MSA ENT Academy Center, Cassino, Italy.
Eur Arch Otorhinolaryngol. 2012 Nov;269(11):2441-5. doi: 10.1007/s00405-012-2127-z. Epub 2012 Aug 7.
The presence of spontaneous nystagmus in darkness with a strong horizontal component has been taken to indicate that there is asymmetrical function of the horizontal semicircular canals. If this horizontal spontaneous nystagmus can be suppressed by vision, then it is regarded as due to peripheral horizontal canal dysfunction. However, we report evidence from one patient (61-year-old male), who visited the MSA ENT Clinic, Cassino (FR) Italy, reporting acute, severe vertigo, postural unsteadiness, nausea and vomiting associated with right sudden hearing loss. The patient received instrumental audiovestibular testing to obtain objective measurements of his inner-ear receptors. At the time of the attack, the patient showed spontaneous nystagmus, mainly with horizontal and vertical components (3D infrared video-oculography). Video head-impulse tests of dynamic horizontal canal function showed that the functional status of both horizontal canals was within the normal range. Cervical VEMPs to 500 Hz bone-conducted vibration at Fz showed normal results; ocular VEMPs to the same stimulus showed a reduced n10 amplitude beneath the left eye, corresponding to the right ear. For this reason, the patient was diagnosed as having right unilateral selective utricular macula lesion due to labyrinthitis. There is considerable evidence of convergence of neural input from the otoliths onto horizontal canal neurons in the vestibular nuclei. The firing of such neurons could reflect either asymmetrical horizontal canal function or asymmetrical utricular function. The problem with this patient was not due to asymmetrical horizontal canal function, but only to asymmetrical utricular function, demonstrated by the results of the oVEMP test.
在黑暗中出现强烈水平成分的自发性眼球震颤，提示水平半规管功能不对称。如果这种水平自发性眼球震颤可以被视觉抑制，则认为是由于外周水平半规管功能障碍引起的。然而，我们报告了一例患者（61 岁男性）的证据，他因急性、严重眩晕、姿势不稳、恶心和呕吐伴右侧突发性听力损失就诊于意大利卡塞诺的 MSA ENT 诊所。患者接受了仪器听觉前庭测试，以获得内耳感受器的客观测量。在发作时，患者表现出主要为水平和垂直成分的自发性眼球震颤（3D 红外视频眼动图）。动态水平半规管功能的视频头脉冲测试显示，两个水平半规管的功能状态均在正常范围内。在 Fz 处用 500 Hz 骨传导振动进行颈性 VEMP 测试显示正常结果；对同一刺激的眼性 VEMP 显示左眼（对应右耳）的 n10 振幅降低。因此，患者被诊断为右单侧选择性耳石器斑病变，原因是迷路炎。有相当多的证据表明，来自耳石器的神经输入在前庭核中的水平半规管神经元中会聚。这些神经元的放电可能反映出水平半规管功能不对称或耳石器功能不对称。该患者的问题不是由于水平半规管功能不对称，而是仅由于耳石器功能不对称，oVEMP 测试的结果证实了这一点。
