Audiology & Speech Theory

TYMPANOMETRY

Tympanomery is an objective test done to analyse middle ear pathology when the tympanic membrane is normal. It can be even done in very small children who are not cooperative for pure tone audiogram. 

Tympanometry is defined as the measurement of the change of impedance of the middle ear at the plane of the tympanic membrane as a result of changes in air pressure in the external auditory meatus. Tympanogram is a graphic representation with impedance or stiffness of the middle ear as the ordinate (Y-axis) and the corresponding air pressure as the abscissa (X-axis).

BRAIN STEM EVOKED RESPONSE AUDIOMETRY

This test is ordered by physicians to help diagnose nervous-system abnormalities,  hearing losses (especially in low-birth weight newborns), and to assess neurologic functions.This helps in early detection and threshold estimation of hearing impairment in children.

This test focuses on changes and responses in brain waves that are stimulated by a clicking sound to evaluate the auditory pathways of the brainstem. The test is performed by placing the patient in a reclining chair or bed. The patient is asked to relax and remain still. Electrodes are placed on the patient’s scalp, along the vertex and on each earlobe. The patient hears clicking noises or tone bursts through earphones, and the electrodes pick up the brains response and record it on a graph.

THE AUDITORY STEADY STATE EVOKED RESPONSE (ASSR)

The Auditory steady state evoked response (ASSR) is a brain response elicited by a continuous or steady state acoustic stimulus. ASSRs are evoked by modulated tonal stimuli and provide frequency – specific measures of hearing sensitivity across a wide rage of frequencies (250 to 8000 Hz). The primary clinical application for Auditory Steady-State Evoked Response is for detailed frequency-specific hearing assessment in babies. Since ASSR measures electrophysiological responses to sounds, it allows us to objectively assess how well a subject hears. This is especially useful in patients who are unable or unwilling to give reliable behavioral responses. ASSR can be reliably recorded in sleeping neonates and children.

They are evoked by frequency-specific tonal stimuli, can be detected objectively using statistical algorithms, have thresholds that are highly correlated with behavioral audiogram thresholds, and can be used to estimate the behavioral pure tone audiogram.  The estimated audiograms obtained from ASSR testing provide a basis for determining whether the child requires a cochlear implant or not. 

OTO ACOUSTIC EMISSIONS

Otoacoustic emissions (OAE) are sounds that are produced by healthy ears in response to acoustic stimulation or occurs spontaneously. They are considered to be epiphenomenona, and by-products of the activity of the outer hair cells in the cochlea. Otoacoustic emissions were first reported by Kemp in 1978 . Although his observations were greeted with skepticism, OAEs have since been reliably confirmed. They appear to be generated by motile elements in the cochlear outer hair cells. Oto acoustic emissions are widely used for newborn hearing screening and for identifying the site of lesion in hearing disorders.

SPEECH & LANGUAGE THERAPY

Auditory verbal therapy, the latest in auditory rehabilitation is a specialty of the institute. This method ensures that the deaf child learns language the proper way (i.e., via listening) and becomes a contributing member of the society. Auditory Verbal Therapy) is a specialized type of therapy designed to teach a child to use the hearing provided by a hearing aid or a cochlear implant for understanding speech and learning to talk. The child is taught to develop hearing as an active sense so that listening becomes automatic and the child seeks out sounds in life. Hearing and active listening become an integral part of communication, recreation, socialization, education and work.

PURE TONE AUDIOMETRY / SPEECH AUDIOMETRY

Equipped with advanced audiologicalequipments, MAHAVIR ENT provides all kinds of audiological investigations which are essential for identifying the pathology related to hearing disorders.   Audiology is the branch of science that studies hearing, balance, and their disorders. Audiology aims to determine whether someone can hear within the normal range , and if not, which portions of hearing (high, middle, or low frequencies) are affected and to what degree. If a hearing loss is present, an audiologist determines whether what kind of hearing loss, if any, is present and he or she proposes to the patient what options (e.g. hearing aids, cochlear implantation, surgery, auditory habilitation, appropriate medical referrals etc.) may help to restore function. Audiologists prescribe, programme and dispense hearing aids. Audiologists are also involved in the prevention of hearing loss, hearing conservations programs and other communication disorders. Audiologists are often in charge of Newborn Hearing Screening Programs designed to identify hearing loss within the first 2 months of life.