title: Average optimal DPOAE primary tone levels in normal-hearing adults.
abstract: OBJECTIVE
  Despite great progress towards optimizing DPOAE primary tone characteristics, factors such as stimulus and intra-subject emission variability have not been addressed. The purpose of this study was to identify optimal primary tone level relationships when these sources of variability were acknowledged, and to identify any influences of test frequency.
  
  
  METHODS
  Following coupler-based measurements assessing primary tone level stability, two experiments were conducted. In experiment 1, DPOAE test-retest reliability without probe replacement was measured for f2 = 1-6 kHz with L1 = L2 = 65 dB SPL. In experiment 2, optimal L1-L2 relationships were identified for f2 = 1-6 kHz. For 20 ≤ L2 ≤ 75 dB SPL, L1 was varied 15 dB SPL above and below the recommendation of L1 = 0.4 L2 + 39 [dB SPL].
  
  
  METHODS
  Eleven normal-hearing adults participated in experiment 1. Thirty normal-hearing adults participated in experiment 2.
  
  
  RESULTS
  Stimulus variability did not exceed 0.1 dB SPL. DPOAE reliability testing revealed an across-frequency mean standard error of measurement of 0.52 dB SPL. The average optimal L1-L2 relationship was described by L1 = 0.49 L2 + 41 [dB SPL]. A significant effect of frequency was identified for 6 kHz.
  
  
  CONCLUSIONS
  Including relevant sources of variability improves internal validity of a primary tone level optimization formula.
authors.affiliation: a Department of Otolaryngology , University Hospital Regensburg , Regensburg , Germany .|b Department of Electrical Engineering and Informatics , Technical University of Munich , Munich , Germany , and.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Marcrum
authors.affiliation: a Department of Otolaryngology , University Hospital Regensburg , Regensburg , Germany .
authors.forename: Peter
authors.initials: P
authors.lastname: Kummer
authors.affiliation: c University of Regensburg School of Medicine , Regensburg , Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kreitmayer
authors.affiliation: a Department of Otolaryngology , University Hospital Regensburg , Regensburg , Germany .
authors.forename: Thomas
authors.initials: T
authors.lastname: Steffens
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000162:Acoustics; D000328:Adult; D001309:Auditory Threshold; D001844:Bone Conduction; D003051:Cochlea / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Otoacoustic emissions; anatomy and physiology; instrumentation; medical audiology; pediatrics