Critically Appraised Topic
I am working in a skilled nursing facility and am working with a 29 year-old female who was in a motor vehicle accident about 6 months ago resulting in paraplegia with neurologically induced weakness of her quadriceps. Her spinal cord injury is incomplete at level T12, and she is slowly regaining sensation and motor control in her lower extremities. This weakness is interfering with her function, making transfers and gait difficult. Her quadriceps strength is 2/5 bilaterally with manual muscle testing. She is currently able to transfer sit → stand and ambulate >100 feet using a front-wheeled walker with stand-by-assistance; however, she occasionally experiences knee buckling, which could lead to injury. She struggles standing from a low surface and is unable to climb stairs. Since she is unable to fully activate her quadriceps, I am wondering if using electrical stimulation could augment her strength training.
Is electrical stimulation effective for strengthening of the quadriceps in patients with spinal cord injuries?
Clinical Bottom Line
Based on the results of the outcomes from Harvey et al. and Rabischong et al. the effectiveness of electrical stimulation for strengthening of the quadriceps in patients with spinal cord injuries is uncertain. Harvey et al found that electrical stimulation combined with progressive resistance training increased voluntary muscle strength by an average of 12 Nm with a 95% confidence interval of -17.03 to 41.03 in the experimental group. The control group, which received no treatment, experienced an average decrease in strength by 4 Nm with a confidence interval of -29.31 to 37.31. These statistics show that there is uncertainty of the true change in both groups, thus no conclusion can be drawn from these results. This study had no major threats to internal or external validity, but did have a small sample size and subjects were slightly different than the population of interest. Rabischong et al. found that electrical stimulation increased quadriceps evoked muscular output to 42.21 Nm (11.73) in the treatment group, while the control group, which received no treatment, only reached a muscular output of 25.78 (11.15). No pre-test data was provided so the change in each group is unknown, however, the authors did report that the experimental group’s change was significant, although no MCID was stated. The MCID stated in the article by Harvey et al. for strength was 8 Nm, so if in fact the experimental group met this MCID, the change would be clinically significant. There also appears to be a clinically significant difference between the groups post-treatment, with a mean difference of 16.43 and a 95% confidence interval of 6.77- 26.09 and a large effect size of 1.44 with a 95% confidence interval of 0.55- 2.34. Using the MCID stated by the previous article of 8 Nm, the mean difference meets this, however the low end of the confidence interval does not. Despite these statistics, there are major threats to this study’s internal and external validity, including a lack of randomization, blinding, reliable and valid outcome measures, small sample size, and a lack of reporting pertinent data. Due to these major threats, the results are unreliable and cannot be extrapolated to a larger population. More research is needed to determine the effectiveness of electrical stimulation on quadriceps strengthening in patients with spinal cord injuries, specifically comparing electrical stimulation plus voluntary muscle contractions with voluntary muscle contractions alone.
Smith, Amy, "Electrical Stimulation for Quadriceps Strengthening in Patients with Spinal Cord Injury" (2010). PT Critically Appraised Topics. 7.