Positron emission tomographic scanning demonstrates a presynaptic dopaminergic lesion in Lytico-Bodig. The amyotrophic lateral sclerosis-parkinsonism-dementia complex of Guam.

We performed positron emission tomography using 18F-6-fluorodopa on four Guamanians with an amyotrophic lateral sclerosis syndrome, eight Guamanians with parkinsonism, and seven clinically normal Guamanians; the results were compared with those of nine Vancouver control subjects. The Guamanian subjects had all been exposed to similar Chamorro lifestyles. The scans were analyzed using a graphic method that calculates a constant for whole striatal 18F-6-fluorodopa uptake. The parkinsonian subjects all had significantly reduced striatal 18F-6-fluorodopa uptake. The group with amyotrophic lateral sclerosis had significantly reduced uptake that was intermediate between that of the control group and the parkinsonian group. Two Guamanian normal subjects had reduced striatal 18F-6-fluorodopa uptake. The nigrostriatal dopaminergic lesion in Guamanian parkinsonism is similar to that found in idiopathic parkinsonism. The nigrostriatal lesions in the subjects with amyotrophic lateral sclerosis and the Guamanian normal subjects are examples of subclinical neuronal damage demonstrable in living subjects with positron emission tomography.