Bloem B R, Beckley D J, van Vugt J P, van Dijk J G, Remler M P, Langston J W, Roos R A
Department of Neurology, University Hospital Leiden, The Netherlands.
Mov Disord. 1995 Sep;10(5):580-8. doi: 10.1002/mds.870100509.
Scaling of posturally stabilizing long latency (LL) reflexes in tibialis anterior muscles induced by "toe-up" rotational perturbations is abnormal in standing patients with Parkinson's disease. To investigate the contribution of dopaminergic pathways to abnormal scaling, we studied LL reflexes in 22 patients with selective hypodopaminergic syndromes: 10 psychiatric patients taking chronic neuroleptic medication (7 with mild parkinsonism), 8 patients with young-onset Parkinson's disease, and 4 patients with MPTP-induced parkinsonism. Results were compared with those of 10 healthy controls. Stimuli consisted of (a) 10 serial (predictable) perturbations of 4 degrees amplitude, (b) 10 serial (predictable) perturbations of 10 degrees amplitude, and (c) 20 randomly mixed (unpredictable) perturbations of either 4 or 10 degrees amplitude. In normal subjects, LL reflex amplitudes were adapted to match predictable variations in stimulus size, whereas under unpredictable conditions a "default" response emerged that anticipated the 10 degrees perturbation. LL reflex scaling under predictable conditions was intact in patients with neuroleptic-induced parkinsonism and young-onset Parkinson's disease, but the large default LL response under unpredictable conditions was absent. In patients with MPTP-induced parkinsonism, LL reflex scaling was absent during both predictable and unpredictable conditions. We conclude that abnormal scaling of posturally stabilizing LL reflexes is related to decreased supraspinal dopaminergic influence.
在帕金森病站立患者中，由“足尖上抬”旋转扰动诱发的胫前肌姿势稳定长潜伏期（LL）反射的缩放是异常的。为了研究多巴胺能通路对异常缩放的作用，我们研究了22例选择性多巴胺能减退综合征患者的LL反射：10例服用慢性抗精神病药物的精神科患者（7例有轻度帕金森综合征）、8例早发型帕金森病患者和4例MPTP诱导的帕金森病患者。将结果与10名健康对照者的结果进行比较。刺激包括：（a）10次幅度为4度的连续（可预测）扰动，（b）10次幅度为10度的连续（可预测）扰动，以及（c）20次幅度为4度或10度的随机混合（不可预测）扰动。在正常受试者中，LL反射幅度会进行调整以匹配刺激大小的可预测变化，而在不可预测的情况下会出现一种“默认”反应，该反应预期为10度的扰动。在服用抗精神病药物诱发的帕金森综合征患者和早发型帕金森病患者中，可预测条件下的LL反射缩放是正常的，但在不可预测条件下没有大的默认LL反应。在MPTP诱导的帕金森病患者中，可预测和不可预测条件下均不存在LL反射缩放。我们得出结论，姿势稳定LL反射的异常缩放与脊髓上多巴胺能影响的降低有关。
