Glossary ( A to L )

Terms M through Z
ABR Test	Auditory Brainstem Evoked Response Test. It tests the response of your child’s auditory nerve and the auditory area of the brain. Young children are usually sleeping or sedated for this test. Electrode stickers placed on your child’s scalp record changes in the activity of the brainstem when sounds are presented to each ear through a headphone.
Atresia	Lack of an ear canal opening where sound normally travels by air waves to the middle ear. Atresia results in a conductive hearing loss.
Audiogram	A chart or graph that shows how well a person hears. It often shows what a person can hear with a hearing aid and without a hearing aid.
Audiologist	A person who tests hearing and works with deaf and hard of hearing individuals. Most audiologists have, as a minimum, a Master’s degree and are certified by the Canadian Association of Speech-Language Pathologists and Audiologists. (In the United States, audiologists are certified by the American Speech-Language-Hearing Association.)
Audiometer	Electronic equipment that is used to test hearing.
Auditory Nerve	The hearing nerve that connects the cochlea to the brain. It sends messages from the ear to the brain.
Auditory Neuropathy	The child’s external, middle, and inner ear or cochlea seems to receive sounds normally, but signals leaving the cochlea may be disorganized or the auditory nerve might not be processing sound normally. A child with auditory neuropathy often has more difficulty understanding speech than would be expected from his audiogram. The child’s hearing may also seem to fluctuate.
Bilateral Hearing Loss	Hearing loss in both ears.
Bone-Anchored Hearing Aid (BAHA)	The BAHA is for children who benefit from bone conduction hearing aids. The BAHA contains a tiny box with a microphone, processor, and a battery, which are all attached to a titanium screw inserted into the skull. Sound vibrations are transmitted directly through the screw to the bone and from there to the cochlea.
Bone-Conduction Testing	A bone vibrator is placed behind the child’s ear. The vibrator stimulates the inner ear directly and bypasses the middle ear. This helps to determine where the child’s hearing problem is located. If the problem is located in the outer or middle ear (conductive hearing loss), then it may be helped with medical intervention. If the problem is located in the inner ear (the auditory nerve, or the auditory area of the brain), then it is a permanent type of hearing loss (sensorineural).
Bone Oscillator	The vibrator used in bone-conduction testing.
BTE hearing aids	Behind-the-ear hearing aids.
Cochlea	Forms the inner ear. It is a spiral-shaped bony casing that has many tiny nerve endings inside.
Cochlear Implant	A surgically implanted electronic device that bypasses damaged structures in the inner ear and directly stimulates the auditory nerve, allowing some deaf children to learn to hear and interpret sounds and speech.
Comfort Level (C Level)	The Maximum Comfort Level is the highest electrical stimulation level that does not produce an uncomfortable sensation for a child using a cochlear implant.
Conditioned Play Audiometry (CPA)	Child responds to sound by performing an action (for instance, putting a block in a bucket or a peg in a pegboard) immediately after he detects a sound.
Conductive Hearing Loss	Something is wrong with the outer ear - for instance, no opening to the ear canal. Problems with the middle ear can be the result of fluid in the middle ear - or there can be something wrong with the three little bones in the middle ear. Sometimes a conductive hearing loss is temporary when it is the kind of problem that can be medically treated.
Congenital Hearing Loss	A hearing loss present at birth or associated with the birth process, or which develops in the first few days of life.
Decibels (dB)	Intensity (loudness) of sound is measured in decibels. For instance, 100 dB is a very loud sound, and 10 dB is a very quiet sound.
Dynamic Range	A hearing loss present at birth or associated with the birth process, or which develops in the first few days of life.
Electrode Array	The internally worn part of the cochlear implant device. The array is inserted surgically into the cochlea. Electrodes along the array are activated to transmit high-pitch and low-pitch information to the auditory nerve.
Eardrum	The eardrum is situated between the outer ear and the inner ear. It is a membrane, or piece of skin, that covers a small opening in the ear. If your child has “tubes,” these were inserted in the eardrum.
ENT	A doctor who is an Ear, Nose, and Throat Specialist.
Frequency/Pitch of Sound	Frequency is measured in Hertz (Hz). For instance, 250 Hz is a low frequency (or pitch) sound, and 4,000 Hz is a high frequency sound.
Hearing Threshold	The quietest sounds that a person can only barely hear. Aided threshold means the quietest sounds a person can just barely hear with his hearing aids on.
Impedance Testing	A small probe is placed in your child’s ear. This test helps to decide what kind of hearing loss your child has (conductive or sensorineural). Impedance testing gives the audiologist information about: (1) flexibility of the eardrum, (2) middle ear pressure, (3) functioning of the middle ear bones, (4) functioning of the Eustachian tube, and (5) the reflex contraction of a small muscle in the middle ear.
Inner Ear	The part of the ear that contains the cochlea and the auditory nerve.
Localized	Child turns his head towards a sound.