Neuropsychiatric studies in a family with presenile dementia different from Alzheimer and Pick disease.

We have studied a family in which 14 persons among 73 are or have been suffering from presenile dementia. Post mortem examination showed atrophy but no sign of any known demential syndrome. Cerebral blood flow measured in the late stage of disease was low, but with no characteristic pattern in flow distribution. In one patient in the initial stage of disease, the cerebral blood flow was unexpectedly increased. The patients with presenile dementia in this family did not reveal pathological signs of any known demential syndrome and showed CBF-changes not earlier reported. Moreover, contrary to widely held views we have evidence that dementia may be connected to a high blood flow at least in the initial state. An increased blood flow was also seen in seven of ten well functioning first degree relatives, in some cases along with cerebral atrophy and/or psychological tests with signs of dementia. Are these people going to develop manifest dementia later in life?