Neuromuscular electrical stimulation and volitional exercise for individuals with rheumatoid arthritis: a multiple-patient case report. (2007)

Abstract
BACKGROUND AND PURPOSE:
Muscle atrophy is common in patients with rheumatoid arthritis (RA). Although neuromuscular electrical stimulation (NMES) is a viable treatment for muscle atrophy, there is no evidence about the use of NMES in patients with RA. The purposes of this multiple-patient case report are: (1) to describe the use of NMES applied to the quadriceps femoris muscles in conjunction with an exercise program in patients with RA; (2) to report on patient tolerance and changes in lean muscle mass, quadriceps femoris muscle strength (force-producing capacity), and physical function; and (3) to explore how changes in muscle mass relate to changes in quadriceps femoris muscle strength, measures of physical function, and patient adherence.
CASE DESCRIPTION:
Seven patients with RA (median age=61 years, range=39-80 years) underwent 16 weeks of NMES and volitional exercises. Lean muscle mass and strength of the quadriceps femoris muscle and physical function were measured before and after treatment.
OUTCOMES:
One patient did not tolerate the NMES treatment, and 2 patients did not complete at least half of the proposed treatment. Patients who completed the NMES and volitional exercise program increased their lean muscle mass, muscle strength, and physical function.
DISCUSSION:
Because of the small sample, whether NMES combined with exercises is better than exercise alone or NMES alone could not be determined. However, the outcomes from this multiple-patient case report indicate that NMES is a viable treatment option to address muscle atrophy and weakness in patients with RA. Strategies to increase tolerance and adherence to NMES are warranted.QUOTE

FROM CONCLUSION:
“…we believe that the changes in quadriceps femoris lean muscle mass observed in this report were more likely due to the NMES program than to the volitional exercises because our volitional exercise program was not of high intensity like the studies that have shown increases in lean muscle mass.”

My comments:

This is an ideal situation for electric muscle stimulation: trying to maintain strength when active exercise might be too stressful, such as during an RA exacerbation. Improvements seem relatively similar to those shown with osteoarthritis and EMS.  

Parameters used in this study were:

• Duty Cycle: 4 second ramp, 6 seconds on 50 seconds off
• Hz: 75
• Pulse duration: 250 uS
• Amplitude: at maximum patient tolerance (38-90 mA)
• Duration: 10-60 minutes working from 10 to 30 contraction over 2 weeks
• Electrodes: 6.98 cm x 12.7cm placed on vastus lateralus proximally and vastus medialus medially.
• Frequency: 16 weeks, with an average of 9 supervised sessions and 31 home sessions, averaging 2.5 treatments per week.

I would use a longer pulse duration, higher Hz, shortened ramp, and set the on time to 10 seconds. That said, the parameters in this study sound reasonably decent. More electrodes on additional muscles would, I’m sure, lead to additional functional improvements, but the EMPI 300 model used in the study only has 2 channels. My preference is for 4 channel units like the EV-906 or Globus Genesy models simply because you can work more muscles at once either at home or in physical therapy.