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Unpleasant dreamlike mentation can occur during non-rapid eye movement 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 le délire de negation are very rare nihilistic delusions, historically described with psychotic disorders. Their association with a variety of neurologic disorders, including migraine and cluster-headache, has also been reported. Here we present three cases of Cotard parasomnia during which distinct states of consciousness defined by nihilistic ideation occurred. Patients described believing they are dead or dying, while unable to perceive or experience their bodies in whole, or in part, as their own. A source analysis of the 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 network and the default mode network, is argued. CITATION: Gnoni V, Higgins S, Nesbitt AD, et al. Cotard parasomnia: le délire de negation that occur during the sleep-wake dissociation? J Clin Sleep Med. 2020;16(6):971–976.

OBJECTIVE: To investigate the diagnostic added value of supplementing the 10-20 EEG array with six electrodes in the inferior temporal chain.METHODS: EEGs were recorded with 25 electrodes: 19 positions of the 10-20 system, and six additional electrodes in the inferior temporal chain (F9/10, T9/10, P9/10). Five-hundred consecutive standard and sleep EEG recordings were reviewed using the 10-20 array and the extended array. We identified the recordings with EEG abnormalities that had peak negativities at the inferior temporal electrodes, and those that only were visible at the inferior temporal electrodes.RESULTS: From the 286 abnormal recordings, the peak negativity was at the inferior temporal electrodes in 81 cases (28.3%) and only visible at the inferior temporal electrodes in eight cases (2.8%). In the sub-group of patients with temporal abnormalities (n = 134), these represented 59% (peak in the inferior chain) and 6% (only seen at the inferior chain).CONCLUSIONS: Adding six electrodes in the inferior temporal electrode chain to the 10-20 array improves the localization and identification of EEG abnormalities, especially those located in the temporal region.SIGNIFICANCE: Our results suggest that inferior temporal electrodes should be added to the EEG array, to increase the diagnostic yield of the recordings.