['Tonic spasms have been most commonly associated with multiple sclerosis. To date, few reports of series of patients with neuromyelitis optica and tonic spasms have been published.', 'We analyzed the characteristics and frequency of tonic spasms in 19 subjects with neuromyelitis optica. Data was collected using a semi-structured questionnaire for tonic spasms, by both retrospectively reviewing medical records and performing clinical assessment.', 'All patients except one developed this symptom. The main triggering factors were sudden movements and emotional factors. Spasms were commonly associated to sensory disturbances and worsened during the acute phases of the disease. Carbamazepine was most commonly used to treat the symptom and patients showed good response to the drug.'] Are tonic spasms a common clinical manifestation in patients with neuromyelitis optica?