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. The OMT signal appears as an irregular oscillatory movement with intermittent burst-like components. The clinical interest in OMT has centered on its use in the assessment of the comatose patient, with broad agreement among authors 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 piezoelectric strain gauge technique. The subjects ranged in age from 21 to 88 years (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 is a highly significant drop in all three frequency parameters of OMT (p < .0001) in subjects older than 60 years of age. CONCLUSIONS These results suggest that different values of normality should operate for subjects over 60 years of age when considering the clinical application of OMT.

[1]  C Bolger,et al.  High frequency eye tremor: reliability of measurement. , 1992, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[2]  P. E. Hallett,et al.  Power spectra for ocular drift and tremor , 1985, Vision Research.

[3]  N G Gençer,et al.  Electrical impedance tomography. Determination of the boundary of an object inserted into a water-filled cylinder. , 1992, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[4]  C. Bolger,et al.  Dominant frequency content of ocular microtremor from normal subjects , 1999, Vision Research.

[5]  A. R. P. Walker.  Mortality from coronary heartdisease in Indian populations. , 1961 .

[6]  Bolger,et al.  Ocular microtremor in brain stem death , 1999, Neurosurgery.

[7]  W. Chamberlain.  Restriction in upward gaze with advancing age. , 1971, American journal of ophthalmology.

[8]  H. Noda,et al.  Effect of aging on sensorimotor functions of eye and hand movements , 1986, Experimental Neurology.

[9]  J. F. Corso,et al.  Sensory processes and age effects in normal adults. , 1971, Journal of gerontology.

[10]  Effect of Age on Horizontal Eye Movement Latency , 1986, American journal of optometry and physiological optics.

[11]  Davis Coakley,et al.  Neuro-muscular model of ocular microtremor , 1992, 1992 14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[12]  J G Thomas,et al.  The prognosis of the outcome of comatose states. , 1980, Resuscitation.

[13]  J. G. Smits.  Equivalent circuit for end-loaded piezoelectric bimorph actuators , 1984 .

[14]  I. Akiguchi,et al.  Localization of atrophy-prone areas in the aging mouse brain: Comparison between the brain atrophy model SAM-P/10 and the normal control SAM-R/1 , 1994, Neuroscience.

[15]  B. Troost,et al.  The effects of age on normal saccadic characteristics and their variability , 1983, Vision Research.

[16]  K. Haywood.  Eye movement pattern and accuracy during perceptual-motor performance in young and old adults. , 1982, Experimental aging research.

[17]  Davis Coakley,et al.  THE OCULAR MICROTREMOR RECORD AND THE PROGNOSIS OF THE UNCONSCIOUS PATIENT , 1977, The Lancet.

[18]  F. H. Adler,et al.  INFLUENCE OF FIXATION ON THE VISUAL ACUITY , 1934 .

[19]  H. Sakata,et al.  Spatial properties of visual fixation neurons in posterior parietal association cortex of the monkey. , 1980, Journal of neurophysiology.