title: The effect of head movement and head positioning on sound field audiometry.
abstract: OBJECTIVE
  Positioning and maintaining the subject's head at the calibration point (CP) of the sound field (SF) during SF assessment remains a challenge. The purpose of this study was to investigate the sound pressure level (SPL) at head positions likely to be encountered in routine audiological practice.
  
  
  METHODS
  Eight National Health Service SF clinics were used to obtain SPL measurements. Part 1 of the study investigated SPL variability at positions around the CP (0.15 m and 0.30 m). Parts 2 and 3 of the study, investigated the SPL at two typical head heights of the infant population.
  
  
  METHODS
  Only sound field measures were obtained.
  
  
  RESULTS
  Part 1: 32% and 40% of measurements of SPL around the CP were >2 dB different from the SPL at the CP (0.15 m and 0.30 m). Parts 2 and 3: 55% and 38% of measurements of SPL, at the two infant head heights, were >2 dB from the SPL at the CP.
  
  
  CONCLUSIONS
  Variability in SPL, due to head movement, is to be expected when performing SF audiometry. Furthermore, the typical head heights of infants will introduce additional variability, unless the position of the CP is chosen carefully.
authors.affiliation: School of Healthcare, University of Leeds, UK. p.shaw@leeds.ac.uk
authors.forename: Paul
authors.initials: P
authors.lastname: Shaw
authors.forename: Hannah
authors.initials: H
authors.lastname: Greenwood
mesh_terms: D000161:Acoustic Stimulation; D001299:Audiometry / Q000295:instrumentation / Q000592:standards; D001306:Auditory Pathways / Q000502:physiology*; D002138:Calibration; D006257:Head; D019416:Head Movements; D006309:Hearing; D006801:Humans; D007223:Infant; D011187:Posture; D011312:Pressure; D015203:Reproducibility of Results; D013016:Sound