Calibration: The electroacoustic or psychoacoustic determination that an audiometer is performing properly in terms of its acoustic output, attenuator linearity, frequency accuracy, harmonic distortion, and so on.
California Consonant Test: A closed-message word-recognition test, with the emphasis on unvoiced consonants to tax the abilities of patients with high-frequency hearing losses.
Caloric test: Irrigation of the external auditory canal with warm or cold water to stimulate the vestibular labyrinth. In normal patients the result is nystagmus with some sensation of vertigo.
Cancellation: The reduction of the amplitude of a sound wave to zero. This results when two tones of the same frequency and amplitude are introduced 180 degrees out of phase.
Carhart notch: An artifactual depression in the bone-conduction audiogram of patients with otosclerosis. It is most evident at 2000 Hz and disappears following corrective surgery.
Carotid artery: The main large artery on either side of the neck. It passes beneath the anterior wall of the middle ear.
Carrier phrase: A phrase, such as "Say the word _____," or "You will say _____," that precedes the stimulus word during speech audiometry. It is designed to prepare the patient for the test word and to assist the clinician (if a monitored live voice is used) in controlling the input loudness of the test word.
Carrier: A phenotypically normal individual, whose body contains a recessive gene for an abnormal trait, along with its normal allele.
Carryover: Transference or generalization; the use of the corrected form outside of the clinical setting.
Case history: Background information on a client.
Caudate: Portion of the basal nuclei.
Cell body: The central portion of a nerve cell.
Central auditory processing disorder (CAPD): Problems along the brain stem pathways and the auditory cortex of the brain resulting in an inability to efficiently utilize and interpret auditory information, although hearing is within the normal range.
Central masking: The shift in the auditory threshold of a tone produced by a noise in the opposite ear when the level of the noise is not sufficient to cause peripheral masking by cross-conduction.
Central nervous system (CNS): The brain and spinal cord.
Central sulcus: Also known as the fissure of Rolando, this valley separates the frontal and parietal lobes of the brain.
Cerebellopontine angle (CPA): That area at the base of the brain at the junction of the cerebellum, medulla, and pons.
Cerebellum: A lower brain structure consisting of two hemispheres that smoothly regulates and coordinates the control of purposeful muscle movement, including very complex and fine motor activities. The cerebellum revises the transmission from the cortex's motor strip to produce accurate, precise movements.
Cerebral arteriosclerosis: A type of ischemic stroke resulting from a thickening of the walls of cerebral arteries in which elasticity is lost or reduced, the walls become weakened, and blood flow is restricted.
Cerebral palsy: A motor disorder produced by damage to the brain; it usually occurs prenatally, perinatally, or in early infant life.
Cerebrovascular accident (CVA): A clot or hemorrhage of one of the arteries within the cerebrum; a stroke.
Cerebrum: The upper brain, which is divided into two hemispheres. The outermost layer is called the cortex.
Cerumen (earwax): A substance produced by the sebaceous glands in the ear canal that provides some lubrication and protects the ear from the invasion of insects.
Cerumenolytic: A chemical substance (such as carbamide peroxide and glycerin) that is used to soften cerumen prior to removal.
Cervical vertebrae: Upper most region of the vertebral column consisting of seven individual vertebrae.
Chin tuck: A posture with the chin down that is helpful with some patients who have a swallowing disability.
Cholesteatoma: A tumor, usually occurring in the middle ear and mastoid, that combines fats and epithelium from outside the middle-ear space.
Chorda tympani nerve: A branch of the facial nerve that passes through the middle ear. It conveys information about taste from the anterior two-thirds of one side of the tongue.
Chorea: A form of hyperkinetic dysarthria characterized by rapid or continual, random, irregular, and/or abrupt hyperkinesia. Speech, when affected, may be characterized by inappropriate silences caused by voice stoppage; intermittent breathiness, strained harsh voice, and hypernasality; imprecise articulation with prolonged pauses; and forced inspiration and expiration resulting in excessive loudness variations.
Chromosome: A structure in every animal cell nucleus that bears the genetic information.
Chronemics: The study of the effect of time on communication.
Chronic laryngitis: Vocal abuse during acute laryngitis that leads to vocal fold tissue damage.
Chronic: A condition characterized by long duration.
Cilia: Eyelash-like projections of some cells that beat rhythmically to move certain substances over their surfaces.
Clavicle: Collar bone.
Cleft palate: A congenital opening in the midline of the roof of the mouth that may extend through the hard palate, soft palate, and uvula.
Cleft: An abnormal opening in an anatomical structure.
Clinical decision analysis (CDA): Procedures by which tests can be assessed in terms of their sensitivity, specificity, efficiency, and predictive value.
Closed syllable: A syllable, or basic acoustic unit of speech, that ends in one or more consonants.
Clustered disfluency: A stuttering behavior that is a combination of a sound repetition and sound prolongation, such as "m-m-m-mmmommy."
Cluttering: Disfluent speech that is characterized by overuse of fillers and circumlocutions associated with word-finding difficulties, rapid speech, and word and phrase repetitions. Cluttering does not seem to contain the fear of words or situations found in stuttering.
Coccygeal vertebrae: Three fused vertebrae immediately below the sacral vertebrae.
Coccyx: Fused structure comprised of three coccygeal vertebrae.
Cochlea: That portion of the inner ear responsible for converting sound waves into an electrochemical signal that can be sent to the brain for interpretation. It is composed of two concentric labyrinths: the outer one is made of bone, the inner one of membrane.
Cochlear duct: See Scala media.
Cochlear implant: A coil and series of electrodes surgically placed in the mastoid and inner ear. It is designed to provide sound to a patient with a profound hearing loss through a processor and external coil.
Cochlear microphonic (CM): The measurable electrical response of the hair cells of the cochlea.
Cognitive ability: The capacity to think and understand.
Cognitive rehabilitation: A treatment regimen for individuals with TBI that is designed to increase functional abilities for everyday life by improving the capacity to process incoming information.
Cold running speech: Rapidly delivered speech, either prerecorded or by monitored live voice, in which the output is monotonous and the peaks of the words strike zero on the VU meter.
Collaborative: A model of intervention in which the classroom teacher and SLP plan and implement intervention in the classroom.
Columella: A strip of tissue connecting the tip of the nose to the base.
Commissure: Nerve fibers connecting similar structures on both sides of the brain.
Communication disorder: An impairment in the ability to receive, send, process, or comprehend concepts of verbal, nonverbal, or graphic symbol systems.
Communication: An exchange of ideas between sender(s) and receivers(s).
Compensatory articulation error: Gross sound substitution errors that are an attempt to make up for the physical inability to produce a given sound correctly.
Complete cleft: A total separation of a normally fused structure.
Complex wave: A sound wave made up of a number of different sinusoids, each with a different frequency.
Compliance: The mobility of the tympanic membrane. The inverse of stiffness.
Component: A pure-tone constituent of a complex wave.
Compression: A decrease in pressure. In a hearing aid, a method of limiting the amplification of louder sounds relative to weaker sounds.
Compression: That portion of a sound wave where the molecules of the medium are compressed together. Also called condensation.
Computed tomography (CT): A procedure for imaging the inside of the body by representing portions of it as a series of sections. The many pictures taken are resolved by computer, and the amount of radiation to the patient is significantly less than with older procedures.
Computerized audiometry: The process of testing human hearing sensitivity by having computers programmed to present the stimuli and interpret the threshold results.
Computerized dynamic posturography (CDP): A quantitative assessment of balance function for postural stability, performed by a computer-based moving platform and motion transducers.
Conditioned orientation reflex (COR): A technique for testing young children in the sound field by having them look in the direction of a sound source in search of a flashing light.
Conduction aphasia: A fluent aphasia in which the individual's conversation is abundant and quick. Characterized by anomia, mildly impaired auditory comprehension if at all, extremely poor repetitive or imitative speech, and paraphasia.
conduction vibrators. It consists of a resilient surface that simulates the vibrating properties of the mastoid process of the skull and an accelerometer. It is connected to a meter that reads in either decibels or units of force.
Conductive hearing loss: A mild to moderate impairment in auditory acuity due to malformation or obstruction of the outer and/or middle ears.
Conductive hearing loss: The loss of sound sensitivity produced by abnormalities of the outer ear and/or middle ear.
Condyle: The rounded projection, or process, of a bone. The condyle of the mandible comes to rest in a fossa (a hollowed or depressed area) just below the osseocartilaginous junction of the external auditory canal.
Congenital laryngeal webbing: Extraneous tissue on the anterior aspects of the vocal folds that can interfere with breathing; present at birth.
Congenital: Present at birth.
Connected Speech Test (CST): A procedure by which the intelligibility of speech passages is measured on a sentence-by-sentence basis in the presence of a related background babble.
Connected speech: See Cold running speech.
Consistent aphonia: Persistent absence of voice.
Consonant: A phoneme that is produced with some vocal tract constriction or occlusion.
Consonant-nucleus-consonant (CNC): words Monosyllabic words used in testing word recognition. Each word has three phonemes; the initial and final phonemes are consonants, and the middle phoneme is a vowel or diphthong.
Contact ulcer: A benign lesion that may develop on the posterior surface of the vocal folds.
Content: The substance or meaning of communication.
Contralateral: Organization of the nervous system that enables motor control to and sensory information from one side of the body to be processed in the opposite side of the brain.
Conversion aphonia: Psychologically based loss of voice.
Conversion disorders: Psychological suppression of emotions.
Conversion neurosis: A Freudian concept by which emotional disorders become transferred into physical manifestations (e.g., hearing loss or blindness).
Cortex: The outer gray layer of cell bodies in the cerebrum, approximately one-quarter inch in thickness.
Corti's arch: A series of arches made up of the rods of Corti in the cochlear duct.
Cosine wave: A sound wave representing simple harmonic motion that begins at 90 degrees.
Costal: Pertaining to the ribs.
Cranial nerves: Motor, sensory, and mixed nerves that are important for the control of speech and other processes.
Craniofacial anomalies: Congenital malformations involving the head (cranio: above the upper eyelid) and face (facial: below the upper eyelid).
Craniosynostosis: Premature closing of the sutures of the skull, which greatly disfigures the forehead.
Cricoid cartilage: Signet ring-shaped cartilage at the base of the larynx.
Cricothyroid muscle: Intrinsic laryngeal muscle that tenses the vocal folds.
Criterion referenced: An evaluation of an individual's strengths and weaknesses with regard to specific skills.
Critical band: A portion of a continuous band of noise surrounding a pure tone. When the sound-pressure level of this narrow band is the same as the sound-pressure level of the tone, the tone is barely perceptible.
CROS (contralateral routing of offside signals): A hearing aid originally developed for patients with unilateral hearing losses. The microphone is mounted on the side of the poorer ear, and the signal is routed to the better ear and presented by an "open" earmold.
Cross-hearing: The reception of a sound signal during a hearing test (either by air conduction or bone conduction) at the ear opposite the ear under test.
Crura: Legs, as of the stapes.
Crus: Singular of Crura.
Cultural identity: The larger social and or ethnic group to which each individual feels a sense of belonging.
Cycle: The complete sequence of events of a single sine wave through 360 degrees.
Cycles approach: A method of phonological therapy in which the same target processes are addressed in several training periods, or cycles.
Cytomegalovirus (CMV): A common virus that is a member of the herpes family of viruses and can cause congenital hearing loss when contracted by a pregnant woman.
Damage-risk criteria: The maximum safe allowable noise levels for different bandwidths.
Damping: Progressive diminution in the amplitude of a vibrating body. Systems are said to be heavily damped when the amplitude decays rapidly, lightly damped when the amplitude decays slowly, and critically damped if all vibration ceases before the completion of one cycle.
DAS: See Developmental apraxia of speech.
Deaf culture: A celebration of the uniqueness of their lifestyle by individuals with deafness.
Deaf: A severe to profound hearing loss in which the auditory system provides little or no access to the world.
Decibel (dB): A unit for expressing the ratio between two sound pressures or two sound powers; one-tenth of a Bel. Degrees of hearing loss refer to a specific decibel change.
Decruitment: The less than normal growth in loudness of a signal as the intensity is increased. Also called subtractive hearing loss, it is suggestive of a loss of nerve units.
Decussation: A crossing over, as of nerve fibers connecting both sides of the brain.
Degree of hearing loss: Amount of hearing loss expressed in units called decibels (dB).
Delayed auditory feedback (DAF): The delay in time between a subject's creation of a sound (e.g., speech) and his or her hearing of that sound.
Dementia: An acquired pathological condition or syndrome that is characterized by intellectual decline, especially memory, due to neurogenic causes. Additional deficits include poor reasoning or judgment, impaired abstract thinking, inability to attend to relevant information, impaired communication, and personality changes.
Dendrite: The branched portion of a neuron that carries the nerve impulse to the cell body.
Dentist: A medical professional who specializes in teeth.
Dentition: The number, type, and arrangement of teeth.
Derived score: A unit of measurement that compares an individual with others on the basis of the normal curve.
Developmental apraxia of speech (DAS): An impairment in programming the musculature for speech without apparent muscle weakness or paralysis. Apraxia of speech in children is characterized by multiple articulation errors including addition of speech sounds, sound and syllable repetitions, and sound prolongations.
Developmental disfluency or developmental stuttering: Whole-word repetitions and other self-conscious nonfluency that is apparent in many young children.
Developmental stuttering: Interruptions of the forward flow of speech that begin in childhood, characterized by sound and syllable repetitions and sound prolongations.
Developmental verbal dyspraxia: See Developmental apraxia of speech.
Diadochokinetic rate: Rate of speed with which an individual can rapidly produce target syllables.
Diagnosis: A statement distinguishing an individual's difficulties from the broad range of possibilities.
Diagnostic therapy: Ongoing assessment and evaluation as intervention takes place.
Dialect: A linguistic variation that is attributable primarily to geographical region or foreign language background. It includes features of form, content, and use.
Diaphragm: Dome-shaped muscle separating the thorax and abdomen; primary muscle of inhalation.
Dichotic digits test: A test for central auditory disorders performed by presenting two pairs of digits simultaneously to both ears.
Dichotic Stimulation: of both ears by different stimuli. This is usually accomplished with earphones and two channels of a CD or tape player.
Dichotically: Different signals are applied either simultaneously or at different time intervals to each ear.
Difference limen for intensity (DLI): A test designed to determine a subject's ability to detect small changes in the intensity of a pure tone. In the 1950s a small DLI was considered a symptom of recruitment.
Difference tone: The perceived pitch of a tone resulting from the simultaneous presentation of two tones of different frequencies. The tone perceived has a frequency equal to the difference in hertz between the other two tones.
Digital hearing aid: An amplification system in which the input signal is stored, as by a computer, as sets of binary digits that represent the frequency, intensity, and temporal patterns of the input acoustical signal.
Diotic Stimulation: of both ears with stimuli that are approximately identical, as through a stethoscope.
Diotically: The same signal is applied to each ear simultaneisly.
Diphthong: Two vowels that are said in such close proximity that they are treated as a single phoneme.
Diplacusis binauralis: Hearing a tone of single frequency as different pitches in the two ears.
Diplacusis monauralis: Hearing a single frequency in one ear as a chord or noise.
Diplophonia: The perception of two vocal frequencies.
Distinctive features: The attributes of phonemes that differentiate one from another on the basis of a binary principle.
Distortion product otoacoustic emission (DPOAE): The emission of a sound from the cochlea, measured in the external auditory canal, which is the result of inner-ear distortion generated when two tones of different frequencies are introduced to the ear.
Distortion: In a hearing aid, the result of an inexact copy of the input signal by the output signal. Distortion is usually caused by the microphone, speaker, and/or amplifier.
Distortional: bone conduction The response to a sound stimulus evoked when the skull is deformed by a bone-conduction vibrator, distorting the cochlea and giving rise to electrochemical activity within the cochlea.
DNA: Deoxyribonucleic acid, the fundamental molecular material that carries the genetic code.
Doerfler-Stewart (D-S) test: A binaural test for nonorganic hearing loss using spondaic words and a masking noise.
Dorsal cochlear nucleus: The smaller of two cochlear nuclei on each side of the brain; it receives the fibers of the cochlea on the ipsilateral side.
Double swallow: A technique in which the patient swallows more than once per bolus.
Down syndrome: Sometimes called "trisomy 21 syndrome," Down disorder is a congenital condition characterized by mental retardation; a small, slightly flattened skull; low-set ears; abnormal digits; and other unusual facial and body characteristics.
Ductus reuniens: A tube connecting the saccule with the scala media that carries endolymph to the cochlea.
Dynamic assessment: Probing during evaluation in an attempt to identify possibly effective intervention procedures.
Dynamic range (DR): for speech See Range of comfortable loudness.
Dynamic: Characterized by energy or effective energy, changing over time.
Dyne (d): A unit of force just sufficient to accelerate a mass of 1 gram at 1 cm/sec2.
Dysacusis: Distortion of an auditory signal that is associated with loss of auditory sensitivity. Evidenced by poor word recognition.
Dysarthria: One of several motor speech disorders that involve impaired articulation, respiration, phonation, or prosody as a result of paralysis, muscle weakness, or poor coordination. Motor function may be excessively slow or rapid, decreased in range or strength, and have poor directionality and timing.
Dysgraphia: A disability that is characterized by difficulty producing written symbols.
Dysinhibition: Bizarre behavior patterns often associated with brain-damaged individuals.
Dyskinesia: Slow, involuntary movement of the body that is beyond the individual's control. Also called athetosis.
Dyslexia: A disability that is characterized by difficulty comprehending printed symbols and recognizing words. Children with dyslexia often exhibit delayed language development, listening comprehension problems, and poor phonological awareness.
Dysphagia: A disorder of swallowing.
Dysphonia: Any impairment of phonation.
Dystonia: A form of hyperkinetic dysarthria that is characterized by a slow, sustained increase and decrease of hyperkinesia involving either the entire body or localized sets of muscles. As a result, there are excessive pitch and loudness variations, irregular articulation breakdown, and vowel distortions.
