Impaired vestibular–proprioceptive interaction in cerebellar patients

Abstract

Background: Vestibulo-spinal reflexes depend on adequate interaction between vestibular and proproceptive signals. Animal experiments indicate that the cerebellum is involved in this fundamental task. Cerebellar disease often leads to deficits in motor control, e.g. stance and gait ataxia. This study examines if vestibular-proprioceptive interaction might be one clinically relevant component of motor disturbance in cerebellar disease. Methods: Patients with cerebellar disorders of different etiology and normal controls were subjected to sinusoidal galvanic vestibular stimulation (0.16Hz) while standing on a force platform that measured reflectory body sway. Head-on-trunk position in the horizontal plane was altered systematically between +-60 degrees, controlled by a mechanical restraining device. Results: Normal controls exhibited a systematic dependence of their dominant sway direction on head-on-trunk position, as previously shown, keeping sway direction approximately aligned with their interaural line. In contrast, this systematic dependence was absent or attenuated in many cerebellar patients. Conclusion: In accord with results from animal experiments, the present data indicate that processing of vestibular and proprioceptive signals can be impaired in cerebellar patients. This impairment of vestibularproprioceptive interaction may be an important aspect of deficient motor control, particularly of gait and stance ataxia, in cerebellar disease.