Bilateral infarction of the anterior cingulate gyri and of the fornices. Report of a case.

A 70-year-old woman had complex behavioural changes of sudden onset. The symptoms consisted of indifference, docility and inappropriate urination, but predominantly in a lack of attention. She was unable to maintain the attention necessary to perform a goal-directed activity and she was distracted by any stimulus, such as a sound, an object, or a word, which might induce behaviour irrelevant to the preconceived activity. She also exhibited confabulatory-amnestic syndrome. Neuropathological examination of the brain revealed infarcts in th territories of both anterior cerebral arteries. The rostral part of the anterior cingulate gyrus (Acg), small areas of the adjacent medial prefrontal cortex, and the underlying white matter were destroyed bilaterally. Infarction involved the deep territory of the left anterior cerebral artery, with a bilateral lesion of the fornices. This cingulate damage was more restricted than the Acg lesions reported in some cases of akinetic-mutism, which extended more caudally, but was presumably larger than the lesions created in psychosurgery. The impairment of attention was analyzed according to the possible roles of the cingulate and of the fornix lesions as causing a dysfunction between the frontal lobes and the hippocampal formations.