MEDICO LEGAL M A G A Z I N E
QUANTIFICATION OF NOISE INDUCED HEARING LOSS – A GAME CHANGER? By Mr George E. Murty M.B.Ch.B, M.D., F.R.C.S., F.R.C.S. (Otolaryngology), F.A.C.S. (USA), Consultant Otolaryngologist/Head and Neck Surgeon George Murty is an ENT Consultant at University Hospitals Leicester and Senior Partner of Forest Medical Services, specialising in noise induced hearing loss.
“Guidelines on the diagnosis of noise-induced hearing loss for medical legal purposes”1 has become the definitive paper on which the diagnosis of noise induced hearing loss (NIHL) in compensation cases is made. However, there has hitherto not been a universally accepted method of quantifying the degree of NIHL once the diagnosis has been made. The original authors in a new publication “Guidelines for quantification of noise induced hearing loss in a medical legal context”2 describe such a method. The original diagnosis guidelines require 3 criteria to be satisfied. R1 is the presence of a high frequency sensorineural impairment. R2 is sufficient noise
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Sp o n s o re d by:
exposure. R3 is the presence of an acoustic notch or an audiometric bulge pattern on the puretone audiogram. The diagnosis guidelines are not however definitive as the method of age associated hearing loss (AAHL) calculation is open to several interpretations and the guidelines do not quantify the degree of NIHL. The new quantification guidelines address these issues. They specify that the age used for estimating the AAHL is the nearest 5 year division, and that the 25th, 50th or 75th percentile is used depending on the best fit to the 1 and 8 kHz anchor points. It also requires the adjusted AAHL to be calculated using
