Hearing Assessments

	Pure Tone Audiometry (PTA)
	Impedance Audiometry (IA)
	Otoacoustic Emissions Test (OAE)
	Tinnitus Evaluation (TE)
	Spech Audiometry (SA)
	Distraction Test (DT)
	Visual Reinforcement Audiometry (VRA)
	Auditory Brainstem Response Audiometry (ABR)

Pure Tone Audiometry (PTA)
Purpose:	Assesses hearing level by demonstrating a specific response (such as hand-raising or button pushing) to an acoustic stimulus.
Age:	Appropriate for testing individuals from school-age through adulthood.
Procedure:	The individual is asked to raise his/her hand or press a button each time he/she hears a sound.
Results:	This test is performed by air and bone conduction to obtain ear- and frequency-specific information. Results define the nature and degree of hearing impairment.

Impedance Audiometry (IA)
Purpose:	Assesses the status of the middle ear system.
Age:	Appropriate for individuals from 4 months through adulthood.
Procedure:	A probe tone is introduced into the ear. The amount of sound reflected by the tympanic membrane is measured by a probe in the ear canal as the pressure in the ear canal is varied.
Results:	To provide information about the status of the tympanic membrane and middle ear system. (i.e., middle ear pathology/effusion, negative pressure possibly indicating Eustachian tube dysfunction).
Limitations:	Specialized equipment is required for accurate assessment of infants under four months of age.

Otoacoustic Emissions Test (OAE)
Purpose:	Assesses the function of cochlear outer hair cells.
Age:	Appropriate for individuals from birth through adulthood.
Procedure:	Acoustic emissions generated by the outer hair cells in the cochlea are elicited by direct acoustic stimulation, and are recorded by a small microphone placed in the ear canal. Data collected will be analyzed by a computer program.
Results:	Presence of evoked Otoacoustic emissions is correlated with hearing thresholds of 30 dB or better.
Limitations:	because measurement of emissions relies on reverse transduction of sound through the middle ear, presence of middle ear pathology will affect recording and/or accuracy of results.

Tinnitus Evaluation (TE)
What is Tinnitus?	Tinnitus is the medical term for 'ringing in the ears' or 'head noise'. It is the perception of ringing, hissing, or other sound in the ears when no external sound is present. Tinnitus may be constant or intermittent, and may happen on one ear or both ears.
Prevalence:	According to data from the United States, tinnitus affects 32% of the general population, predominately in the elderly community. It was also found that 80% of persons with tinnitus also have some degree of hearing impairments.
Types of Tinnitus:	Subjective Tinnitus Subjective tinnitus is a phenomenon in which sufferer hears noise which cannot be heard by an outside observer. It accounts for 95% of all tinnitus cases. It is much less understood than objective tinnitus and there is no general agreement about the causes.   Objective Tinnitus Objective tinnitus is a phenomenon in which sufferer may or may not hear noise which can be heard by an outside observer. It occurs in less than 5% of cases and is often associated with inner ear structural defects, vascular disorders or muscular disorders. Since the cause of objective tinnitus can be determined in most cases, it can usually be treated, either medically or surgically.
Causes:	For 43% of tinnitus sufferers, the cause for their suffering is unknown. For other sufferers, tinnitus may be caused by exposure to loud noise, cerumen accumulation, acoustic neuroma, consumption of ototoxic drugs, ear infection, Meniere's Disease, etc.
Audiological Evaluation of Tinnitus:	Apart from a medical examination by an otorhinolaryngologist, tinnitus sufferer should consult an audiologist for hearing and tinnitus evaluation. A tinnitus evaluation is usually comprised of pure tone audiometry, tinnitus pitch matching, tinnitus loudness matching, minimum masking level determination and loudness discomfort level determination.
Tinnitus Masker:	Tinnitus maskers are electronic devices which produce sounds to cover up tinnitus. Maskers do not make tinnitus go away, yet they make tinnitus less noticeable. The characteristics of tinnitus obtained from tinnitus evaluation determine the type of masking noise to be used. Like any treatment, maskers are useful for some, but not all, sufferers.

Spech Audiometry (SA)
Purpose:	Assesses the sensitivity to speech materials
Age:	Appropriate for individuals from 8 years old
Procedure:	Testing stimuli are given through headphones. Client is encouraged to give response even if she is unsure of what words is heard. Scores are given on phoneme basis.
Results:	For normal hearing people, the maximum discrimination score is 100%.

Distraction Test (DT)
Purpose:	Assesses hearing ability using conditioned responses to sound.
Age:	Appropriate for infants from 6 through 9 months.
Procedure:	The infant is observed for head turns after presentation of sound through noisemakers.
Results:	This test provides information about age-appropriateness of an infant's response to supra-threshold sound. Results can help to rule-out significant hearing loss.
Limitations:	This method relies on the audiologist's observations to determine when a response to sound has occurred. It cannot be used to define auditory thresholds.

Visual Reinforcement Audiometry (VRA)
Purpose:	Assesses hearing sensitivity using conditioned responses to sound, i.e., head turning.
Age:	Appropriate for testing children from 7 through 30 months of age.
Procedure:	The child is conditioned to provide a specific response to an acoustic stimulus. For example, a head turn in the direction of the sound source is rewarded by lighting and/or activating an animated toy. Once the child is conditioned to respond to the sound, the intensity of the signal is reduced to determine threshold of hearing.
Results:	This procedure can be used to determine threshold of hearing
Limitations:	Because signals are typically presented through a loudspeaker, thresholds obtained indicate hearing level of the 'better hearing ear' only.

Auditory Brainstem Response Audiometry (ABR)
Purpose:	Assesses auditory function from cochlea level up to the brainstem.
Age:	Appropriate for individuals from birth through adulthood.
Procedure:	The auditory system is stimulated by a brief acoustic signal via air or bone conduction. The resulting neuro-electric activity is recorded by surface electrodes placed on the head. The response is assessed based on the identification of component waves, their morphology and the measurement of absolute and interwave latencies compared to normative data collected via various previous studies and normal groups of subjects.
Results:	Provides ear-specific information and some frequency-specific information about hearing acuity within 5-10 dB of behavioral thresholds. Can also detect cochlea and/ or neural pathologies
Limitations:	Requires individuals to be in sleep state. Some infants and young children may require sedation.