Division of Neurology, Lebanese American University Medical Center, Beirut, Lebanon; Hamidy Charitable Medical Center, Tripoli, Lebanon.
Division of Neurosurgery, Lebanese American University Medical Center, Beirut, Lebanon.
Clin Neurophysiol. 2018 Aug;129(8):1699-1703. doi: 10.1016/j.clinph.2018.05.017. Epub 2018 Jun 11.
To explore the value of a novel sensory criterion, the ulnar ratio - defined as the SNAP amplitude of the palmar cutaneous (pUN) over that of the dorsal branch (dUN) of the ulnar nerve - as a predictor of Acute Inflammatory Demyelinating Polyneuropathy (AIDP).
We prospectively included 22 patients with AIDP, 20 patients with diabetic peripheral neuropathy (DPN), and 18 controls. Eligible subjects underwent nerve conduction studies including, among others, the dUN, pUN, and sural nerve.
A sural sparing pattern was found in 72% of AIDP cases. The ulnar ratio was significantly lower in patients with AIDP compared to those with DPN or controls. The ROC curve area to discriminate AIDP (versus controls and diabetics together) was higher with the ulnar ratio and pUN compared to dUN. An ulnar ratio ≥ 0.78 seems to be the best threshold to rule out the diagnosis of AIDP, with a specificity of 100% and a sensitivity of 87%. The ulnar ratio was equally reliable in the subgroup of patients presenting within a week of symptoms onset.
The ulnar ratio is a highly sensitive and specific marker of AIDP and can help confirm the diagnosis when direct signs of demyelination are lacking.
Incorporating specific sensory abnormalities, such as the ulnar ratio, in the electrodiagnostic criteria of AIDP could enhance their reliability.
探讨一种新的感觉标准——尺神经 SNAP 波幅与掌皮支（pUN）波幅的比值（定义为尺神经比值）——作为急性炎症性脱髓鞘性多发性神经病（AIDP）预测指标的价值。
我们前瞻性纳入了 22 例 AIDP 患者、20 例糖尿病周围神经病（DPN）患者和 18 例对照者。合格的受试者接受了神经传导研究，包括尺神经的正中支、掌皮支和腓肠神经等。
72%的 AIDP 病例存在腓肠神经保留模式。与 DPN 或对照组患者相比，AIDP 患者的尺神经比值明显降低。与正中支相比，尺神经比值和掌皮支 SNAP 波幅的 ROC 曲线面积能更好地区分 AIDP（与对照组和糖尿病患者一起）。尺神经比值≥0.78 似乎是排除 AIDP 诊断的最佳阈值，特异性为 100%，敏感性为 87%。对于症状发作后一周内就诊的患者亚组，尺神经比值同样可靠。
尺神经比值是 AIDP 的高度敏感和特异性标志物，当缺乏脱髓鞘的直接征象时，有助于确诊。
在 AIDP 的电诊断标准中纳入特定的感觉异常，如尺神经比值，可能会提高其可靠性。
