<p>Steady-state auditory evoked potentials are useful for studying the human auditory system and diagnosing hearing disorders. Identifying the generators of these potentials is essential for interpretation of data and for determining appropriate clinical and research applications. Here we infer putative generators of a steady-state potential measured from an electrode on the eardrum and compare this potential with the traditional envelope following response (EFR) measured from an electrode on the high forehead (<i>N</i> = 18, 10 female). We hypothesized that responses from the eardrum electrode would be consistent with an auditory nerve (AN) compound action potential (CAP) evoked by each cycle of the stimulus envelope, resulting in a potential we call CAP<sub>ENV</sub>. Steady-state potentials were evoked by a 90&#xa0;dB peSPL, 3000-Hz puretone carrier whose envelope was modulated by a tone sweep with frequencies from 20 to 160&#xa0;Hz or 80 to 640&#xa0;Hz. We calculated group delay to infer potential generators. We also compared the empirically measured CAP<sub>ENV</sub> with simulated CAP<sub>ENV</sub> from a humanized model of AN responses. Response latencies and model simulations support the interpretation that CAP<sub>ENV</sub> is generated by the AN rather than hair cell or brainstem generators for all modulation frequencies tested. Conversely, latencies for the traditional EFR were consistent with a shift from cortical to brainstem generators as the modulation frequency increased from 20 to 200&#xa0;Hz. We propose that CAP<sub>ENV</sub> may be a fruitful tool for assessing AN function in humans with suspected AN fiber loss and/or temporal coding disorders.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Evidence for the Auditory Nerve Generating Envelope Following Responses When Measured from Eardrum Electrodes

  • Skyler G. Jennings,
  • Jessica Chen,
  • Nathan Johansen,
  • Shawn S. Goodman

摘要

Steady-state auditory evoked potentials are useful for studying the human auditory system and diagnosing hearing disorders. Identifying the generators of these potentials is essential for interpretation of data and for determining appropriate clinical and research applications. Here we infer putative generators of a steady-state potential measured from an electrode on the eardrum and compare this potential with the traditional envelope following response (EFR) measured from an electrode on the high forehead (N = 18, 10 female). We hypothesized that responses from the eardrum electrode would be consistent with an auditory nerve (AN) compound action potential (CAP) evoked by each cycle of the stimulus envelope, resulting in a potential we call CAPENV. Steady-state potentials were evoked by a 90 dB peSPL, 3000-Hz puretone carrier whose envelope was modulated by a tone sweep with frequencies from 20 to 160 Hz or 80 to 640 Hz. We calculated group delay to infer potential generators. We also compared the empirically measured CAPENV with simulated CAPENV from a humanized model of AN responses. Response latencies and model simulations support the interpretation that CAPENV is generated by the AN rather than hair cell or brainstem generators for all modulation frequencies tested. Conversely, latencies for the traditional EFR were consistent with a shift from cortical to brainstem generators as the modulation frequency increased from 20 to 200 Hz. We propose that CAPENV may be a fruitful tool for assessing AN function in humans with suspected AN fiber loss and/or temporal coding disorders.