Spastic movement disorder

Abstract

This review deals with the neuronal mechanisms underlying spastic movement disorder, assessed by electrophysiological means with the aim of ®rst, a better understanding of the underlying pathophysiology and second, the selection of an adequate treatment. For the patient usually one of the ®rst symptoms of a lesion within the central motor system represents the movement disorder, which is most characteristic during locomotion in patients with spasticity. The clinical examination reveals exaggerated tendon tap re¯exes and increased muscle tone typical of the spastic movement disorder. However, today we know that there exists only a weak relationship between the physical signs obtained during the clinical examination in a passive motor condition and the impaired neuronal mechanisms being in operation during an active movement. By the recording and analysis of electrophysiological and biomechanical parameters during a functional movement such as locomotion, the signi®cance of, for example, impaired re¯ex behaviour or pathophysiology of muscle tone and its contribution to the movement disorder can reliably be assessed. Consequently, an adequate treatment should not be restricted to the cosmetic therapy and correction of an isolated clinical parameter but should be based on the pathophysiology and signi®cance of the mechanisms underlying the disorder of functional movement which impairs the patient. Spinal Cord (2000) 38, 389 ± 393

Spasticity after spinal cord injury

“…Immediately following SCI, a period exists whereby the individual presents with flaccid muscle paralysis and loss of tendon reflexes below the level of the lesion. 5 This period was first described in 1750, with the term 'spinal shock' introduced by Marshall Hall in 1850. 30 Spinal shock has been reported to end from 1 to 3 days 31 to a few weeks postinjury, with the gradual development of exaggerated tendon reflexes, increased muscle tone, and involuntary muscle spasms: 5 the symptoms of spasticity.…”

“…3 The development of tonic stretch reflex hyperexcitability could be due to a lower threshold, an increased gain of the stretch reflex, or a combination of the two. 22 The resultant increase in muscle tone is thought to be due to a combination of increased denervation hypersensitivity 2,3,5,9,33 and changed muscle properties. 11,13,22,34,35 Denervation leads to an initial downregulation of neuronal membrane receptors, followed by an upregulation, with enhanced sensitivity to neurotransmitters.…”

“…[1][2][3] The most commonly cited definition for spasticity is that published by Lance in 1980: 4 'Spasticity is a motor disorder characterized by a velocitydependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one component of the upper motoneuron syndrome'. There remains, however, discrepancy in the literature about the definition of spasticity; whereas some authors include symptoms such as clonus, hyperactive tendon reflexes, and spasms within the umbrella term 'spasticity', 1,[5][6][7] others discuss these same symptoms as related to but separate from spasticity, which is defined by these authors as increased muscle tone. 3,[8][9][10][11] Decq 2 recently has suggested the use of a modified definition, whereby spasticity, in general, is defined as a symptom of the upper motor neuron syndrome characterized by an exaggeration of the stretch reflex secondary to hyperexcitability of spinal reflexes.…”

Lumbar repetitive magnetic stimulation reduces spastic tone increase of the lower limbs

“…4 Evidence indicates that the sensory feedback produced by passive movements of the affected limb, as well as the activation of commissural pathways due to the activation of interneurons, that is, by moving the contralateral extremity, causes a reduction in spastic tone. 3 This also explains why physiotherapy helps. 5 Electrical stimulation can also reduce spastic tone, [6][7][8] but has not yet been introduced in the clinic as standard therapy due to its various side effects.…”

“…Other problems are muscle weakness and painful muscle activity during stretches, sometimes induced by only slight touches of the skin. 2 The basic treatment remains physical therapy and pharmacotherapy, 3 often in combination. 4 Evidence indicates that the sensory feedback produced by passive movements of the affected limb, as well as the activation of commissural pathways due to the activation of interneurons, that is, by moving the contralateral extremity, causes a reduction in spastic tone.…”