title: Disability evaluation in acoustic blast trauma.
abstract: BACKGROUND
  Acoustic blast trauma is different from Noise induced hearing loss. Blast trauma can damage the tympanic membrane, ossicles and cochlea singly or in combination. It produces immediate severe hearing loss and may be associated with tinnitus and vestibular symptoms. Hearing loss recovers spontaneously in many cases but may be permanent in 30-55% cases. Thirteen patients working in an explosive manufacturing unit in Andhra Pradesh were exposed to blast trauma at work place. All these workers complained of immediate hearing loss and were subjected to audiological investigations.
  
  
  METHODS
  Initial evaluation showed a severe sensorineural type of hearing loss 10 of the 13 cases (77%). They were referred to our Medical board for disability evaluation after 2-3 years of initial injury. Pure tone audiometry indicated severe hearing loss in 12 of 13 cases (92%) that was not correlating clinically. Re-evaluation with Acoustic reflex and ABR (BERA) tests were done and permanent disability was evaluated with the results of these investigations.
  
  
  METHODS
  No significant hearing loss was found in most patients and these patients had minimal disability.
  
  
  CONCLUSIONS
  Objective hearing tests should be carried out after one year or more before evaluation of permanent disability.
authors.affiliation: Department of ENT, Occupational Disease Centre, ESIC Medical College and Post Graduate Institute of Medical Sciences and Research, Chennai, Tamil Nadu, India.
authors.forename: Ganesan
authors.initials: G
authors.lastname: Raju
keywords: ABR; audiometry; blast trauma; permanent disability; sensorineural hearing loss