Validation of the auditory hazard assessment algorithm for the human with impulse noise data

Predicting auditory hazard from intense acoustic impulses, such as weapons fire or airbags, has been an intractable problem. The U.S. Army developed a theoretically based mathematical model of the ear designed to predict such hazards [the Auditory Hazard Assessment Algorithm for the Human (AHAAH)]. To validate it as a predictor of hazard, data from the literature (wave forms and changes in hearing sensitivity) were processed with the model in order to predict the onset of unacceptable threshold shift (25 dB or more) in the 95th percentile human ear. For comparison, alternate standards MIL-STD-1747D and A-weighted energy were also used to compute hazards for the same data. The primary dataset was that of the US Army's "Albuquerque studies" (53 different cases) and other impulses from the literature (19 additional predictions). The AHAAH model predicted correctly in over 95% of the cases, the MIL-STD-1474D was correct in 42% of the cases, and A-weighted energy was correct in 25% of the cases. Errors for all methods tended to be in the direction of overprediction of hazard. In addition to greatly increased accuracy, the AHAAH model also has the advantage of being theoretically based and including novel diagnostic features.