Bloem B R, Van Dijk J G, Beckley D J, Roos R A, Remler M P, Bruyn G W
Department of Neurology, University Hospital, Leiden, The Netherlands.
Med Hypotheses. 1992 Nov;39(3):243-7. doi: 10.1016/0306-9877(92)90116-t.
In subjects standing on a movable platform, sudden dorsiflexion of the ankle joint elicits a set of reflexes in leg muscles. These responses include a short latency (SL) and medium latency (ML) stretch reflex in the gastrocnemius muscle and a distal to proximal innervation sequence of long latency (LL) reflexes in the shortened tibialis anterior and vastus lateralis muscles. Because of their role in maintaining upright stance these responses have been termed postural reflexes. In patients with Parkinson's disease (PD), the following abnormalities have been described: 1) enhanced ML-amplitudes; 2) a reversed LL innervation sequence; and 3) delayed onset latencies. These abnormalities are thought to be due to defective motor programming and disturbed control of spinal and supraspinal reflex centers by basal ganglia circuits. The altered reflexes have been held responsible for some of the clinical features of PD, including balance impairment and rigidity. In this paper, we argue the reverse hypothesis that postural reflexes are essentially normal in PD, and that the observed alterations are at least in part consequence rather than cause of balance impairment, the stooped parkinsonian posture and rigidity of PD patients.
在站在可移动平台上的受试者中，踝关节突然背屈会引发腿部肌肉的一系列反射。这些反应包括腓肠肌中的短潜伏期（SL）和中潜伏期（ML）牵张反射，以及在缩短的胫骨前肌和股外侧肌中从远端到近端的长潜伏期（LL）反射的神经支配顺序。由于它们在维持直立姿势中的作用，这些反应被称为姿势反射。在帕金森病（PD）患者中，已描述了以下异常情况：1）ML振幅增强；2）LL神经支配顺序逆转；3）起始潜伏期延迟。这些异常被认为是由于运动编程缺陷以及基底神经节回路对脊髓和脊髓上反射中枢的控制紊乱所致。反射改变被认为是PD的一些临床特征的原因，包括平衡障碍和僵硬。在本文中，我们提出相反的假设，即PD患者的姿势反射本质上是正常的，并且观察到的改变至少部分是平衡障碍、帕金森病患者弯腰姿势和僵硬的结果而非原因。
