Laboratory Evaluation of the Warned Middle-Ear Assumption of the Auditory Hazard Assessment Algorithm for Humans (AHAAH)

Abstract

Currently, the United States Department of Defense acquisition standard (MIL-STD-1474E) mandates that the U.S. Army is required to use the Auditory Hazard Assessment Algorithm for Humans (AHAAH) for calculating impulse noise exposure limits of military systems. However, several concerns have been raised about the model. The current study addresses a major concern raised about the middle-ear muscle contraction (MEMC) associated with the acoustic reflex that is assumed, and implemented, as a protective mechanism for certain instances in which a person is warned prior to the impulse. If a MEMC can be warned and is engaged during an exposure, it could produce significant attenuation, which would alter the risk prediction. Fifty-nine subjects were consented and verified to show clinically assessable MEMCs prior to testing. Using laser-Doppler vibrometry (LDV), we directly measured the time course and relative magnitude changes of a MEMC on TM velocity.

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Document Details

Document Type
Technical Report
Publication Date
Feb 26, 2019
Accession Number
AD1077789

Entities

People

  • Heath G. Jones
  • Nathaniel T. Greene
  • William A. Ahroon

Organizations

  • United States Army Aeromedical Research Lab

Tags

DTIC Thesaurus Topics

  • Acquisition
  • Biological Sciences
  • Biomedical Research
  • Contracts
  • Department Of Defense
  • Design Criteria
  • Doppler Effect
  • Ear
  • Frequency
  • Impulse Noise
  • Laser Doppler Vibrometers
  • Measurement
  • Military Acquisition
  • Pressure Measurement
  • Sound Transmission
  • Standards
  • United States

Readers

  • Auditory Neuroscience/Auditory Physiology.
  • Defense Financial Management and Audit.

Technology Areas

  • Directed Energy