Question
Can you perform ABR on a patient with hyperacusis? If so, how? Is it necessary to sedate the patient? What happens to the patient's hearing if you sedate him and test ABR on 70 dB when he has his UCL at 60 dB?
Answer
It is possible to perform ABR on patients with hyperacusis. In fact, ABR may be one of several tests ordered by physicians who specialize in ear diseases to diagnose hyperacusis. Understandably, neurodiagnostic ABRs are generally done with moderately-high intensity levels around 80 to 90 dB nHL. Gopal et al (2000) presented 70 and 80 dB nHL clicks to an unmedicated (selective serotonin reuptake inhibitors) hyperacusic patient with UCLs at 80 and 85 dB HL for the right and left ears. In a study on hyperacusis in Williams syndrome, ABRs were reportedly performed at 70 dB HL (probably more accurately 70 dB nHL). Again, the average UCL range was between 85 and 90 dB HL. In both of these studies, click level was at or below UCL. Sedation may be a worthwhile and necessary approach for patient comfort, but it may not be required. Wave I may be recorded at intensity levels as low as 50 to 60 dB nHL. You might also consider optimizing the ABR test by using a faster rate (21.1/s) and as few as 1500 stimulus presentations per run to shorten test time without negatively influencing ABR morphology. If done right with clean recordings and little to no artifacts, replicated runs in each ear at a single intensity level could be done in about four and a half minutes. Realize, however, that making these stimulus and recording parameter adjustments will likely deviate from your local norms and should be interpreted with caution. Performing a quick UCL-like measurement using the click stimuli from your evoked potential system may help you determine the highest tolerable intensity level by the patient. Also, giving advanced notice to the already anxious patient and walking him or her through the each step of the procedure is highly recommended.
References:
Gopal, K.V., Daly, D.M., Daniloff, R.G., & Pennartz, L. (2000). Effects of selective serotonin reuptake inhibitors on auditory processing: case study. J Am Acad Audiology, 11, 454-463.
Gothelf, D., Farber, N., Raveh, E., Apter, A., & Attisas, J. (2006). Hyperacusis in Williams syndrome. Neurology, 66, 390-396.
Samuel R. Atcherson, Ph.D. is assistant professor at the University of Arkansas at Little Rock with joint appointment at the University of Arkansas for Medical Sciences. He received his Ph.D. from the University of Memphis in 2006. Dr. Atcherson's research and clinical interests are in the areas of auditory electrophysiology and electrodiagnostics, central auditory processing, and hearing assistive technology. He is former President of the Association of Medical Professionals with Hearing Losses (AMPHL), board member of the Arkansas Hands & Voices chapter, a proud colleague of a thriving group of hard-of-hearing audiologists.
