Effects of biofeedback on secondary-task response time and postural stability in older adults

Abstract

Real-time single- and multiple-axis vibrotactile feedback of trunk motion has been shown to significantly decrease mean trunk tilt and decrease time spent outside a no vibrotactile feedback zone (dead zone) in older adults within a laboratory setting. This study aimed to determine if these improvements can translate into everyday use, during which other tasks may simultaneously demand attention. A dual-task paradigm was used in which 10 community-dwelling older adults were asked to perform standing trials in the presence of a secondary task (verbal or push-button), vibrotactile feedback, or both (dual-task). Results show that subjects significantly increased the percentage of time inside the dead zone when feedback was provided compared to when it was not during both verbal (+13.6%) and push-button (+10.1%) secondary tasks. Providing feedback also decreased RMS of trunk tilt during both secondary tasks (verbal: -0.1298; push-button: -0.1388). However, response times for secondary tasks increased (verbal: +119 ms; push-button: +110 ms) when feedback was provided. These results suggest that while vibrotactile feedback does increase attentional load in older adults, it can still be used effectively to improve postural metrics in high cognitive load situations.

Effects of dual tasks and dual-task training on postural stability: a systematic review and meta-analysis

“…The average PEDro score for the 42 included studies was computed to be 4.7 out of 10, indicating fair quality of the overall studies. One study scored 7,36 three studies scored 6,21,35,65 20 studies scored 5,16,17,20,34,69–72,74,77,79–84,86,92–95 and 18 studies scored 4 22,48,61–63,66–68,73,75,76,78,81,85,87–89,91…”

“…Two fair-quality studies evaluated the effects of dual tasks on elderly participants 70,74. Both the studies reported a significant reduction in postural stability post dual-task intervention.…”

Postural Reorganization Induced by Torso Cutaneous Covibration

“…Such devices provide cues for directional correction of body motion with vibrating actuators placed on the torso. These cutaneous "alarm" signals triggered at predefined thresholds and historically accompanied with the instruction to "Move away from the vibration" (repulsive cuing) have been shown to significantly reduce body sway in various populations during quiet and perturbed stances (Wall and Kentala, 2005;Sienko et al, 2008Sienko et al, , 2010Bechly et al, 2012;Haggerty et al, 2012;Lee et al, 2012c). Although repulsive cuing strategies have been regularly used for such applications, they may not be congruent with kinesthetic information from the stimulated cutaneous receptors.…”

Effects of co-vibrotactile stimulations around the torso on non-volitional postural responses

“…In general, the displays map directions of postural sway captured by a sensor with vibrating actuators around the torso. These "alarm signals" allow users to correct postural sway that would compromise balance [1][2][3][4][5][6][7][8]. When the body tilt exceeds the pre-defined threshold, one of the tactors vibrates to indicate the direction of body correction.…”

“…Wall et al [9] initially selected repulsive ("move away from the vibration") versus attractive ("move toward the vibration") cuing based on the notion that such vibrations may provoke an avoidance response similar to bumping into an obstacle. Torso-based vibrotactile biofeedback systems incorporating repulsive cuing strategies have been shown to significantly reduce body sway in individuals with vestibular deficits [3][4][5][6][7], older adults [2,8], and healthy young adults [1,3,9] during quiet and perturbed stances [4][5][6].…”