Postural disorders induced by cochlear implantation in normo-reflexic patients: A potential origin of a transient geocentric perception disorder

Abstract Background Profound hearing loss is a public health problem with serious consequences for patient's quality of life. Some of them, submitted to cochlear implantation, revealed various postural disorders such as balance and spatial perception disorders without detail on their vestibular status. Research question The purpose of this preliminary study was to analyze the evolution of the balance control and geocentric perception after cochlear implantation procedure in normo-reflexic patients before the implant activation. Methods We assessed balance control of five patients with profound hearing loss and five healthy participants by means of computerized dynamic posturography and their geocentric perception by the subjective visual vertical test before surgery, three days and forty-five days after surgery (prior to implant activation). Results Before surgery, the patients showed some difficulties to control their balance in challenged postural context without geocentric perception disorder. Patients presented an improvement in their postural accuracy, but their balance control remained inappropriate in challenging environment. Moreover, their geocentric perception was deviated towards their healthy ear immediately after cochlear implantation. This misperception naturally fades before the implant activation. Significance This transient spatial perception alteration might probably cause the perceived postural discomforts and the daily difficulties often reported by these patients in their clinical records early after cochlear implantation. This preliminary study allows for the first time the distinction between the both components of posture: balance control and geocentric perception. Therefore, a specific therapeutic care targeting the rehabilitation of spatial cognition could be proposed to these patients in order to reduce their transient postural disorders.