Baclofen for Patients with Congenital Periodic Alternating Nystagmus

Purpose: To describe the clinical effect of baclofen on a group of patients with congenital periodic alternating nystagmus. Methods: A retrospective review of case notes was carried out of all patients with congenital periodic alternating nystagmus (PAN) treated with baclofen between 1999 and 2004. Eight patients were identified, 6 males and 2 females with a mean age of 21 years (range 9 to 34 years). Clinical data were recorded for all patients pre- and post-treatment with the GABA agonist baclofen. Adverse effects of the treatment were recorded and a questionnaire was constructed to evaluate patient satisfaction with the treatment. Results: All 8 patients had an abnormal head posture (AHP) before treatment which improved following treatment in 4 patients, one of whom had recurrence following treatment withdrawal. Binocular Snellen visual acuity (VA) improved by one line in 4 cases, while none of the other 4 patients suffered any loss of vision from the treatment. Three of the eight patients have continued on treatment long-term, in one case for 6 years. In the other five, treatment was withdrawn due to side effects in 4 cases, and in the fifth due to a lack of effect. The most commonly reported side effect was drowsiness, which occurred in 3 patients. Using a patient-centered survey, complete responses were obtained from 6 of the 8 patients treated. Five patients were either pleased or very pleased that they had tried the treatment. The reasons given were: improved vision or head posture, an appreciation of slowing of ocular movements, improved cosmesis and improved confidence. Conclusions: Baclofen may be effective in a select group of patients with congenital PAN and a trial of treatment may be worthwhile, prior to considering surgical intervention in this condition.