TABLE 1.
Previous studies of extraocular movements in ALS patients.
| Study and year of publication | Type of study | Number of ALS/control patients | Disease duration (months) | ALSFRS score | Alterations in ocular movements in ALS |
| Leveille et al., 1982 | – | 10/– | – | – | ↓Saccadic pursuit, unidirectional saccadic pursuit, ↓saccadic velocities |
| Saito and Yamamoto, 1989 | Observational | 23/100 | – | – | Slight limitations of upward only, upward and downward and upward and horizontal gaze, incomplete convergence, horizontal gaze nystagmus. ↑Amplitude ratio of saccade and ↑degree of ocular dysmetria |
| Marti-Fàbregas and Roig, 1993 | Cross-sectional | 13/16 | 29.09 | – | ↑Saccadic latencies and ↓smooth pursuit gain. Positive relationship between smooth pursuit saccadic intrusions and the bulbar clinical score and the rate of progression and a ↓optokinetic nystagmus maximal velocity in patients with pseudobulbar syndrome |
| Shaunak et al., 1995 | Cross-sectional | 17/11 | 24.5 (6–60) | – | ↑Error rates (distractibility) and latency in the anti-saccade and remembered saccade paradigms. ↑Square−wave jerks. Gaze fixation instability |
| Donaghy et al., 2010 | Cross-sectional | 30 spinal and 14 bulbar/45 | 52 | 35 (18–47) | ↓Reflexive saccades in bulbar-onset vs. to spinal-onset patients and controls. ↑Anti-saccade latency and ↑anti-saccade type 1 errors. ↓“Proportion of time spent in smooth pursuit” and ↓smooth pursuit “velocity gain” |
| Moss et al., 2012 | Cross-sectional | 63/37 | 43.2 ± 37.25 (7.2–204) | 16 (6–46) | Gaze impersistence, voluntary upgaze restriction, eyelid opening apraxia, saccadic horizontal pursuits |
| Ohki et al., 1994 | Observational | 9/– | 13 (3–49) | Early stages | ↓Velocity of saccades. Abnormalities of smooth pursuit, optokinetic nystagmus, and visual poor suppression of vestibular ocular reflect |
| Proudfoot et al., 2016 | Cross-sectional/longitudinal | 61/39 | 38.6 (31) | 33.5 (6.5) | ↓Executive and visual search tasks; normal basic saccadic function. ↓Anti-saccade performance, ↑error rate and latency |
| Kang et al., 2018 | Retrospective/observational | 22 spinal cord/10 bulbar | Spinal 55.1 ± 9.5, bulbar 62.2 ± 11.1 | – | Square wave jerks, saccadic dysmetria, abnormal cogwheeling smooth pursuits, head shaking, and positional nystagmus of central origin. ↑ Abnormal smooth pursuits and saccadic dysmetria |
ALS, amyotrophic lateral sclerosis; ALSFRS, Amyotrophic Lateral Sclerosis Functional Rating Scale.