(1) What are the sites of origin of epileptic nystagmus?
(2) How do you differentiate between epileptic nystagmus originating from saccadic areas and smooth pursuit areas?
(3) What are the features of epileptic nystagmus originating from a central optokinetic region?
(1) Three pathogenic types are recognized with three different regions. The cortical saccade region, cortical pursuit region and a central optokinetic region.
(2) Occuloclonia originating from saccadic areas results in contralesional ocular deviation with decreasing slow-phase velocity (SPV) and does not cross the midline. In contrast, Occuloclonia originating from smooth pursuit areas results in ipsilesional ocular deviation with linear SPV and a reflex quick phase crossing the midline towards contralesional side (Tusa et al., 1990).
(3) It is similar to seizures originating from a pursuit region with slow initial ipsiversive and a reflexive quick phase. It is usually accompanied by vertigo because of its connections with the vestibular nucleus.
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