Abstract
Repetitive supramaximal stimulation (RSS) testings of the ulnar or median nerve were performed on 35 children with ocular myasthenia. Serum titers of antiacetylcholine receptor antibody were also determined.
Sixteen patients (46%) had the abnormal decremental response to RSS even in clinically uninvolved muscles. However, none of these 16 patients developed generalized myasthenia. The duration of the drug therapy in these patients was 4.7±3.5 years (mean±SD), while that in patients with the normal response to RSS was 2.6±2.5 years. Fourteen (88%) of 16 patients who had the abnormal response received steroid therapy, while 13 (68%) of 19 patients with the normal response were treated with the steroid hormone. No difference was seen in the remission rate between patients with the abnormal response (75%) and those with the normal response (79%). However, patients with the abnormal response tended to have a higher recurrence rate of myasthenic signs, a longer duration of therapy, and slightly higher serum titers of antiacetylcholine receptor antibody.
Our results suggested that in juvenile ocular myasthenia the positive abnormal decremental response to RSS in clinically uninvolved muscles correlated with the clinical response to the drug therapy as well as higher titers of serum antiacetylcholine receptor antibody.
