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Previous studies have shown that preplanned movements can be rapidly released when a startling acoustic stimulus (SAS) is presented immediately prior to, or coincident with, the imperative signal to initiate movement. Based on the short latency of the onset of muscle activity (typically in less than 90 ms) and the frequent co-expression of startle responses(More)
BACKGROUND Spasticity is a common impairment that follows stroke, and it results typically in functional loss. For this reason, accurate quantification of spasticity has both diagnostic and therapeutic significance. The most widely used clinical assessment of spasticity is the modified Ashworth scale (MAS), an ordinal scale, but its validity, reliability(More)
OBJECTIVE The objective of this cross-sectional study was to test the hypothesis that patients with Parkinson disease (PD) and freezing of gait (PD+FOG) would demonstrate sleep disturbances comparable to those seen in patients with REM sleep behavior disorder (RBD) and these changes would be significantly different from those in PD patients without FOG(More)
BACKGROUND Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by(More)
We examined the intrinsic and reflex contributions to ankle stiffness in people with chronic stroke and healthy subjects using the parallel system identification technique. Modulation of intrinsic and reflex stiffness was characterized by applying pseudorandom binary sequence (PRBS) perturbations to the ankle at different initial ankle joint over the entire(More)
After stroke, hemiparesis will result in impairments to locomotor control. Specifically, muscle coordination deficits, in the form of inappropriately phased muscle-activity patterns, occur in both the paretic and nonparetic limbs. These dysfunctional paretic muscle-coordination patterns can adapt to somatosensory inputs, and also the sensorimotor state of(More)
Locomotor coordination depends on precise and appropriate adjustments of intra- and interlimb muscle activity phasing. Muscle coordination deficits, in the form of inappropriately phased muscle activity patterns, are well recognized in both the paretic and non-paretic limbs of stroke survivors. Our recent work demonstrated that muscle phasing can be(More)
It is well established that the sensorimotor state of one limb can influence another limb and therefore bilateral somatosensory inputs make an important contribution to interlimb coordination patterns. However, the relative contribution of interlimb pathways for modifying muscle activation patterns in terms of phasing is less clear. Here we studied(More)
BACKGROUND Muscle activity during rapid eye movement sleep is markedly increased in people with rapid eye movement sleep behavior disorder and people with Parkinson's disease (PD) who have freezing of gait. This study examined whether individuals with rapid eye movement sleep behavior disorder who do not have a diagnosis of PD show abnormalities in gait(More)
27 After stroke, hemiparesis will result in impairments to locomotor control. Specifically, 28 muscle coordination deficits, in the form of inappropriately phased muscle activity patterns, 29 occur in both the paretic and non-paretic limbs. These dysfunctional paretic muscle coordination 30 patterns can adapt to somatosensory inputs and also, the(More)