Nystagmus: A Parameter of Mental Function

Abstract
Nystagmographic records from an unusual case of spontaneous nystagmus probably of the central vestibular type were presented, demonstrating that nystagmus under selected conditions reflects with exquisite sensitivity certain aspects of mental functioning. Something of the process or processes monitored seems to be communicated by what is popularly indicated by such terms as “concentration,” “mental activity,” and “mental effort” and are not adequately explained by such concepts as changes in “alertness” or “attention” and “release from a central inhibition.” The importance of these mental factors lies in the additional hazard they impose on the use of quantitative changes in nystagmus for neurological diagnosis. Studies using nystagmus to demonstrate vestibular dysfunction in patient groups characterized by less than optimal cooperation must be reassessed. The usefulness of this parameter in the future study of mental function is emphasized.