Local cerebral metabolic rate for glucose during petit mal absences

Authors

  • Dr Jerome Engel Jr MD, PhD,

    Corresponding author
    1. Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90024
    2. Department of Anatomy, UCLA School of Medicine, Los Angeles, CA 90024
    3. Laboratory of Nuclear Medicine, UCLA School of Medicine, Los Angeles, CA 90024
    4. Brain Rearch Institute, UCLA School of Medicine, Los Angeles, CA 90024
    • Reed Neurological Research Center, UCLA School of Medicine, Los Angeles, CA 90024
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  • Perry Lubens MD,

    1. Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90024
    Current affiliation:
    1. Memorial Hospital of Long Beach, Long Beach, CA 90806
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  • David E. Kuhl MD,

    1. Laboratory of Nuclear Medicine, UCLA School of Medicine, Los Angeles, CA 90024
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  • Michael E. Phelps PhD

    1. Laboratory of Nuclear Medicine, UCLA School of Medicine, Los Angeles, CA 90024
    2. Division of Biophysics, UCLA School of Medicine, Los Angeles, CA 90024
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Abstract

Four patients with primary generalized or true petit mal epilepsy were studied with positron emission tomography using f'{18} fluorodeoxyglucose (FDG). FDG studies were carried out during 10 minutes of hyperventilation before and again after medical control of spontaneous absences. Before seizures were controlled all 4 patients demonstrated frequent bilaterally synchronous three-per-second spike-and-wave discharges associated with altered consciousness. After spontaneous seizures were controlled, hyperventilation produced only electroencephalographic slowing without clinical symptoms in 3; the fourth patient had absences less frequently. Patterns of local cerebral metabolic rate for glucose (CMRGlc) were normal and identical for ictal and interictal scans; there was, however, a 2.5- to 3.5-fold diffuse ictal increase in global CMRGlc evident when ictal studies were compared with hyperventilation control studies in which no seizures occurred. The CMRGlc was similar in the two scans obtained from the patient who had absences during both studies. No anatomical substrate of petit mal epilepsy was identified. The CMRGlc in these patients during petit mal absences was higher than that recorded in other patients during partial or generalized convulsive seizures. This difference may reflect the fact that petit mal absences are not associated with postictal depression.

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