How Best to do Electromyographic Feedback Training? To the Editor: After reading and rereading the paper by Skrotzky and associates entitled "Effects of Electromyographic Feedback Training on Motor Control in Spastic Cer­ ebral Palsy," appearing in PHYSICAL THERAPY, May 1978, I was struck with two thoughts. First, there is indeed, as the authors pointed out, a need for research on the effects of biofeedback on spasticity. Second, the authors in their discussion appear to have little understanding of the nature of a CNS lesion. The function of one extremity in a spastic patient cannot be isolated without taking into consideration the rel­ ative position, tone, and movement patterns of the remaining body segments. Basic to the understanding of movement patterns in CNS lesions is an appreciation of the concept of volition and associated reactions. Volition should not be construed as meaning only the act of moving a limb willingly, since all "voluntary" movements are accompanied by appropriate postural adjustment oc­ curring at the automatic level. Therefore, in active dorsiflexion and plantar flexion, one would expect automatic components or movements to be occurring. In the normal individual, these automatic compo­ nents occur in smooth, controlled patterns, becoming exaggerated only when forceful or difficult movement is elicited. In the case of a CNS lesion, the automatic reactions are deprived of cortical control, occur in exaggerated intensity, and are termed associated re­ actions.1 Associated reactions have been defined by Walshe1 and Bobath2 as an exaggerated expression of the postural reflex mechanism. In the involved pa­ tient, associated reactions are apparent during "vol­ untary" movement, but not necessarily in the vicinity of the limb being moved. Without understanding these reactions and their effects on the patient, it is feasible that a program outlined by Skrotzky and her colleagues could be detrimental to the patient. For example, on the command "ready" and "go," the subject was to execute either plantar flexion or dorsiflexion of the ankle. In this case, one would expect associated reactions on active and selective movement of the ankle because diplegia is the result of a CNS lesion. In fact, performing isolated ankle dorsiflexion when in a sitting position appears to be Volume 59 / Number 1, January 1979

a rather awkward and difficult motion for the patient with diplegia, and associated reactions tend to in­ crease. In my experience, the associated reactions that would probably be manifest in these subjects would be increased flexor tone in the upper extremities and increased tone in hip flexors, adductors, and internal rotators. This increase in tone may or may not pro­ duce movement. Be that as it may, the patient will experience abnormal patterns of muscle contraction which, if frequently facilitated, may aid in contracture formation. Perhaps even more important is the feed­ back the subjects are receiving from the inappropriate reciprocal innervation. It is possible that, if reinforced enough, the subjects will learn these movements as part and parcel of active ankle motion. At this time, I can only assume that these move­ ments occurred and the investigators were either un­ aware of their existence or they simply chose to ignore them. I appreciate the importance of knowing that it is indeed possible to make gains in ankle range of motion with biofeedback; however, those in clinical settings must be made aware of the limitations this study has for practice. Skrotzky's paper, therefore, would have made a greater contribution had the basic issues of volition and associated reactions been ad­ dressed. JOSEPH A. LUCCA Assistant Professor School of Life and Health Sciences Allied Health Professions University of Delaware Newark, DE 19711

REFERENCES 1. Walshe FMR: On certain tonic or postural reflexes in hemiplegia with special reference to the so-called associated movements. Brain 46:2-23, 1973 2. Bobath B: Abnormal Postural Reflex Activity Caused by Brain Lesions. London, William Heinemann Medical Books, Ltd, 1971, pp 407-417

The Authors Respond: We have read the letter to the editor with interest. Our first impression was that Mr. Lucca seems rela­ tively unfamiliar with the area of biofeedback and its use in rehabilitation. We are, therefore, forwarding a selected bibliography of 130 references that served as 55

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How best to do electromyographic feedback training?

How Best to do Electromyographic Feedback Training? To the Editor: After reading and rereading the paper by Skrotzky and associates entitled "Effects...
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