Upper extremity rehabilitation robots have become crucial in stroke rehabilitation due to their high durability, repeatability, and task-specific capabilities. A significant challenge in assessing the comfort performance of these robots is accurately calculating the human-robot interaction forces. In this study, a four-degree-of-freedom (4-DOF) upper extremity rehabilitation robot mechanism, kinematically compatible with the human upper limb, is proposed. Based on this mechanism, an algorithm for estimating human-robot interaction forces is developed using Newton-Euler dynamics. A prototype of the proposed robot is constructed, and a series of comparative experiments are carried out to validate the feasibility of the proposed force estimation approach. The results indicate that the proposed method reliably predicts interaction forces with minimal deviation from experimental data, demonstrating its potential for application in upper limb rehabilitation robots. This work provides a foundation for future studies focused on comfort evaluation and optimization of rehabilitation robots, with significant practical implications for improving patient rehabilitation outcomes.

Inertial measurement units (IMUs) have proven to be valuable tools in measuring the range of motion (RoM) of human upper limb joints. Although several studies have reported on the validity of IMUs compared to the gold standard (optical motion capture system, OMC), a quantitative summary of the accuracy of IMUs in measuring RoM of upper limb joints is still lacking. Thus, the primary objective of this systematic review and meta-analysis was to determine the concurrent validity of IMUs for measuring RoM of the upper extremity in adults. Fifty-one articles were included in the systematic review, and data from 16 were pooled for meta-analysis. Concurrent validity is excellent for shoulder flexion–extension (Pearson’s r = 0.969 [0.935, 0.986], ICC = 0.935 [0.749, 0.984], mean difference = −3.19 (p = 0.55)), elbow flexion–extension (Pearson’s r = 0.954 [0.929, 0.970], ICC = 0.929 [0.814, 0.974], mean difference = 10.61 (p = 0.36)), wrist flexion–extension (Pearson’s r = 0.974 [0.945, 0.988], mean difference = −4.20 (p = 0.58)), good to excellent for shoulder abduction–adduction (Pearson’s r = 0.919 [0.848, 0.957], ICC = 0.840 [0.430, 0.963], mean difference = −7.10 (p = 0.50)), and elbow pronation–supination (Pearson’s r = 0.966 [0.939, 0.981], ICC = 0.821 [0.696, 0.900]). There are some inconsistent results for shoulder internal–external rotation (Pearson’s r = 0.939 [0.894, 0.965], mean difference = −9.13 (p < 0.0001)). In conclusion, the results support IMU as a viable instrument for measuring RoM of upper extremity, but for some specific joint movements, such as shoulder rotation and wrist ulnar-radial deviation, IMU measurements need to be used with caution.

Objective: Submissions on recovery of post-stroke motor performance vary, especially in relation to increasing time after stroke. This study examined the trajectory of motor performance over the first 12 months after stroke.

Methods: Consecutive first-incidence stroke survivors (N = 83) were recruited within 1 month of onset from a tertiary health institution in Nigeria. Simplified Fugl Meyer scale (S-FM) was used to assess motor performance at monthly intervals. Changes in overall motor performance, and differences between the affected upper and lower extremities, were examined using Friedman's ANOVA and paired t-tests, respectively.

Results: Significant improvement in motor performance was observed across 12 months (p < .001), with the proportion of stroke survivors with severe impairment at onset (53.3%) decreasing to 20% by 12 months. Lower extremity motor performance scores were significantly higher than for the upper extremity from 1 to 12 months (p <.01 at 3, 4, 5, 6 and 12 months; and p < .05 at the remaining months).

Conclusions: The potential for long-term improvement in motor performance after stroke was observed, suggesting that this can be harnessed by long-term rehabilitation efforts. The comparatively poorer outcome in the upper extremity indicates the need for extra rehabilitation strategies to enhance upper-extremity motor recovery in the first year of stroke.

Objective: To summarise the effect of upper limb rehabilitation interventions on motor function in adults with traumatic brain injury. Data sources: Databases were last searched on August 2, 2008. Sources included the Cochrane Central Register of Controlled Trials (CENTRAL); Cochrane Database of Systematic Reviews, the Database of Effectiveness Reviews; MEDLINE, EMBASE, CINAHL, Physiotherapy Evidence Database (PEDro), Occupational Therapy Systematic Evaluation of Evidence database (OTseeker); Google Scholar; and reference lists of included studies. Review methods: Two reviewers determined whether retrieved abstracts met the inclusion criteria: systematic reviews and randomised controlled trials (RCTs); English language; adult participants; ≥ 50% of study participants with a brain injury; interventions designed to improve upper limb motor function. Included papers were appraised for: study design, participants, therapy approach, therapy protocol (indications, contra-indications, intensity and duration), safety and adverse events, and outcomes. The methodological quality of RCTs was rated using the PEDro scale (1–10 highest). Methodology of systematic reviews was rated using the QUOROM criteria. Results: Of the 333 references identified, six were appraised: three systematic reviews and three RCTs. Methodological quality was high for two RCTs, and moderate for one, based on the PEDro scale score. Interventions included upper limb casting, electrical stimulation, and coordination training using meal preparation tasks (making a sandwich and hot drink). In the latter trial, practice of functional kitchen tasks improved fine motor coordination speed on one of four Jebsen-Taylor hand function subtests by 9.38 seconds (95% CI, 1.1 to 17.7). Remaining trials reported non-significant effects for hand function. Small sample sizes and limited reporting of results reduce the interpretability of two RCTs. Conclusion: No conclusive evidence was found on which to base upper limb motor rehabilitation after brain injury, however, lack of evidence does not equate to evidence of no effect.