Article

Binocular saccadic eye movements in multiple sclerosis

Department of Physiology, Faculty of Medicine, Erasmus University Rotterdam, The Netherlands.
Journal of the Neurological Sciences (Impact Factor: 2.47). 06/1997; 148(1):53-65. DOI: 10.1016/S0022-510X(96)05330-0
Source: PubMed

ABSTRACT

We attempted to increase the sensitivity for detection of abnormal binocular saccadic eye movements, particularly of the internuclear ophthalmoplegia (INO) type associated with multiple sclerosis (MS). Saccades of 10 and 20 degrees were binocularly recorded with scleral sensor coils in 10 normal control subjects and 26 patients with definite or probable MS, seven of whom had a clinically manifest INO in one or both directions. In the cases in which this was accompanied by a dissociated nystagmus of the abducting eye, our recordings showed that such secondary saccades were also expressed, in a strongly reduced form, by the adducting eye. The patients with manifest INO showed lower average peak velocities and peak accelerations, especially for adduction of the eye on the affected side, but the distribution of these parameters overlapped with the normal distribution. A much sharper distinction between normals and patients with INOs was found by considering the ratios between peak accelerations and velocities of saccade pairs (abducting eye/adducting eye). These ratios, which eliminate much intra- and inter-individual variability, had a narrow range in normals, and all values for INOs were outside this range. On this basis, the 19 patients without clinically manifest INO were easily separated into subgroups of 14 patients with completely normal interocular ratios and five patients with elevated peak velocity and acceleration ratios, identified as sub-clinical (uni- or bilateral) INOs. Measurements of vertical saccades and of interocular timing differences provided no useful criteria for disturbances of binocular coordination in MS. We conclude that in particular, the acceleration of the adducting eye is strongly reduced in patients with an INO, and that this reduction is best identified by interocular comparison between binocular pairs of saccades.

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    • "Flipse, Straathof, Van der Steen, Van Leeuwen, Van Doorn, Van der Meché, and Collewijn (Flipse et al., 1997 "
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    ABSTRACT: The occurrence of systematic interocular differences in the time of initiation of saccades in various directions was investigated in normal human subjects (n=4). Saccades were recorded binocularly with scleral sensor coils on each of the eyes with a temporal resolution of 0.1 ms (sampling frequency 10000 Hz). Analysis was done in the velocity domain after digital differentiation. It was found that, in the initial phase of horizontal saccades, the nasalward moving eye lagged the temporalward moving eye consistently by slightly less than 1 ms. No such difference was found in vertical (upward or downward) saccades. In oblique saccades, the systematic initial lag of the nasalward moving eye was similarly present in the horizontal component of the saccade, but absent in the vertical component. It is postulated that this interocular timing difference in horizontal saccades is due to the additional synaptic delay caused by the abducens internuclear neuron in the pathway to the medial rectus muscle of the eye.
    Full-text · Article · Feb 2001 · Vision Research
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    • "In the same way, the classi®cation of complete or uncomplete INO according to the complete or not paresis of the adducting eye, based on clinical evaluation, it is not useful in detecting early involvement of MLFs lesions. Flipse et al (1997) attempted to increase the sensitivity for detection of abnormal binocular saccadic eye movements calculating the ratios between peak acceleration and velocities of saccades pairs (abducting eye/adducting eye). A much sharper distinction between normal and patients with INOs was found by considering this ratio. "
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    ABSTRACT: One of the most frequent disorders of the brainstem in multiple sclerosis (MS) is internuclear opthalmoplegia (INO). The aim of this study is to show how it is possible to monitor the course of MS grading INO on the basis of electro-oculographic findings. We selected 130 patients with a diagnosis of clinically defined multiple sclerosis (78 males and 52 females, mean age 43.5 years) from a population of 354 MS patients. Both saccadic eye movements and spontaneous, vestibular (VOR), visuo-vestibular (VVOR) and optokinetich nystagmus (OKN) were assessed. Slowing of the adducting eye was considered as a sign of lesion of the interocular pathways. Statistical analyses showed that the most sensitive test was VVOR, the least sensitive being randomised saccades. An impairment of random saccades was always associated with abnormal results on all other tests. It seems thus possible to grade the involvement of the medial longitudinal fasciculi (MLF) in MS from an abnormality limited to the VVOR test up to an impairment of randomised saccadic movements. Grading brainstem involvement in MS is particularly important in therapeutic trials and during rehabilitation.
    Full-text · Article · Jun 2000 · Journal of NeuroVirology
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    • "In the same way, the classi®cation of complete or uncomplete INO according to the complete or not paresis of the adducting eye, based on clinical evaluation, it is not useful in detecting early involvement of MLFs lesions. Flipse et al (1997) attempted to increase the sensitivity for detection of abnormal binocular saccadic eye movements calculating the ratios between peak acceleration and velocities of saccades pairs (abducting eye/adducting eye). A much sharper distinction between normal and patients with INOs was found by considering this ratio. "
    [Show abstract] [Hide abstract]
    ABSTRACT: One of the most frequent disorders of the brainstem in multiple sclerosis (MS) is internuclear opthalmoplegia (INO). The aim of this study is to show how it is possible to monitor the course of MS grading INO on the basis of electro-oculographic findings. We selected 130 patients with a diagnosis of clinically defined multiple sclerosis (78 males and 52 females, mean age 43.5 years) from a population of 354 MS patients. Both saccadic eye movements and spontaneous, vestibular (VOR), visuo-vestibular (VVOR) and optokinetich nystagmus (OKN) were assessed. Slowing of the adducting eye was considered as a sign of lesion of the interocular pathways. Statistical analyses showed that the most sensitive test was VVOR, the least sensitive being randomised saccades. An impairment of random saccades was always associated with abnormal results on all other tests. It seems thus possible to grade the involvement of the medial longitudinal fasciculi (MLF) in MS from an abnormality limited to the VVOR test up to an impairment of randomised saccadic movements. Grading brainstem involvement in MS is particularly important in therapeutic trials and during rehabilitation.
    Full-text · Article · Jan 2000 · Journal of NeuroVirology
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