Auditory brainstem response
[7] In 1967, Sohmer and Feinmesser were the first to publish human ABRs recorded with surface electrodes, showing that cochlear potentials could be obtained non-invasively.
In 1971, Jewett and Williston gave a clear description of the human ABR and correctly interpreted the later waves as arriving from the brainstem.
[4] Long and Allen were the first to report abnormal brainstem auditory evoked potentials (BAEPs) in an alcoholic woman who recovered from acquired central hypoventilation syndrome.
Stacked ABR is the sum of the synchronous neural activity generated from five frequency regions across the cochlea in response to click stimulation and high-pass pink noise masking.
[9] This technique was based on the 8th cranial nerve compound action potential work of Teas, Eldredge, and Davis in 1962.
[10] In 2005, Don defined the Stacked ABR as "...an attempt to record the sum of the neural activity across the entire frequency region of the cochlea in response to a click stimuli.
Although the click stimulates a wide frequency region on the cochlea, phase cancellation of the lower-frequency responses occurs as a result of time delays along the basilar membrane.
In order to compensate for these latency shifts, the wave V component for each derived waveform is stacked (aligned), added together, and then the resulting amplitude is measured.
[13] Tone-burst ABR is used to obtain thresholds for children who are too young to otherwise reliably respond behaviorally to frequency-specific acoustic stimuli.
It is an electrophysiologic response to rapid auditory stimuli and creates a statistically valid estimated audiogram (evoked potential predicts hearing thresholds).
ASSR uses statistical measures to identify thresholds is a "cross-check" for verification purposes prior to arriving at a differential diagnosis.
In 1995, Lins and Picton found that simultaneous stimuli presented at rates in the 80 to 100 Hz range made it possible to obtain auditory thresholds.
Gain settings of 10,000 are common, artifact reject is "on", and manual "override" allows the clinician to make decisions during test and correct as appropriate.
[14] Similarities: Differences: Analysis is dependent upon the fact that related bioelectric events coincide with the stimulus repetition rate.
It occurs in the spectral domain and is composed of specific frequency components that are harmonics of the stimulus repetition rate.
Correction data depends on variables such as equipment, frequencies, collection time, subject age, sleep state, and stimulus parameters.
[16] Previously, brainstem audiometry was used for hearing aid selection by using normal and pathological intensity-amplitude functions to determine appropriate amplification.
[17] The principal idea was based on the assumption that amplitudes of the brainstem potentials were directly related to loudness perception.
[18] ABR can be an inaccurate indicator of hearing aid benefit due to difficulty processing the appropriate amount of fidelity of the transient stimuli used to evoke a response.
A 2006 study measured the P1 response in deaf children who received cochlear implants at different ages to examine the limits of plasticity in the central auditory system.
