[Analysis of oculomotor disorders in motor neuron disease]

Oculomotor disorders have been considered to be one of the negative symptoms in motor neuron disease (MND). However, recently, ophthalmoplegia, abnormal Bell's phenomenon and disturbance of pursuit movement have been reported. We tried to evaluate 32 patients with MND (19 males and 13 females; age, 35 to 77 years; 52.4 +/- 10.1 years) by bedside examination and electro-oculography (EOG) using an eye tracking method. Twenty-three of them were classified as amyotrophic lateral sclerosis (ALS) and seven as bulbospinal muscular atrophy, and two were unclassified. One hundred healthy persons for bedside examination and twenty-two for EOG were investigated as controls. Findings by bedside examinations were as follows; 1) Slight limitations of upward only, up & downward and upward & horizontal gaze were observed in 5 cases (15.6%), 1 case (3.1%) and 1 case (3.1%), respectively. 2) Incomplete convergence was observed in 11 cases. (34.4%) 3) Horizontal gaze nystagmus was observed in 6 cases. (18.8%) 4) As regards the frequency of limitation of upward gaze and incomplete convergence, there were no statistically significant differences from those in controls. Electrooculographic results were: 1) square wave jerks (SWJs) were recorded in 3 cases. (9.4%) 2) Amplitude ratio of saccade was significantly higher in MND than that in controls with the risk less than 0.1%. 3) The degree of ocular dysmetria was significantly higher in MND than that in controls with the risk less than 0.5%. These abnormalities were not directly related to suffering period. Although the mechanism is not known, several reports of the effectiveness of thyrotropin releasing hormone (TRH) in ALS were recently published.(ABSTRACT TRUNCATED AT 250 WORDS)