The Effects of Treatment Intensity and Dose-Response Relationship in Robot-Assisted Stroke Rehabilitation
Date Issued
2011
Date
2011
Author(s)
Hsieh, Yu-wei
Abstract
Background and purposes
Stroke remains a compelling public health issue worldwide. With high percentages of stroke survivors left with motor deficits, motivating the search for effective rehabilitation to improve motor recovery. Robot-assisted therapy (RT) has emerged as a prominent approach in the last decade that incorporates successful therapeutic elements of motor rehabilitation into its design. However, scientific evidence for the effects of the RT on clinical outcomes and physiological responses in stroke patients remains limited. Also, there is a need to identify the proper level of treatment intensity to elucidate the dose-response relations. This dissertation consisted of two parts of study: Efficacy Study of Robot-Assisted Therapy, and Clinimetric Study of Outcomes. In the first part of study, the purposes were (1) to investigate the treatment effects of RT relative to a comparison treatment (CT) in patients with stroke on clinical outcomes, (2) to test the dose-response relations by using 2 RT groups with higher- and lower-intensity, and (3) to examine the effects of intensive RT on a biomarker of oxidative stress (i.e., 8-hydroxy-2''-deoxyguanosine [8-OHdG]). In the second part of study, the purposes were to define the appropriate populations for RT and to examine the clinimetric properties of outcomes used in RT.
Methods
A total of 54 patients with stroke were recruited in this study and were randomized into the higher-intensity RT, the lower-intensity RT, or the CT group for a 4-week intervention. Primary outcome measures, including the Fugl-Meyer Assessment (FMA) and Medical Research Council scale (MRC), were administered to patients before intervention, at midterm (2 weeks after intervention), and immediately after intervention. Secondary outcomes, including Box and Block Test (BBT), modified Ashworth scale (MAS), Motor Activity Log (MAL), and physical domains of the Stroke Impact Scale (SIS), were administered to patients before and after intervention. In addition, urinary 8-OHdG levels of patients, pain and fatigue evaluation were also investigated as adverse responses. Two-way repeated measures analysis of covariance (ANCOVA) was used to evaluate the effects of primary outcomes among the 3 groups at 3 assessments. ANCOVA was used to examine treatment effects of secondary outcomes among the 3 groups. To represent the dose-response relations between the 2 RT groups with different intensities, the recovery rates and dose-response curves of each outcome were examined. Moreover, multiple regression models were used to identify the significant predictors for primary outcomes. The capacity of outcome measures to capture minimal clinically important changes after RT and the responsiveness of outcomes were also examined.
Results
Each group had 18 patients who participated in the study. For the primary outcomes, there was a significant group × time interaction effect (F3.4, 83.8 = 3.95, P = 0.01) on the FMA-total score. All 3 groups showed significant within-group gains in the FMA from baseline to midterm and from baseline to posttreatment (all P < 0.05). The higher-intensity RT group had significantly higher improvements in the FMA than the other 2 groups at midterm and posttreatment (all P < 0.05). On the MRC, no significant group × time interaction effect was found (F4, 100 = 1.41, P = 0.24). The analysis revealed a significant time main effect (F2, 100 = 4.54, P = 0.01), but there was no significant differences for the group main effect (F2, 50 = 0.87, P = 0.43). For the secondary outcomes, a significant difference in the BBT among the 3 groups was observed (F2, 50 = 4.68, P = 0.01). Post hoc analysis revealed that the higher-intensity RT and CT groups had greater gains in the BBT than the lower-intensity RT group. However, the improvements in the MAS, MAL, and physical domains of the SIS did not show significant difference among the 3 groups. For the adverse responses, the mean ratings of fatigue and pain of the 3 groups were mild (mean scores < 3). Further, there were no significant differences in the 8-OHdG levels among the 3 groups (P = 0.24) and the mean 8-OHdG levels of the 3 groups were in the normal reference range. In addition, recovery rates of the higher-intensity RT group were significantly higher than those of the lower-intensity RT group at midterm and at posttreatment, particular in the FMA (P < 0.05) and the BBT (P = 0.05). The initial severity levels of the patients were found to affect their treatment effects on the primary outcomes. The patients in a middle range of motor deficits or muscle weakness gained most improvements after the higher-intensity RT. For the second part of study, motor ability of the distal part of the upper extremity, RT treatment group, and amount of affected hand use in daily activities were significantly predictive of the FMA model (adjusted R2 = 0.662, P < 0.01) after RT. Motor ability of the distal part of the upper extremity and RT treatment group were the significant predictors for the MRC model (adjusted R2 = 0.597, P < 0.01) after RT. Moreover, there were about 20% to 40% of the patients receiving RT with clinically meaningful improvement on the outcomes. The outcome measures used in this study had large responsiveness in detecting improved changes after RT (standardized response mean = 0.96 to 1.69).
Conclusions
The findings of this study suggest that the higher-intensity RT intervention had better treatment effects, especially in upper-extremity motor ability, than the other 2 interventions. Recovery rates of the higher-intensity RT group were greater than those of the lower-intensity RT group on motor outcomes. The initial severity levels of the patients were found to affect their treatment outcomes after the higher-intensity RT. The better predictors for motor ability and muscle power outcomes after RT were motor ability of the distal part of the upper extremity and RT treatment group. The outcome measures used in this study are responsive to improvements of stroke patients after RT. The intervention protocols in this study generally can be tolerated by the participants without exacerbation of pain or fatigue and did not increase more oxidative stress after treatment. Based on the results, the higher-intensity RT is suggested to deliver in chronic stoke with moderate to mild motor deficits to improve motor recovery. The overall results enrich our understandings of treatment effects, dose-response relations, oxidative responses, prediction models, and clinimetrics of outcomes after robot-assisted rehabilitation in stroke patients. The promising results and experiences provide insights for continued study of these critical issues in stroke rehabilitation to contribute to evidence-based neurorehabilitation.
Subjects
stroke
robot-assisted therapy
treatment dosage
oxidative stress
randomized controlled trial
SDGs
Type
thesis
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