Errors in cognitive performance trigger postural instability in Parkinson's disease

BACKGROUND

Globally, postural stability and cognitive performance are intimately linked in Parkinson's disease (PD). However, a fundamental gap exists in understanding the precise relationship between a disruption in executive function and its impact on postural stability.

OBJECTIVE

This project aimed to determine the precise effects of cognitive errors on postural stability under dual-task conditions in participants with PD and controls.

METHODS

Twenty-eight individuals with PD and 27 healthy controls completed a series of postural stability tests under single- and dual-tasks. The dual-task required maintenance of balance while performing an audio number discrimination task.

RESULTS

In general, postural stability in PD and control subjects was similar across single-task conditions. In controls, an error in the cognitive task during dual-task conditions did not impact measures of postural sway. In contrast, in PD, postural sway increased in epochs surrounding cognitive errors relative to epochs without errors.

CONCLUSIONS

Postural task selection plays a critical role when testing for balance deficits in PD compared to healthy controls. Furthermore, time synchronized analysis of cognitive and balance data revealed the greatest episodes of postural instabilities occurred around cognitive errors. The measurement and evaluation of cognitive-motor linkages, relative to postural stability, could provide a patient-specific fingerprint of balance function and provide more sensitive measures for fall risk in PD.

Quantifying turning behavior and gait in Parkinson's disease using mobile technology

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Improvements in mobility were detected from meds using a mobile device IMU in PD.

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Algorithms using mobile device IMU data can segment the TUG into subtasks.

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The Cleveland Clinic Mobility App can provide an objective assessment of mobility.

Gait and balance impairments associated with Parkinson’s disease (PD) are often refractory to traditional treatments. Objective, quantitative analysis of gait patterns is crucial in successful management of these symptoms. This project aimed to 1) determine if biomechanical metrics from a mobile device inertial measurement unit were sensitive enough to characterize the effects of anti-parkinsonian medication during the Timed Up and Go (TUG) Test, and 2) develop the Cleveland Clinic Mobility and Balance application (CC-MB) to provide clinicians with objective report following completion of the TUG. The CC-MB captured 3-dimensional acceleration and rotational data from people with PD (pwPD) to characterize center of mass movement while performing the TUG. Trials were segmented into four components: Sit-to-Walk, Gait, Turning, and Stand-to-Sit. Thirty pwPD were tested On and Off (12 h) anti-PD medication. Significant improvements (p < 0.05) between On versus Off conditions included: reduction in MDS-UPDRS III motor scores (10.7%), faster trial times (9.3%), more dynamic walking as evident by increased normalized jerk scores (vertical: 17.3%, medial-lateral: 12.3%), shorter turn durations (10.4%), and faster turn velocities (8%). Measures in Sit-to-Walk and Stand-to-Sit did not show significant changes. Trial time and turn velocity showed excellent test-retest reliability (ICC range: 0.83-0.96) across both medication states. A mobile device platform provided quantitative measures of gait and turning during the TUG that detected significant improvements from anti-parkinsonian medications. This platform is a low-cost, easy-to-use tool that can provide objective reports immediately following the clinical assessments, making it ideal for use in and outside the clinical setting.