Pure Tone Audiometry- PTA

Air Conduction Audiometry (A/C) – measurement of hearing sensitivity to pure tones, usually in the range of 250Hz – 8K Hz. The pure tone signal is detected after it passes through the complete auditory pathway, including outer, middle and inner ear, brainstem, through the brain and auditory cortex. Results of PTA are shown on an audiogram.

Bone Conduction Audiometry (B/C)

Same as A/C but pure tone stimulus bypasses outer and middle ear and stimulates the inner ear and subsequent auditory structures to the cortex. The resulting measurement is the sensori-neural component of the hearing loss children(or ‘nerve loss’).

The difference between A/C and B/C is referred to as the air-bone gap or conductive hearing loss.

Speech Audiometry

Tests the ability to perceive and discriminate words; may be affected by dysfunction of the auditory pathway at any level.

Play Audiometry

Pure tone audiometry (in free field or under headphones) where a child is conditioned to respond to a sound stimulus by placing a peg in a pegboard or dropping a block in a box or something similar. This assessment also includes the Kendall Toy Test, which helps demonstrate the child’s ability to discriminate sounds of different objects without visual cues.

VRA- Visual Reinforcement Audiometry

In free field- conditions the child to associate frequency-specific sounds (500 to 4000 Hz) with a reinforcement visual stimulus such as a lighted animated toy. Minimum response levels are obtained (MRLs).

DPOAE’s- Distortion Product Otoacoustic Emissions

Cochlear response involving the outer hair cells. Middle ear function can impede the stimulus as well as the detection of the response. Used as a screening test, (OAE’s are absent if hearing thresholds are greater than about 40 dB). Test is also used for additional/ supplementary individual ear information. It also indicates middle ear status.

Central Auditory Processing Evaluation

Central auditory processing disorder: A condition in which there is an inability to differentiate, recognize or understand sounds while both the hearing and intelligence are normal.

Tympanometry / Reflex Testing

Evaluation of middle ear and Eustachian Function.

Measurement of acoustic stapedial muscle reflexes

Electrophysiological measurements

ABR- Auditory Brainstem (Evoked) Response

Generated in the brainstem, by using a ‘click’ stimulus which activates the cochlea in the 2000 to 4000 Hz region- not affected by higher auditory pathways.

ASSR- Auditory Steady State (Evoked) Response

Automated estimation of a frequency specific audiogram. Frequency specific responses obtained, 500, 1000, 2000 and 4000 Hz.

CERA- Cortical Evoked Response Audiometry

Measurement of auditory cortex responses to tonal stimuli (500Hz – 4K Hz)