Memantine Improves Fixation Stability in Recessive Cerebellar Ataxia with Saccadic Intrusions (P02.262)

Abstract

Objective: To measure instability of gaze due to saccadic intrusions (SI) in two sisters with autosomal recessive spinocerebellar ataxia and evaluate the effects of memantine on gaze stability. Background Fixation instability due to SI is a possible feature of autosomal recessive spinocerebellar ataxias. Affected patients often complain of difficulties with vision, especially during reading. Design/Methods: Two sisters, ages 58 and 70 with adult-onset spinocerebellar ataxia, SI and peripheral neuropathy were examined. Horizontal visually-guided saccades at 10°-18° and three minutes of steady fixation were tested in each patient. Thirty healthy controls were similarly tested. Eye movements were recorded before and after treatment with memantine 10 mg/daily for 6 months (open-trial design). We analyzed size, frequency, amplitude, duration and peak velocity of SI during attempted steady fixation. Standard saccadic parameters were also carried out. Results: Patients saccades showed significant reduction of peak velocity, increase of duration and smaller amplitude (mainly hypometria) compared with control subjects. Both patients showed large square-wave SI interrupting steady fixation; amplitude ranged from 1° to 6° (mean 3,2° in the younger and 4,2° in the older sister respectively); intersaccadic intervals were 100-400 ms; frequency was 70/min and 110/min respectively. After treatment, frequency of SI was reduced to about 40/min and 75/min and amplitude significantly decreased to 2,9° and 3,5°, respectively. Peak velocity and mean velocity of SI showed the same trend with more marked reduction after six months of therapy. Saccade parameters did not change after treatment. Conclusions: Our data support a previous observation in recessive spinocerebellar ataxias on the effectiveness of memantine in ameliorating fixation abnormalities by reducing the frequency of SI. There is need for a controlled trial of memantine to evaluate its effect on saccadic intrusions in other recessive forms of ataxia, including Friedreich9s ataxia in which case SI are prominent. Disclosure: Dr. Rosini has nothing to disclose. Dr. Federighi has nothing to disclose. Dr. Serra has nothing to disclose. Dr. Leigh has nothing to disclose. Dr. Piu has nothing to disclose. Dr. Federico has nothing to disclose. Dr. Rufa has nothing to disclose.