Page 138 - Demo

Chapter 4136Table 1. continuedHearing loss, grading of severity aType of hearing loss bConductive Normal BC thresholds (<20 dB HL) and ABG >15 dB averaged over 0.5, 1, 2 and 4 kHzSensorineural BC thresholds >20 dB HL and ABG <15 dB HL averaged over 0.5, 1, 2 and 4 kHzMixed BC thresholds >20 dB HL and ABG >15 dB averaged over 0.5, 1, 2 and 4 kHzAudiometric configuration bLow-frequency ascending >15 dB HL difference between the worst low frequency thresholds and the better high frequency thresholdsMid-frequency n-shaped >15 dB HL difference between the worst mid frequency thresholds and the better low and high frequency thresholdsHigh-frequency Gently sloping Steeply sloping15-29 dB HL difference between the mean of 0.5 and 1 kHz and the mean of 4 and 8 kHz, or 15 -29 dB HL between 4 and 8 kHz≥30 dB HL difference between the above frequencies or≥30 dB HL between 4 kHz and 8 kHzFlat <15 dB HL difference between the mean of 0.25 and 1 kHz, the mean of 1 and 2 kHz, and the mean of 4 and 8 kHzFrequency rangesLow frequencies ≤0.5 kHzMid frequencies >0.5 kHz and ≤2 kHzHigh frequencies >2 kHz and ≤8 kHzSymmetry of hearing impairmentUnilateral >10 dB HL difference between the ears in at least two frequencies<20 dB HL average over 0.5, 1, 2 and 4 kHz of the better ear Bilateral symmetrical <10 dB HL difference between the ears in at least two frequencies. Average over 0.5, 1, 2 and 4 kHz of both ears >20 dBBilateral asymmetrical >10 dB HL difference between the ears in at least two frequencies>20 dB HL average over 0.5, 1 ,2 and 4 kHz of the better eara=increasing severity of hearing loss according to the Muenster classification,12 b=of the betterhearing ear. Adapted from the definitions by the European Working Group on the Genetics ofHearing Impairment (See methods section for details),13 HL=hearing level, kHz=kilo Hertz, ABG=airbone gap, BC=bone-conduction.