Enhancement of parkinsonian rigidity with contralateral hand activation

Abstract

Objective-Quantify the enhancement of parkinsonian rigidity associated with a contralateral activation maneuver.Methods-Twelve subjects with PD and eight controls participated in the study protocol. Subjects' tested hand was displaced by a servo-motor throughout wrist flexion and extension motions of 60° without and with a concurrent gripping activation in the contralateral hand, referred to as passive and active conditions, respectively. Subjects with PD were tested in both OFF-Med and ON-Med states. Rigidity was quantified by integrating torque with position during both flexion and extension (torque resistance). ANOVA was performed to assess the effect of contralateral activation on rigidity.Results-PD patients had significantly (0.038) enhanced torque resistance in OFF-Med compared to healthy controls and ON-MED. In the Active condition, differences in torque resistance were magnified (p=0.002). Medication substantially reduced differences in torque resistance between controls and PD patients in the passive and active conditions. Conclusions-A contralateral activation maneuver substantially increases rigidity in patients with PD, specifically the OFF-MED state. Rigidity is reduced with the application of dopaminergic medication, even with the presence of a contralateral activation maneuver.Significance-These data support the use of a contralateral activation maneuver as a tool in the diagnosis of PD.

Amplitude- and velocity-dependency of rigidity measured at the wrist in Parkinson’s disease

“…Flexors = FCR + FCU + FDS; Extensors = ECR + ECU +EDC). For example, the mean EMG of stretched muscles was calculated as an average of normalized mean EMG of the extensors during the flexion motion and the average of normalized mean EMG of the flexors during the extension motion (Xia et al , 2009; Powell et al , 2011). The mean EMG of shortened muscles was calculated as the average of normalized mean EMG signals of the flexors during flexion and the average of normalized mean EMG signals of the extensors during extension.…”

Long-Term Task- and Dopamine-Dependent Dynamics of Subthalamic Local Field Potentials in Parkinson’s Disease

“…In these controlled environments, brief recordings are performed with subjects in a reclined operating table or hospital bed and may not be representative of the variable recordings that will be present in a real-world setting. As PD symptoms are dependent on the patient’s attention, alertness and behavior, the STN-LFP activity likely varies with these factors, as well [39,40,41,42,43]. Therefore, inter-day variability will be a challenge that must be addressed in a closed-loop DBS system.…”

Physiological and Biomechanical Analyses of Rigidity in Parkinson's Disease

“…Figure 4B shows that the extreme joint position, the larger displacement amplitude, caused increase in rigidity work score. Finally, the phenomenon that rigidity can be reinforced by a concurrent ipsi-or contralateral voluntary activation has recently been further quantified using biomechanical measures (Hong et al, 2007;Powell et al, 2011). Figure 5 illustrates torque-angle traces of the entire cycle of flexion and extension movements when a subject with PD was tested in the Off-medication condition.…”

“…Several studies have examined the changes in muscle activation, joint torque resistance and torque-angle slope associated with rigidity reduction as a result of medication therapy (Kirollos et al, 1996;Mera et al, 2009;Powell et al, 2011;Xia & Rymer, 2004;Xia et al, 2006Xia et al, , 2009. Following a standard protocol, patients are tested initially in the Off-medication state, i.e., 12 hours after the last dose of medication when the majority of the beneficial effects of medication therapy are eliminated (Defer et al, 1999).…”