Stiffness and postural stability in adults with Down syndrome

Abstract

The purpose of this study was to characterize postural sway in quiet standing under eyes-open and eyes-closed conditions, and to obtain a measure of postural stiffness during quiet standing in adults with Down syndrome (DS) versus control subjects. We obtained descriptive measures from centre-of-pressure (COP) data and analysed and compared COP trajectories and postural stiffness estimates from two stochastic models, the "pinned polymer" (PP) and "inverted pendulum" (IP) models. These estimates were correlated with clinical measures of muscle tone. Our results showed that overall, estimated values for postural stiffness from both models were larger for the DS group than for normal controls. In addition, average stiffness measures were greater under the eyes-closed condition than under the eyes-open condition for the DS group. The IP model detected significant trends over trials whereas the PP model did not. Clinical assessment of muscle tone for the DS group ranged from low to high-normal and there was no significant correlation with the postural stiffness measures obtained from either model. These results suggest that individuals with DS have the ability to modulate their underlying "stiffness" under conditions of quiet standing. Furthermore, there appears to be no strong relationship between clinical measures of muscle tone and postural stiffness measures under dynamic conditions.

Perceptual-motor deficits in children with Down syndrome: Implications for intervention

“…Much of this developmental delay continues to be attributed to isolated factors such as low muscle tone (Harris, 1985). Yet, recent research indicates that muscle tone evaluated under passive conditions may have little relationship with the strategies used by the nervous system under more dynamic conditions such as during standing (Webber, Virji-Babul et al 2004). In fact, Latash (2000) has suggested that over time, individuals with Down syndrome learn to develop adaptive motor strategies that optimise safety and stability.…”

Motor Behavior in Down Syndrome: Atypical Sensoriomotor Control

“…Repeated room mobile exposure of babies (illusory) led to a more coherent and stable coupling between visual information and the body oscillation (Polastri e Barela, 2005). Reduced stiffness over the trials during maintenance of static posture signaled the ability of adults to vary its stiffness with practice (Webber et al, 2004). Similarly Smith et al, (2007) observed the reduction of muscle stiffness values in tweens with SD after treadmill training, although the kinematic patterns adopted before and training have deferred of the control group patterns.…”

“…Exists therefore an inconsistency between the clinical evaluation of tone in this population and the abovementioned findings remain the relationship between hypotonia and co-contraction little understood. For Webber et al, (2004) and Vuillerme et al, (2001) evaluation of tone about passive conditions can provide limited information about the strategies used by SNC. Among the explanations for the postural deficits found in individuals with DS, the favored explanatory hypothesis is that of a compromised sensorimotor system (Carvalho & Almeida 2009).…”

Posture control after 5 months body balance training in Down syndrom children and youth

“…Otyłość, a w konsekwencji częste występowanie płaskostopia u dzieci i młodzieży z DS [9] oraz nierzadko pojawiające się dysfunkcje wzroku i słuchu mogą być przyczyną zaburzeń kontroli równowagi ciała [10]. Badania kontroli rów-nowagi przeprowadzone przez innych autorów wskazują, że osoby z DS mają problemy z normalną kontrolą równowagi ciała [11,12]. Cabeza-Ruiz i wsp.…”