Characteristic Alterations in Responses to Imposed Wrist Displacements in Parkinsonian Rigidity and Dystonia Musculorum Deformans

Background: Perception of vibration induced illusionary movement (VIIM) is subnormal in dystonic patients, suggesting abnormal sensory-motor processing in patients with idiopathic focal dystonia. Objective: To examine the effects of fatigue on VIIM in patients with idiopathic torticollis. Methods: An illusionary sensation of arm extension was evoked by an 80 Hz transcutaneous vibratory stimulus applied to the biceps brachii tendon while the arm was restrained. Blindfolded patients attempted to copy the perceived movement of the vibrated arm with the opposite (tracking) arm and the change in elbow angle of the tracking arm was quantified over 45 seconds. The tasks were repeated following volitional fatigue of the vibrated arm. Results: The subnormal perception of VIIM perceived by patients with torticollis, occurring bilaterally and remote from the location of dystonic symptoms, was corrected by fatigue of the vibrated arm compared with prefatigue values (mean (SEM): 19.04°(1.76)°v 24.25°(2.41°); p = 0.01, paired t test). Conclusions: While a combination of central or peripheral factors may be involved in the correction of abnormal perception of the vibration induced illusion of movement in dystonia, subnormal elasticity of muscle spindles could be implicated in the impaired perception of vibration induced illusionary movement and may predispose an individual towards developing idiopathic focal dystonia.

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“…10 Our results show that impaired sensitivity to muscle stretch occurs bilaterally and remote from the location of dystonic symptoms.…”

Section: Discussionmentioning

confidence: 50%

The effect of fatigue on abnormal vibration induced illusion of movement in idiopathic focal dystonia

Frima

Rome²,

Grünewald³

2003

Journal of Neurology, Neurosurgery & Psychiatry

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“…The mean (SD) amplitude of fast movements in the 150 task was 20.10 (2.30), and in the 300 task was 360 (2)(3)(4)(5)(6)(7)(8)(9)(10). This overshoot was not as evident when the same subjects were moving more slowly (mean [SD] amplitudes of movements were 170 (1 30), and 320 (20) for the 150 and 300 tasks respectively). The 300 movements were performed at about one and a half times the speed of 150 movements (figure 2a).…”

Section: Resultsmentioning

confidence: 98%

Rapid elbow movements in patients with torsion dystonia.

Kamp¹,

Berardelli²,

Rothwell³

et al. 1989

Journal of Neurology, Neurosurgery & Psychiatry

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SUMMARY Rapid, selfpaced and selfterminated elbow flexion movements were studied in a group of 10 patients with dystonia affecting the arms. The movements were slower and for small amplitude movements, more variable than those recorded in normal subjects. The duration of the first agonist burst was prolonged, even when compared with normal subjects deliberately moving slowly. Cocontraction of agonist and antagonist muscles during ballistic movements was common and may contribute to the bradykinesia. These findings are compared with similar studies of other diseases of the motor system. Unlike many other conditions which also reduce the speed of ballistic voluntary movements, the patients with dystonia in the present study showed a normal symmetry of acceleration and deceleration times. One interpretation of this finding is that aspects of the basic motor programmes are relatively preserved in this condition and account for the surprising retention of motor skills shown by some patients with dystonia.

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“…In Parkinson's disease the long latency response (M2) to limb perturbation is exaggerated.2 [12][13][14][15][16][17][18][19] We also examined patients with Parkinson's disease to determine whether any long latency responses obtained from electrical stimulation of low theshold afferents were exaggerated in these patients. Methods…”

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confidence: 99%

Afferents contributing to the exaggerated long latency reflex response to electrical stimulation in Parkinson's disease.

Hunter

Ashby²,

Lang³

1988

Journal of Neurology, Neurosurgery & Psychiatry

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SUMMARY Reflex pathways to tibialis anterior motoneurons from low threshold afferents of the common peroneal nerve were examined in 13 Parkinsonian subjects and 12 age-matched normals. Post-synaptic events occurring in single motoneurons were derived from changes in the firing probability of single voluntarily activated motor units during afferent stimulation. A period of increased firing probability of "monosynaptic" latency (about 33 ms) occurred in all subjects in both groups. A second, later, period of increased firing probability (latency about 64 ms) was seen in 2/12 normals and 8/13 Parkinsonian subjects. Neither of these responses could be produced by cutaneous stimulation. The electrical threshold of the afferents mediating the later effect was 0-82 of the threshold of alpha motoneuron axons which is similar to that of the afferents mediating the shorter latency response. Thus, large non cutaneous afferents contribute to this long latency response in man presumably through polysynaptic pathways. Transmission in these pathways is enhanced in Parkinson's disease.Perturbations of a limb in man can cause segmented reflex responses in the stretched muscles.1 The reflex response with the shortest latency, labelled Ml by Lee and Tatton,2 is attributed to the predominantly "monosynaptic" facilitation of motoneurons from primary spindle endings.3 A longer latency response, labelled M2 by Lee and Tatton,2 has a number of possible explanations which include two opposing theories; first, that the response is mediated by large, fast conducting afferents to the spinal cord and then by polysynaptic, and possibly "long loop" pathways to motoneurons, the main delay being in the central nervous system;4-7 second, that the response is mediated by slowly conducting afferents to the spinal cord then by oligosynaptic pathways to motoneurons the main delay being in the peripheral nervous system.89 These two possibilities cannot be distinguished by limb perturbation since this stimulus excites many

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Characteristic Alterations in Responses to Imposed Wrist Displacements in Parkinsonian Rigidity and Dystonia Musculorum Deformans

Cited by 74 publications

References 20 publications

The effect of fatigue on abnormal vibration induced illusion of movement in idiopathic focal dystonia

The effect of fatigue on abnormal vibration induced illusion of movement in idiopathic focal dystonia

Rapid elbow movements in patients with torsion dystonia.

Afferents contributing to the exaggerated long latency reflex response to electrical stimulation in Parkinson's disease.

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