Listening in on the listening brain

www.physicstoday.org An article published in the journal Brain some 40 years ago forever changed the world of hearing assessment.1 Don Jewett and John Williston reported that neural firing recorded from the human scalp with electroencephalogram electrodes could determine whether a sound was heard. The measured electrical impulses originated in the midbrain, a part of the auditory brainstem, and auditory brainstem response (ABR) recording entered the clinic as an objective, passive means to determine whether newborn babies could hear. Audiologists no longer needed to wait until children were old enough to raise their hands in response to the beeps and bleeps of an audiometer to determine whether they could hear normally. There soon emerged other uses of ABR—tumor detection, diagnosis of nerve-damaging diseases such as multiple sclerosis, and more.2