title: Audiometric thresholds and portable digital audio player user listening habits.
abstract: OBJECTIVE
  To examine the relationship between portable digital audio player listening behaviours and (1) measured sound pressure levels, (2) audiometric measures, (3) self-reported hearing loss symptoms.
  
  
  METHODS
  A questionnaire to evaluate listening behaviours, including self-reported hearing loss symptoms and listening duration/volume settings. Multivariate regression analysis was used to determine the relationship between these variables, audiometric evaluation, calculated exposure levels, Lex(8hr), and measured sound pressure levels, Leq(32sec).
  
  
  METHODS
  This study included 103 males and 134 female subjects aged 10 to 17 years.
  
  
  RESULTS
  Calculated Lex(8hr) and measured Leq(32sec) levels increased with age and self-reported usage time. Audiometric thresholds averaged over 4 and 8 kHz were higher when usage exceeded five years as compared to less than one year. Higher measured sound pressure levels were associated with worse audiometric thresholds at (0.5, 1, 2 kHz, averaged) and 4 kHz. Self-reported hearing loss symptoms were reported by 33% to 50% of subjects.
  
  
  CONCLUSIONS
  In this cohort sample, our results support a statistical association between hearing acuity and (1) Self-reported weekly usage in hours; (2) Tightness of fit; (3) Years of usage; and (4) Measured sound pressure levels. Generalizing these results beyond the current sample would require additional research.
authors.affiliation: Health Canada, Consumer and Clinical Radiation Protection Bureau, Health Effects and Assessment Division, Ottawa, Ontario, Canada.
authors.forename: Katya
authors.initials: K
authors.lastname: Feder
authors.forename: Leonora
authors.initials: L
authors.lastname: Marro
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Keith
authors.forename: David S
authors.initials: DS
authors.lastname: Michaud
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000294:Adolescent Behavior; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D016009:Chi-Square Distribution; D002648:Child; D002652:Child Behavior; D005260:Female; D006184:Habits; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D006801:Humans; D055539:MP3-Player; D008297:Male; D015999:Multivariate Analysis; D009146:Music; D011312:Pressure; D012307:Risk Factors; D057566:Self Report; D013997:Time Factors