A brain PET study in patients with narcolepsy-cataplexy

Abstract

Hypermetabolism was found in the executive network in narcolepsy at baseline in fully awake condition. Wake state assessment during scanning appears critical to avoid results showing altered functional neurocircuitry secondary to sleepiness and not to the underlying neurological disorder per se. Finally, cataplexy attacks were characterised by a hypometabolism in the hypothalamus associated with wide bilateral brain area hypermetabolisms.

[18F]Fludeoxyglucose-Positron Emission Tomography Evidence for Cerebral Hypermetabolism in the Awake State in Narcolepsy and Idiopathic Hypersomnia

“…All had low CSF hypocretin-1 level (<110 pg/ml). Seven drug-free patients with NT1 were already included in our previous PET scan study (2). …”

“…For instance, a 18 F-fludeoxyglucose (FDG) positron emission tomography (PET) study reported reduced metabolism in narcolepsy in a wide set of cortico-subcortical areas including the bilateral rectal and subcallosal gyri, the right superior frontal gyrus and inferior parietal lobule, the left supramarginal gyrus, the precuneus bilaterally, and the posterior hypothalamus and mediodorsal thalamic nuclei (3). Using a similar procedure, we found, on the opposite, increased metabolism in the anterior and mid-cingulate cortex, the cuneus, and the lingual gyrus in drug-free patients with narcolepsy–cataplexy scanned in a fully awake condition (2). A more recent PET study found hypometabolism in the right mid-frontal lobe and angular gyrus in young type 1 narcoleptic patients and hypermetabolism in the hippocampus, parahippocampus, amygdala, fusiform, left inferior parietal lobe, left superior temporal lobe, striatum, basal ganglia and thalamus, right hypothalamus, and pons (6).…”

“…Changes in structural and functional central nervous system have been reported in central hypersomnia disorders and especially in narcolepsy (2–6). However, results are inconsistent with either increased or decreased relative regional metabolism and perfusion in particular areas.…”

“…Considering in this framework, the results of the three aforementioned studies (2, 3, 6), patients with NT1 may exhibit decreased activity in part of the executive-control network and/or increased activity in part of the salience network. Importantly, relative hyper- or hypometabolism might be contingent upon the conditions and instructions given to the subjects at the time of PET scanning, more than to the development of the disorder in itself and/or the consequences of the sleep pathology.…”

Transient Paralysis during Acupuncture Therapy: A Case Report of An Adverse Event

“…11 A positron emission tomographic study has demonstrated shared neural substrates in subjects with narcolepsy/cataplexy. 17 Intravenous procaine activates limbic system structures and produces sensations similar to CPS. 18 Clinical experience suggests that acupuncture can increase as well as decrease activity in the anterior limbic area, especially in the presence of brain pathology.…”