Binaural Processing Deficits in a Child with Chiari Malformation (Type 1).

Chiari malformation is a condition involving caudal descent of the hindbrain which herniates the cerebellar tonsils through the foramen magnum. The purpose of this study was to quantify auditory deficits in an affected individual and to explore the hypothesis that cerebellar malformation specifically disrupts binaural processing. We present audiometric, electrophysiologic, imaging and auditory perceptual findings for a 17-year-old female with Chiari 1 malformation and for a cohort of 35 hearing- and age-matched controls. The patient presented with auditory deficit consistent with cerebellar disorder-that is, an impaired ability to judge the duration of auditory stimuli. In addition, she showed evidence of abnormal binaural processing affecting her capacity to localise sound sources to optimise speech perception in background noise. The provision of a remote microphone listening device was successful in improving her perceptual ability to normal levels. Despite normal sound detection ability, this child with Chiari 1 malformation suffered functional hearing deficits severe enough to impact everyday listening/communication and educational progress. These limitations were ameliorated through auditory intervention.