Standardized voluntary force measurement in a lower extremity rehabilitation robot

Journal of NeuroEngineering and Rehabilitation, 2008 · DOI: 10.1186/1743-0003-5-23 · Published: October 28, 2008

Assistive Technology Neurorehabilitation Musculoskeletal Medicine

Simple Explanation

This study introduces a method for measuring muscle strength in the legs using a robotic device called the Lokomat. The Lokomat is a driven gait orthosis (DGO) used for rehabilitation. The research aimed to determine if the new muscle strength measurement method is reliable. Reliability means that the measurements are consistent, whether taken by different therapists (inter-rater reliability) or by the same therapist on different days (intra-rater reliability). The study found that the Lokomat's muscle strength measurements are fairly reliable, meaning it can be a useful tool for tracking progress in patients undergoing rehabilitation.

Study Duration

10 weeks (single case study), 2 days (reliability study)

Participants

16 subjects without neurological deficits, 14 subjects with NMD, and a single case study subject with an acute incomplete spinal cord injury

Evidence Level

Not specified

Key Findings

1
The study demonstrated fair to good inter- and intra-rater reliability for measuring isometric muscle force in the lower extremities using the Lokomat in subjects with and without neurological movement disorders.
2
In subjects without NMD, inter-rater reliability (ICC) ranged from 0.72 to 0.97, and intra-rater reliability ranged from 0.71 to 0.90.
3
In subjects with NMD, inter-rater reliability (ICC) ranged from 0.66 to 0.97, and intra-rater reliability ranged from 0.50 to 0.96.

Research Summary

This study evaluated the reliability of a novel method for assessing isometric muscle force of leg muscles using the Lokomat, a driven gait orthosis (DGO). Inter- and intra-rater reliability were determined in subjects with and without neurological movement disorders (NMD). The results indicated fair to good reliability for the new measurement method. Reliability was assessed using intraclass correlation coefficients (ICC), standard error of measurement (SEM), and coefficient of variation of the method error (CVME). The study suggests that the Lokomat-integrated assessment tool is valuable for documenting and controlling the rehabilitation process in patients using a DGO, providing an objective outcome measure in rehabilitation units.

Practical Implications

Rehabilitation Monitoring

The Lokomat can be used to objectively monitor and document the rehabilitation process of patients with neurological movement disorders.

Treatment Control

Muscle strength measurements obtained via the Lokomat can assist therapists in controlling and adjusting rehabilitation treatments based on patient progress.

Clinical Practice

The presented method allows therapists to assess voluntary muscle force during a training session in the DGO and reliably monitor the course of voluntary force generation in leg muscles.

Study Limitations

1
Healthy athletic male subjects were able to push the DGO out of the desired position, limiting the application area of the method.
2
Intra-rater reliability was lower than inter-rater reliability, possibly due to motivation differences or muscle soreness on different testing days.
3
The large heterogeneity in the group of subjects with NMD might have affected reliability values.

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