Dementia with impaired temporal glucose metabolism in late-onset metachromatic leukodystrophy.

An unusual case of very-late-onset metachromatic leukodystrophy (MLD) with dementia was studied. The patient was a 41-year-old male who presented with mild dementia and a single generalized tonic clonic seizure. Neuropsychological assessment demonstrated mild amnesia, visuospatial dysfunction and attention deficits with a slow psychomotor speed. MR brain imaging displayed confluent hyperintensities of periventricular and subcortical white matter. Low levels of arylsulfatase A confirmed the diagnosis. Impaired cortical glucose metabolism especially of the medial temporal and frontal cortices was observed using positron emission tomography and fluor-18-labeled fluorodesoxyglucose. The neuropsychological deficits are related to the location of deficits in glucose metabolism.