Page 138 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Chapter 4
Table 1. continued
Hearing loss, grading of severity a
Type of hearing loss b
Conductive Sensorineural Mixed Normal BC thresholds (<20 dB HL) and ABG >15 dB
averaged over 0.5, 1, 2 and 4 kHz
BC thresholds >20 dB HL and ABG <15 dB HL averaged
over 0.5, 1, 2 and 4 kHz
BC thresholds >20 dB HL and ABG >15 dB averaged over
0.5, 1, 2 and 4 kHz
Audiometric configuration b
Low-frequency ascending Mid-frequency n-shaped High-frequency
Gently sloping
Steeply sloping
Flat >15 dB HL difference between the worst low frequency
thresholds and the better high frequency thresholds
>15 dB HL difference between the worst mid frequency
thresholds and the better low and high frequency
thresholds
15-29 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 kHz
<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
kHz
Frequency ranges
Low frequencies ≤0.5 kHz
Mid frequencies High frequencies >0.5 kHz and ≤2 kHz
>2 kHz and ≤8 kHz
Symmetry of hearing impairment
Unilateral Bilateral symmetrical Bilateral 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
ear
<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 dB
>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
a=increasing severity of hearing loss according to the Muenster classification,12 b=of the better-
hearing ear. Adapted from the definitions by the European Working Group on the Genetics of
Hearing Impairment (See methods section for details),13 HL=hearing level, kHz=kilo Hertz, ABG=air-
bone gap, BC=bone-conduction.
136