Faist M, Ertel M, Berger W, Dietz V
Department of Clinical Neurology and Neurophysiology, University of Freiburg, Germany.
Brain. 1999 Mar;122 ( Pt 3):567-79. doi: 10.1093/brain/122.3.567.
In healthy subjects, functionally appropriate modulation of short latency leg muscle reflexes occurs during gait. This modulation has been ascribed, in part, to changes in presynaptic inhibition of Ia afferents. The changes in modulation of quadriceps tendon jerk reflexes during gait of healthy subjects were compared with those of hemi- or paraparetic spastic patients. The spasticity was due to unilateral cerebral infarction or traumatic spinal cord injury, respectively. The modulation of the quadriceps femoris tendon jerk reflex at 16 phases of the step cycle was studied. The reflex responses obtained during treadmill walking were compared with control values obtained during gait-mimicking standing postures with corresponding levels of voluntary muscle contraction and knee angles. In healthy subjects the size of the reflexes was profoundly modulated and was generally depressed throughout the step cycle. In patients with spinal lesion the reflex depression during gait was almost removed and was associated with weak or no modulation during the step cycle. In patients with cerebral lesion there was less depression of the reflex size associated with a reduced reflex modulation on the affected side compared with healthy subjects. On the 'unaffected' side of these patients reflex modulation was similar to that of healthy subjects, but the reflex size during gait was not significantly different from standing control values. These observations suggest that the mechanisms responsible for the depression of reflex size and the modulation normally seen during gait in healthy subjects are impaired to different extents in spasticity of spinal or cerebral origin, possibly due to the unilateral preservation of fibre tracts in hemiparesis.
在健康受试者中，短潜伏期腿部肌肉反射在步态过程中会发生功能上适当的调制。这种调制部分归因于Ia传入纤维突触前抑制的变化。将健康受试者步态期间股四头肌肌腱反射的调制变化与偏瘫或截瘫痉挛患者的进行了比较。痉挛分别由单侧脑梗死或创伤性脊髓损伤引起。研究了步周期16个阶段的股四头肌肌腱反射的调制。将跑步机行走期间获得的反射反应与在模拟步态的站立姿势下、具有相应水平的随意肌肉收缩和膝关节角度时获得的对照值进行比较。在健康受试者中，反射的大小受到深刻调制，并且在整个步周期中通常受到抑制。在脊髓损伤患者中，步态期间的反射抑制几乎消失，并且与步周期中微弱或无调制相关。在脑损伤患者中，与健康受试者相比，患侧反射大小的抑制较少，且反射调制减少。在这些患者的“未受影响”侧，反射调制与健康受试者相似，但步态期间的反射大小与站立对照值无显著差异。这些观察结果表明，在脊髓或脑源性痉挛中，负责健康受试者步态期间通常所见的反射大小抑制和调制的机制受到不同程度的损害，这可能是由于偏瘫中纤维束的单侧保留所致。
