Disequilibrium of unknown cause in older people.

Many older people complain of a sense of unsteadiness when standing or walking and many are fearful of falling. The cause of this disequilibrium is often difficult to determine even after thorough clinical evaluation. To better understand the pathogenesis of this symptom in a community-dwelling population, we studied 26 patients > 75 years old who complained of disequilibrium in whom no cause was evident after clinical evaluation. Each patient and each of 26 age-matched controls underwent a comprehensive evaluation that included a history and examination, a questionnaire, functional scales, a gait and balance scale, mini-mental state testing, audiometry, visual acuity, visual tracking, rotational vestibular testing, and quantitative posturography. Although none had Romberg's sign, patients tended to sway more and do poorer on semiquantitative gait and balance testing than did controls. Patients showed few differences from controls for most other measurements. However, 7 patients, designated Group V, had profoundly reduced vestibular function. In the remaining 19 patients (Group D), the average vestibular function was still significantly lower than controls. Sway velocity measured with posturography was increased in the patients compared with controls, particularly in Group V patients. Measures of vestibular function correlated with increased sway velocity both in Group D alone and among all study participants. Quantitative measurement of vestibular function should be considered in older people complaining of disequilibrium, particularly if the cause is not apparent after the initial evaluation.