Objective: To investigate the clinical and neuroelectrophysiological characteristics of patients with primary peripheral nerve hyperexcitability syndrome (PNHS). Methods: The clinical data of 20 patients who were diagnosed with PNHS in Beijing Tiantan Hospital from April 2016 to January 2023 were retrospectively collected. All patients underwent neuroelectrophysiological examinations. Clinical and electrophysiological characteristics were compared between the antibody positive and antibody negative groups, according to serum and cerebrospinal fluid anti-contactin-associated protein-like 2 (CASPR2) and/or anti-leucine-rich glioma-inactivated protein 1 (LGI-1) antibodies. Results: There were 12 males and 8 females, with a mean age of (44.0±17.2) years and the disease course of [M (Q1, Q3)] 2.3 (1.1, 11.5) months. Motor symptoms included fasciculations, myokymia, muscle pain, cramps, and stiffness. These symptoms were commonly seen in the lower limbs (17 patients), followed by upper limbs (11 patients), face (11 patients) and trunk (9 patients). Nineteen (19/20) patients had sensory abnormalities and/or autonomic dysfunction, 13 patients had central nervous system involvement, and 5 patients had concomitant lung cancer or thymic lesions. The characteristic spontaneous potentials on needle electromyography (EMG) were myokymia potential (19 patients), fasciculation potential (12 patients), spastic potential (3 patients), neuromyotonic potential (1 patients), etc, which were commonly seen in the lower limb muscles, especially the gastrocnemius muscle(12 patients). After-discharge potential was found in 8 patients, and 7 were in the tibial nerve. Seven patients had positive serum anti-CASPR2 antibodies, and 3 of them had concomitant anti-LGI1 antibodies. And 1 patient had positive serum anti-LGI1 antibody alone. Compared with patients in the antibody negative group (n=12), the patients who had anti-VGKC complex antibodies (n=8) had a shorter course of disease [M (Q1, Q3): 1.8 (1, 2) months vs 9.5 (3.3, 20.3) months, P=0.012], higher incidence of after-discharge potential (6/8 vs 2/12, P=0.019). The immunotherapy regimen (multi-dru, single-drug, no immunotherapy: 6, 2, 0 patients) in antibody-positive patients was different from the antibody-negative group (3, 6, 3 patients, U=21.00, P=0.023). Conclusions: The symptoms of motor nerve hyperexcitation, characteristic EMG spontaneous potentials and after-discharge potentials in PNHS patients are most commonly seen in the lower limbs. Attention should be paid to concomitant sensory and autonomic nerve hyperexcitation. PNHS patients with positive serum anti-CASPR2 antibodies may require immunotherapy with multiple drugs.目的： 探讨原发性周围神经过度兴奋综合征（PNHS）患者的临床和神经电生理特征。 方法： 回顾性纳入2016年4月至2023年1月就诊于首都医科大学附属北京天坛医院的原发性PNHS患者20例。记录患者的临床表现及神经电生理检测结果。依据血和脑脊液抗结旁区接触蛋白相关蛋白-2（CASPR2）和（或）抗富亮氨酸胶质瘤失活1蛋白（LGI1）抗体检测结果，比较抗体阳性组和抗体阴性组患者的临床和电生理特征。 结果： 患者男12例，女8例，年龄（44.0±17.2）岁，病程［M（Q1，Q3）］2.3（1.1，11.5）个月。运动症状包括肌束颤动、肌颤搐和肌肉酸痛，肌肉痉挛和僵硬；以下肢（17例）多见，其次是上肢（11例）、头面部（11例）和躯干（9例）。19例（19/20）患者存在感觉异常和（或）自主神经障碍。13例患者出现中枢神经系统症状。5例患者合并肺癌或胸腺病变。针极肌电图特征性异常自发电位包括肌颤搐电位（19例）、束颤电位（12例）、痉挛电位（3例）、神经性肌强直电位（1例）等，以下肢肌肉、特别是腓肠肌（12例）多见。8例患者存在后发放电位，7例出现胫神经后发放。7例患者血清抗CASPR2抗体阳性，其中3例同时存在抗LGI1抗体；1例患者单纯血清抗LGI1抗体阳性。与抗体阴性组相比（n=12），抗体阳性组（n=8）患者的病程更短［M（Q1，Q3），1.8（1，2）个月比9.5（3.3，20.3）个月，P=0.012］，胫神经后发放电位的出现率更高（6/8 比 2/12，P=0.019）。抗体阳性患者免疫治疗方案（多药、单药、未免疫治疗分别为6、2、0例）与抗体阴性组（3、6、3例）比较差异有统计学意义（U=21.00，P=0.023）。 结论： 原发性PNHS患者运动神经兴奋症状、针极肌电图自发放电和M波后发放电位均以下肢多见；临床应重视对感觉神经和自主神经过度兴奋的表现的识别。抗CASPR2抗体阳性的PNHS患者可能需要多种药物联合免疫治疗。.