Utilization of Robotic Exoskeleton for Overground Walking in Acute and Chronic Stroke

 I guess you have to get the full research to find out which exoskeleton was tested.

Utilization of Robotic Exoskeleton for Overground Walking in Acute and Chronic Stroke

Karen J. Nolan^1,2*, Kiran K. Karunakaran^1,2, Pamela Roberts³, Candy Tefertiller⁴, Amber M. Walter⁵, Jun Zhang⁶, Donald Leslie⁷, Arun Jayaraman^8,9 and Gerard E. Francisco^10,11

• ¹Kessler Foundation, Center for Mobility and Engineering Research, West Orange, NJ, United States
• ²Rutgers—New Jersey Medical School, Department of Physical Medicine and Rehabilitation, Newark, NJ, United States
• ³Cedars-Sinai Medical Center, Department of Physical Medicine and Rehabilitation, Los Angeles, CA, United States
• ⁴Craig Hospital, Department of Physical Therapy, Englewood, CO, United States
• ⁵Sheltering Arms Physical Rehabilitation Centers, Mechanicsville, VA, United States
• ⁶St. Charles Hospital, Port Jefferson, NY, United States
• ⁷Shepherd Center, Atlanta, GA, United States
• ⁸Shirley Ryan AbilityLab, Max Nader Center for Rehabilitation Technologies and Outcomes Research, Chicago, IL, United States
• ⁹Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, United States
• ¹⁰University of Texas at Houston McGovern Medical School, Houston, TX, United States
• ¹¹TIRR Memorial Hermann, Houston, TX, United States

Stroke commonly results in gait deficits which impacts functional ambulation and quality of life. Robotic exoskeletons (RE) for overground walking are devices that are programmable to provide high dose and movement-impairment specific assistance thus offering new rehabilitation possibilities for recovery progression in individuals post stroke. The purpose of this investigation is to present preliminary utilization data in individuals with acute and chronic stroke after walking overground with an RE. Secondary analysis on a subset of individuals is presented to understand the mechanistic changes due to RE overground walking. Thirty-eight participants with hemiplegia secondary to stroke were enrolled in a clinical trial conducted at eight rehabilitation centers. Data is presented for four sessions of overground walking in the RE over the course of 2 weeks. Participants continued their standard of care if they had any ongoing therapy at the time of study enrollment. Gait speed during the 10 Meter Walk Test, Gait deviations and the Functional Ambulation Category (FAC) data were collected before (baseline) and after (follow-up) the RE walking sessions. Walking speed significantly increased between baseline and follow-up for participants in the chronic (p <0.01) and acute (p < 0.05) stage of stroke recovery. FAC level significantly improved (p < 0.05) and there were significantly fewer (p < 0.05) gait deviations observed for participants in the acute stages of stroke recovery between baseline and follow-up. Secondary analysis on a subset of eight participants indicated that after four sessions of overground walking with the RE, the participants significantly improved their spatial symmetry. The walk time, step count and ratio of walk time to up time increased from first session to the last session for participants in the chronic and acute stages of stroke. The RE was effectively utilized for overground walking for individuals with acute and chronic stroke with varying severity levels. The results demonstrated an increase in walking speed, improvement in FAC and a decrease in gait deviations (from baseline to follow-up) after four sessions of overground walking in the RE for participants. In addition, preliminary data indicated that spatial symmetry and step length also improved after utilization of an RE for overground walking.

Introduction

Stroke is a leading cause of severe disability in adults, affecting ~15 million people each year worldwide (Association, 2013). Individuals with stroke often present with gait and balance deficits, leading to activity limitations and participation restrictions (Wade and Hewer, 1987; Friedman, 1990). Regaining independent ambulation is a priority among acute and chronic stroke patients.

Current post stroke rehabilitation strategies can be effective but individuals are often left with residual gait deviations, resulting in compensatory mechanisms such as hip circumduction, toe walking, hip hiking, among others for ambulation. These gait deviations and pathological compensations often result in inefficient gait and reduced speed, which can negatively affect community ambulation.

Post stroke rehabilitation is based on the theory that repeated task specific mass practice will lead to recovery of ambulatory function (Partridge et al., 2000; Cooke et al., 2010). In addition, the closer the practiced task (reciprocal stepping) is to the functional goal (healthy walking) better the learning transfer and ultimately recovery. Therefore some of the critical parameters for improving mobility post stroke are activity-specific, mass practice that is progressively more challenging (Langhorne et al., 2009).

Stroke research has shown that improvements in functional outcome measures, such as increased walking speed, are strong predictors of independent community ambulation. Individuals with walking speeds of 0.4–0.8 m/s are classified as limited community ambulators, <0.4 m/s are classified as household ambulators, and >0.8 m/s are classified as community ambulators on all surfaces (Perry et al., 1995). The walking speed of individuals during the chronic stages of stroke recovery has been reported to be between the range of 0.3 and 0.8 m/s (Hill et al., 1997; Duncan et al., 1998; Eng et al., 2002; Green et al., 2002), classifying them as either household ambulators or limited community ambulators (Hill et al., 1997; Duncan et al., 1998; Eng et al., 2002; Green et al., 2002).

Another clinical assessment scale, the Functional Ambulation Category (FAC), distinguishes six levels of walking ability based on the amount of physical support required during ambulation. The FAC is a quick visual measurement of walking, and it correlates with walking speed and step length (Holden et al., 1984, 1986).

Though walking speed and FAC could indicate deficits and improvements in functional ambulation, they do not provide information about the underlying impairments in mechanisms or inter-limb coordination during recovery. Observational gait deviations, temporal and spatial characteristics have been previously studied to understand and quantify the underlying mechanisms associated with pathological compensations. Research has shown that temporal and spatial asymmetry are significant predictors of hemiparetic walking performance such as walking speed and falls in adults (Roth et al., 1997; Patterson et al., 2010). Individuals with stroke often present with higher asymmetries between their limbs, leading to ambulatory deficits (Patterson et al., 2010). Quantifying the change in temporal and spatial characteristics would help us further understand the effect of using RE on functional/clinical outcomes such as falls (Hausdorff et al., 2001). Understanding these characteristic changes will help further improve the design of rehabilitation interventions for individuals with deficits (Wall and Turnbull, 1986).

Commercial wearable robotic exoskeletons (RE) for overground walking offer new rehabilitation possibilities by providing task specific, high repetitive practice for individuals with acute and chronic stroke (Molteni et al., 2021). In addition, most of the REs can also provide stability and balance to keep the users in an upright position even in users with severe balance and gait deficits who are unable to maintain upright posture. REs are anthropomorphic mobile electromechanical devices usually powered bilaterally by two electric motors at the knee and hip joints (Dollar and Herr, 2008). The motorized movement trajectories at the hip and knee reduces the need for manual range of motion guidance by a physical therapist during motor rehabilitation. This allows physical therapists to focus on training cues and feedback to drive gait quality. During overground walking, the RE can assist gait initiation and limb advancement with complete or partial assistance and the support structure provides stability and balance. For individuals with moderate to severe impairments the RE provides reciprocal motor assistance including limb coordination (symmetry), and proprioceptive input during limb loading (Rojek et al., 2020). These mechanisms are critical elements for the recovery of independent ambulation post stroke.

Robotic exoskeletons (REs) have been used for rehabilitation during the chronic and subacute stages of stroke (Louie and Eng, 2016; Høyer et al., 2020; Molteni et al., 2021). As new rehabilitation robotic technology emerges for acute and chronic stroke rehabilitation, it is important to investigate the feasibility and safety of the device in order to expand their utility in clinical rehabilitation. Therefore, the purpose of this multicenter investigation is to present preliminary utilization data after walking overground in a robotic exoskeleton (RE) for acute and chronic post stroke patients. Secondary analysis is presented to begin to understand the functional changes and mechanistic changes in temporal and spatial characteristics and symmetry due to RE overground walking.

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