Haptic information provided by the "anchor system" reduces trunk sway acceleration in the frontal plane during tandem walking in older adults

Role of the Functional Gait Assessment in Validating Item Difficulty Hierarchy and Fall Risk for Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Falls along with gait-balance disturbances are important symptoms of idiopathic normal pressure hydrocephalus (iNPH).

OBJECTIVES

This study aimed to validate the Functional Gait Assessment (FGA) item-difficulty hierarchy, determine its optimal fall cutoff value, and identify key items for assessing fall risk in iNPH.

METHODS

One hundred eighty-eight iNPH patients underwent pre-intervention assessments using the FGA, timed up-and-go (TUG), 10-Meter Gait Speed (10MGS) tests, and their falls history in the past 6 months. Rasch analysis confirmed the validity of the FGA item-difficulty hierarchy and established the relationship between total scores and logit estimates. Logistic regression identified the optimal FGA cutoff value and key fall-related items.

RESULTS

The FGA's item-difficulty hierarchy was confirmed to range from item 5 ("gait and pivot turn") at -2.58 logits (easiest) to item 7 ("gait with narrow base of support") at 5.35 logits (most difficult). Total scores corresponded to logits from -10.39 (score 0) to 11.64 (score 30). The fall rate was 63.3%. The optimal FGA cutoff value was ≤15 points (area under curve [AUC]: 0.901, P < 0.001), outperforming TUG (AUC: 0.712) and 10MGS (AUC: 0.742). Key fall-related items (R2: 0.545, P < 0.001) were item 2 ("change in gait speed"), item 7 ("gait with narrow base of support"), item 1 ("gait on level surface"), item 10 ("stair steps"), and item 5 ("gait and pivot turn").

CONCLUSIONS

Our findings may facilitate early diagnosis and timely interventions, including tailored rehabilitation and fall prevention strategies, by leveraging the item difficulty and characteristics of the FGA for iNPH patients.

Effect of the haptic anchors during balancing and walking tasks in older adults: A systematic review

BACKGROUND

Older adults are benefited from the continuous tactile information to enhance postural control. Therefore, the aim was to evaluate the effect of the haptic anchors during balancing and walking tasks in older adults.

METHODS

The search strategy (up to January 2023) was based on the PICOT (older adults; anchor system during balance and walking tasks; any control group; postural control measurements; short and/or long-term effect). Two pairs of reviewers independently examined all titles and abstracts for eligibility. The reviewers independently extracted data from the included studies, assessed the risk of bias, and certainty of the evidence.

RESULTS

Six studies were included in the qualitative synthesis. All studies used a 125-g haptic anchor system. Four studies used anchors when standing in a semi-tandem position, two in tandem walking on different surfaces, and one in an upright position after plantar flexor muscle fatigue. Two studies showed that the anchor system reduced body sway. One study showed that the ellipse area was significantly lower for the 50% group (reduced frequency) in the post-practice phase. One study showed that the reduction in the ellipse area was independent of the fatigue condition. Two studies observed reduced trunk acceleration in the frontal plane during tandem waking tasks. The studies had low to moderate certainty of evidence.

CONCLUSION

Haptic anchors can reduce postural sway during balance and walking tasks in older adults. Also, positive effects were seen during the delayed post-practice phase after the removal of anchors only in individuals who used a reduced anchor frequency.

Rehabilitation effects in idiopathic normal pressure hydrocephalus: a randomized controlled trial

BACKGROUND

Gait-balance disturbances are core symptoms of idiopathic normal pressure hydrocephalus (iNPH). However, the rehabilitation effects of cerebrospinal fluid (CSF) shunting along with other treatment or no further treatment (natural course [NC]) for iNPH are unknown.

OBJECTIVES

This study evaluated whether dynamic equilibrium gait training (DEGT) can improve gait-balance functions after CSF shunting of patients with iNPH compared to standard exercise (SE) and NC. Furthermore, it investigated the incidence of falls.

METHODS

A total of 70 patients with iNPH who underwent CSF shunting were randomly assigned to 6 weeks of DEGT (n = 23), 6 weeks of SE (n = 23), or NC (n = 24). Evaluation was performed at baseline (preoperatively) and at 1 week, 7 weeks (postintervention), and 6 months postoperatively (follow-up). Outcomes were measured using the functional gait assessment (FGA), 10-m walk test, timed up-and-go test, life-space assessment (LSA), and fall incidence.

RESULTS

A total of 65 participants completed the study. During the intention-to-treat analysis, the DEGT group demonstrated significant recovery of gait-balance functions according to only the FGA at postintervention and follow-up compared to the SE and NC groups; however, recovery of the SE group did not differ from that of the NC group. The DEGT group had a significantly lower fall incidence than the other groups at follow-up. Significantly better LSA results were observed for all groups at follow-up compared to baseline; however, no difference in LSA results were observed between groups.

CONCLUSIONS

DEGT in addtion to CSF shunting can facilitate the recovery of gait-balance function and reduce the fall incidence of iNPH patients.

Acute Effects of a Haptic Anchor System on Postural Sway of Individuals with Parkinson's Disease: A Preliminary Study

Some investigators have demonstrated that an anchor system can improve postural control in elderly persons during balance tasks, but none have reported on the use of this approach in individuals with Parkinson's disease (PD). Therefore, we aimed to evaluate the effect of an anchor system on postural sway in elderly individuals with (n = 13) and without (n = 14) PD. In this cross-sectional study, we measured postural sway with a force platform based on the Clinical Test of Sensory Interaction of Balance (CTSIB). We calculated center of pressure (COP) parameters, as a function of time, based on the ellipse sway area (cm²) and evaluated self-efficacy for postural control based on the degree of difficulty in each task. With the anchor system (i.e., handheld ropes attached to weights on the floor), we observed a significant reduction in the ellipse sway area in the semi-tandem position among individuals with PD (p = .04). For participants without PD, there was no significant difference in sway with or without the anchor system in all positions. Also, for participants with PD, there was an improvement in self-efficacy for postural control associated with the anchor system in several positions while there was only a self-efficacy improvement with the anchor system in the semi-tandem position for those without PD. Acute use of a haptic anchor system reduced postural sway in the semi-tandem position in individuals with PD, and the anchor system generally improved postural control self-efficacy for body sway in individuals with PD.

Three days of beam walking practice improves dynamic balance control regardless of the use of haptic anchors in older adults

Balance deficits during walking increase the risk of falls in older adults. Providing haptic information through anchors improves dynamic balance control, but the benefits of practicing with anchors during walking need to be evaluated. We investigated the effect of practice with haptic anchors in the beam walking task in older adults. Twenty-five older adults participated in this study divided into 0% (G0, practice without the anchors) and 50% (G50, practice with the haptic anchors in 50% of the trials) groups. With the anchors, participants held in each hand a cable with a mass of 0.125 kg affixed to the end of the cable that contacted the ground. They walked and kept the anchors in contact with the ground such that they dragged them. Participants increased the distance walked on the beam and reduced the trunk angular acceleration after training, but this effect was independent of the anchors. The use of haptic anchors during beam walking training did not significantly affect older adults' performance and dynamic balance control. Both groups showed improvements in the post-test and 24-hr retention conditions, indicating that older adults can learn to adapt their gait to more challenging contexts.

Adding Light Touch While Walking in Older Adults: Biomechanical and Neuromotor Effects

Adding haptic input may improve balance control and help prevent falls in older adults. This study examined the effects of added haptic input via light touch on a railing while walking. Participants (N = 53, 75.9 ± 7.9 years) walked normally or in tandem (heel to toe) with and without haptic input. During normal walking, adding haptic input resulted in a more cautious and variable gait pattern, reduced variability of center of mass acceleration and margin of stability, and increased muscle activity. During tandem walking, haptic input had minimal effect on step parameters, decreased lower limb muscle activity, and increased cocontraction at the ankle closest to the railing. Age was correlated with step width variability, stride length variability, stride velocity, variability of medial-lateral center of mass acceleration, and margin of stability for tandem walking. This complex picture of sensorimotor integration in older adults warrants further exploration into added haptic input during walking.

Trunk balance control during beam walking improves with the haptic anchors without the interference of an auditory-cognitive task in older adults

BACKGROUND

Prior studies have shown that older adults reduced trunk acceleration when walking on a balance beam with haptic inputs provided by anchors; however, it is unknown whether these benefits would remain in the presence of a concurrent cognitive task.

RESEARCH QUESTION

This study aimed to evaluate the effect of a cognitive task on balance control when using the anchors while walking on a balance beam in older adults.

METHODS

Thirty older adults participated in this study. They walked on a balance beam under four conditions combining haptic inputs (with and without anchors) and a cognitive task (present and absent). The anchors consisted of a flexible cable with a small load (125 g) attached at the end contacting the ground. Participants held one anchor in each hand and dragged the loads over the ground while walking. In the cognitive task, participants silently counted the number of times they heard a target number within a series of random numbers and provided their response at the end of each trial. Trunk acceleration and normalized step speed were assessed.

RESULTS

The anchors reduced the normalized step speed and the trunk acceleration amplitude in the frontal plane when walking on the beam. The cognitive task also diminished the normalized step speed in the beam walking. The use of the anchors did not influence the cognitive task performance.

SIGNIFICANCE

Even on a balance beam in the presence of a cognitive task, haptic anchors were able to reduce trunk acceleration in older adults to improve balance control. The cognitive task did not affect the use of haptic anchors.

Effects of the Use of Anchor Systems in the Rehabilitation of Dynamic Balance and Gait in Individuals With Chronic Dizziness of Peripheral Vestibular Origin: A Single-Blinded, Randomized, Controlled Clinical Trial

OBJECTIVE

To assess the effectiveness of the anchors in the balance rehabilitation of participants with chronic peripheral vestibulopathy who failed to respond positively to conventional rehabilitation for dynamic balance and gait.

DESIGN

Assessor-blind, randomized controlled trial.

SETTING

Department of Otoneurology and Laboratory of Assessment and Rehabilitation of Equilibrium.

PARTICIPANTS

Women with chronic dizziness of peripheral vestibular origin (N=42), who continued to show otoneurologic symptoms for more than 6 months after starting classic vestibular rehabilitation, with no clinical improvement observed.

INTERVENTIONS

Participants were randomly assigned to receive a clinical intervention with the anchor system, a clinical intervention without the anchor system, or no intervention or anchor system. The intervention was based on multi-sensory exercises for 6 weeks, twice a week, totaling 12 sessions, in groups of up to 4 participants, with an average time of 40 minutes per session.

MAIN OUTCOME MEASURES

The primary outcome was functional balance as assessed by the short version of the Balance Evaluation Systems Test. The secondary outcomes were gait parameters of step width in meters, step length in meters, and gait speed in meters per second. The measures were assessed preintervention and postintervention, and after a 3-month follow-up period.

RESULTS

The proposed intervention was beneficial for dizziness, balance, and gait for both groups studied. At the 3-month follow-up, only the group that used anchors retained the benefits related to the physical aspects of dizziness, balance, and gait.

CONCLUSIONS

The present study found that the proposed intervention protocol, with or without the use of anchors, was beneficial for improving the dizziness, balance, and gait. However, retention of the benefits achieved through the exercise protocol was observed only for those using the anchor system, which promotes the use of haptic information. The use of anchors was effective, in short protocols (12wk), with maintenance of results after 3 months.

Are there attentional demands associated with haptic modalities while walking in young, healthy adults?

STUDY DESIGN

A prospective, observational study.

OBJECTIVES

To assess the attentional demands of using haptic modalities during walking using a multi-task paradigm in young, healthy adults.

SETTING

Biomechanics of Balance and Movement (BBAM) Lab, University of Saskatchewan.

METHODS

Twenty-two (12 male) young, healthy adults performed walking trials with and without a verbal reaction time (VRT) task, as well as with and without the use of haptic anchors and light touch on a railing. Walking performance was evaluated using normalized stride velocity and step width, and dynamic stability was evaluated using step width variability and medial-lateral margin of stability (ML MOS) and its variability.

RESULTS

There were no significant differences in VRT when walking with and without added haptic input and no interactions between the added VRT task and added haptic input. Step width increased and variability of the ML MOS increased during trials with the VRT task compared to trials without the VRT task. The ML MOS decreased when using both haptic tools with a greater decrease when using light touch on the railing compared to when using the haptic anchors. Normalized stride velocity and step width decreased when using light touch on the railing only.

CONCLUSION

Both haptic tools affected stability during walking. Using the railing to add haptic input had a greater effect on walking stability and was the only haptic tool to affect walking performance. Attentional demands should be considered in future research and applications of adding haptic input during walking.

Comparing the effect of haptic modalities on walking balance control: Is using one or two arms better?

BACKGROUND

Adding haptic input by lightly touching a railing or using haptic anchors may improve walking balance control. Typical use of the railing(s) and haptic anchors requires the use of one and two arms in an extended position, respectively. It is unclear whether it is arm configuration and/or the number of arms used or the addition of sensory input that affects walking balance control.

RESEARCH QUESTION

This study examined whether using one arm or two arms to add haptic input through light touch on a railing or using the haptic anchors affects walking balance control.

METHODS

In this study, young adults (n = 24) walked while using (actual use) or pretending to use (pretend use) the railing(s) and haptic anchors with one or two arms. Inertial-based sensors (Mobility Lab, APDM) were used to measure stride velocity, relative time spent in double support (%DS), and peak normalized medio-lateral trunk velocity (pnMLTV).

RESULTS

Using two arms lead to a decrease in pnMLTV compared to using one arm and pnMLTV was lower in the actual use trials compared to the pretend use trials for the anchors only. Stride velocity and %DS did not change between trials when one or two arms were used or when participants actually or pretended to use the haptic tools. Participants walked slower when using the railing compared to the anchors.

SIGNIFICANCE

The importance of considering the number of arms is highlighted in the improved balance control when using two arms with either tool. The augmented sensory input adds to the stabilizing effect of arm configuration for the anchors but not the railings. These results have implications for future research and rehabilitation efforts emphasizing sensorimotor integration to improve walking balance control.

The Use of the Anchor System Reduces Postural Sway During Upright Standing Irrespective of Plantar Flexors Muscle Fatigue in Young and Older Adults

Our purpose was to verify the effects of the use of the anchors on postural control after the fatigue of the plantar flexor muscles in young and older adults. They stood barefoot, with their eyes closed in four conditions combining the use of the anchors and the fatigue. When using the anchors, participants held one cable in each hand and kept the cable taut without removing the loads (125 g) from the ground. The fatigue protocol consisted of performing a single series of bilateral plantar flexion movements. The fatigue protocol increased postural sway in both groups. Both groups reduced postural sway with the anchors, but this effect was independent of fatigue. We conclude that the anchors contributed to the reduction of postural sway in young and older adults, but they were unable to compensate for the disturbing effect in postural control created by fatigue of the plantar flexor muscles.

Additional Haptic Information Provided by Anchors Reduces Postural Sway in Young Adults Less Than Does Light Touch

This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the “light touch” (LT) and “anchor system” (AS) paradigms on postural sway. Additionally, it compared the effect of location and number of points of contact to the control of posture in young adults. The location consisted of using the anchors tied to the finger and held by the hands, and, for LT, the fingertip. For the number of points of contact, participants used two hands, and then separately the dominant hand, and the non-dominant hand, for both anchor and LT paradigms. Participants stood upright with feet-together and in tandem position while performing tasks that combined the use of anchors and LT, points of contact (hand grip and finger), and number of points of contact (two hands and one hand). In this study, the anchors consist of holding in each hand a flexible cable with the other end attached to the ground. The LT consists of slightly touching a rigid surface with the tip of the index finger. The results showed, first, that the anchors improved postural control less than did the LT. Second, they revealed that holding the anchors with the hands or with them tied to the fingertip resulted in a similar reduction in postural sway only in the tandem position. For the feet-together position, the anchors tied to the fingertip were ineffective. Similarly, the use of one or two hands did not affect the contribution of the anchors. However, using two hands in the LT condition was more effective than was one hand. Third, our results showed the presence of a temporal delay between force and center-of-pressure (COP) for the anchors, only in the AP direction with feet-together. In conclusion, overall, the anchors were less effective in reducing postural sway than was the LT. The anchors attached to fingertips were as effective as the hand-held anchors in the tandem position, yet ineffective during foot-together standing. Force-COP timing explains reduced postural sway with LT but not for the anchor; hence, exploratory and supra-postural components may be involved.

The effect of light touch on balance control during overground walking in healthy young adults

Balance control is essential for safe walking. Adding haptic input through light touch may improve walking balance; however, evidence is limited. This research investigated the effect of added haptic input through light touch in healthy young adults during challenging walking conditions. Sixteen individuals walked normally, in tandem, and on a compliant, low-lying balance beam with and without light touch on a railing. Three-dimensional kinematic data were captured to compute stride velocity (m/s), relative time spent in double support (%DS), a medial-lateral margin of stability (MOS_ML) and its variance (MOS_MLCV), as well as a symmetry index (SI) for the MOS_ML. Muscle activity was evaluated by integrating electromyography signals for the soleus, tibialis anterior, and gluteus medius muscles bilaterally. Adding haptic input decreased stride velocity, increased the %DS, had no effect on the MOS_ML magnitude, decreased the MOS_MLCV, had no effect on the SI, and increased activity of most muscles examined during normal walking. During tandem walking, stride velocity and the MOS_MLCV decreased, while %DS, MOS_ML magnitude, SI, and muscle activity did not change with light touch. When walking on a low-lying, compliant balance beam, light touch had no effect on walking velocity, MOS_ML magnitude, or muscle activity; however, the %DS increased and the MOS_MLCV and SI decreased when lightly touching a railing while walking on the balance beam. The decreases in the MOS_MLCV with light touch across all walking conditions suggest that adding haptic input through light touch on a railing may improve balance control during walking through reduced variability.

Task difficulty has no effect on haptic anchoring during tandem walking in young and older adults

This study assessed the contribution of the "anchor system's" haptic information to balance control during walking at two levels of difficulty. Seventeen young adults and seventeen older adults performed 20 randomized trials of tandem walking in a straight line, on level ground and on a slightly-raised balance beam, both with and without the use of the anchors. The anchor consists of two flexible cables, whose ends participants hold in each hand, to which weights (125 g) are attached at the opposing ends, and which rest on the ground. As the participants walk, they pull on the cables, dragging the anchors. Spatiotemporal gait variables (step speed and single- and double-support duration) were processed using retro-reflective markers on anatomical sites. An accelerometer positioned in the cervical region registered trunk acceleration. Walking on the balance beam increased single- and double-support duration and reduced step speed in older adults, which suggests that this condition was more difficult than walking on the level ground. The anchors reduced trunk acceleration in the frontal plane, but the level of difficulty of the walking task showed no effect. Thus, varying the difficulty of the task had no influence on the way in which participants used the anchor system while tandem walking. The older adults exhibited more difficulty in walking on the balance beam as compared to the younger adults; however, the effect of the anchor system was similar in both groups.

The effects of haptic input on biomechanical and neurophysiological parameters of walking: A scoping review

Walking is an important component of daily life requiring sensorimotor integration to be successful. Adding haptic input via light touch or anchors has been shown to improve standing balance; however, the effect of adding haptic input on walking is not clear. This scoping review systematically summarizes the current evidence regarding the addition of haptic input on walking in adults. Following an established protocol, relevant studies were identified using indexed data bases (Medline, EMBASE, PsychINFO, Google Scholar) and hand searches of published review articles on related topics. 644 references were identified and screened by a minimum of two independent researchers before data was extracted from 17 studies. A modified TREND tool was used to assess quality of the references which showed that the majority of studies were of moderate or high quality. Results show that adding haptic input changes walking behaviour. In particular, there is an immediate reduction in variability of gait step parameters and whole body stability, as well as a decrease in lower limb muscle activity. The effect of added haptic input on reflex modulation may depend on the limb of interest (i.e., upper or lower limb). Many studies did not clearly describe the amount and/or direction of haptic input applied. This information is needed to replicate and/or advance their results. More investigations into the use and design of the haptic tools, the attentional demands of adding haptic input, and clarity on short-term effects are needed. In addition, more is research needed to determine whether adding haptic input has significant, lasting benefits that may translate to fall prevention efforts.

A contribuição do sistema âncora em diferentes segmentos corporais para o controle da postura em idosos

RESUMO O sistema âncora é uma ferramenta não rígida que fornece informação háptica adicional, consistindo de dois cabos maleáveis com 125 g de massa repousando no solo, devendo-se segurar a outra extremidade com as mãos (âncora-mão). Considerando que o toque leve em diferentes partes do corpo reduz a oscilação corporal, é possível, da mesma forma, que o uso do sistema âncora em diferentes partes do corpo seja efetivo. Portanto, o objetivo deste estudo foi investigar o efeito do uso do sistema âncora em diferentes segmentos corporais sobre a oscilação corporal de idosos. Trinta idosos participaram do presente estudo. Eles ficaram na postura ereta com os pés na posição semi-tandem sobre uma plataforma de força para a obtenção do deslocamento do centro de pressão (CP). Cinco condições experimentais foram realizadas: sem âncora, âncora-mão, âncoras nas mãos presas com presilhas, âncoras nos antebraços presas com presilhas e âncoras nos ombros presas com presilhas. Os resultados mostraram uma redução da área da elipse ajustada ao deslocamento do CP e na amplitude média de oscilação na direção anteroposterior nas condições com as âncoras posicionadas nas mãos (âncora-mão e presilha) e antebraços em comparação à condição sem âncora. Assim, o uso do sistema âncora foi efetivo quando as âncoras foram posicionadas no antebraço da mesma forma que quando foram seguras pelas mãos. A melhora observada com o uso das âncoras parece não estar relacionada com a quantidade de receptores táteis no ponto de contato dos cabos das âncoras.