[Fischer's "one and a half" syndrome: associated paralysis of horizontal eye movements and anterior internuclear ophthalmoplegia: report of 5 cases (author's transl)].

Five cases of Fischer's "one and a half" syndrome are reported. A complex central ophthalmoplegia provokes paralysis of horizontal eye movements on the affected side in both eyes and an internuclear ophthalmoplegia on the same side. No horizontal movement, except in convergence, is possible in the eye on the affected side, the other eye exhibiting movement between the median line and abduction only. Three patients with this syndrome were examined by oculography. The outcome was fatal in one case, pathological examination demonstrating widespread damage to half the pontine protuberance. In another case scanner imaging showed a paramedian protuberential lesion. The syndrome is most frequently observed in multiple sclerosis and cerebrovascular accidents but may follow any lesion in this region. Physiopathological features of the disorder are discussed.