Binocular saccadic eye movements in multiple sclerosis.
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.
- Journal of Urology - J UROL. 01/2011; 185(4).
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ABSTRACT: Internuclear ophthalmoparesis (INO) is the most common saccadic eye movement disorder observed in patients with multiple sclerosis (MS). It is characterized by slowing of the adducting eye during horizontal saccades, and most commonly results from a demyelinating lesion in the medial longitudinal fasciculus (MLF) within the midline tegmentum of the pons (ventral to the fourth ventricle) or midbrain (ventral to the cerebral aqueduct). Recent research has demonstrated that adduction velocity in MS-related INO, as measured by infrared eye movement recording techniques, is further reduced by a systematic increase in core body temperature (utilizing tube-lined water infusion suits in conjunction with an ingestible temperature probe and transabdominal telemetry) and reversed to baseline with active cooling. These results suggest that INO may represent a model syndrome by which we can carefully study the Uhthoff's phenomenon and objectively test therapeutic agents for its prevention.Annals of the New York Academy of Sciences 09/2011; 1233:313-9. · 4.38 Impact Factor
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ABSTRACT: Multiple sclerosis (MS) patients frequently develop some form of ocular motor dysfunction during the disease. In previous studies, ocular motor abnormalities were found to correlate with clinical disability and with impaired cognitive performance. The objective of this study was to assess the pursuit ocular movement (POM) frequency in relapsing-remitting (RR) and secondary progressive (SP) MS patients by using a vision-based non-intrusive eye tracker. POM frequency was significantly lower (p < 0.001) in MS patients compared to normal controls. No differences between RR and SP-MS patients and no correlation between POM and expanded disability status scale (EDSS) score were found. This exploratory study suggests that our vision-based system is a new simple non-intrusive method showing impairment of POM values in MS patients, even in the absence of association with clinical disability (EDSS). Future works on larger cohorts of MS patients might validate this eye tracking in MS clinical practice.Neurological Sciences 02/2011; 32(1):67-71. · 1.41 Impact Factor