628 J Neurol Neurosurg Psychiatry 1998;64:628–635 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.64.5.628 on 1 May 1998. Downloaded from Does spasticity contribute to walking dysfunction after stroke? Louise Ada, Wantana Vattanasilp, Nicholas J O’Dwyer, Jack Crosbie Abstract of the so called “spastic gait” discloses Objectives—Clinically, it is assumed that common abnormalities such as the toes not spasticity of the calf muscles interferes clearing the ground during the swing phase.34 with walking after stroke. The aim was to The assumption has been that spasticity, in the examine this assumption by evaluating form of hyperactive reflexes, produces overac- the contribution of spasticity in the gas- tivity in the calf muscles and the resulting trocnemius muscle to walking dysfunction hypertonia resists dorsiflexion of the ankle in an ambulant stroke population several joint.5 The clinical sequel of this assumption months after stroke. has been to inhibit the calf muscles after brain Methods—Fourteen stroke patients who damage—for example, with drugs6 or by reha- were able to walk independently and 15 bilitation strategies.2 The purpose of this study neurologically normal control subjects was to revisit these assumptions by determin- were recruited. Both resting and action ing the contribution of spasticity in the calf stretch reflexes of the gastrocnemius mus- cle were investigated under conditions muscles to walking dysfunction in a population that simulated walking. Resting tonic of patients at least six months after stroke. stretch reflexes were measured to assess Clinically, spasticity is a term commonly spasticity whereas action tonic stretch applied to a wide range of motor impairment. reflexes were measured to assess the However, it has been defined as an increase or possible contribution of spasticity to gait exaggeration of the stretch reflexes—both the dysfunction. tonic and phasic components.7 The gastrocne- Results—Two thirds of the stroke patients mius is the multijoint calf muscle which flexes exhibited resting tonic stretch reflexes the knee and plantarflexes the ankle. During which indicate spasticity, whereas none of the single support phase of stance, the foot the control subjects did. However, the remains flat on the ground and the shank stroke patients exhibited action tonic rotates forward. This results in the gastrocne- stretch reflexes that were of similar mag- mius muscle being stretched at the end of its nitude to the control subjects, suggesting range because the knee is extended and the that their reflex activity during walking ankle achieves maximum dorsiflexion. It is was not diVerent from that of control sub- possible, therefore, that any abnormal stretch jects. Furthermore, there was no evidence reflex would produce overactivity in the muscle that the action stretch reflex in the stroke thereby interfering with dorsiflexion. It is diY- http://jnnp.bmj.com/ patients contributed a higher resistance to cult to measure stretch reflexes during walking. stretch than the control subjects. Normally, during the period of stance when the —Whereas most of the stroke Conclusions foot is flat on the ground, there is activity in the patients exhibited spasticity when meas- gastrocnemius muscle which increases from ured both clinically and physiologically, 89 they did not exhibit an increase in resist- mid-stance to reach a peak at heel oV. It is School of ance to dorsiflexion due to exaggerated impossible to distinguish the contribution of Physiotherapy, Faculty action tonic stretch reflexes. It is con- the stretch reflex to this activity from voluntary on October 1, 2021 by guest. Protected copyright. of Health Sciences, activation. This study, therefore, investigated The University of cluded that it is unlikely that spasticity Sydney, PO Box 170, causes problems in walking after stroke in the nature of the stretch reflex in the Lidcombe NSW 2141, ambulant patients. Therefore, it seems gastrocnemius muscle after stroke under con- Australia inappropriate to routinely reduce or in- ditions that simulated the ankle movement L Ada hibit the reflex response to improve func- during walking as far as possible. W Vattanasilp N J O’Dwyer tional movement in stroke rehabilitation. Reflexes were measured under both passive J Crosbie Factors other than spasticity should be and active conditions. When a relaxed muscle considered when analysing walking after is stretched slowly (resting tonic stretch reflex), Correspondence to: stroke, so that appropriate treatment is there is normally no electrical response.10–14 Dr Louise Ada, School of Physiotherapy, Faculty of provided to patients. After neurological impairment, however, there Health Sciences, The is often an abnormal response which is labelled University of Sydney, PO (J Neurol Neurosurg Psychiatry 1998;64:628–635) as spasticity. On the other hand, when an active Box 170, Lidcombe NSW muscle is stretched the muscle activity is 2141, Australia. Telephone Keywords: spasticity; tonic stretch reflex; stroke; walk- 00612 6466544; fax 00612 ing; ankle modulated by the stretch and this phenomenon 6466278; email 15 16 [email protected] has been termed an action tonic stretch. Resting stretch reflexes were, therefore, meas- Received 21 January 1997 Problems in walking after stroke have often ured to assess spasticity and action stretch and in final revised form 12 November 1997 been attributed to spasticity by both medical reflexes were measured to assess the possible Accepted 19 November 1997 and physiotherapy practitioners.12Observation contribution of spasticity to gait dysfunction. Spasticity and walking 629 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.64.5.628 on 1 May 1998. Downloaded from Table 1 Characteristics of subjects Time after stroke MAS* Ashworth scale† Tendon jerk‡ Subjects Age (y) Sex (months) walking (1–6) Side tested (0–4) (+ to ++++) Stroke: 1 58 M 11 5 L 0 +++ 2 56 M 9 5 L 3 +++ 3 69 F 5 5 R 1 +++ 4 71 F 18 5 L 3 ++++ 5¶ 71 M 20 3 L 0 +++ 6 56 F 13 5 L 2 +++ 7 59 M 7 4 R 1 +++ 864F55L1+ 976M85R2++ 10¶ 65 F 16 3 L 1 +++ 11 64 M 18 4 R 1 ++ 12 45 F 14 4 L 2 +++ 13 72 F 18 4 L 1 ++ 14¶ 78 F 7 3 L 0 +++ Control: 15 49 F —§ —§ L 0 ++ 16 46 F — — R 0 ++ 17 63 F — — L 0 ++ 18 62 F — — R 0 ++ 19 53 F — — L 0 ++ 20 52 M — — L 0 ++ 21 46 M — — R 0 ++ 22 57 F — — R 0 ++ 23 48 M — — L 0 ++ 24 48 F — — R 0 ++ 25 47 F — — L 0 ++ 26 51 F — — R 0 ++ 27 46 F — — L 0 ++ 28 56 M — — R 0 ++ 29 54 M — — R 0 ++ *Motor assessment scale (MAS)17; grade 1=stands on aVected leg and steps forward with other leg. (weight bearing hip must be extended); therapist may give standby help; grade 2=walks with standby help from one person; grade 3=walks 3 metres alone or using any aid but no standby help; grade 4=walks 5 metres with no aid in 15 seconds; grade 5=walks 10 metres with no aid, turns around, picks up a small sandbag from the floor, and walks back in 25 seconds (may use either hand); grade 6=walks up and down 4 steps with or without an aid but without holding the rail 3 times in 35 seconds. †Ashworth scale18; grade 0=no increase in muscle tone; grade 1=slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the range of motion when the aVected part is moved in flexion or extension; grade 2=more marked increase in muscle tone through most of the range of motion, but aVected part easily moved; grade 3=considerable increase in muscle tone, passive movement diYcult; grade 4=aVected part rigid in flexion or extension. ‡=Tendon jerk19; 0=absent; +=hyporeflexia; ++=normal; +++=slight hyperreflexia; ++++=marked hyperreflexia. §Not applicable. ¶These patients walk with a one point cane. Methods single support, the knee extends and the ankle SUBJECTS joint rotates from 10° of plantarflexion to 10° Fourteen stroke patients were recruited for of dorsiflexion20 which eVectively stretches the this study (table 1). They presented clinically gastrocnemius muscle. Perry21 has shown that as hemiparetic and were within five to 20 there is no diVerence in the reflex response of http://jnnp.bmj.com/ (mean 12 (SD 5))months of their first stroke. the gastrocnemius muscle when tested in a sit- The mean age of the subjects was 65 (SD 9) ting position compared with a standing posi- years. The only inclusion criteria were that tion. Therefore, the subject sat with the knee subjects who could walk independently with or extended while the ankle was rotated through without an aid—that is, they scored 3 or above 20° at frequencies of 0.5, 1, 1.5, and 2 Hz, on the walking item of the motor assessment which were chosen to cover the frequency scale (MAS),17 and had enough cognitive abil- range of ankle movement in normal walking as on October 1, 2021 by guest. Protected copyright. ity to participate in the measurement proce- well as the slower walking of stroke patients. dures. Clinical measures of lower limb muscle The subject sat with the foot securely strapped tone18 and Achilles tendon jerks19 were per- to the movable arm of an instrumented foot formed on all subjects (table). Stroke patients frame (fig 1). A potentiometer aligned with the ranged evenly between 0 to 3 on the Ashworth lateral malleolus measured ankle angular dis- scale with most demonstrating an increase in placement. A load cell (capacity: 450N; linear- muscle tone and exaggerated tendon jerks ity 97%) measured the resistance of the foot to compared with control subjects. Fifteen neu- movement to quantify hypertonia, and silver- rologically normal subjects were recruited to silver chloride surface electrodes measured act as control subjects.