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

Background:Falls 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/Design:Patients 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.Discussion:This 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.publishe

Supplementary Material for: Ambulatory Activity Components Deteriorate Differently across Neurodegenerative Diseases: A Cross-Sectional Sensor-Based Study

<b><i>Background and Purpose:</i></b> Reduced ambulatory activity is a major burden in neurodegenerative disease (NDD), leading to severe restrictions in social participation and further deterioration of motor capacities. However, objective evidence on walking behavior patterns and components underlying this impairment and its decline with disease progression is scarce for many NDDs. We aimed to unravel the detailed metrics underlying the reduced ambulatory activity in selected NDDs, and their relation to disease duration. We hypothesized that progressively reduced ambulatory activity is a feature shared across different NDDs, characterized by changes in both common and distinct components. <b><i>Methods:</i></b> Sixty-five subjects with NDD (n = 34 degenerative ataxia; n = 15 progressive supranuclear palsy, and n = 16 Parkinson's disease) and 38 healthy older adults (total n = 103) wore a three-axial accelerometer (activPAL3™) for 7 consecutive days. Detailed metrics of ambulatory activity were calculated. <b><i>Results:</i></b> The average daily walking duration was significantly decreased in all three NDDs, yet characterized by a differential pattern of changes in number and length of walking bouts and sit-to-stand transfers. Decline in walking duration progressed with increased disease duration in all three NDDs, yet at a differing rate. This decline was associated with progressive reductions in walking bout length and walking behavior pattern diversity in all three NDDs. <b><i>Conclusions:</i></b> These findings provide objective evidence that reduced ambulatory activity is a shared feature across different NDDs. Moreover, they reveal that several underlying walking behavior components change with increasing disease duration, yet at a differing rate in different NDDs. This indicates that metric analysis of ambulatory activity might provide ecologically relevant and disease-specific progression and outcome markers in several NDDs

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

Background Falls 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/Design Patients 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. Discussion This 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