Cotard's Parasomnia: Le Délire de Negation that occur during the Sleep-Wake Dissociation?

Unpleasant dreamlike mentation can occur during NREM parasomnias, leading to associated panic attacks. The mentations are rarely remembered, and are likely underreported. However, they may lead to significant personal distress, and if not addressed, may contribute to poorer clinical outcomes. Cotard's 'Le Délire de Negation', are very rare nihilistic delusions, historically described with psychotic disorders. Their association with variety of neurologic disorders, including migraine and cluster-headache, has also been reported. Here we present three cases of Cotard's parasomnia during which distinct states of consciousness defined by nihilistic ideation are reported. Patients described believing to be dead or dying, whilst unable to perceive or experience their bodies in whole, or in part, as their own. The source analysis of electroencephalographic fingerprint of these mentations suggests right hemispheric hypoactivity subsequent to confusional arousals. Mechanistically, an aberrant activation of two major intrinsic brain networks of wakefulness, the salience and the default-mode-network is argued.