The initiation of gait in Parkinson's disease

Lateral leg raising in patients with Parkinson's disease: Influence of equilibrium constraint

“…The duration of the postural phase is increased in patients with PD for initiation of gait, 8,9 but the onset of intended movement is not delayed during the execution of various other tasks such as forward raising of the arms, 22 raising on tiptoes, 23 or flexion of the ankle. 24 Similarly, following inactivation of the globus pallidus in monkeys, the time of onset of movement is not increased.…”

“…8,17 In patients with PD, the ground reaction force is weak, the backward displacement of CP is reduced, tonic activity is present in many muscles that are normally at rest, and no clear synergy is apparent. 8 Inability to produce significant force, which is a feature of bradykinesia in patients with PD, is the first possible explanation for the deficits in postural adjustment. Electromyographic analysis showed that in these subjects, phasic activity is characterized by bursts of small amplitude.…”

“…2,6,7 Studies on initiation of gait in patients with Parkinson's disease (PD) showed that the main abnormalities were an increased duration of the postural phase before heel lift-off, a decrease of the propulsive force and of the velocity of the center of gravity, and finally a decrease in the length of the first step. [8][9][10] Several hypotheses have been proposed to explain the impairment of gait initiation in patients with PD. It could be a primary deficiency in energizing and producing a movement of sufficient strength, 11,12 a deficiency of postural control, [13][14][15][16] or a defect in coordination between different tasks during the same motor act.…”

Bilateral subthalamic stimulation improves gait initiation in patients with Parkinson's disease

“…Patients with PD have shown a significantly increased movement preparation time, but similar movement execution time compared to normal subjects [6][7][8][9]. Abnormalities of gait initiation in PD patients also include reduced lateral shift of the body mass over the stance limb and decreased propulsive forces [10,11].…”

The Influence of a Cognitive Task on the Postural Phase of Gait Initiation in Parkinson’s Disease: An Electromyographic-Based Analysis

“…The TA muscle activated later and with lower magnitude in the individuals with PD in comparison to the controls. The TA is the main muscle to propel the body forward in the postural phase of the GI (Elble et al, 1994), but its activity is usually impaired in individuals with PD (Gantchev et al, 1996) as it tends to become weaker as the disease progresses (Crenna, Frigo, Giovannini, & Piccolo, 1990). This TA impairment can explain the longer duration of the mediolateral CoP displacement in individuals with PD compared to controls, in fact the lower backward displacement tends to increase the lateral displacement in order to release the swing limb (Carpinella et al, 2007;Nocera et al, 2013;Yiou et al, 2012) and tends to be lower in the dual-task condition relatively to the single-task condition.…”