Vestibular function in children with the CHARGE association

Background: Histopathological examinations and computed tomographic scans of the temporal bone in patients with the CHARGE association (a malformative syndrome that includes coloboma, heart disease, choanal atresia, retarded development, genital hypoplasia, and ear anomalies, including hypoplasia of the external ear and hearing loss) have shown an absence of semicircular canals and a Mondini form of cochlear dysplasia. Until recently, no information was available concerning a passible loss of vestibular function, which could be a factor in retarded posturomotor development. To our knowledge, this is the first report of otolith tests done on patients with the CHARGE association. Objective: To test residual vestibular function in patients with the CHARGE association. Study Design: In 7 patients with the CHARGE association, we made electro-oculographic recordings of vestibule-ocular responses to earth-vertical and off-vertical axis rotations to evaluate the function of the canal and the otulith-vestibular systems. Results: None of the 7 patients had semicircular canals in the computed tomographic scan, and none had canal vestibule-ocular responses to earth-vertical axis rotation, but all had normal otolith vestibule-ocular responses to the off-vertical axis rotation test. Conclusions: These results support the hypothesis of a residual functional otolith organ in the hypoplastic posterior labyrinth of children with the CHARGE association. The severe delays in psychomotor development presented by these children are more likely a consequence of multiple factors: canal vestibular deficit, visual impairment, and environmental conditions (long hospital stays and breathing and feeding problems). The remaining sensitivity of the otolith system to gravity and linear acceleration forces in these children could be exploited in early education programs to improve their posturomotor development.