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Zhou H, Wei L, Jiang Y, Wang X, Sun Y, Li F, Chen J, Sun W, Zhang L, Zhao G, Wang Z. Abnormal Ocular Movement in the Early Stage of Multiple-System Atrophy With Predominant Parkinsonism Distinct From Parkinson's Disease. J Clin Neurol 2024; 20:37-45. [PMID: 38179630 PMCID: PMC10782091 DOI: 10.3988/jcn.2023.0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/02/2023] [Accepted: 05/01/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND AND PURPOSE The eye-movement examination can be applied as a noninvasive method to identify multiple-system atrophy (MSA). Few studies have investigated eye movements during the early stage of MSA with predominant parkinsonism (MSA-P). We aimed to determine the characteristic oculomotor changes in the early stage of MSA-P. METHODS We retrospectively selected 17 patients with MSA-P and 40 with Parkinson's disease (PD) with disease durations of less than 2 years, and 40 age-matched healthy controls (HCs). Oculomotor performance in the horizontal direction was measured in detail using videonystagmography. RESULTS We found that the proportions of patients with MSA-P and PD exhibiting abnormal eye movements were 82.4% and 77.5%, respectively, which were significantly higher than that in the HCs (47.5%, p<0.05). Compared with HCs, patients with MSA-P presented significantly higher abnormal proportions of fixation and gaze-holding (17.6% vs. 0%), without-fixation (47.1% vs. 0%), prolonged latency in reflexive saccades (29.4% vs. 5.0%), memory-guided saccades (93.3% vs. 10.0%), and catch-up saccades in smooth-pursuit movement (SPM, 41.2% vs. 0) (all p<0.05). Compared with those with PD, patients with MSA-P presented a significantly higher proportion of catch-up saccades in SPM (41.2% vs. 2.5%, p<0.001). CONCLUSIONS MSA-P presented the characteristic of catch-up saccades in SPM in the early stage, which may provide some value in differentiating MSA-P from PD.
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Affiliation(s)
- Hong Zhou
- Department of Neurology, Peking University First Hospital, Beijing, China
- Department of Neurology, Civil Aviation General Hospital, Beijing, China
| | - Luhua Wei
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Yanyan Jiang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Xia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Yunchuang Sun
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Fan Li
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Jing Chen
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Wei Sun
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Lin Zhang
- Department of Neurology, UC Davis Medical Center, Sacramento, CA, USA
| | - Guiping Zhao
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China.
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China.
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Abstract
Smooth pursuit is punctuated by catch-up saccades, which are thought to automatically correct sensory errors in retinal position and velocity. Recent studies have shown that the timing of catch-up saccades is susceptible to cognitive modulation, as is the timing of fixational microsaccades. Are the timing of catchup and microsaccades thus modulated by the same mechanism? Here, we test directly whether pursuit catch-up saccades and fixational microsaccades exhibit the same temporal pattern of task-related bursts and subsidence. Observers pursued a linear array of 15 alphanumeric characters that translated across the screen and simultaneously performed a character identification task on it. At a fixed time, a cue briefly surrounded the central element to specify it as the pursuit target. After a random delay, a probe (E or 3) appeared briefly at a randomly selected character location, and observers identified it. For comparison, a fixation condition was also tested with trial parameters identical to the pursuit condition, except that the array remained stationary. We found that during both pursuit and fixation tasks, saccades paused after the cue and then rebounded as expected but also subsided in anticipation of the task. The time courses of the reactive pause, rebound, and anticipatory subsidence were similar, and idiosyncratic subject behavior was consistent across pursuit and fixation. The results provide evidence for a common mechanism of saccade control during pursuit and fixation, which is predictive as well as reactive and has an identifiable temporal signature in individual observers.NEW & NOTEWORTHY During natural scene viewing, voluntary saccades reorient the fovea to different locations for high-acuity viewing. Less is known about small "microsaccades" that also occur when fixating stationary objects and "catch-up saccades" that occur during smooth pursuit of moving objects. We provide evidence that microsaccade and catch-up saccade frequencies are generally modulated by the same mechanism. Furthermore, on a finer time scale the mechanism operates differently in different observers, suggesting that neural saccade generators are individually unique.
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Affiliation(s)
- Jeremy B Badler
- Smith-Kettlewell Eye Research Institute, San Francisco, California
| | - Scott N J Watamaniuk
- Smith-Kettlewell Eye Research Institute, San Francisco, California.,Wright State University, Dayton, Ohio
| | - Stephen J Heinen
- Smith-Kettlewell Eye Research Institute, San Francisco, California
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Van Nechel C, Bostan A, Duquesne U, Hautefort C, Toupet M. Visual Input Is the Main Trigger and Parametric Determinant for Catch-Up Saccades During Video Head Impulse Test in Bilateral Vestibular Loss. Front Neurol 2019; 9:1138. [PMID: 30662427 PMCID: PMC6328459 DOI: 10.3389/fneur.2018.01138] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/10/2018] [Indexed: 11/13/2022] Open
Abstract
Patients with vestibular deficit use slow eye movements or catch-up saccades (CUS) to compensate for impaired vestibulo-ocular reflex (VOR). The purpose of CUS is to bring the eyes back to the visual target. Covert CUS occur during high-velocity head rotation and overt CUS are generated after head rotation has stopped. Dynamic visual acuity is improved with an increased rate and gain of CUS. Nevertheless, the trigger and the parametric determinants of CUS are still under debate. To clarify the underlying mechanism, especially the visual contribution, we analyzed the number, amplitude and latencies of the CUS in relation with the extent of VOR deficiency. The head and eye movements were recorded in 17 patients with bilateral vestibular loss (BVL) and in 33 subjects with normal VOR gain using the Video Head Impulse Test (vHIT) in two conditions: with visible target and in darkness with an imaginary target. Our study shows that in darkness without visible target the number of CUS is significantly reduced and the relationship between the amplitude of CUS and gaze position error is lost. Results showed that there is a correlation between the number of CUS and the drop in VOR gain. CUS occurring during the head movement and when the head remained still were not always sufficiently accurate. Up to four consecutive CUS could be required to bring eyes back to the visible target. A positive correlation was found between the amplitude of overt saccades with visible target and the gaze position error, namely the remaining eye movement to reach the target. These results suggest that the visual inputs are the main trigger and parametric determinant of the CUS or at least the presence of a visual target is necessary in most cases for a CUS to occur.
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Affiliation(s)
- Christian Van Nechel
- Unité Troubles de l'Equilibre et Vertiges, Centre Hospitalier Universitaire Brugmann, Brussels, Belgium.,Unité de Neuro-Ophtalmologie, Hôpital Erasme, Brussels, Belgium.,Institut de Recherche Oto-Neurologique (IRON), Paris, France.,Clinique des Vertiges, Brussels, Belgium
| | - Alionka Bostan
- Unité Troubles de l'Equilibre et Vertiges, Centre Hospitalier Universitaire Brugmann, Brussels, Belgium.,Unité de Neuro-Ophtalmologie, Hôpital Erasme, Brussels, Belgium
| | - Ulla Duquesne
- Institut de Recherche Oto-Neurologique (IRON), Paris, France.,Clinique des Vertiges, Brussels, Belgium
| | - Charlotte Hautefort
- Institut de Recherche Oto-Neurologique (IRON), Paris, France.,Service ORL, APHP CHU Lariboisière, Paris, France
| | - Michel Toupet
- Institut de Recherche Oto-Neurologique (IRON), Paris, France.,Centre d'Explorations Fonctionnelles Otoneurologiques, Paris, France
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Heinen SJ, Potapchuk E, Watamaniuk SNJ. A foveal target increases catch-up saccade frequency during smooth pursuit. J Neurophysiol 2015; 115:1220-7. [PMID: 26631148 DOI: 10.1152/jn.00774.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/02/2015] [Indexed: 11/22/2022] Open
Abstract
Images that move rapidly across the retina of the human eye blur because the retina has sluggish temporal dynamics. Voluntary smooth pursuit eye movements are modeled as matching object velocity to minimize retinal motion and prevent retinal blurring. However, "catch-up" saccades that are ubiquitous during pursuit interrupt it and disrupt clear vision. But catch-up saccades may not be a common feature of ocular pursuit, because their existence has been documented with a small moving spot, the classic pursuit stimulus, which is a weak motion stimulus that may poorly emulate larger pursuit objects. We found that spot pursuit does not generalize to that of larger objects. Observers pursued a spot or a larger virtual object with or without a superimposed spot target. Single-spot targets produced lower pursuit acceleration than larger objects. Critically, more saccadic intrusions occurred when stimuli had a central dot, even when position and velocity errors were equated, suggesting that catch-up saccades result from pursuing a single, small object or a feature on a large one. To determine what differentiates a large object from a small one, we progressively shrank the featureless virtual object and found that catch-up saccade frequency was highest when it fit in the fovea. The results suggest that pursuit of a small target or an object feature recruits a saccade mechanism that does not compensate for a weak motion signal; rather, the target compels foveation. Furthermore, catch-up saccades are likely generated by neural circuitry typically used to foveate small objects or features.
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Affiliation(s)
- Stephen J Heinen
- Smith-Kettlewell Eye Research Institute, San Francisco, California; and
| | - Elena Potapchuk
- Smith-Kettlewell Eye Research Institute, San Francisco, California; and
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