Associations between Tactile Sensory Threshold and Postural Performance and Effects of Healthy Aging and Subthreshold Vibrotactile Stimulation on Postural Outcomes in a Simple Dual Task.

Marius Dettmer,Charles S Layne,Beom-Chan Lee,Amir Pourmoghaddam

doi:10.1155/2016/9797369

Abstract

Specific activities that require concurrent processing of postural and cognitive tasks may increase the risk for falls in older adults. We investigated whether peripheral receptor sensitivity was associated with postural performance in a dual-task and whether an intervention in form of subthreshold vibration could affect performance. Ten younger (age: 20–35 years) and ten older adults (70–85 years) performed repeated auditory-verbal 1-back tasks while standing quietly on a force platform. Foot sole vibration was randomly added during several trials. Several postural control and performance measures were assessed and statistically analyzed (significance set to α-levels of .05). There were moderate correlations between peripheral sensitivity and several postural performance and control measures (r = .45 to .59). Several postural performance measures differed significantly between older and younger adults (p < 0.05); addition of vibration did not affect outcome measures. Aging affects healthy older adults' performance in dual-tasks, and peripheral sensitivity may be a contributor to the observed differences. A vibration intervention may only be useful when there are more severe impairments of the sensorimotor system. Hence, future research regarding the efficacy of sensorimotor interventions in the form of vibrotactile stimulation should focus on older adults whose balance is significantly affected.

Highlights

Aging is known to cause multiple changes in anatomy and physiology of the human body
The fact that older adults performed at similar levels to younger adults is unexpected but may be based on the specific task and the group of older adults that served as participants in the study
The n-back task performed concurrently in this experiment was designed to divert attention from postural control processes. It has been shown in younger adults that a fairly simple cognitive task can lead to improved posture, associated with even less sway than when performing a single-task

Summary

Introduction

Aging is known to cause multiple changes in anatomy and physiology of the human body. It is believed that progressive decline of sensory systems function (e.g., plantar mechanoreceptors, vestibular system, muscle spindle afferents, vision) and impairments in proprioceptive-spinal circuits lead to issues regarding the detection of small fluctuations in postural orientation during upright stance [6], which in turn increases the risk for postural balance performance decline and falls [7] Such deterioration of function often interacts with the affordances posed by specific tasks: Among the major challenges to postural stability is the simultaneous processing. Considering the potential to enhance peripheral sensory detection and information transmission, it may be possible that a SRbased intervention may have effects on performance dualtask performance This augmentation of feedback emerging from the foot soles could improve postural control efficiency, which would be associated with less cognitive demand, as potentially expressed either in better cognitive or postural performance in concurrent tasks. We further hypothesized that an SR intervention would affect participants’ postural characteristics

Methods

N-Back Cognitive Task

Results

Discussion

Conclusions