Spiegel Rainer, Rettinger Nicole, Kalla Roger, Lehnen Nadine, Straumann Dominik, Brandt Thomas, Glasauer Stefan, Strupp Michael
Department of Neurology, University of Munich, Munich, Germany.
Ann N Y Acad Sci. 2009 May;1164:293-9. doi: 10.1111/j.1749-6632.2009.03865.x.
On the basis of reports by patients with downbeat nystagmus (DBN) that their symptoms were worse during the morning but better during the daytime, we investigated whether the intensity of DBN changes during the daytime. DBN was measured at 9 am, 11 am, and 1 pm. The mean peak slow phase velocity (MPSPV) of DBN was determined in different eye positions, with and without fixation, as well as in three different body positions: sitting upright, lying supine with the nose up, and lying prone with the nose down. Twelve patients with DBN either due to cerebellar degeneration or of idiopathic etiology were examined. The major findings of this study were as follows. First, the intensity of DBN significantly decreased during the daytime. When measured in the sitting upright position and primary eye position, MPSPV decreased from 4.32 deg/sec (+/-SEM 1.02) at 9 am to 2.12 deg/sec (+/- 0.5) at 11 am (P < 0.01) and stayed constant around 1.93 deg/sec (+/- 0.57) at 1 pm (P < 0.01 from 9 am to 1 pm) and 2.08 deg/sec (+/- 0.75) at 3 pm (P < 0.01 from 9 am to 3 pm). Second, this change did not depend on fixation during the measurements. Third, this effect was not influenced by the eye position during the measurements (upward, downward, or straight ahead). Our data show that the intensity of DBN decreases during the daytime. This decrease correlates with the symptoms of the patients. This change during daytime did not depend on visual fixation. Another possible mechanism is the modulation of DBN by head position relative to gravity, that is, by otolith input. This should be evaluated in further studies.
基于下跳性眼球震颤（DBN）患者报告称其症状在早晨更严重而在白天有所缓解，我们研究了DBN的强度在白天是否会发生变化。分别于上午9点、11点和下午1点测量DBN。在不同眼位（有注视和无注视）以及三种不同体位（直立坐姿、头朝上仰卧位、头朝下俯卧位）下测定DBN的平均峰值慢相速度（MPSPV）。对12例因小脑变性或特发性病因导致DBN的患者进行了检查。本研究的主要发现如下。首先，DBN的强度在白天显著降低。在直立坐姿和第一眼位测量时，MPSPV从上午9点的4.32度/秒（±标准误1.02）降至上午11点的2.12度/秒（±0.5）（P<0.01），并在下午1点保持在1.93度/秒（±0.57）左右（与上午9点相比P<0.01），下午3点为2.08度/秒（±0.75）（与上午9点相比P<0.01）。其次，这种变化在测量过程中不依赖于注视。第三，这种效应不受测量时眼位（向上、向下或向前直视）的影响。我们的数据表明，DBN的强度在白天会降低。这种降低与患者的症状相关。白天的这种变化不依赖于视觉注视。另一种可能的机制是头部相对于重力的位置对DBN的调节作用，即通过耳石输入。这一点应在进一步研究中进行评估。
