Auditory Brainstem Response Paper

Auditory Brainstem Response (ABR) audiometry is an evoked potential test of auditory brainstem function, using brief click or tone pip stimuli in order to generate a response. These stimuli are transmitted from an acoustic transducer (an insert earphone or headphone) (Bhattacharyya, 2015). The waveform response produced is measured by surface electrodes, which are usually placed on the mastoid process behind the outer ear and the vertex (top of the head). A ground electrode is placed on the opposite mastoid (opposite outer ear). The amplitude of the signal is averaged and placed against time much like an electroencephalogram (EEG). Each wave represents electrical activity at one or more point along the auditory brainstem pathway (Martin & Clark, 2014). An ABR often takes place if a newborn baby fails the hearing
Firstly, auditory brainstem responses are measurable in all normal individuals, including newborn babies. The patient’s state of arousal, sedation and anaesthesia do not affect the ABR and as a result, the test can be performed with or without the patient’s cooperation. Performing the test on a patient under sedation is an advantage as it makes it possible to test young children or children who are difficult to test. As well as this, the tone-burst ABR can produce frequency-specific estimates of hearing loss, including the degree of hearing loss and the type. This means that when hearing loss is identified in a patient using an ABR test, treatment and further tests can take place that are specific to their degree and type of hearing loss (Gelfand, 2001). A further advantage of an ABR is that it is considered effective when evaluating suspected retrocochlear pathology, which is where hearing loss is caused by damage to the auditory nerve. Examples of this are acoustic neuromas or vestibular schwannoma, both of which are benign tumours on the auditory nerve (Bhattacharyya,