Processing moving visual scenes during upright stance in elderly patients with mild cognitive impairment

Abstract

Background The ability to maintain balance in an upright stance gradually worsens with age and is even more difficult for patients with cognitive disorders. Cognitive impairment plays a probable role in the worsening of stability. The purpose of this study was to expose subjects with mild cognitive impairment (MCI) and healthy, age-matched controls to moving visual scenes in order to examine their postural adaptation abilities. Methods We observed postural responses to moving visual stimulation while subjects stood on a force platform. The visual disturbance was created by interposing a moving picture in four directions (forward, backward, right, and left). The pre-stimulus (a static scene for 10 s), stimulus (a dynamic visual scene for 20 seconds) and post-stimulus (a static scene for 20 seconds) periods were evaluated. We separately analyzed the total path (TP) of the center of pressure (COP) and the root mean square (RMS) of the COP displacement in all four directions. Results We found differences in the TP of the COP during the post-stimulus period for all stimulus directions except in motion towards the subject (left p = 0.006, right p = 0.004, and away from the subject p = 0.009). Significant RMS differences between groups were also observed during the post-stimulus period in all directions except when directed towards the subject (left p = 0.002, right p = 0.007, and away from the subject p = 0.014). Conclusion Exposing subjects to a moving visual scene induced greater destabilization in MCI subjects compared to healthy elderly controls. Surprisingly, the moving visual scene also induced significant aftereffects in the MCI group. Our findings indicate that the MCI group had diminished adaptation to the dynamic visual scene and recovery. These results suggest that even mild cognitive deficits can impair sensory information integration and alter the sensory re-weighing process.

Perturbation-based dual task assessment in older adults with mild cognitive impairment

“…Real-life environments may incorporate the additional dynamics of perceptual cognitive demands, like standing and visually searching for cues, or standing and tracing items in the environment. Research has shown that OAwMCI experience a decline in visual processing capacity, visual search, and attention-related processing ( 37 ), which leads to difficulty processing moving visual scenes during standing, causing losses of balance ( 38 ). These scenarios may require more substantial attentional demands to recruit the appropriate motor strategies to recover from unexpected balance control threats, due to potential overlapping resources between reactive balance control and cognitive function.…”

Linking cognitive functioning and postural balance control through virtual reality environmental manipulations

“…The results showed that both healthy older and young adults swayed more in the anterior-posterior direction when they were exposed to the moving VR environments compared to the baseline eyes-open (EO) condition without the VR headset (refer to <2-1> with corresponding blue and yellow arrows in Figure 1 ). Other studies also induced postural sway by giving various visual stimuli to healthy older adults and people suffering from MCI and AD (Gago et al, 2016 ; Kucharik et al, 2020 ). The studies revealed that the population with MCI and AD took longer reaction times to the stimuli and swayed more compared to the healthy population (refer to <2-2> with corresponding blue and yellow arrows in Figure 1 ).…”