Improved proprioceptive function by application of subsensory electrical noise: Effects of aging and task-demand

Abstract

The application of subsensory noise stimulation over the lower limbs has been shown to improve proprioception and postural control under certain conditions. Whereas the effect specificity seems to depend on several factors, studies are still needed to determine the appropriate method for training and rehabilitation purposes. In the current study, we investigated whether the application of subsensory electrical noise over the legs improves proprioceptive function in young and older adults. We aimed to provide evidence that stronger and age-related differential effects occur in more demanding tasks. Proprioceptive function was initially assessed by testing the detection of passive ankle movement (kinesthetic perception) in twenty-eight subjects (14 young and 14 older adults). Thereafter, postural control was assessed during tasks with different sensory challenges: i) by removing visual information (eyes closed) and; ii) by moving the visual scene (moving room paradigm). Tests performed with the application of electrical noise stimulation were compared to those performed without noise. The results showed that electrical noise applied over the legs led to a reduction in the response time to kinesthetic perception in both young and older adults. On the other hand, the magnitude of postural sway was reduced by noise stimulation only during a more challenging task, namely, when the optical flow was changing in an unpredictable (nonperiodic) manner. No differential effects of stimulation between groups were observed. These findings suggest that the relevance of proprioceptive inputs in tasks with different challenges, but not the subjects' age, is a determining factor for sensorimotor improvements due to electrical noise stimulation.

“Walking” through the sensory, cognitive, and temporal degradations of healthy aging

“…Assessing one's multisensory capabilities (e.g., width of the temporal window of integration) would, therefore, allow for the early detection and intervention by introducing multisensory perceptual training paradigms that can narrow the temporal window of integration, refine older adults’ temporal discrimination abilities of auditory and visual stimuli, and, consequently, reduce susceptibility to audiovisual illusions (i.e., improving accuracy), as it has been already shown in young individuals . The latter finding suggests that multisensory temporal discrimination training can generalize to other perceptual processes that are not directly trained, and probably yield transfer effects to the motor domain, thus reducing the fall‐risk in older adults, ameliorating the common age‐related gait and postural deficits, and ensuring low gait variability …”

Age-related changes in leg proprioception: implications for postural control

“…The authors suggested that mechanical noise may constitute a means of improving postural stability in subjects with sensory deficits. Similarly, electrical noise stimulation applied over the knee or leg muscles improved proprioception and postural control in young and older adults (Gravelle et al 2002;Toledo et al 2017).…”

Sensory Sub‐ and Suprathreshold TENS Exhibit No Immediate Effect on Postural Steadiness in Older Adults with No Balance Impairments

“…e strength of the signal, which is interpreted as noise, is below conscious perception; therefore, subjects are not aware of its presence. is kind of stimuli decreases vibratory threshold detection in young [13] and elderly persons [14], enhances kinesthetic perception [15] and joint position sense [10], and decreases postural sway when skin receptors in the area above the muscles that stabilize posture are stimulated [11,12,15,16].…”

“…e application of subthreshold electrical stimulation (ES) was reported to reduce postural sway in young healthy [11,17] and healthy elderly adults [15,18] and may consequently reduce the risk of falls in elderly persons. e reported studies differ in various features and protocols.…”

“…Different types of electrical stimuli were used: stochastic resonance stimuli, white noise, and transcutaneous electrical nerve stimulation (TENS). Some researchers applied stochastic resonance [11,12,15], quasi-white noise with a sweep of frequencies from 5 to 1500 or 2000 Hz, and reported the decrease of postural sway [17]. A low-frequency conventional TENS was also used to attenuate postural sway.…”