Evidence for a relationship between bilateral coordination during complex gait tasks and freezing of gait in Parkinson\u27s disease

BACKGROUND: Freezing of gait is a debilitating and common gait disturbance observed in individuals with Parkinson’s disease (PD). Although the underlying mechanisms of freezing remain unclear, bilateral coordination of steps, measured as a phase coordination index, has been suggested to be related to freezing. Phase coordination index has not, however, been measured during tasks associated with freezing such as turning and backward walking. Understanding how bilateral coordination changes during tasks associated with freezing may improve our understanding of the causes of freezing. METHODS: Twelve individuals with PD who freeze (freezers), 19 individuals with PD who do not freeze (non-freezers), and 10 healthy, age-matched older adults participated. General motor disease severity and freezing severity were assessed. Phase coordination index was calculated for all subjects during forward walking, backward walking, continuous turning in small radius circles, and turning in large radius circles. RESULTS: Freezers and non-freezers had similar disease duration and general motor severity. Stepping coordination (measured as phase coordination index) was significantly worse in freezers compared to non-freezers and controls. Turning and backward walking, tasks related to freezing, resulted in worse coordination with respect to forward walking. Coordination was associated with severity of freezing scores such that worse coordination was correlated with more severe freezing. CONCLUSIONS: These results provide evidence that stepping coordination is related to freezing in people with PD. Identifying variables associated with freezing may provide insights into factors underlying this symptom, and may inform rehabilitative interventions to reduce its occurrence in PD

Experimental realization of a topological Anderson insulator

We experimentally demonstrate that disorder can induce a topologically non-trivial phase. We implement this “Topological Anderson Insulator” in arrays of evanescently coupled waveguides and demonstrate its unique features

Is Freezing of Gait in Parkinson's Disease a Result of Multiple Gait Impairments? Implications for Treatment

Several gait impairments have been associated with freezing of gait (FOG) in patients with Parkinson's disease (PD). These include deteriorations in rhythm control, gait symmetry, bilateral coordination of gait, dynamic postural control and step scaling. We suggest that these seemingly independent gait features may have mutual interactions which, during certain circumstances, jointly drive the predisposed locomotion system into a FOG episode. This new theoretical framework is illustrated by the evaluation of the potential relationships between the so-called “sequence effect”, that is, impairments in step scaling, and gait asymmetry just prior to FOG. We further discuss what factors influence gait control to maintain functional gait. “Triggers”, for example, such as attention shifts or trajectory transitions, may precede FOG. We propose distinct categories of interventions and describe examples of existing work that support this idea: (a) interventions which aim to maintain a good level of locomotion control especially with respect to aspects related to FOG; (b) those that aim at avoiding FOG “triggers”; and (c) those that merely aim to escape from FOG once it occurs. The proposed theoretical framework sets the stage for testable hypotheses regarding the mechanisms that lead to FOG and may also lead to new treatment ideas

Submicron Structures Technology and Research

Contains reports on thirteen research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)National Science Foundation (Contract ECS82-05701)U.S. Department of Energy (Contract DE-ACO2-82-ER-13019)Lawrence Livermore Laboratory (Contract 2069209)National Aeronautics and Space Administration (Contract NGL-22-009-638)U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)National Science Foundation (Grant ECS80-17705)National Science Foundation (Grant ENG79-09980

Submicron Structures Technology and Research

Contains reports on fourteen research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)National Science Foundation (Grant ECS82-05701)Semiconductor Research Corporation (Grant 83-01-033)U.S. Department of Energy (Contract DE-ACO2-82-ER-13019)Lawrence Livermore National Laboratory (Contract 2069209)National Aeronautics and Space Administration (Contract NAS5-27591)Defense Advanced Research Projects Agency (Contract N00014-79-C-0908)National Science Foundation (Grant ECS80-17705)National Aeronautics and Space Administration (Contract NGL22-009-638

Submicron Structures Technology and Research

Contains reports on ten research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)Joint Services Electronics Program (Contract DAAL03-86-K-0002)National Science Foundation (Grant ECS82-05701)National Science Foundation (Grant ECS85-06565)Lawrence Livermore Laboratory (Subcontract 2069209)National Science Foundation (Grant ECS85-03443)U.S. Air Force - Office of Scientific Research (Grant AFOSR-85-0154)National Aeronautics and Space Administration (Grant NGL22-009-638)National Science Foundation (through KMS Fusion, Inc.)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908