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Paroxysmal non-kinesigenic dyskinesia: pathophysiological investigations
1Department of Neurology, Children's Hospital, Boston, MA, USA. LombrosoC@aol.com
Summary
Paroxysmal non-kinesigenic dyskinesia (PNKD) in a boy originated from the caudate nuclei, not the cortex. Brain imaging revealed altered dopamine receptor density and presynaptic activity in the striatum.
Area of Science:
- Neuroscience
- Neurology
- Medical Imaging
Background:
- Paroxysmal dyskinesias are a poorly understood group of movement disorders.
- The exact pathophysiology and classification of these conditions remain largely unknown.
Observation:
- A case study of a boy with severe paroxysmal non-kinesigenic dyskinesia (PNKD) was investigated.
- Video-electrographic studies indicated seizure activity originating from the caudate nuclei.
- Cerebral cortex activity was not identified as the source of the dyskinesia.
Findings:
- Positron Emission Tomography (PET) scans using 18FDG showed no metabolic abnormalities.
- 18FDOPA and 11C raclopride PET scans revealed reduced presynaptic dopa decarboxylase activity in the striatum.
- An increased density of postsynaptic dopamine D2 receptors was observed in the striatum.
Implications:
- The findings suggest a potential chronic upregulation of striatal dopamine D2 receptors.
- This upregulation may be linked to reduced dopamine synthesis or altered release.
- Further research is needed to determine if these receptor changes are primary or compensatory mechanisms in PNKD.