Abstract
A 35-year-old female with symptoms of dysequilibrium was found to have bilateral medial longitudinal fasciculus (MLF) syndrome on the basis of neurotological tests and MRI findings. This patient began to note some dysequilibrium on standing or walking. Three days later, double vision on gazing towards the left side developed. Neurotological findings at the first examination demonstrated that the velocity of adducting saccades in right eye movement was markedly less than normal while the left eye was normal. A reduction in the velocity of adducting saccades in the left eye was observed two weeks later. Follow-up observation suggested that the main lesion of MLF was on the right side, with partial involvement of the left. At the same time no double vision on gazing towards the right was noted. However, electronystagmography revealed that the left MLF signs had become more pronounced than at the first examination. Subjective symptoms gradually disappeared. MRI with T2-weighted images revealed high signal intensity in the area of the right MLF at the level of the mid-pons, but CSF, serological viral examinations and CT were normal. These findings suggested an infarction of the mid-pons. Optokinetic nystagmus pattern (OKP) test and saccadic eye movement test (alternate two point gazing) were useful in monitoring the progress of MLF signs and evaluating the effectiveness of treatment.
