IIFVELOPMEN I’AL. MEDICINE A N D CHILD NEUROLOGY. 1975, 17

The Importance of Memory Traces of Motor Efferent Discharges for Learning Skilled Movements

SIR-I thank Dr. Bobath for his comments on my paper ( D M C N , 16, 837). May I repeat what I said in that paper-that the Robath method of treatment for cerebral palsy seems to me to be a considerable conceptual advance on many other methods of physiotherapy, in that patterns of movement, rather than single movements, are seen as the basic ‘units’ of voluntary control.

The basic question for physiotherapy is how best can the patient achieve voluntary con- trol, and it is here. I think, that Dr. Bobath has missed the point of my paper. He suggests that I must accept the importance of proprioception for voluntary movement; on the contrary, 1 tried to show that proprioception may not be a necessary condition for voluntary control and that skill development may depend upon some co-ordination of visual afference and the central monitoring of efferent signals to the muscles. I would add some further evidence on the importance of visual (rather than proprioceptive) afference for basic motor skills. Walters and Walk’ have shown that extension of the arms on approaching an object in infants before about 12 months-a response previously thought to be a sign of vestibular co-ordination with the upper extremities (e .g . Paine and OppC I 9662)-may depend largely upon visual afference. Secondly, Lee and Aronson3 have shown that in young infants standing is dependent upon visual afference (they talk about ‘visual proprioception’, that is, vision as a source of information about voluntary movement), rather than upon vestibular cues. Balancing in adults may also be largely dependent upon visual control‘. Therefore there is evidence, contrary to Dr. Bobath’s assumption, for my suggestion that voluntary control of movement may be taught to cerebral palsied children through com- pletely visual means.

Dr. Bobath argues that in his own method of therapy the emphasis has shifted from passive manipulation of the child to allowing voluntary movement. 1 would simply like to see this emphasis shift much further. At the same time, other physiotherapy techniques are based on theories of the importance of proprioceptive inflow for motor control, and theoretically, at least, the overriding importance of proprioceptive input is still asserted within the Bobath school (see, for example, Manning 1972)5. Unfortunately, there is no clear evidence that any such techniques lead to the acquisition of voluntary motor control.

The purpose of my article was to show why some common styles of physiotherapy may not achieve important effects and to suggest other presuppositions on which physiotherapy for the cerebral palsied can be based. Ofcourse we badly need further controlled evaluations, following Wright and Nicholson6, of different methods of physiotherapy.

Department of Psychology, University of Queensland, St. Lucia, Queensland, Australia 4067.

BILL JONES

REFERENCES I . Walters, C. P.. Walk. R. D. (1974) ‘Visual placing by human infants.’ Jorrr-nu/ of Experinrental Child

2. Paine, R. S., OppC, T. E. (1966) Nerrrological Exanrim/ion o/ Chi/clr-c~n. Clinics in Developmental Medicine

3 . Lee, D. N., Aronson, E. (1974) ‘Visual proprioceptive control of standing in human infants.’ Perceprion

4 . Lishman. J. R.. Lee, D. N. (1973) ‘The autonomy of visual kinaesthesis.‘ Perceprion, 2, 287. 5. Manning, J . (1972) ‘Facilitation of movement-the Bobath approach.’ Pli.vsiotherupy, 58, 403. 6 . Wright. T.. Nicholson, J . ( 1973) ‘Physiotherapy for the spastic child : an evaluation.’ Devrlop/?r~n/

Psychology, 18, 34.

No. 20121. London: S.I.M.P. with Heinemann Medical.

unit Psvchophysics, 15, 529.

Mdic i r ie and Child Neioology. 15, 146.

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