Page 140 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Chapter 4
mid-frequencies. Of those with hearing loss, sensorineural loss was most
common (n=14, 35.9%). Because of missing bone conduction thresholds,
that were not measured at 6 and 8 kHz, the type of hearing loss could not
be established in 18 adults (46.2%). The audiometric configuration that was
observed most, was flat (n=27, 45.0%, Figure 1).
Figure 1. Audiometric configurations of 60 adults with 22q11.2 deletion syndrome.
Audiometric configurations were mostly flat (45%), or high-frequency steeply (23.3%) or gently
(18.3%) sloping. Dotted horizontal line represents the threshold for normal hearing at 20 dB HL. dB
HL=decibel hearing level, kHz=kilo Hertz.
Plots of individual sensory thresholds against the 90th and 50th percentile
of normative data showed that the majority of adults with 22q11.2DS
performed worse than the 90th percentile (Figure 2). For the mid-frequency
of 1 kHz, 52 adults (86.7%) scored worse than the 50th and 25 (41.7%)
scored worse than the 90th percentile of normative data. At 8 kHz, 56 adults
(93.3%) scored worse than the 50th percentile and 55 (91.7%) had sensory
thresholds above the 90th percentile.
Tympanometry
Tympanometry was performed in 24 adults (40.0%) for the better-hearing
ear. Most (n=13, 54.2%) had a normal tympanogram (type A) as per the
Jerger classification for adults,14 5 (20.8%) had normal admittance with the
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