Glabellar tap or reflex (GR) is an old bedside clinical test used in the diagnostics of Parkinson’s disease (PD), but its diagnostic value is unclear. This study examines the diagnostic validity and reliability of GR in PD in relation to brain dopaminergic activity. GR was performed on 161 patients with PD, 47 patients with essential tremor (ET) and 40 healthy controls immediately prior to dopamine transporter (DAT) [¹²³I]FP-CIT SPECT scanning. The binding ratios were investigated with consideration of the GR result (normal/abnormal). In addition, the consistency of the GR was investigated with 89 patients after a mean follow-up of 2.2 years. PD and ET patients had higher GR scores than healthy controls (p < 0.001), but there was no difference in GR between PD and ET patients (p = 0.09). There were no differences in the ratio of abnormal to normal GRs between the PD and ET groups (73% vs. 64% abnormal, respectively, p = 0.13) or in DAT binding between PD patients with abnormal and normal GRs (p > 0.36). Over follow-up, the GR changed from abnormal to normal in 20% of PD patients despite the presence of clinically typical disease. The sensitivity and specificity of GR for differentiating PD from ET were 78.3% and 36.2%, respectively. Although GR has been used by clinicians in the diagnostics of PD, it does not separate PD from ET. It also shows considerable inconsistency over time, and abnormal GR has no relationship with dopamine loss. Its usefulness should be tested for other clinical diagnostic purposes.

眉间叩击或反射 (GR) 是一种古老的床边临床试验，用于诊断帕金森病 (PD)，但其诊断价值尚不清楚。本研究检验了 GR 在 PD 中与脑多巴胺能活动相关的诊断有效性和可靠性。在多巴胺转运蛋白 (DAT) [ ¹²³ I] FP-CIT SPECT 扫描之前，立即对 161 名 PD 患者、47 名特发性震颤 (ET) 患者和 40 名健康对照进行了 GR 。结合GR结果(正常/异常)研究结合率。此外，在平均随访 2.2 年后，对 89 名患者的 GR 一致性进行了调查。PD 和 ET 患者的 GR 评分高于健康对照组（p  < 0.001），但 PD 和 ET 患者的 GR 没有差异（p  = 0.09）。PD 和 ET 组之间异常与正常 GR 的比率（分别为 73% 和 64% 异常，p  = 0.13）或具有异常和正常 GR 的 PD 患者之间的 DAT 结合率没有差异（p  > 0.36） . 在随访期间，尽管存在临床典型疾病，但仍有 20% 的 PD 患者的 GR 从异常变为正常。GR 区分 PD 和 ET 的敏感性和特异性分别为 78.3% 和 36.2%。尽管 GR 已被临床医生用于 PD 的诊断，但它并没有将 PD 与 ET 分开。随着时间的推移，它也表现出相当大的不一致，异常 GR 与多巴胺损失无关。应测试其有效性以用于其他临床诊断目的。