Thickbroom Gary W, Sacco Paul, Faulkner Deborah L, Kermode Allan G, Mastaglia Frank L
Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Queen Elizabeth II Medical Centre, Perth, Western Australia WA 6009.
J Neurol. 2008 Jul;255(7):1001-5. doi: 10.1007/s00415-008-0818-6. Epub 2008 Mar 14.
To determine if task performance and fatigability during rapid repetitive exercise of the lower limb differ in a group of MS subjects compared to a control group, and what central changes accompany the development of fatigue and the period of recovery.
Transcranial magnetic stimulation (TMS) was used to compare motor evoked potential (MEP) responses between 10 clinically definite MS subjects (7F, 33-64 years of age; EDSS <or= 4; MRC grade >or= 4/5) and 13 control subjects during and after 5 bouts of a 15-second maximum rate foot-tapping task performed at 1 minute intervals.
Maximum voluntary contraction (MVC) force of ankle dorsiflexion was lower (15 %) in the MS group compared to controls; however there were no differences in the rate of foot tapping. The rate of foot tapping decreased during each bout of exercise to a comparable degree in both groups, but there was no overall deterioration in performance across the 5 repeat bouts in either group. MS subjects showed a greater decline in strength than controls after exercise (20.7+/-7.7% vs. 6+/-3.6%; p<0.05). MEP amplitude increased significantly for the exercised limb in both groups, but the increase was greater in MS subjects (65.9+/-27% vs. 31+/-19.6%; MS vs. control; p<0.05). MEP amplitude also increased for the non-exercised limb in controls (40.6+/-15.6%, p<0.01) but not in MS subjects.
Mild to moderately affected MS subjects can perform a fatiguing exercise requiring a high level of central motor control but this is associated with a greater strength loss and increase in corticomotor excitability compared to unaffected individuals.
Central adaptive processes are likely to have a significant role in maintaining task performance in MS.
确定与对照组相比，一组多发性硬化症（MS）患者在下肢快速重复运动期间的任务表现和疲劳性是否存在差异，以及疲劳发展和恢复期间伴随的中枢变化情况。
在10名临床确诊的MS患者（7名女性，33 - 64岁；扩展残疾状态量表[EDSS]≤4；医学研究委员会[MRC]分级≥4/5）和13名对照者中，采用经颅磁刺激（TMS）比较在以1分钟间隔进行5组15秒最大速率足部轻敲任务期间及之后的运动诱发电位（MEP）反应。
与对照组相比，MS组踝关节背屈的最大自主收缩（MVC）力量较低（低15%）；然而，足部轻敲速率没有差异。两组在每次运动回合中足部轻敲速率均下降至相当程度，但两组在5次重复回合中任务表现均未出现整体恶化。运动后，MS患者的力量下降幅度大于对照组（20.7±7.7%对6±3.6%；p<0.05）。两组中运动肢体的MEP波幅均显著增加，但MS患者增加幅度更大（65.9±27%对31±19.6%；MS组对对照组；p<0.05）。对照组中未运动肢体的MEP波幅也增加（40.6±15.6%，p<0.01），但MS患者中未增加。
轻度至中度受影响的MS患者能够进行需要高水平中枢运动控制的疲劳性运动，但与未受影响个体相比，这与更大的力量损失和皮质运动兴奋性增加有关。
中枢适应性过程可能在维持MS患者的任务表现中起重要作用。
