Effect of age on ocular microtremor activity

Background. Ocular microtremor (OMT) is a high-frequency tremor of the eyes . It is present in all individuals and is related to brainstem activity. Th e OMT signal appears as an irregular oscillatory movement with intermittent burst-like components. The clinical interest in OMT has centered on its us e in the assessment of the comatose patient, with broad agreement among aut hors of its prognostic value. The purpose of this study was to examine the changes in OMT activity related to aging. Methods. OMT was recorded from 72 normal healthy subjects using the piezoel ectric strain gauge technique. The subjects ranged in age from 21 to 88 yea rs (54.22 +/- 20.43 years, mean +/- SD). Results. Our results show that the overall frequency and frequency content of the bursts falls with age (p < .002 and p < .001, respectively). There i s a highly significant drop in all three frequency parameters of OMT (p < . 0001) in subjects alder than 60 years of age. Conclusions. These results suggest that different values of normality shoul d operate for subjects over 60 years of age when considering the clinical a pplication of OMT.