title: Comparison of Psychophysical and Physical Measurements of Real Ear to Coupler Differences.
abstract: OBJECTIVE
  The purpose of the study is to compare real ear to coupler difference (RECD) curves based on physical and psychophysical measures. For the physically measured RECD, the RECD was measured with real ear and coupler measurements for the ear simulator and HA1- and HA2 2-cc couplers. The psychophysically measured RECDs were derived from audiogram measures.
  
  
  METHODS
  RECDs were measured in 19 normally hearing subjects. The coupler measurement was done with the probe microphone and the coupler microphone itself. Psychophysically measured RECDs were derived for all subjects by measuring the audiogram in sound field and with an ER-3A insert phone.
  
  
  RESULTS
  Reference data were obtained for the three coupler types. It was possible to derive the RECD curve with psychophysical methods. There was no overall statistical difference between the physically and psychophysically measured RECD curves for the HA2 2-cc coupler and the ear simulator. The standard deviation was, however, much higher for the psychophysically derived RECD, indicating that physically measured RECDs are more precise than psychophysically derived RECDs.
  
  
  CONCLUSIONS
  For the physical RECD measurements, the coupler microphone should be used for the coupler measurement. Physically measured RECDs were validated on group level by the reliable derivation of the RECD curve from audiogram measures.
authors.affiliation: Research Group Experimental Oto-Rhino-Laryngology, Department Neurosciences, University of Leuven, Leuven, Belgium.
authors.forename: Raphael
authors.initials: R
authors.lastname: Koning
authors.forename: Jan
authors.initials: J
authors.lastname: Wouters
authors.forename: Tom
authors.initials: T
authors.lastname: Francart
mesh_terms: D000162:Acoustics; D000293:Adolescent; D000328:Adult; D012048:Correction of Hearing Impairment; D004423:Ear / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D006310:Hearing Aids; D006801:Humans; D017755:Prosthesis Fitting / Q000379:methods*; D011571:Psychoacoustics; D011601:Psychophysics; D055815:Young Adult