Department of Neurology, Eginition Hospital, University of Athens, Athens, Greece.
Muscle Nerve. 2021 May;63(5):765-769. doi: 10.1002/mus.27204. Epub 2021 Feb 26.
Spinal muscular atrophy (SMA) most prominently affects proximal limb and bulbar muscles. Despite older case descriptions, ocular motor neuron palsies or other oculomotor abnormalities are not considered part of the phenotype.
We investigated oculomotor function by testing saccadic eye movements of 15 patients with SMA. Their performance was compared with that of age-matched healthy controls. Horizontal rightward and leftward saccades were recorded by means of video-oculography, whereas subjects looked at light-emitting diode targets placed at ±5°, ±10°, and ±15° eccentricities.
No differences in saccade amplitude gains, peak velocities, peak velocity-to-amplitude ratios, or durations were observed between controls and patients. More specifically, for 5° target eccentricities, patients had a mean saccadic peak velocity of 153°/s, whereas for 10° and 15° these values were 268°/s and 298°/s, respectively. The corresponding mean peak velocities of the control group were 151°/s, 264°/s, and 291°/s.
Our results indicate that patients with SMA perform fast and accurate horizontal saccades without evidence of extraocular muscle weakness. These quantitative oculomotor data corroborate clinical experience that neuro-ophthalmic symptoms in SMA are not common and, if present, should prompt suspicion for an alternative neuromuscular disorder.
脊髓性肌萎缩症（SMA）主要影响近端肢体和延髓肌肉。尽管有较早的病例描述，但眼运动神经元麻痹或其他眼球运动异常并不被认为是表型的一部分。
我们通过测试 15 名 SMA 患者的眼球运动来研究眼球运动功能。他们的表现与年龄匹配的健康对照组进行了比较。通过视频眼动描记术记录了水平向右和向左的眼球扫视，而受试者则注视着放置在±5°、±10°和±15°偏心率处的发光二极管目标。
在扫视幅度增益、峰值速度、峰值速度与幅度比或持续时间方面，对照组和患者之间没有差异。更具体地说，对于 5°目标偏心率，患者的平均扫视峰值速度为 153°/s，而对于 10°和 15°，这些值分别为 268°/s 和 298°/s。对照组的相应平均峰值速度为 151°/s、264°/s 和 291°/s。
我们的结果表明，SMA 患者能够进行快速准确的水平扫视，没有眼外肌无力的证据。这些定量眼动数据证实了临床经验，即 SMA 中的神经眼科症状并不常见，如果存在，应提示怀疑其他神经肌肉疾病。
