Lee Eun Ah, Kim B Joon, Lee Won Yong
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Mov Disord. 2002 Nov;17(6):1242-7. doi: 10.1002/mds.10225.
The clonidine-growth hormone test (CGHT) has been proposed as a means of differentiating multiple system atrophy (MSA) from idiopathic Parkinson's disease (PD). However, it is controversial whether the CGHT is valid. We sought to confirm the validity of the CGHT and to compare the diagnostic accuracy of the CGHT with that of external anal sphincter electromyelography (Sph-EMG) for MSA. We performed the CGHT and the Sph-EMG on 21 PD patients, 23 patients with probable MSA of parkinsonian type (MSA-p), and 22 patients with probable MSA of cerebellar type (MSA-c). We compared the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of CGHT, Sph-EMG, and a combination of the two tests. We also evaluated the correlations of Unified Parkinson's Disease Rating Scale (UPDRS) scores with the results of the two tests. There was no significant difference between the UPDRS scores for the PD and MSA-p groups. Serum growth hormone concentrations after clonidine significantly increased in PD (mean increase +/- SEM, 4.19 +/- 0.92 ng/ml; P < 0.0001), but remained unchanged in both MSA-p (0.83 +/- 0.61 ng/ml) and MSA-c (1.45 +/- 0.58 ng/ml). The growth hormone responses to clonidine in MSA-p were significantly different from those in PD (P < 0.05). Abnormal, denervated Sph-EMG was observed in 95.7% of MSA-p, 86.4% of MSA-c, and 33.3% of PD patients. Compared to Sph-EMG, the CGHT was less sensitive but more specific in both MSA-p and MSA-c. The result of neither test correlated with the severity of parkinsonism. Interestingly, combining the results of the CGHT and Sph-EMG markedly increased the specificity (85.7% in the CGHT and 66.7% in Sph-EMG vs. 95.2% in the combination study) and the PPV in both MSA-p (85.7% and 75.9% vs. 94.4%) and MSA-c (82.4% and 73.1% vs. 91.7%). We confirm that the CGHT can distinguish MSA-p from PD. Its sensitivity is lower and its specificity higher than Sph-EMG. Compared to either test alone, combined testing with the CGHT and Sph-EMG increased specificity and PPV, thereby enhancing accuracy in the diagnosis of MSA.
可乐定-生长激素试验（CGHT）已被提议作为区分多系统萎缩（MSA）和特发性帕金森病（PD）的一种方法。然而，CGHT是否有效存在争议。我们旨在证实CGHT的有效性，并比较CGHT与肛门外括约肌肌电图（Sph-EMG）对MSA的诊断准确性。我们对21例PD患者、23例帕金森型可能的MSA（MSA-p）患者和22例小脑型可能的MSA（MSA-c）患者进行了CGHT和Sph-EMG检查。我们比较了CGHT、Sph-EMG以及两种检查联合使用时的敏感性、特异性、阳性和阴性预测值（PPV和NPV）。我们还评估了统一帕金森病评定量表（UPDRS）评分与两种检查结果的相关性。PD组和MSA-p组的UPDRS评分之间无显著差异。可乐定给药后，PD患者血清生长激素浓度显著升高（平均升高±标准误，4.19±0.92 ng/ml；P<0.0001），但MSA-p组（0.83±0.61 ng/ml）和MSA-c组（1.45±0.58 ng/ml）均保持不变。MSA-p组对可乐定的生长激素反应与PD组显著不同（P<0.05）。95.7%的MSA-p患者、86.4%的MSA-c患者和33.3%的PD患者观察到Sph-EMG异常、失神经改变。与Sph-EMG相比，CGHT在MSA-p和MSA-c中敏感性较低但特异性较高。两种检查的结果均与帕金森病的严重程度无关。有趣的是，将CGHT和Sph-EMG的结果结合起来显著提高了特异性（CGHT为85.7%，Sph-EMG为66.7%，联合研究为95.2%）以及MSA-p（85.7%和75.9%，联合研究为94.4%）和MSA-c（82.4%和73.1%，联合研究为91.7%）的PPV。我们证实CGHT可以将MSA-p与PD区分开来。其敏感性低于Sph-EMG，特异性高于Sph-EMG。与单独的任何一种检查相比，CGHT和Sph-EMG联合检查提高了特异性和PPV，从而提高了MSA诊断的准确性。
