title: Comparison of real-ear to coupler difference values in the right and left ear of adults using three earmold configurations.
abstract: OBJECTIVE
  The purpose of the study was to compare real-ear to coupler difference (RECD) values in the right and left ear of adults using three earmold configurations.
  
  
  METHODS
  The RECD was obtained from both ears of 18 normal hearing adults by subtracting the HA2 2-cc coupler response from the real-ear response using an ER-3A insert earphone and a swept pure tone on the Audioscan RM500 probe-tube microphone system. The measurements were made with a personal earmold, foam eartip, and oto-admittance tip.
  
  
  RESULTS
  The mean difference between the right and left RECD was close to 0 dB for all earmold configurations and was not statistically significant on a repeated-measures analysis of variance (p > 0.05). In 90% of participants, the difference between ears was generally less than 3 dB at 0.5 to 4 kHz.
  
  
  CONCLUSIONS
  Cooperative participants with non-occluding wax and normal middle ear function (on tympanometry) show small differences in RECD between the right and left ear, irrespective of the earmold configuration. The study has yet to be extended to the clinical setting where subject cooperation and earmold fit may differ from the present study. In the meantime, the findings from the present study indicate that where an RECD can be obtained from only one ear of a participant, it is probably best to use this to derive real-ear SPL of both ears instead of relying on average age appropriate corrections.
authors.affiliation: School of Psychological Sciences, University of Manchester, Manchester, United Kingdom.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Munro
authors.forename: Louise M
authors.initials: LM
authors.lastname: Buttfield
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone / Q000295:instrumentation* / Q000379:methods*; D001307:Auditory Perception / Q000502:physiology*; D004424:Ear Canal / Q000502:physiology*; D004867:Equipment Design; D005260:Female; D007839:Functional Laterality; D006310:Hearing Aids / Q000592:standards; D006801:Humans; D008297:Male; D008875:Middle Aged