title: Hearing risk associated with the usage of personal listening devices among urban high school students in Malaysia.
abstract: OBJECTIVE
  To investigate listening habits and hearing risks associated with the use of personal listening devices among urban high school students in Malaysia.
  
  
  METHODS
  Cross-sectional, descriptive study.
  
  
  METHODS
  In total, 177 personal listening device users (13-16 years old) were interviewed to elicit their listening habits (e.g. listening duration, volume setting) and symptoms of hearing loss. Their listening levels were also determined by asking them to set their usual listening volume on an Apple iPod TM playing a pre-selected song. The iPod's sound output was measured with an artificial ear connected to a sound level meter. Subjects also underwent pure tone audiometry to ascertain their hearing thresholds at standard frequencies (0.5-8 kHz) and extended high frequencies (9-16 kHz).
  
  
  RESULTS
  The mean measured listening level and listening duration for all subjects were 72.2 dBA and 1.2 h/day, respectively. Their self-reported listening levels were highly correlated with the measured levels (P < 0.001). Subjects who listened at higher volumes also tend to listen for longer durations (P = 0.012). Male subjects listened at a significantly higher volume than female subjects (P = 0.008). When sound exposure levels were compared with the recommended occupational noise exposure limit, 4.5% of subjects were found to be listening at levels which require mandatory hearing protection in the occupational setting. Hearing loss (≥25 dB hearing level at one or more standard test frequencies) was detected in 7.3% of subjects. Subjects' sound exposure levels from the devices were positively correlated with their hearing thresholds at two of the extended high frequencies (11.2 and 14 kHz), which could indicate an early stage of noise-induced hearing loss.
  
  
  CONCLUSIONS
  Although the average high school student listened at safe levels, a small percentage of listeners were exposed to harmful sound levels. Preventive measures are needed to avoid permanent hearing damage in high-risk listeners.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Wilayah Persekutuan, Malaysia.
authors.forename: A H
authors.initials: AH
authors.lastname: Sulaiman
authors.forename: K
authors.initials: K
authors.lastname: Seluakumaran
authors.forename: R
authors.initials: R
authors.lastname: Husain
mesh_terms: D000293:Adolescent; D003430:Cross-Sectional Studies; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000209:etiology*; D006801:Humans; D055539:MP3-Player / Q000706:statistics & numerical data*; D008296:Malaysia; D008297:Male; D018570:Risk Assessment; D057566:Self Report; D013334:Students / Q000523:psychology* / Q000706:statistics & numerical data; D014505:Urban Population / Q000706:statistics & numerical data*
keywords: Adolescents; High school students; High-frequency audiometry; Mp3 players; Noise-induced hearing loss; Personal listening devices