Bobath H. Adult Hemiplegia: Evaluation and Treatment (third edition). London: William HeinemannMedical, 1990.

Brown P. Pathophysiology of spasticity. Journal of Neurology, Neurosurgery and Psychiatry 1994; 57:773–777.

BBTA. Tutors’ Week. Unpublished consensus definitions. London, 1994.BBTA Tutors’ Week. Unpublished consensus defintiions. London, 1996.Carr et al. Spasticity: research findings and implications for intervention. Physiotherapy 1995; 81:

421–429.Cornall C. Self propelling wheelchairs: the effects on spasticity in hemiplegic patients. Physiotherapy

Theory and Practice 1991; 7: 13–21.Davies P. Steps to Follow: A Guide to the Treatment of Adult Hemiplegia. Berlin: Springer Verlag,

1985.Dvir Z, Panturin E. The effects of graded effort on the severity of associated reactions in hemiplegic

patients. Clinical Rehabilitation 1996; 10: 155–158.Kidd G, Laws N, Musa I. Understanding Neuromuscular Plasticity. London: Edward Arnold, 1992.Lennon S. The Bobath Concept: a critical review of the theoretical assumptions that guide physiother-

apy practice in stroke rehabilitation. Physical Therapy Review 1996; 1: 35–45.Lynch ME, Grisogono V. Strokes and Head Injuries. London: John Murray, 1991.O’Dwyer NJ, Ada L, Neilson PD. Spasticity and muscle contracture following stroke. Brain 1996; 119:

1737–1749.Rothwell J. Control of Human Voluntary Movement (second edition). London: Chapman & Hall,

1994.Walshe F. On certain tonic or postural reflexes in hemiplegia, with special reference to the so called

‘associated movements’. Brain 1923; 46(1): 1–37.

Mary E Lynch ElleringtonSenior Tutor BBTA & IBITAHLondon, UK

STEPHENSON ET AL. – A RESPONSE

EditorThank you for inviting me to respond to the Discussion Paper by Stephenson et al.

I must confess to considerable irritation when reading this paper, due principallyto the exclusion of so much of the available literature on the subject and the misrep-resentation of the available information. I propose to start by citing some examplesfrom the broad range of literature on this most interesting topic in an attempt to setany ensuing discssion on a more scholarly (and illuminating) track.

Gaining control over those muscle activations and movements which are inexcess of those necessary to perform an action (variously termed ‘excitation over-flow’, ‘associated movements/reactions’, ‘associated muscle activity’ etc.) is consid-ered to be an integral part of the acquisition of skill in action and, indeed, there isexperimental evidence that this is so (see Jaegers et al., 1989, on dart throwing; alsoCarey et al., 1983; Sparrow et al., 1987). Such activity is seen in able-bodied sub-jects (infants, children and adults) under conditions of stress and/or lack of skill(Hellebrandt & Waterland, 1962; Waterland & Munsen, 1964). In childhood, theoccurrence of redundant movements declines with age (Fog & Fog, 1963; Connolly

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& Stratton, 1968; Todor & Lazarus, 1986), re-emerging whenever maximal force,speed of response or dexterity are required and when a new action is being learned.Indeed, the development of motor control in a particular task has been suggested todepend more on the progressive inhibition of unwanted muscle activity than on theactivation of additional motor units (Basmajan, 1977), although this may be anover-simplification. Todor and Lazarus (1986) showed in an experimental clip-grip-ping task that older children were better able to control the tendency to activategripping muscles in the opposite hand than younger children. However, the inhibi-tion of redundant muscle contractions became progressively harder to invoke athigher levels of exertion. What may be a similar phenomenon, mirror movements,are also observed in young children, usually associated with unimanual activities anddecreasing in the first decade (Wolff et al., 1983).

Motor learning (the acquisition of skill) is associated, therefore, with increasingproficiency in the performance of the action being practised. As Bernstein (1967)proposed, the co-ordination of a movement involves mastering the redundantdegrees of freedom of the moving limb(s). The gaining of control over muscle acti-vations and movements which are unnecessary to the task represents the masteringof the available degrees of freedom and therein lies skill in performance.

Redundant muscle activations and movements are typically taken by clinicians toinfer pathology (Bobath, 1971) and are often taken as a manifestation of ‘spasticity’.Clinical terms such as ‘abnormal movement patterns’ and ‘spastic syndergies’ reflecton this link. It is very likely, however, that motor redundancy reflects — as it does inthe able-bodied — attempts by the individual to achieve effective performance of anaction which has to be newly ‘learned’ in the presence of a broken-down controlsystem. If we refer back to the points above regarding the acquisition of motor con-trol for a particular action, the degrees of freedom (i.e. the potential for muscle acti-vation/movement) may differ in a disabled individual as a result of mechanical andneural barriers to movement (such as shortened muscle or increased muscle stiff-ness), and neural influences (such as reflex hyperactivity, absent innervation ofmuscle). Hence, redundant muscle activity may reflect those constraints normallyimposed on a learner or on a person trying to exert maximum force but also con-straints resulting from the lesion and musculoskeletal adaptations.

I share my colleagues’ concern about the use of the term ‘AR’ in some clinicalpractice, the lack of scientific rigor and general confusion about the topic. However,the authors are themselves adding to the confusion. For example, throughout thepaper, peer-reviewed scientific reports are juxtaposed with books relating therapists’observations and opinions, with no indication as to the different types of informa-tion contained. The discussion of spasticity is so careless of the scientific facts asthey are presently understood that I despair for the poor reader. For example, Katzand Rymer are cited as viewing an increase in the velocity dependent stretch reflexas a positive aspect of ‘spasticity’ and Carr and colleagues are reported to have writ-ten that weakness is a negative feature of ‘spasticity’ [sic]. Wrong on both counts.The authors have missed the point that spasticity is said to be a positive feature ofthe upper motor neurone syndrome and weakness a negative feature of the syndrome.

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Such inaccuracy is inexcusable but it also makes the intelligent discussion theyadvocate rather difficult!

Carr and colleagues have also been cited as ‘suggesting’ that it is ‘the negativefeatures of spasticity, such as weakness and decreased co-ordination, together withmusculoskeletal changes which impact on the function of the patient’. Although itis flattering to be seen to be making such a definitive statement, I must point out tothe reader that we were reporting the available scientific evidence to date and sug-gesting that this information may be relevant to clinical practice.

It may not be convenient for some physiotherapists to have to deal with experi-mental information which runs counter to treasured beliefs, but, nevertheless, forthe sake of disabled individuals (and, dare I say, for the sake of knowledge itself), it israther important to be able to read scientific literature outside the field of physio-therapy and to distinguish between clinical observations and experimental findings.

In answer to the authors’ final questions: yes, it is useful to measure spasticity.However, firstly, it is necessary to define what is being measured (i.e. resistance topassive movements or reflex hyperactivity); secondly, a suitable measurement toolhas to be used (such as the equipment used in laboraties to standardize movementvelocity in testing reflex activity). The measurement of so-called ARs may also beuseful as an indication of changes in motor skill but, again, using suitable tools suchas EMG. Yes, there are many valid and reliable methods of evaluating variousaspects of motor performance and muscle activity (see, for example, Carr & Shep-herd, 1998, for outlines of some available tools). Before clinicians rush in to attemptto measure spasticity or associated reactions, however, I would caution that facilitiesfor such testing do not exist in most rehabilitation departments. Reliable and validmeasures of motor performance do, however, and perhaps clinicians should focus onthose at the present time and leave the investigation of muscle activation and reflexstatus to the laboratory study which is certainly needed.

What is necessary at this time is that neurological physiotherapists read, studyand discuss in fields relevant to but not outside the physiotherapy profession. As aprofession (particularly in neurology), we are increasingly at risk of becoming an iso-lated little community outside science and medicine, with our own idiosyncratic(and often uninformed) views of the way things are.

Professor Roberta Shepherd DipPhty MA EdD FACPThe University of SydneyAustralia

REFERENCES

Basmajan JV. Motor learning and control. Archives of Physical Medicine and Rehabilitation 1977; 58:38–41.

Bernstein N. Coordination and Regulation of Movement. New York: Pergamon, 1967.Bobath B. Abnormal Postural Reflex Activity caused by Brain Lesions. London: Heinemann, 1971.Carey JR, Allison JD, Mundale MO. Electromyographic study of muscular overflow during precision

handgrip. Physical Therapy 1983; 63: 505–511.

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Carr JH, Shepherd RB. Neurological Rehabilitation: Optimizing Motor Performance. Oxford: Butter-worth Heinemann, 1998.

Connolly K, Stratton D. Developmental changes in associated movements. Developmental Medicineand Child Neurology 1968; 10: 49–56.

Fog E, Fog M. Cerebral inhibition examined by associated movements. In: M Bax, RC MacKeith (eds),Minimal Cerebral Dysfunction. Clinics in Developmental Medicine 10. London: Heinemann,1963.

Hellebrandt FA, Waterland JC. Expansion of motor patterning under exercise stress. American Journalof Physical Medicine 1962; 41: 56–66.

Jaegers SMH, Peterson RP, Dantuma R et al. Kinesiological aspects of motor learning in dart throwing.Journal of Human Movement Studies 1989; 16: 161–171.

Sparrow WA, Trizarry-Lopez VM. Mechanical efficiency and metabolic cost as measures of learning anovel gross motor task. Journal of Motor Behavior 1987; 19: 240–264.

Todor JI, Lazarus JC. Exertion level and the intensity of associated movements. Developmental Medi-cine and Child Neurology 1986; 28: 205–212.

Waterland JC, Munsen N. Involuntary patterning evoked by exercise stress. Journal of the AmericanPhysical Therapy Association 1964; 44: 91–97.

Wolff PH, Gunnoe CE, Cohen C. Associated movements as a measure of developmental age. Develop-mental Medicine and Child Neurology 1983; 25: 417–429.

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