RT Book, Section A1 Dobie, Robert A2 LaDou, Joseph A2 Harrison, Robert J. SR Print(0) ID 1104101687 T1 Hearing Loss T2 CURRENT Diagnosis & Treatment: Occupational & Environmental Medicine, 5e YR 2013 FD 2013 PB McGraw-Hill Education PP New York, NY SN 9780071808156 LK accessmedicine.mhmedical.com/content.aspx?aid=1104101687 RD 2024/03/29 AB Occupational hearing loss may be partial or (rarely) total, unilateral or bilateral, and conductive, sensorineural, or mixed (conductive and sensorineural). Conductive hearing loss involves the external or middle ear, and impairs the passage of sound to the inner ear; sensorineural hearing loss (SNHL) results from dysfunction of the inner ear, auditory nerve, or brain. In the workplace, conductive and mixed hearing loss can be caused by blunt or penetrating head injuries, explosions, and thermal injuries such as slag burns sustained when a piece of welder's slag penetrates the eardrum. SNHL usually results from damage to the cochlea, especially loss of hair cells from the organ of Corti. Among the causes of occupational SNHL are continuous exposure to noise in excess of 85 dBA, blunt head injury, and exposure to ototoxic substances.