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

Abstract

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.

Haptic contact with a walking dog improves human balance during a quiet tandem task with various levels of difficulty

“…7 The haptic connection of an individual with another, and even with objects (e.g., an anchor system, light touch of surfaces), illustrates how complex systems and subsystems convey information dynamically to comply with task demands of various types (e.g., walking, standing). [8][9][10][11][12][13][14][15] All of these studies on the use of haptic contact during walking and standing tasks have shown some improvement in balance and stability in motor patterns.…”

Fingertip-Coupled Spindle Signaling Does Not Contribute to Reduce Postural Sway Under Light Touch

“…In this vein, experiments from different research groups demonstrated a markedly diminished postural sway in tandem (Lackner et al, 1999), semi-tandem (Baccini et al, 2007), single-leg (Bonfim et al, 2008), and bipedal (Franzén et al, 2012) stances. Within the scope of this fingertip LT, the putative mechanisms behind the effects of LT on postural sway have been associated with proprioceptive feedback from finger and hand muscles as well as from fingertip cutaneous mechanoreceptors (Holden et al, 1994; Jeka and Lackner, 1994; Clapp and Wing, 1999; Rabin et al, 2008; Baldan et al, 2014; Martinelli et al, 2015; Moraes et al, 2018).…”

O efeito da informação háptica adicional no controle da postura em adultos jovens e em idosos (caidores e não caidores) durante a realização de tarefas cognitivas concomitantes

“…Estudos mostram que adultos jovens e idosos podem reduzir a oscilação postural com a adição de dicas hápticas (FREITAS; MAUERBERG-DECASTRO;BALDAN et al, 2014;MORAES et al, 2018) fornecidas pelo TL ou pelas âncoras (BALDAN et al, 2014;MAUERBERG DE-CASTRO et al, 2014;TSAI, 2015;CHEN et al, 2015;CHEN et al, 2018;MORAES et al, 2018). Estudos que utilizaram o paradigma do TL da ponta do dedo indicador (i.e., aplicação de força < 1N sendo insuficiente para promover um suporte mecânico) observaram redução da oscilação corporal (JEKA; LACKNER, 1994;RILEY et al, 1999;RABIN;DIZIO, 2001;BALDAN et al, 2014), especialmente quando outros sistemas sensoriais não estavam disponíveis ou totalmente funcionais (olhos fechados, reduzida acuidade visual, perda vestibular, dentre outros) como no caso dos idosos (FREITAS; DUARTE, 2005;BALDAN et al, 2014).…”

“…Além disso, as âncoras incorporam um número maior de graus de liberdade, possibilitando que movimentos exploratórios sutis sejam realizados com as mãos em busca de informações do meio ambiente através do contato das mãos, com os cabos e com a superfície de suporte fornecendo a orientação espacial do corpo em relação ao ambiente (MAUERBERG-DECASTRO et al, 2014;SANTOS et al, 2015). No entanto, o fato das âncoras incorporarem um número maior de graus de liberdade do que o paradigma do toque leve, as torna mais desafiadoras pela demanda de controlar os graus de liberdade (MAUERBERG-DECASTRO et al, 2014;MORAES et al, 2018). O TL, por sua vez, por ser realizado em uma superfície restrita e estável através do toque do dedo indicador apresenta um número limitado de graus de liberdade de movimentos durante a tarefa postural.…”

“…É possível que a base de suporte reduzida (ou seja, ficar em pé com os pés juntos) não tenha sido desafiadora o suficiente para diferenciar entre caidores e não caidores. Uma tarefa postural mais desafiadora poderia criar mais oportunidades para os caidores mudarem sua oscilação postural com os recursos hápticos disponíveis, conforme sugerido anteriormente(MAUERBERG-DECASTRO et al, 2014;MORAES et al, 2018).Ambos os grupos se beneficiaram de forma semelhante com a adição de informação háptica fornecida pelas âncoras e pelo TL em ambas as direções AP e ML. Esta adição deinformação háptica reduziu a AMO e VMO nas direções AP e ML e o RMS da margem de estabilidade dinâmica em relação a todos os limites da base de suporte.…”