Acoustic trauma: single neuron basis for the "half-octave shift"

J Acoust Soc Am. 1981 Sep;70(3):707-11. doi: 10.1121/1.386906.


Exposure to an intense pure tone can induce a loss of hearing sensitivity. If this loss recovers, then the desensitization is regarded as a temporary threshold shift (TTS). At the single auditory neuron level this TTS was monitored as a loss of sensitivity at the neuron's most sensitive or characteristic frequency (CF). When pure-tone exposures were presented at frequency intervals measured from the neuron CF, then a frequency half an octave below the CF was the most effective for inducing a CF TTS. All exposure frequencies higher than half an octave below the CF produce a marked reduction in TTS growth with intensity, when compared to lower exposure frequencies. This behavior is such that, with increasing exposure frequency higher than the -1/2-octave point, the intensity needed to produce a given TTS grew faster than the neuron sensitivity. However, below the -1/2-octave point all exposure frequencies were similarly behaved. Strong similarities exist between the frequency-specific requirements for TTS and the mechanical and neural nonlinearities found in other studies. This suggests that the half-octave shift may well be a direct result of basilar membrane nonlinearities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustics
  • Animals
  • Auditory Fatigue / physiology
  • Auditory Threshold / physiology
  • Guinea Pigs
  • Hearing Loss, Noise-Induced / physiopathology*
  • Neurons / physiopathology*
  • Vestibulocochlear Nerve / physiopathology*