Neuroscience Letters 584 (2015) 378–381 Contents lists available at ScienceDirect Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet Short communication Light touch and medio-lateral postural stability during short distance gait E. Kodesh ∗ , F. Falash, E. Sprecher, R. Dickstein Department of Physical Therapy, Faculty of Social Welfare and Health Sciences, University of Haifa, Mount Carmel, Haifa, Israel highlights • Light touch on an external static reference enhances medio-lateral gait stability. • Light touch on a self-moved stick does not contribute to medio-lateral stability. • Light touch on a static reference provides spatial and self positional cues. article info Article history: Received 3 July 2014 Received in revised form 21 October 2014 Accepted 27 October 2014 Available online 4 November 2014 Keywords: Haptic Gait variability Balance Walking abstract While standing, light fingertip touch on an external stable object attenuates sway and improves balance in healthy adults as well as in individuals with poor postural control. The effect of light touch on balance during gait is, however, not well known. Therefore, the purpose of this work was to study the effects of light fingertip touch on balance during gait. We hypothesized that similar to its effect during stance light touch would increase postural stability. Forty healthy young adults were tested under four gait conditions: (1) eyes open (EO), (2) eyes closed (EC), (3) eyes closed while lightly touching a static object on the right side of the walking lane (ECLTS), (4) eyes closed while lightly touching a dynamic object, namely, a stick that was moved forwards by the subject with the right hand (ECLTD). The main outcome measure was medio-lateral step width variability, a well established indicator of gait balance in the medio-lateral plane. During the EC condition, light touch of an external static object (ECLTS) decreased medio-lateral vari- ability (i.e., balance improved); however, this stabilizing effect was not observed with light touch on the stick. The availability of self positional and spatial cues when touching a static external reference, and their absence when touching a stick that is moved forwards by the subject as he walks, can explain the different effects of light touch in the ECLTS vs the ECLTD gait conditions. © 2014 Elsevier Ireland Ltd. All rights reserved. 1. Introduction In healthy subjects haptic information from light fingertip touch of an external stable plate, without force transfer onto the plate, reduces postural sway during stance [1,2]. Similarly, light touch (LT) of an external stable platform attenuates exaggerated sway in various patient groups [3–6]. In contrast, LT of an external platform that is sway referenced to subjects’ own sway does not decrease postural sway [7,8]. Jeka and co-workers showed that during stance, light touch of a cane by the hand, at levels below those necessary to provide ∗ Corresponding author. Tel.: +972 4 8249065; fax: +972 4 8288140. E-mail address: ekodesh@univ.haifa.ac.il (E. Kodesh). force transition and support, is as effective as higher force con- tact in reducing postural sway in healthy young and elderly adults [9–11], as well as in congenitally blind and healthy blindfolded sub- jects [10,11]. In addition, they showed that a slanted cane was more effective than a perpendicular cane in reducing postural sway [11]. In an another study a cane held in several different positions was also shown to be effective in reducing postural sway [9]. Moreover, in a recent study, the stabilizing effect of gripping a cane in several stance positions and at different force levels (1–9 N) was confirmed [12]. Although the favorable effects of somatosensory haptic infor- mation via LT on postural control and balance during stance have been studied in various stance conditions and populations, the effects of similar somatosensory cues on balance during gait have scarcely been addressed. During walking on a treadmill, light http://dx.doi.org/10.1016/j.neulet.2014.10.048 0304-3940/© 2014 Elsevier Ireland Ltd. All rights reserved.