From the Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, Michigan.

All correspondence should be addressed to: Sandra L. Hearn, MD, Burlington Office Center, 325 E. Eisenhower Parkway, Suite 100, Ann Arbor, MI 48108.

This study involved use of a medical device: a diagnostic electromyograph (Carefusion Nicolet EDX with Viking 4 Software, FDA 510(K) #K112052) used on-label to conduct electromyography and nerve conduction studies on subjects.

Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.