title: Is it reasonable to use 1 and 8 kHz anchor points in the medico-legal diagnosis and estimation of noise-induced hearing loss?
abstract: BACKGROUND
  In the United Kingdom, use of 1 and 8 kHz as anchor point frequencies has been recommended for the medico-legal diagnosis and estimation of noise-induced hearing loss. There appear to be four assumptions behind the use of 1 and 8 kHz anchor point approach: (i) The frequencies of 1 and 8 kHz are not damaged by noise; therefore, the measured hearing thresholds at the said frequencies solely reflect age-related hearing loss, even in the noise-exposed; (ii) The hearing thresholds at 1 and 8 kHz are a valid predictor of the likely age-related hearing loss thresholds at the other frequencies; (iii) Age and noise damage are always completely additive; (iv) Individual's susceptibility to age and noise damage is not proportionate. Doubts have been expressed in the medical circles about the legitimacy and validity of their use as anchor points.
  
  
  OBJECTIVE
  Is it reasonable to use 1 and 8 kHz anchor points in the medico-legal diagnosis and estimation of noise-induced hearing loss?
  
  
  METHODS
  Medico-legal.
  
  
  METHODS
  Literature search; Medline, Embase, Internet, and medico-legal records.
  
  
  METHODS
  Equating and comparing the assumptions in the anchor point approach with the information in medical literature.
  
  
  RESULTS
  Based upon the information in medical literature, technical reports, and professional statements, the assumptions behind the use of anchor point approach cannot be reliably substantiated.
  
  
  CONCLUSIONS
  'Carte Blanche' use of 1 and 8 kHz anchor points is probably unreasonable and may well be unsafe in the medico-legal diagnosis and estimation of noise-induced hearing loss.
authors.affiliation: Otolaryngology Clinic, The Park Hospital, Sherwood Lodge Drive Arnold, Nottingham, UK.
authors.forename: S
authors.initials: S
authors.lastname: Ali
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University Hospital, Nottingham, UK.
authors.forename: M
authors.initials: M
authors.lastname: Morgan
authors.affiliation: Graduate Entry Program, Medical University of Silesia, Katowice, Poland.
authors.forename: U I
authors.initials: UI
authors.lastname: Ali
mesh_terms: D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D007883:Legislation, Medical; D009623:Noise, Occupational / Q000009:adverse effects* / Q000331:legislation & jurisprudence*; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D006113:United Kingdom