The long-term objective of this study is to evaluate how saccadic eye motion and the vestibulo-ocular reflexes shift gaze and control head and body posture in high-risk elderly women. This pilot project will provide the basis for a subsequent intervention study (RO1) that will assess the effectiveness of exercise to modify the use of eye motion strategies for postural stability in older persons.
Specific aims are to: 1) Measure the temporal (phase) and amplitude relationships between eye, head, and trunk coupled motions during activities of daily living (ADL), 2) Determine the association between the phase and amplitude of eye-head and eye-trunk motion, the level of functional status, and number of fall risk factors, and 3) Identify the demographic, clinical, and eye motion variables that predict functional status. A case-control design will be used to compare 26 older persons living in the community who have balance and mobility impairments with 26 elders who have unimpaired mobility. A person assigned to the case group will be at least 70 years of age who is living at home or in a community-based assisted living facility, is ambulatory (with or without assistive device), is not enrolled in a hospice program, and is mentally intact. Each case subject must be able to walk 30 feet without stopping, demonstrate postural instability on balance testing, and have a minimum of two other fall risk factors. Controls will be matched to cases on age, living status (living alone or with someone), educational level, income level and marital status, but control subjects will have one or fewer fall risk factors and will score above the established cutoff for balance and mobility impairment. The phase (amount of lead or lag in ms) and the peak-to-peak amplitude ratio of eye-to-head and eye-to-trunk motion will be measured during the performance of 8 ADLs. Each ADL will be tested under four visual conditions: 1) eyes open-no visual target, 2) eyes open-near target, 3) eyes open-far target, and 4) wearing Frenzel glasses to prevent the subject from using visual fixation. Visual conditions and performance of ADLs will be systematically randomized and the tester will be blind to subject group assignment. This study will provide information about the use of eye movement to establish balance during functional activities.
| Greany, John F; Di Fabio, Richard P (2008) Saccade to stepping delays in elders at high risk for falling. Aging Clin Exp Res 20:428-33 |
| Di Fabio, Richard P; Zampieri, Cris; Greany, John F (2003) Aging and saccade-stepping interactions in humans. Neurosci Lett 339:179-82 |
| Di Fabio, Richard P; Greany, John F; Emasithi, Alongkot et al. (2002) Eye-head coordination during postural perturbation as a predictor of falls in community-dwelling elderly women. Arch Phys Med Rehabil 83:942-51 |
| Di Fabio, R P; Emasithi, A; Greany, J F et al. (2001) Suppression of the vertical vestibulo-ocular reflex in older persons at risk of falling. Acta Otolaryngol 121:707-14 |
| Di Fabio, R P; Paul, S; Emasithi, A et al. (2001) Evaluating eye-body coordination during unrestrained functional activity in older persons. J Gerontol A Biol Sci Med Sci 56:M571-4 |
