39-71-805. Determining percent of hearing loss. (1) The percent of hearing loss, for purposes of the determination of compensation claims for occupational deafness, must be calculated as the average in decibels of the thresholds of hearing for the frequencies of 500, 1,000, and 2,000 cycles a second. Pure tone air conduction audiometric instruments, approved by nationally recognized authorities in this field, must be used for measuring hearing loss. If the losses of hearing average 25 decibels or less in the three frequencies, as measured under American national standards institute ANSI/S3.6, 1996, the losses of hearing may not then constitute any compensable hearing disability. If the losses of hearing average 92 decibels or more in the three frequencies, as measured under ANSI/S3.6, 1996, then those losses constitute total or 100% compensable hearing loss.
     (2) In measuring hearing impairment, the lowest measured losses in each of the three frequencies must be added together and divided by three to determine the average decibel loss. For every decibel of loss exceeding 25 decibels, an allowance of 1 1/2% must be made, up to the maximum of 100%, which is reached at 92 decibels.
     (3) In determining the binaural percentage of loss, the percentage of impairment in the better ear must be multiplied by five. The resulting figure must be added to the percentage of impairment in the poorer ear and the sum of the two divided by six. The final percentage must be representative of the binaural hearing impairment.
     (4) Before determining the percentage of hearing impairment, in order to allow for the average amount of hearing loss from nonoccupational causes found in the population at any given age, one-half decibel for each year of the employee's age over 40 at the time of last exposure to industrial noise must be deducted from the total average decibel loss.
     (5) Consideration may not be given to the question of whether or not the ability of an employee to understand speech is improved by the use of a hearing aid.

     History: En. 92-710 by Sec. 1, Ch. 366, L. 1971; amd. Sec. 1, Ch. 381, L. 1973; R.C.M. 1947, 92-710(1)(b) thru (f); amd. Sec. 11, Ch. 214, L. 2001.