Difference between individuals with left and right hemiparesis in the effect of gluteus medius vibration on body weight shifting

Objective. - To test the effect of gluteus medius (GM) vibration on the reduction of asymmetric body weight distribution in individuals with hemiparesis (HP) at two stages of postural recovery. Methods. - The effects of GM vibration according to the shift of the body weight (%Shift) onto the paretic leg during GM vibration were registered while standing on a force-platform in 40 HP (19 left and 21 right; mean age 54.7 +/- 10.6 years, mean time after stroke 2.0 +/- 1.3 months), as soon as they could stand without assistance and 4 to 6 weeks later, and in 40 control subjects (mean age 54.7 +/- 10.5 years). Results. - Without vibration, baseline body weight (BW) distribution was characterized by underloading of the paretic limb (mean BW on the paretic limb 37.2%+/- 13.1%). At the early stage of balance recovery, % shift toward the paretic limb induced by GM vibration differed significantly between left and right HP (P=0.049) and between left HP and controls (C) (P = 0.022) and was related to BW asymmetry (r = 0.437, P = 0.004). Later, GM vibration reduced asymmetric BW distribution in most HP and no difference was found between left and right HP and between left and C. Conclusion. - At an advanced stage of postural recovery, GM vibration could help encourage HP to put weight on the affected limb. Interestingly, a behavioral difference was initially observed between right and left HP that could probably be explained by a different strategy due to the baseline severity of the BW asymmetry. (C) 2017 Elsevier Masson SAS. All rights reserved.