The long-term objectives of the proposed research are: (1) to learn more about human ocular motor disorders that impair the vision necessary for everyday activities, and (2) to appraise therapeutic measures to restore clear vision. The research strategies are to relate reliable measurements of eye movements to visual complaints of patients doing natural behaviors; and to use measurements of normal and abnormal eye movements to test mathematical models that are biologically plausible; and evaluate new treatments of disorders of ocular motility using controlled trials. There are five specific aims, which grow out of prior studies: The first project comprises tests of models for acquired pendular nystagmus. Determination of the effects of large gaze shifts and luminance changes will be used to test control systems and neural network models. The second project aims to determine whether eye movements prior to head rotation improve the gain of the vestibulo-ocular reflex, during sudden head turns. This """"""""priming"""""""" effect may occur with a variety of prior eye movements but not in patients with a deficient gaze-holding mechanism (neural integrator). The third project aims to test whether Hering's law applies to saccadic pulses (i.e., equal pulse size) during disjunctive gaze shifts. Normal subjects and patients with internuclear ophthalmoplegia will be studied. The fourth project comprises tests of models that account for saccadic oscillations. Using a new experimental technique to induce saccadic oscillations in normal subjects and patients, the effects of cerebellar and brainstem lesions will be systematically investigated. The fifth project is a controlled evaluation of scopolamine and gabapentin as treatment for acquired forms of nystagmus. It has been shown that gabapentin suppresses pendular nystagmus, but side-effects such as ataxia limit the dosage tolerated. Scopolamine may prove more effective in patients with oculopalatel tremor. In sum, these projects will prove new information on the pathogenesis and treatment of a range of common disorders of eye movements that disrupt clear vision.
| Shaikh, Aasef G; Ghasia, Fatema F (2017) Novel Eye Movement Disorders in Whipple's Disease-Staircase Horizontal Saccades, Gaze-Evoked Nystagmus, and Esotropia. Front Neurol 8:321 |
| Shaikh, Aasef G; Ghasia, Fatema F (2017) Fixational saccades are more disconjugate in adults than in children. PLoS One 12:e0175295 |
| Ghasia, Fatema F; Wilmot, George; Ahmed, Anwar et al. (2016) Strabismus and Micro-Opsoclonus in Machado-Joseph Disease. Cerebellum 15:491-7 |
| Shaikh, Aasef G (2016) Abnormal head oscillations in neuro-ophthalmology and neuro-otology. Curr Opin Neurol 29:94-103 |
| Shaikh, Aasef G; Otero-Millan, Jorge; Kumar, Priyanka et al. (2016) Abnormal Fixational Eye Movements in Amblyopia. PLoS One 11:e0149953 |
| Shaikh, Aasef G; Ghasia, Fatema F; DeLong, Mahlon R et al. (2015) Ocular palatal tremor plus dystonia - new syndromic association. Mov Disord Clin Pract 2:267-270 |
| Shaikh, Aasef G; Ghasia, Fatema F (2015) Neuro-ophthalmology of type 1 Chiari malformation. Expert Rev Ophthalmol 10:351-357 |
| Ghasia, Fatema F; Shaikh, Aasef G; Jacobs, Jonathan et al. (2015) Cross-coupled eye movement supports neural origin of pattern strabismus. Invest Ophthalmol Vis Sci 56:2855-66 |
| McCamy, Michael B; Otero-Millan, Jorge; Leigh, R John et al. (2015) Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique. PLoS One 10:e0128428 |
| Shaikh, Aasef G; Ghasia, Fatema F (2014) Gaze holding after anterior-inferior temporal lobectomy. Neurol Sci 35:1749-56 |
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