Audio-vestibular Evaluation of Children and Young Adults With Osteogenesis Imperfecta

Overview

The aim is to determine whether vestibular deficits are present in OI, then to establish whether a correlation exists between genetic type, severity of OI and audiovestibular phenotype. OI patients aged 12 to 20 years will undergo an audiometric, immittance, and vestibular assessment. When hearing loss is conductive or mixed or in cases where vestibular deficits are identified, a CT scan without injection will be performed. In case of sensorineural hearing loss or abnormal CT results, an MRI will be performed.

Osteogenesis Imperfecta (OI), or Lobstein's disease, is a form of congenital osteoporosis, with a prevalence between 1/10,000 and 1/20,000 in France. As of 1979, four phenotypes have been described according to severity: moderate (type I), lethal (type II), severe (type III), and moderate-to-severe (type IV). OI exhibits phenotypic and genotypic variability, however, to date no correlations have been established between specific mutations and clinical presentation. There is a well-established association between OI and hearing loss, however, the reported prevalence of hearing loss varies between 2% to 94.1%. In patients with OI, Computed Tomography (CT) has revealed bone demineralization that progresses with age. The extent of the hypodense areas on the CT corresponds to the type of hearing loss: conductive hearing loss is associated with lesions of the fissula ante fenestram and round and oval windows while mixed hearing loss is associated with additional retrofenestral lesions. Severity of hearing loss is positively correlated with OI-related bone damage in the petrous bone. Magnetic Resonance Imaging (MRI) has also revealed in the pericochlear lesions with soft tissue hypersignal and enhancement on contrast medium injection in the otic capsule. Bone demineralization has also been linked to vestibular deficits, and some studies have reported correlations between Osteogenesis Imperfecta and vestibular deficits in adult patients, however, this relationship is less clear. The aim of the study is to determine whether vestibular deficits are also present in OI. Furthermore, the study will aim to establish whether a correlation exists between genetic type, severity of OI and audiovestibular phenotype. OI patients aged 12 to 20 years will be recruited and an audiometric, immittance, and vestibular assessment (videonystagmography, video Head Impulse Test (vHIT), vestibular evoked muscular potentials (cVEMP)) will be performed during their annual visit to the Centre de Référence des Maladies Rares des maladies osseuses constitutionnelles (henceforth CRMR OI) of Hôpital Necker-Enfants malades, Paris, France. When hearing loss is conductive, or mixed or in cases where vestibular deficits are identified, a CT scan without injection will be performed for the care. In case of sensorineural hearing loss, or abnormal CT results, an MRI will be proposed for the care. The investigation team will try to establish if there is a significant association between OI and vestibular deficit, and if so, whether the degree of vestibular impairment is correlated to radiological findings with respect to bone abnormalities, as well as the type and severity of the deafness.