PATTERNS OF GLIAL-CELL ACTIVITY IN FRONTOTEMPORAL DEMENTIA (LOBAR ATROPHY)

Fronto-temporal dementia is a clinical syndrome with a number of patho logical substrates, including frontal lobe degeneration, Pick's diseas e, and motor neuron disease with dementia; it also includes patients w ith a primary progressive language disorder. Twenty-four brains were e xamined, using immunohistochemistry for glial fibrillary acidic protei n (GFAP) and ferritin, Five cases of fronto-temporal dementia with a P ick's disease type of histology showed marked cortical gliosis with st riking microglial activity in both grey and white matter. In seven cas es of frontal lobe degeneration, there was little gliosis and microgli al activity was confined largely to the white matter; two of the seven cases of progressive language disorder showed similar changes to fron tal lobe degeneration. Five cases of motor neuron disease with dementi a showed both astrocytic and microglial activity within the white matt er. We suggest that cases of fronto-temporal dementia due to rick type histology may result from a process which primarily involves grey mat ter, whereas cases of frontal lobe degeneration might represent a diso rder of white matter.