Department of Otorhinolaryngology-Head and Neck Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
Department of Otorhinolaryngology-Head and Neck Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
J Clin Neurosci. 2022 Jan;95:118-122. doi: 10.1016/j.jocn.2021.12.002. Epub 2021 Dec 9.
The most common symptoms of tumours involving the cerebellopontine angle (CPA) are unilateral sensorineural hearing loss, dizziness, and asymmetric tinnitus. While the clinical manifestations have been well documented in previous studies, the nystagmus findings in these patients have not been thoroughly investigated yet. This study aimed to investigate the incidence of direction-changing spontaneous nystagmus in patients with CPA tumours, evaluate their radiologic characteristics, and gain insight into the mechanisms underlying nystagmus. Direction-changing spontaneous nystagmus was observed in 6 out of 83 patients (7%) with CPA tumours during the 7-year period. Temporal bone magnetic resonance imaging findings revealed the presence of an intrameatal mass in CPA tumours in all six patients with direction-changing spontaneous nystagmus. Vestibular schwannomas were confined within the internal auditory meatus in four patients, and petroclival meningiomas extended into the internal auditory meatus in two patients. The mechanism of direction-changing spontaneous nystagmus may be explained as paroxysmal secondary central hyperactivity in the vestibular nucleus due to the long-standing pressure effect in the vestibular nerve by tumours, or by ephaptic discharges in the vestibular nerve.
桥小脑角（CPA）肿瘤最常见的症状是单侧感觉神经性听力损失、头晕和不对称性耳鸣。虽然这些临床表现在前瞻性研究中已有详细记载，但这些患者的眼震表现尚未得到彻底研究。本研究旨在调查 CPA 肿瘤患者出现变向自发性眼震的发生率，评估其影像学特征，并深入了解眼震的发生机制。在 7 年期间，83 例 CPA 肿瘤患者中有 6 例（7%）出现变向自发性眼震。颞骨磁共振成像结果显示，6 例出现变向自发性眼震的患者中均存在 CPA 肿瘤内鼓室段肿块。4 例前庭神经鞘瘤局限于内听道，2 例岩斜脑膜瘤延伸至内听道。变向自发性眼震的发生机制可能是由于肿瘤对前庭神经的长期压迫作用导致前庭核阵发性继发性中枢活性亢进，或者是由于前庭神经的电突触放电。
