EQUILIBRIUM  [ back to Glossary Index ]
Equilibrium refers to maintaining an upright posture while standing or moving by means of coordinated muscular adjustments responsive to auditory, visual, proprioceptive and somato-sensory feedback from the ear, eye, joints and skin. Environmental cues (orientation inputs) are fed to the cerebellum from the "pontine nuclei" and "inferior olive" in the brain stem. The Purkinje cells in the cerebellum, which contain "maps" of the body, instruct other parts of the brain to inhibit movement (e.g. to stop walking before falling into a hole) or to re-calibrate the speed or force of reflex movements. Dysequilibrium is a condition of motor incoordination and poor balance due to brain injury (or other factor such as effects of alcohol or drugs) which disrupts the loop between the environmental feedback from sensory organs and adaptive cerebellar functioning. Ataxia, a stumbling uncoordinated gait, indicates malfunction of the cerebellum from conditions as various as alcohol ingestion, brain tumor, stroke or TBI.