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Obstructive sleep apnea is linked to cardiovascular disease, metabolic disorders and dementia. The precise nature of the association between respiratory events in obstructive sleep apnea, cortical or subcortical arousals, and cognitive, autonomic and oxidative stress consequences remains incompletely elucidated. Previous studies have aimed to understand the relationship between obstructive sleep apnea and arousal patterns, as defined by the cyclic alternating pattern, but results have been inconsistent, in part likely due to the presence of associated comorbidities. To better define this relationship, we analysed cyclic alternating patterns in patients with obstructive sleep apnea without any additional comorbidities. We identified 18 adult male, non-obese subjects with obstructive sleep apnea and no other comorbidities or medication history, who underwent whole-night electroencephalography and polysomnography. Cyclic alternating pattern analysis was performed and verified by certified somnologists. Pairwise linear regression analysis demonstrated an inverse relationship between obstructive sleep apnea severity and cyclic alternating pattern subtype A1, and a direct correlation with cyclic alternating pattern subtype A3. Cyclic alternating pattern subtypes A1 prevail in milder obstructive sleep apnea phenotype, whilst cyclic alternating pattern subtypes A2 and A3 overcome among moderate-to-severe obstructive sleep apnea patients. The milder obstructive sleep apnea group also presented higher sleep efficiency, and increased percentages of non-rapid eye movement stage 3 and rapid eye movement sleep, as well as longer cyclic alternating pattern sequences in N3, while severe obstructive sleep apnea patients spent more time in lighter sleep stages. These results imply/suggest a balance between cyclic alternating pattern's adaptive and maladaptive arousal processes in obstructive sleep apnea of differing severities. In milder obstructive sleep apnea (apnea-hypopnea index < 20), sleep continuity may be reinforced by cyclic alternating pattern subtype A1, whereas in more severe obstructive sleep apnea, decompensation of these sleep-stabilizing mechanisms may occur and more intrusive cyclic alternating pattern fluctuations disrupt sleep circuitry.

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.

Danielle Wasserman,1,2,* Dorothea Bindman,1,* Alexander D Nesbitt,1– 3 Diana Cash,4 Milan Milosevic,5 Paul T Francis,6 K Ray Chaudhuri,7 Guy D Leschziner,1,2 Luigi Ferini-Strambi,8 Clive Ballard,9 Amy Eccles,10 Ivana Rosenzweig1,2 1Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK; 2Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK; 3Headache Group, Department of Clinical Neurosciences, King’s College Hospital NHS Foundation Trust, London, UK; 4BRAIN, Department of Neuroimaging, King’s College London, London, UK; 5School of Public Health “Andrija Stampar“, University of Zagreb School of Medicine, Zagreb, Croatia; 6Wolfson Centre for Age-Related Diseases, King’s College London, London, UK; 7Movement Disorders Unit, King’s College Hospital, Department of Clinical and Basic Neurosciences, Institute of Psychiatry, Psychology & Neuroscience, Parkinson Foundation Centre of Excellence, King’s College London, London, UK; 8Sleep Disorders Center, Department of Clinical Neurosciences, Università Vita-Salute San Raffaele, Milan, Italy; 9Medical School, University of Exeter, Exeter, UK; 10Department of Nuclear Medicine, Guy’s and St. Thomas’ NHS Foundation Trust, London, UK*These authors contributed equally to this workCorrespondence: Ivana RosenzweigSleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, Box 089, De Crespigny Park, London SE5 8AF, UKEmail ivana.1.rosenzweig@kcl.ac.ukIntroduction: Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is increasingly recognised as an important precursor disease state of alpha-synucleinopathies. This parasomnia is characterized by a history of recurrent nocturnal dream enactment behaviour, loss of skeletal muscle atonia, and increased phasic muscle activity during REM sleep. Neuroimaging studies of striatal dopamine transporter uptake tracer signaling suggest increasing dopaminergic deficit across the continuum of the alpha-synucleinopathies, with early sleep dysfunction suggestive of early caudate dysfunction. Henceforth, we set out to investigate the relationship between early sleep changes and the striatal dopaminergic availability in iRBD.Methods: Twelve patients with iRBD, who had undergone a video polysomnography and a neuroimaging assessment of striatal dopamine transporter (DaT) uptake tracer signaling, and 22 matched controls who had similarly undergone a video polysomnography were retrospectively identified. Data were statistically analyzed to identify altered sleep parameters and correlate them with striatal dopamine transporter uptake tracer signaling.Results: The iRBD patients exhibited an increased number of periodic limb movements during sleep (P=0.001), compared to 22 age-matched healthy subjects. In addition, several significant links were found between regional DaT-uptakes and sleep architecture. Correlational analyses suggested a strong positive association between sleep fragmentation and dopamine deficiency in left caudate (r=− 0.630, P=0.028), whilst an increased uptake in the whole striatum was strongly linked to the sleep efficiency, and to a lesser degree to the length of sleep duration.Discussion: To the best of our knowledge, this is the first demonstration of a close relationship between dopaminergic availability in striatum and the quality of sleep in iRBD. Taken together, our exploratory findings suggest that subtle but functionally significant striatal changes in early stages of iRBD may contribute to the further shaping of sleep architecture.Keywords: isolated rapid eye movement behaviour disorder, polysomnography, sleep architecture, striatum, striatal dopamine transporter uptake tracer signalling imaging, DaTSCAN

Psychogenic non epileptic seizures (PNES) are present in up to 30% of patients undergoing video EEG. Delay in PNES diagnosis is an average of 7.2years. Patients are exposed to costly, hazardous medications and other iatrogenic morbidities. Our aim was to investigate the ability to correctly diagnose ES from PNES in different groups and seniorities of medical professionals based on video alone. We showed ten video episodes' recordings (5 PNES, 5 ES) to doctors and nurses from ER, Internal Medicine ward and Neurology department, and inquired about the episodes' nature. 46 participants, 26 non-neurological and 20 neurological personnel. Seniority of responders varied. Epileptologists diagnosed correctly 87.5% of cases, General neurologists 72.8%. Neurology nurses 69.8%, ER nurses 58%, Internal Medicine physicians 54.1% and ER physicians 44.4%. Statistical significant difference between the general physicians to all neurology group professions was >0.05. We pointed out the lack of awareness of first responders to patients presenting with seizures. Neurologist ability to recognize seizures using semiology alone is higher than other medical personnel. Take home messages is the need for video taking of episodes and education plan to first responders.

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.