Department of Medical Sciences, University Magna Graecia, Cosenza, Italy.
Neurology. 2012 Oct 2;79(14):1490-5. doi: 10.1212/WNL.0b013e31826d5f83. Epub 2012 Sep 19.
An increased R2 recovery component of the blink reflex (R2-BRrc) has been commonly observed in Parkinson disease, cranio-cervical dystonia, and dystonic tremor, while the BRrc was reported normal in patients with essential tremor (ET). We studied BRrc in patients with ET associated with resting tremor (rET) in comparison with patients with ET.
This was a cross-sectional study investigating R2-BRrc at interstimulus intervals (ISI) of 100, 150, 200, 300, 400, 500, and 750 msec in 14 patients with rET, 14 patients with ET, and 16 healthy controls. To compare individual patients, we calculated an R2 recovery index in each subject as the mean of R2 area ratio values at ISIs of 150, 200, 300, 400, and 500 msec. All patients and controls underwent DAT-SPECT.
Patients with rET differed from those with ET for the presence of resting tremor associated in several cases (36%) with a subtle arm dystonia. DAT-SPECT was normal in all patients and controls. All patients with rET (with and without dystonia) had an increased R2-BRrc while all patients with ET had a normal BRrc comparable to that of control subjects. The R2 recovery index was abnormal in all patients with rET but in none of the patients with ET.
Patients with rET showed increased R2-BRrc, suggesting that this form of tremor may be a dystonic tremor rather than a subtype of ET. BRrc helps to correctly diagnose DAT-negative patients with resting tremor also in the absence of overt dystonic posturing.
眨眼反射（R2-BRrc）的 R2 恢复成分增加在帕金森病、颅颈肌张力障碍和肌张力震颤中较为常见，而 BRrc 则被报道在特发性震颤（ET）患者中正常。我们研究了与静止性震颤（rET）相关的 ET 患者的 BRrc，与 ET 患者进行了比较。
这是一项横断面研究，在 14 例 rET 患者、14 例 ET 患者和 16 例健康对照者中，分别在刺激间隔（ISI）为 100、150、200、300、400、500 和 750 msec 时，研究 R2-BRrc。为了比较个体患者，我们在每个受试者中计算了 R2 恢复指数，作为 ISI 为 150、200、300、400 和 500 msec 时 R2 面积比的平均值。所有患者和对照者均行 DAT-SPECT。
rET 患者与 ET 患者不同，前者存在静止性震颤，在某些情况下（36%）伴有轻微的手臂肌张力障碍。所有患者和对照者的 DAT-SPECT 均正常。所有 rET 患者（伴或不伴肌张力障碍）均有 R2-BRrc 增加，而所有 ET 患者均有正常的 BRrc，与对照者相当。rET 患者的 R2 恢复指数均异常，但 ET 患者均无异常。
rET 患者表现出 R2-BRrc 增加，提示这种震颤形式可能是肌张力震颤，而不是 ET 的一个亚型。BRrc 有助于在缺乏明显的肌张力障碍姿势的情况下，正确诊断伴有静止性震颤的 DAT 阴性患者。
