The main aim of this study is to unravel the biomechanics of postural balance reactions during head-motion perturbed standing and walking in older adults who fall, while integrating the influence of frailty, sensory functioning and cognitive processing.
Older adults above 65 years old experience falls at a rate of 20-40% annually, with women being more affected than men. Unintentional falls are the second leading cause of accidental injury death and a major contributor to disability levels worldwide. Falls pose an even bigger burden on society in the future due to the increasing number of older adults and the higher prevalence of falls as people age. Gait and balance instability are major risk and causative factors for falls in older adults. As people age, their stability decreases. This is evident in the careful way that older adults walk. To prevent and predict falls, it is essential to understand how humans maintain their stability during locomotor activities. Balance disruptions are typically not caused by walking itself, but rather by internal or external disturbances or the performance of multiple tasks simultaneously. In daily life, people often face complex situations that require high levels of sensory input and cognitive processing. This can be especially challenging when also trying to maintain a safe walking pattern, such as when checking the environment before crossing the street. This task requires coordinated movement of both the head and eyes to track moving objects. Gaze control requires accurate cognitive processing, including multisensory integration, attention, executive functioning, and motor responses to coordinate eye and head movements. Older adults use different strategies than younger adults to control head movement for stabilizing their head during walking. Therefore, changes in head position may affect gait stability differently in older adults. Ageing can cause frailty, decline in sensorimotor and cognitive abilities, and a reduced capacity to adjust gait to changing environments. These changes may increase the risk of falls in older adults. However, research on these issues is currently insufficient.
Study Type
OBSERVATIONAL
Enrollment
100
1. The CatchU® app quantitatively and objectively measures the ability to integrate visual-somatosensory information using reaction time test data. 2. Digit Symbol Substitution test assesses processing speed and attention by requiring individuals to match symbols with corresponding numbers within a specified time frame. 3. Trail Making Test part 1 and 2: assesses cognitive flexibility, visual attention, and task-switching by having individuals connect numbered circles in sequence (part 1) and then alternate between numbers and letters (Part 2). 4. Go/No Go test measures an individual's ability to inhibit a prepotent response (No-Go) and execute a response when required (Go). This test provides insights into executive functioning, particularly inhibitory control.
1. Cervical Sensorimotor control will be measured through a wireless wearable sensor 3D-cervical trainer by Sensamove on the placed on the head of the participant. The 3DCT registers cervical position sense by the Head Repositioning Accuracy test where the subject must relocate the head to the previously memorized (neutral) head position with the eyes closed and the joint position error degrees are registered. Cervical movement sense is examined using 'The Fly'-test where the subject ought to follow a movement pattern displayed on the screen in front of them. The movement of the neck-head unit is there upon tracked by the 3DCT and projected on the screen. 2. Vestibular function will be assessed through 3D-video Head Impulse Testing (vHIT), examining the state of the three semicircular canals by delivering the vestibulo-ocular reflex (vor) gain and vor gain asymmetry. 3. For the assessment of static and dynamic visual acuity, functional Head Impulse Testing (fHIT) will be used.
University of Antwerp
Antwerp, Belgium
RECRUITINGSpatio-temporal parameters of gait
step length and width (cm)
Time frame: baseline
Foot placement estimator
measure which estimates where the foot should be placed for stable gait
Time frame: baseline
Onset latency
latency in msec between onset of movements and activation recorded by surface EMG of bilateral m. Erector Spinae (trunk stabilization), m. Gluteus medius (hip strategy), m. Tibialis anterior and m. Soleus (ankle strategy)
Time frame: baseline
Peak amplitude
peak amplitude in microvolts of the surface EMG of bilateral m. Erector Spinae (trunk stabilization), m. Gluteus medius (hip strategy), m. Tibialis anterior and m. Soleus (ankle strategy)
Time frame: baseline
Fixation duration
Duration of fixation of the eyes on target, measured by the Hololens 2
Time frame: baseline
Gain
Accuracy of the fixation of the eyes on target as measured by the Hololens 2
Time frame: baseline
Latency
Latency in msec between the movement of the target and the movement of the eyes and the head when following the target as measured by the Hololens 2.
Time frame: baseline
Fall characteristics
Fall diaries provide information on occurrence and number of falls, activity preceding a fall, cause of fall, obtained injuries and potential care that was received.
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Frailty will be assessed using the Fried criteria, comprising 5 categories (each accounting for 1 point if scored positive): Unintentional weight loss (interview), weakness (grip strength with hand-held dynamometer), poor endurance and energy (two statements of the CES-D Depression Scale), slowness (walking speed over 15ft through gait analysis) and low physical activity level (Minnesota Leisure Time Activity questionnaire)(Fried et al., 2001).
Markers will be placed on the predefined anatomical locations and surface electrodes for electromyography will be applied at the predefined muscle locations following the SENIAM-guidelines. The Microsoft HoloLens 2 is fixated on the participant's head which will, on one hand, provide the cue to the participant for the head movement and on the other hand track eye and head movements. A safety harness is attached to the body and the ceiling of the lab. At the start of the trial, the subject will see a projection by the HoloLens 2 on the real environment moving to the left; right; upward; downward (cue in randomized order) which the participant is ought to follow with eyes and head. First while standing still and second while walking the 10-meter overground walkway at a self-preferred walking speed.
The researcher will visit the possible participants (at their home, community centre, etc.) and after written consent on screening procedure is provided, the tests for eligibility will be performed. 1. Interview: asking about age (years), gender (male/female), medical history and the number of falls in the last 12 months . 2. Timed Up-and-Go (TUG) to check walking ability. TUG is a sensitive and specific measure for identifying risk for falls (Shumway-Cook et al., 2000).
Participants are followed up for 12 months. They fill in a fall diary and telephone reminders will be performed monthly to encourage participants to complete and return their diaries.
Time frame: monthly during 12 months of follow-up
Multisensory integration
reaction times in visual/sensory vs. visuo-sensory conditions (ratio, in %) measured with CatchU app
Time frame: baseline
Digit symbol substitution test
number of correct symbol-digit pairs completed
Time frame: baseline
Trail making test
Time to complete part A vs. B (ratio in seconds)
Time frame: baseline
Go/No Go test
Accuracy (number of correct responses)
Time frame: baseline
Head Repositioning Accuracy
joint position error in degrees
Time frame: baseline
Fly test
directional accuracy (in %) of movement
Time frame: baseline
Fly test
Amplitude (in mm) of movement
Time frame: baseline
vHIT
VOR-gain and VOR-gain asymmetry in %
Time frame: baseline
fHIT
statfHIT (Static visual acuity): logMAR-score and dynfHIT (Dynamic visual acuity): % correct responses
Time frame: baseline
Frailty
Fried criteria: Frailty level (categorical): non-frail (0/5), pre-frail( 1-2/5) or frail (≥3/5)
Time frame: baseline