Abstract:
Sclerosteosis is a rare genetic bone dysplasia disorder characterised by generalised
craniotubular bone modelling. Alongside many clinical appearances marked in
sclerosteosis, the auditory system is considerably compromised on several levels during
the disease progression. Extensive otolaryngological research on the history of
sclerosteosis, the clinical presentation of sclerosteosis, radiographic studies and the
gene causing the condition had been documented. No studies had been found describing
the audiological profiles, auditory functioning and abnormalities for subjects with
sclerosteosis. Thus the object of this study aimed to describe the auditory profile of
subjects with sclerosteosis.
A cross-sectional descriptive research design and quantitative research approach was
followed to investigate the auditory characteristics of subjects with sclerosteosis.
Subjects were selected from a database of patients with confirmed diagnoses of
sclerosteosis. Ten subjects responded and provided written informed consent. Test
procedures included otoscopy, tympanometry, acoustic reflexes, diagnostic pure-tone airand
bone-conduction audiometry, speech audiometry, distortion product otoacoustic
emissions (DPOAE), auditory brainstem responses (ABR) and computed tomographic
(CT) scans. The subjects were assessed with a comprehensive audiological test-battery
within a single test session lasting approximately two hours. A CT scan was conducted
on a separate occasion shortly after the audiological data were obtained.
Normal type A tympanograms were obtained in 50% (n=10/20) of ears. All subjects
presented with mixed hearing losses varying from moderate (5%; n=1), severe (55%;
n=11) and profound (40%; n=8) degrees across ears. Hearing loss configurations ranged
from rising (15%), sloping (35%) and air-conduction thresholds peaking at 2000 Hz
(50%). Air bone gaps (ABG) were larger in older subjects, although not statistically
significant (p>.05). The CT scans indicated anatomical abnormalities of the external
auditory canal, tympanic membrane, middle ear space, ossicles, oval window, round
window and the internal auditory canal. The progressive abnormal bone formation in sclerosteosis involved the middle ear, the
round and oval windows of the cochlea and internal auditory canal. The progressive
abnormal bony overgrowth, which is the hallmark of sclerosteosis, led to functional
impairment at various levels in the auditory system. The current findings provided a
comprehensive auditory profile for sclerosteosis. Results might be utilised alongside
future research findings to direct criteria and audiological indications for surgical and
audiological intervention.
