Glossary
Adjust for greater loss in better ear (NIHL)
Yes/No. The assessment shows that in this audiogram, the estimated hearing loss from noise in the better hearing ear at 1kHz, 2kHz and 3kHz and/or at 1kHz, 2kHz, and 4kHz is greater than the estimated hearing loss from noise in the worst hearing ear.
The conventional assessment will result in an estimated binaural hearing loss that is smaller than that estimated in the better hearing ear at the same frequencies.
Some experts suggest that this will underestimate the impairment of the individual in this case, which they consider is reflected in the hearing loss from noise in the better hearing ear. Any hearing loss in the worse hearing ear will add to and not diminish the impairment of any hearing loss from noise in the better hearing ear.
You may want to re-run the assessment with an adjustment to assess the impairment found just in the better hearing ear at 1kHz, 2kHz, and 3kHz.
Adjust for no better ear (NIHL)
Yes/No. The assessment shows that in this audiogram, the sum of the thresholds in both ears at 1kHz, 2kHz 3kHz, and/or at 1kHz, 2kHz and 4kHz is the same.
Conventional assessment will result in an estimated binaural hearing loss that is smaller than the greater NIHL.
Some experts may consider that this will underestimate the impairment of the individual, which they consider to be reflected by the greater hearing loss. The asymmetry is usually due to the asymmetry at the anchor points or the depth of any notch or bulge at 4kHz.
Anchor Points (NIHL)
The default assessment is based on anchor points at 1kHz and 8kHz. If the Expert considers that other anchor points (500Hz, 2kHz and 6kHz) are appropriate, these can be selected.
CLB 2000 (NIHL)
“Guidelines on the diagnosis of noise induced hearing loss for medicolegal purposes” R.R.A Coles, M.E. Lutman & J.T. Buffin Clin Otolaryngol 2016, 41, 347-357
Dataset year (M-NIHL)
Whereas the NIHL calculator allows the user to select the AAHL dataset, the M-NIHL calculator uses only the ISO 2029 2017 dataset, per Moore 2020.
Dataset year (NIHL 1984 or 2017)
Select 1984 – The AAHL will be the modified baseline values of CLB 2000
Select 2017 – The AAHL will the be ISO7029 : 2017 values
DHSS Method (NIHL)
Expresses hearing loss averaged over 1,2 and 3kHz or 1,2 and 4kHz with weighting for better ear.
Fixed Percentile – Right Ear / Left Ear (M-NIHL)
For M-NIHL the commonly utilised 25th, 50th and 75th percentiles are available together with the 10,20, 30, 40 50,60,70,80,90
Interpolation Method (NIHL)
The Logarithmic interpolation method used is as prescribed in LCB 2016.
LCB 2016 (NIHL)
“Guidelines for quantification of noise-induced hearing loss in a medicolegal context” Lutman, M.E., Coles, R.R.A. & Buffin, J.T. Clin. Otolaryngol. 2016, 41, 347–357
Moore 2020 (NIHL)
“Diagnosis and quantification of military noise-induced hearing loss” Brian C. J. Moore J. Acoust. Soc. Am. 148 (2), August 2020
Optional Bekesy Correction (NIHL)
Yes/No. If you select Yes then 3dB is added to each input and this then rounded to nearest 5dB
The Guidelines for Medicolegal Practice: Assessment of Hearing Disability, (King, Coles, Lutman & Robinson, 1992, Whurr Publishers) suggest using this correction for comparison between a Bekesy and a manual audiogram.
Made available for use at user discretion.
Selected Percentile(Right Ear Left Ear Pass 1 Pass 2) (NIHL)
You can select individual AAHL percentiles for each ear and for each of Pass 1 and Pass 2 of LCB 2016.
“Calculated” – The calculator selects the best fit as per the suggestion within LCB 2016:- “By default, the median should be selected, unless an alternative percentile clearly gives a better fit at the anchor points (based on the sum of the differences between the anchor point values and the age associated hearing loss values at the same frequencies)”. (The algebraic difference is minimised. That is, the positive and negative signs are preserved. The calculator selects the percentile for which the result is closest to zero.)
- “25” – 25th percentile
- “50” – 50th percentile
- “75” – 75th percentile
TDH 39 headphones (NIHL)
Yes/No. If you select Yes then the 6dB deduction will be applied at 6kHz
As per Note 2 of CLB 2000 –
“When Telephonics TDH-39 audiometer ear phones have been used, subtract 6 dB from the measured HTL values at 6 kHz. This is to take account of the calibration artefact associated with use of those earphones”