Association between vestibulo-ocular reflex suppression, balance, gait, and fall risk in ageing and neurodegenerative disease: protocol of a one-year prospective follow-up study.

Karin Srulijes,Matthis Synofzik,Jörn K Pomper,Kathrin Brockmann,Srijana K.C,Espen A F Ihlen,Isabel Wurster,Erich Schneider,Miriam Meyer,Daniela Berg,Jochen Klenk,Ulrich Lindemann,Michael Schwenk,Lars Schwickert,Clemens Becker,David J Mack,Walter Maetzler,Markus A Hobert,Uwe Ilg

doi:10.1186/s12883-015-0447-5

Abstract

BackgroundFalls frequency increases with age and particularly in neurogeriatric cohorts. The interplay between eye movements and locomotion may contribute substantially to the occurrence of falls, but is hardly investigated. This paper provides an overview of current approaches to simultaneously measure eye and body movements, particularly for analyzing the association of vestibulo-ocular reflex (VOR) suppression, postural deficits and falls in neurogeriatric risk cohorts. Moreover, VOR suppression is measured during head-fixed target presentation and during gaze shifting while postural control is challenged. Using these approaches, we aim at identifying quantitative parameters of eye-head-coordination during postural balance and gait, as indicators of fall risk.Methods/DesignPatients with Progressive Supranuclear Palsy (PSP) or Parkinson’s disease (PD), age- and sex-matched healthy older adults, and a cohort of young healthy adults will be recruited. Baseline assessment will include a detailed clinical assessment, covering medical history, neurological examination, disease specific clinical rating scales, falls-related self-efficacy, activities of daily living, neuro-psychological screening, assessment of mobility function and a questionnaire for retrospective falls. Moreover, participants will simultaneously perform eye and head movements (fixating a head-fixed target vs. shifting gaze to light emitting diodes in order to quantify vestibulo-ocular reflex suppression ability) under different conditions (sitting, standing, or walking). An eye/head tracker synchronized with a 3-D motion analysis system will be used to quantify parameters related to eye-head-coordination, postural balance, and gait. Established outcome parameters related to VOR suppression ability (e.g., gain, saccadic reaction time, frequency of saccades) and motor related fall risk (e.g., step-time variability, postural sway) will be calculated. Falls will be assessed prospectively over 12 months via protocols and monthly telephone interviews.DiscussionThis study protocol describes an experimental setup allowing the analysis of simultaneously assessed eye, head and body movements. Results will improve our understanding of the influence of the interplay between eye, head and body movements on falls in geriatric high-risk cohorts.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-015-0447-5) contains supplementary material, which is available to authorized users.

Highlights

Falls frequency increases with age and in neurogeriatric cohorts
This study protocol describes an experimental setup allowing the analysis of simultaneously assessed eye, head and body movements
Many risk factors for falls like gait and balance deficits [2] have been identified in the older population, but the contribution of failures in the interplay between oculo- and locomotion to the risk of falls has not yet been studied in detail

Summary

Introduction

Falls frequency increases with age and in neurogeriatric cohorts. The interplay between eye movements and locomotion may contribute substantially to the occurrence of falls, but is hardly investigated. Many risk factors for falls like gait and balance deficits [2] have been identified in the older population, but the contribution of failures in the interplay between oculo- and locomotion (especially combined head and body movement) to the risk of falls has not yet been studied in detail. This is surprising given that visual exploration of the environment while standing or walking is regularly required during daily life (e.g. crossing a street), and deficits in the oculomotor system may have impacts on the performance of the locomotor system, and vice versa. Glasauer and colleagues described another interaction between eye movements and postural control: retinal slip provides a relevant feedback for postural control, and slow eye movements [5]

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