Surface electromyography (sEMG) is a noninvasive technique used to measure muscle activity (both voluntary and involuntary) in individuals with neuromuscular conditions (Pullman et al. 2000).

Number of items: N/a

Procedure/Administration: Surface electrodes are placed on the skin overlying the muscles of interest.  Patients are instructed to voluntarily activate lower limb muscles to provide either maximal muscle strength or to perform simple movements (e.g. ankle flexion/extension).  

How scored: N/a

Interpretability: No normative values exist and interpretation of the data is not standardized.

Acceptability: N/a

Languages: N/a

Usability:  The technique is well tolerated and is much less intrusive than the gold standard (needle EMG), so there is minimal burden for patients. However, an EMG can range in cost from several hundred to over a thousand dollars depending on features

Time to administer: 15-20 minutes

Time to score: N/a

Training required: Special training is mandatory to conduct and interpret the results.

Availability: N/a

Equipment required: N/a

Summary:

• sEMG recordings can complement the clinical examination specifically by providing objective and quantifiable measures of muscle activity. They have been shown to be valid in comparison to the clinical testing of motor strength and might be of highest value to monitor motor recovery in incomplete SCI.
• As these measures need special training and equipment they will be most suitable in the frame of clinical studies rather than for clinical day to day routine.

Psychometric Summary:

Note: TR= Test re-test; IC= Internal Consistency; Inter-O= Inter-observer; Intra-O= Intra-observer; SS= Sensitivity/Specificity; N/a= No information.

Red light= A single study involving SCI subjects which has less than adequate findings of reliability, validity, and/or responsiveness.

Yellow light= A single study involving subjects with SCI which has adequate to excellent findings of reliability, validity, and/or responsiveness.

Green light= At least 2 studies involving subjects with SCI which have adequate to excellent findings of reliability, validity, and/or responsiveness.

References

• Calancie B, Molano MR, Broton JG, Bean JA, Alexeeva N. Relationship between EMG and muscle force after spinal cord injury. J Spinal Cord Med 2001;24:19-25.
• Lim HK, Lee DC, McKay WB, Priebe MM, Holmes SA, Sherwood AM. Neurophysiological assessment of lower-limb voluntary control in incomplete spinal cord injury. Spinal Cord 2005;43:283-290.
• Lim HK, Sherwood AM. Reliability of surface electromyographic measurements from subjects with spinal cord injury during voluntary motor tasks. Journal of Rehabilitation Research & Development 2005;42:413-421.
• Pullman SL, Goodin DS, Marquinez AI, Tabbal S, Rubin M. Clinical utility of surface EMG: report of the therapeutics and technology assessment subcommittee of the American Academy of Neurology. Neurology 2000;55:171-177.