Is high hypnotizability a trouble in balance control?

Hypnotizability is a cognitive trait measured by standard scales and associated with peculiar physiological responses to cognitive and physical stimulations. Hypnotizability-related differences can also be observed in non-hypnotic state and in the absence of specific suggestions. In the normal bipedal stance subjects with high hypnotizability (Highs) exhibit a higher tolerance of alteration of the visual and leg/neck proprioceptive input with respect to low hypnotizable individuals (Lows). Aim of the study was to investigate whether this characteristic represents a disadvantage during highly demanding postural tasks. Sixteen Highs and 16 Lows of both genders participated in an experimental session consisting of maintaining balance while standing with open or closed eyes on a seesaw platform allowing roll movements. The results did not show significant differences between Highs and Lows in inclination area and time, with the exception of a greater ability of Highs with respect to Lows when they began the task displacing the body weight from the left to the right leg. Thus, high hypnotizability does not represent a disadvantage for balance control during highly demanding postural tasks. Together with previous studies, the present findings suggest that the Highs' postural control might shift from a very "economic", preeminently centrally driven functioning mode, characteristic of easy postural tasks, to an efficaciously periphery-controlled mode, required by difficult postural tasks.