[Insomnia and hallucinations caused by vascular lesions of the pontine]

Small ischemic vascular lesions or hemorrhages provide a pathological model useful for the study of sleep disturbances in human due to lesions in the pontine tegmentum. We present 7 patients, 4 men and 3 women, with severe insomnia and hallucinations due to small vascular lesions of the pontine tegmentum. Nocturnal-sleep and/or 24-h polygraphic studies were done on all patients, as were neurophysiological and image studies; pathological studies were performed in one patient. Insomnia affected both non-REM and REM sleep, appeared in the acute phase and tended to improve with time. The patients tolerated insomnia with no serious effects on general health. Insomnia was not affected by administration of L-tryptophan with or without carbidopa. Hallucinations were mainly visual, but were also auditory in 2 cases; they were unrelated to the occurrence of normal or dissociated REM sleep. Imaging studies, and autopsy in 1 case, revealed damage to the pontis centralis caudalis and pontis centralis oralis nuclei, which appeared to be responsible for insomnia. The relationship between visual and/or auditory hallucinations and sleep disturbances remain speculative.