Frontal lobe degeneration of non-Alzheimer type. IV. White matter changes.

The cerebral white matter in 16 cases of frontal lobe non-Alzheimer degeneration with dementia (FLD), four cases of Pick's disease and five age-matched controls was studied microscopically. All cases of dementia had white matter alterations, consisting of gliosis and loss of myelin, with a regional spread of changes that roughly corresponded with that of the cortical degeneration. The white matter changes were less severe than the cortical alterations, although the relative degree of severity between grey and white matter pathology varied from case to case. The white matter changes were in some respects similar in FLD and Pick's disease. They differed from those of other organic dementias. In FLD, they seem to be part of the histopathologic picture and to be secondary to the cortical degeneration.