Young and Older Adults Differ in Integration of Sensory Cues for Vertical Perception

Abstract

Introduction. The subjective visual vertical (SVV) measures the perception of a person’s spatial orientation relative to gravity. Weighted central integration of vestibular, visual, and proprioceptive inputs is essential for SVV perception. Without any visual references and minimal proprioceptive contribution, the static SVV reflects balance of the otolith organs. Normal aging is associated with bilateral and progressive decline in otolith organ function, but age-dependent effects on SVV are inconclusive. Studies on sensory reweighting for visual vertical and multisensory integration strategies reveal age-dependent differences, but most studies have included elderly participants in comparison to younger adults. The aim of this study was to compare young adults with older adults, an age group younger than the elderly. Methods. Thirty-three young and 28 older adults (50–65 years old) adjusted a tilted line accurately to their perceived vertical. The rod’s final position from true vertical was recorded as tilt error in degrees. For otolithic balance, visual vertical was recorded in the dark without any visual references. The rod and frame task (RFT) with tilted disorienting visual frames was used for creating visuovestibular conflict. We adopted Nyborg’s analysis method to derive the rod and frame effect (RFE) and trial-to-trial variability measures. Rod alignment times were also analyzed. Results. There was no age difference in signed tilts of SVV without visual reference. There was an age effect on RFE and on overall trial-to-trial variability of rod tilt, with older adults displaying larger frame effects and greater variability in rod tilts. Alignment times were longer in the tilted-frame conditions for both groups and in the older adults compared to their younger counterparts. The association between tilt accuracy and tilt precision was significant for older adults only during visuovestibular conflict, revealing an increase in RFE with an increase in tilt variability. Correlation of σSVV, which represents vestibular input precision, with RFE yielded exactly the same contribution of σSVV to the variance in RFE for both age groups. Conclusions. Older adults have balanced otolithic input in an upright position. Increased reliance on visual cues may begin at ages younger than what is considered elderly. Increased alignment times for older adults may create a broader time window for integration of relevant and irrelevant sensory information, thus enhancing their multisensory integration. In parallel with the elderly, older adults may differ from young adults in their integration of sensory cues for visual vertical perception.

The effect of virtual visual scene inclination transitions on gait modulation in healthy young vs older adults - a virtual reality study

“…However, the locomotive reactions, which are behaviorally reflected by variations in gait speed, are not fully understood. Herein we strengthen the notion that visual field dependency increases with aging 27,28 , this can be seen by (1) significant increase in the older adults group compared to the young group, and (2) only within the older adults, there is a significant correlation between age and rod and frame index. Future studies should measure visual field dependency across the lifespan to detect at which age the increase starts, and whether is plateaus eventually.…”

“…figure 2, middle row). As older adults have increased reliance on visual cues 27,28 , an observation that was confirmed in our study as can be seen by the results of the rod and frame test (Figure 3) we expected to see larger speed modulations following virtually induced braking and exertion effect. Surprisingly, no significant difference was seen in the magnitude nor the timing of the peaks/troughs.…”

“…In the present study we turned to explore to what extent these effects are preserved in older adults. Since there is growing reliance on vision with aging 27,28 , we hypothesized to see similar locomotor adaptations following virtually visual transitions in an elderly healthy population, but with a higher relative change in walking speed in comparison to the young healthy population. Furthermore, we hypothesized that the visual field dependence would be higher in the elderly population yet associated to their gait speed modulations.…”

The reliability of a subtype-determining questionnaire in efficient benign paroxysmal positional vertigo diagnosis in geriatrics

“…Surprisingly, the diagnostic accuracy of these three questions was similar to those in the general population, with 80.7% accuracy, 78.7% sensitivity, and 87.2% specificity ( Wan et al, 2023 ). Originally, we expected less competent predictive ability of these parameters because hair cell and neuronal loss, a functional decline of the vestibular nerve, and reduced blood flow to the inner ear all contributed to an aging vestibular system ( Zalewski, 2015 ; Ji and Zhai, 2018 ; Abdul Razzak et al, 2020 ). These degenerative changes happen in the forms of decreased cervical/ocular vestibular-evoked myogenic potentials amplitudes and abnormal head impulse (HIT) and modified Romberg tests ( Davalos-Bichara and Agrawal, 2014 ; Fernández et al, 2015 ).…”

“…The enhanced multisensory integration in the elderly seems to be a good candidate for an explanation, with the potential mechanism such as increased time window of integration; deficits in top-down attention control enable more distraction by stimuli through sensory modalities, inverse effectiveness, and elevated background sensory processing baseline ( McGovern et al, 2014 ; Abdul Razzak et al, 2020 ). Similarly, Anson et al (2016) found that older adults exhibited significantly larger compensatory saccades relative to the young in the HIT test, which was used to evaluate the function of the three semicircular canals.…”