Abstract:
Positron emission tomography with fluorodeoxyglucose F 18 (18F-
fluorodeoxyglucose) was used to examine regional cerebral glucose
metabolism in individuals with motor neuron disease. Motor neuron
disease involves selective loss of motor neurons, large pyramidal cells
in the motor cortex, and corticospinal tract degeneration. We postulated
that the local cerebral metabolic rate of glucose should correlate with
this regional neuronal cell loss. Glucose metabolism values in patients
with motor neuron disease were reduced compared with those of controls
in several regions; however, when corrected for multiple comparisons, no
significant difference was observed between patients with motor neuron
disease and age-matched controls. No correlation was noted between the
local cerebral metabolic rate of glucose and duration or severity of
illness. Correlation between metabolic changes with objective findings
on neurologic examination, including motor weakness and tendon reflexes,
provided interesting results, including a decline in glucose metabolism
with progressive weakness and upper motor neuron dysfunction. Moreover,
in supplementary motor areas, there appears to be an increase in
regional glucose metabolism as the neurologic condition deteriorates,
possibly representing increased metabolic activity of the motor
association cortex in response to primary loss of pyramidal cells