Electrooculographic analysis in myasthenia gravis

ABSTRACT

Myasthenia gravis is an autoimmune disease affecting the neuro-muscular junction of skeletal muscles that is characterized by fatigable muscle weakness. It commonly affects the extraocular muscles. The aim of the present study was to use a non-invasive and a quantitative tool [electronystagmography] to evaluate the different eye movement abnormalities in myasthenia gravis and the efficacy of treatment in such patients. This study was conducted on 15 patients of both genders. Oculography tests were performed to all patients deprived from medication for 12 hours, and after medical treatment by 2-3 hours. Statistical analysis was done using Excel version release 2000. None of the patients showed spontaneous nystagmus whether in eyes open or closed situations. Two of the patients showed eccentric gaze nystagmus that was direction fixed. Although the mean values of saccadic acceleration, latency and peak velocity were close to the normative values, they showed statistically significant improvement after medical treatment. The smooth pursuit and accordingly the optokinetic tests showed gain abnormalities that statistically significantly improved after therapy. This study suggests that quantitative recording of eye movements have as good or better discriminative ability and could make a significant contribution to diagnosis and efficacy of drug therapy in myasthenia gravis