Clinical picture of frontal lobe degeneration of non-Alzheimer type.

Frontal lobe degeneration of non-Alzheimer type (FLD) is the second most common primary degenerative dementia in southern Sweden. Clinical findings in 30 FLD cases with postmortem-verified diagnoses are described. FLD starts in the presenium with a mean disease duration of 7.5 years (range 3-17 years). Clinical onset is insidious and slow and the early stage is dominated by personality changes with lack of insight and judgement and signs of disinhibition. A typical feature is progressive loss of expressive speech with stereotyped phrases, late mutism and amimia. Restlessness, changes of oral/dietary behavior and utilization behavior are prevalent as also psychotic features. Temporal and spatial orientation are usually preserved for a long time in contrast to Alzheimer's disease. Dementia in FLD is similar to that of Pick's disease and ALS with dementia. Early recognition of FLD seems possible based on standardized clinical evaluation supported by neuropsychological tests, measurement of regional cerebral blood flow and other types of brain imaging. The etiology of FLD is unknown but a positive heredity was reported in 60%.