Interpersonal light touch assists balance in the elderly.

Previous researchers have shown that light touch contact with a fixed object reduces body sway, whereas light touch with a moving object entrains and increases sway. Given the importance of interpersonal touch and, for example, its use in care for the elderly, it is interesting to ask whether light touch contact between two people reduces or increases sway? The authors measured ground reaction forces and trunk movements in 5 pairs of older participants (M age = 65.1 years, SD = 4.2 years) during quiet standing, when contacting another person using light touch at the index finger and during light touch with a fixed object. Postural sway was reduced in both light touch conditions, by 13% with interpersonal light touch and by 31% with the fixed object. A small but significant positive correlation in sway with near 0 phase lag during interpersonal light touch may reflect the role of anticipation in maintaining light touch. The authors conclude interpersonal light touch affords an interesting new paradigm for the study of balance.