Over the years, the Click-Evoked ABR has played a major role for evaluating the peripheral auditory function and continued its efforts in determining hearing loss problems in infants and children.
The Auditory Brainstem Response (ABR) is neurological process to determine hearing sensitivity and abnormalities in auditory nerve or pathway. Traditional ABR has shown a poor sensitivity to tumours and unable to detect any problem associated with it, as ABR rely on latency changes of peak V. To enhance ABR quality to detect small tumours, Stacked derived ABR is used to identify small acoustic tumours (small than 1cm) missed by standard ABR.
What is Stacked ABR?
The Stacked ABR is a test used in testing for acoustic tumours and Meniere’s disease. In addition to existing neural activity produced from 5 regions of frequency across cochlea in response to (click) stimulation and high-pass noise masked responses. It is a combination of test for all frequency regions of the cochlea. The Stacked ABR is a valuable screening process because it is sensitive, specific, widely available, comfortable, and cost-effective.
What to expect?
An audiologist will place electrodes on forehead and earlobes which is directly connected to a computer to take recordings. Earphones are placed in the ears to deliver click stimulus. You are not required to respond to the clicks while sitting in a reclined position. You are instructed to sit as relaxed as possible with closed eyes.
What does ABR measure?
The electrodes start to measure the electrical activity from the auditory pathway as the earphones began to deliver the clicks. Then the computer analyses the electrical responses in a form of a wavelength. The high and low peaks of wavelength respond according to the stimulus.
Any delay in peaks aids in recognizing the acoustic neuromas along the auditory pathway. Using the ABR for patients the problem of hearing sensitivity can also be estimated especially in those patients who cannot be tested using behavioural testing that is in infants and adults who are mentally challenged.
In the ABR diagnoses, the electrodes measure the wavelength of electrical activity along the auditory pathway. However, SABR diagnoses in a different manner other than ABR. SABR is a latest technology that helps to identify tumours (smaller than 1cm) and cochlear hydrops and Meniere’s disease.