Bilateral paramedian thalamic artery infarcts: report of eight cases.

Eight consecutive patients with CT scan evidence of a bilateral infarct in the territory of the paramedian thalamic artery are reported. In seven cases the infarct also extended to the territory of the polar artery. The main symptoms were: disorder of vigilance which cleared in a few days, and hypersomnolence which lasted longer and in two patients was still present a year later; amnesia, detectable clinically in four patients and only with tests in two patients, which persisted in one patient for three years; changes of mood and bulimia present in five and four patients respectively; and vertical gaze paresis in five patients. Only one patient died, and in the remainder the symptoms tended to subside, but none of the patients who could be followed-up for a year returned to normal behaviour. Clinical and CT scan correlations pointed to the mammillo-thalamic tract as the structure whose damage was responsible for the memory disorders.