearing aids.

Auditory steady state evoked potentials

These auditory evoked potentials or measured electrical responses of the nervous system are derived from the use of acontinuous or prolonged auditory (sound) stimulus by way of electrodes.

Bilateral implantation

Cochlear implants placed in both ears.

Cochlear implantation follow-up appointments

Post-implantation cochlear implant follow-up appointments are necessary to ensure that the device is working properly andset to most closely fit the hearing needs of the recipient. Follow-up appointments vary from individual to individual and may require weekly, monthly, or yearly appointments.

Coding strategies

The manner in which an acoustic sound pattern is picked up and translated into an electrical signal.

Conductive hearing loss

A hearing loss due to damage in the middle or outer ear.

Congenitally deafened

Deafness present at birth.

Electric stimulation

The method by which the auditory nerve is stimulated when utilizing a cochlear implant.

Electrode array

The portion of the cochlear implant which is surgically placed in the cochlea. The array contains individual electrode contacts which provide electrical stimulation.

Electrically evoked compound action potential (ECAP) and physiologic measures to program the speech processor

The ECAP is an electrophysiological measure of the auditory nerve response to the electrical stimulation provided bya cochlear implant. With current cochlear implant technology, it is possible to record these electrophysiological measures with the electrodes of the cochlear implant. No surface electrodes need to be placed on the skin.

Additionally, no response is needed from the listener. The measurements are objective and do not rely on participant report. ECAP responses can only be measured when stimulation from the cochlear implant is audible to the user. Consequently, these measures can be combined with subjectivemeasures of loudness to aid in programming the speech processor.

Electrophysiology

The measurement of neural activity in response to astimulus. Neural activity can be measured by electrodes placed on the skin, and can then in turn be displayed on a computer screen and/or plotted on paper. Auditory Evoked Potentials (AEP) are acommonly utilized electrophysiological measure used to estimate hearing sensitivity. The most common AEP measurements used at our center are the Auditory Brainstem Response (ABR) and the Auditory Steady State Response (ASSR). They are often used in determining cochlear implant candidacy.

Additionally, the Electrically Evoked Compound Action Potential (ECAP) is an electrically evoked response that is often measured from cochlear implant users. It measures the function and integrity of the auditory nerve.

Electrophysiological techniques

Electrophysiological measures are non-invasive and arealmost always measured from outside the body with electrodes on the surface of the skin. Typically, the electrodes look like small stickers attached to wires which are then attached to a machine.

Greatest benefit derived from a cochlear implant

The desired outcome of the cochlear implant in terms of its greatest benefit is to positively enhance the user's life more so than would be possible without the device. There is not one identical outcome for all users of cochlear implants. Each recipient experiences their own individual triumphs and setbacks.

Habilitation

Working on a skill that has not yet been developed, such as working on speech with a prelingually deafened child.

High-rate stimulation

One method of providing information to the auditory nerve via a cochlear implant. Fast stimulation rates theoretically provide a more detailed signal to the hearing nerve by attempting to preserve temporal or timing cues.

Language

A system of symbols in the brain representing objects,actions, and feelings that can be recalled and used to communicate.

Multi-channel cochlear implant system

A multi-channel cochlear implant system utilizes several electrode contacts, which are laid out along the cochlea to stimulate different frequency regions. Multi-channel systems provide frequency as well as timing and loudness information.

Mixed hearing loss

A hearing loss due to damage in both the middle or outerear and the inner ear or auditory nerve.

Postlingually deafened

Deafness that occurs after speech and language have beenlearned and established.

Prelingually deafened

Deafness that occurs prior to the development of speechnand language.

Rehabilitation

Working on an impaired skill that has already been developed, such as working on speech with an adult that has developed a hearing impairment later in life.

Research protocols

A detailed plan of a scientific or medical experiment, treatment, or procedure.

Residual hearing

The amount of hearing that an individual is able toutilize, even in the presence of a hearing loss. Typically, residual acoustic hearing is lost following implantation.

Sensorineural hearing loss

A hearing loss due to damage either within the inner ear or the auditory nerve.

Severity of hearing loss

Severity of a hearing loss is determined by the airconduction thresholds obtained by an audiologist during a hearingtest. Ask your audiologist the severity of your hearing loss based on your most recent audiogram.

Normal hearing = 15 dB HL or above
Slight hearing loss = 16-25 dB HL
Mild hearing loss = 26-40 dB HL
Moderate hearing loss = 41 and 55 dB HL
Moderate-to-severe hearing loss = 56-71 dB HL
Severe hearing loss = 71 and 90 dB HL
Profound hearing loss = greater than 90 dB HL

Short electrode array

This device is often referred to as a Hybrid Cochlear Implant or Electrical Acoustical Stimulation (EAS). It was designed for use with patients who have a significant amount of low frequency residual hearing. It consists of a short electrodearray that is implanted only in the basal end of the cochlea. The external equipment used with this device combines electronics to control both a cochlear implant and a hearing aid, allowing patients to make use of residual hearing.

Signal processing

A set of rules that define how the speech analyzes acoustic signals and codes them for delivery to the cochlear implant.

Signal processing parameters

A set of guidelines for processing input and translating it into electrical signals emitted by the cochlear implant. Signal processing is carried out by the external speech processor. The possible parameters are limited by the processing limits of and power supply to the cochlear implant. Signal processing is often referred to as a coding strategy.

Single channel cochlear implant system

A single channel cochlear implant system utilizes an electrode array with only one electrode contact. This single channel allows for timing and loudness cues, but does not provide frequency information. Most modern implants are multi-channel devices.

Sound

Sound can be described as a type of vibration that travels through the air in the form of a wave of pressure. Not all sounds are speech.

Speech

Speech can be classified as orally produced sound waves shaped by the vocal tract (oral cavity, nasal cavity, pharynx, larynx, and the respiratory system) that a listener of that language can derive meaning from. All speech is sound.

Speech production

Ability to produce speech.

Speech recognition or perception testing

Speech recognition or perception testing is one way to determine the benefit obtained by a cochlear implant. When testing for speech recognition, cochlear implant recipients are typically required to repeat speech stimuli (i.e., consonants, vowels, words, or sentences, etc.), either with or without the aid of visual cues and either with or without background noise to determine the percent that can be correctly understood with the use of the cochlear implant. These scores are often compared to scores obtained prior to implantation when individuals were wearing hearing aids.