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Recent advances in electrophysiological [e.g., surface high-density electroencephalographic (hd-EEG) and intracranial recordings], video-polysomnography (video-PSG), transcranial stimulation and neuroimaging techniques allow more in-depth and more accurate investigation of the neural correlates of dreaming in healthy individuals and in patients with brain-damage, neurodegenerative diseases, sleep disorders or parasomnias. Convergent evidence provided by studies using these techniques in healthy subjects has led to a reformulation of several unresolved issues of dream generation and recall [such as the inter- and intra-individual differences in dream recall and the predictivity of specific EEG rhythms, such as theta in rapid eye movement (REM) sleep, for dream recall] within more comprehensive models of human consciousness and its variations across sleep/wake states than the traditional models, which were largely based on the neurophysiology of REM sleep in animals. These studies are casting new light on the neural bases (in particular, the activity of dorsal medial prefrontal cortex regions and hippocampus and amygdala areas) of the inter- and intra-individual differences in dream recall, the temporal location of specific contents or properties (e.g., lucidity) of dream experience and the processing of memories accessed during sleep and incorporated into dream content. Hd-EEG techniques, used on their own or in combination with neuroimaging, appear able to provide further important insights into how the brain generates not only dreaming during sleep but also some dreamlike experiences in waking. [ABSTRACT FROM AUTHOR]

Nocturnal frontal lobe epilepsy (NFLE) is a focal epilepsy with seizures arising mainly during sleep and characterized by complex, often bizarre, motor behavior or sustained dystonic posturing. First described in 1981, it was initially considered a motor disorder of sleep and was named nocturnal paroxysmal dystonia (NPD). The unusual seizure semiology, onset during sleep, and often uninformative scalp EEG and brain MRI make it difficult to distinguish NPD attacks from other non-epileptic nocturnal paroxysmal events, namely parasomnias. The long-debated epileptic origin of the condition was finally demonstrated in 1990 and the term NFLE introduced. Even though many aspects of parasomnias and NFLE have been clarified in the last two decades, the differential diagnosis remains a challenge for clinicians. To address controversial issues and define the diagnostic criteria for NFLE, a Consensus Conference was held in Bologna, Italy in 2014. Major points of agreement emerged on: (i) the relationship of the seizures with sleep and not with the circadian pattern of seizure occurrence; (ii) the possible extrafrontal origin of hypermotor seizures, without substantial differences in seizure semiology. In the wake of the Consensus, the syndrome was renamed Sleep-Related Hypermotor Epilepsy (SHE). [ABSTRACT FROM AUTHOR]

Background and aims: Rapid eye movement (REM) sleep behavior disorder (RBD) is commonly associated with neurodegenerative disorders characterized by α-synuclein deposition, including Parkinson's disease, multiple system atrophy, and Lewy body dementia. However, this tendency in tauopathy-mediated diseases is rare and only sporadically reported. We systematically illustrate the occurrence of RBD and sleep features among a cohort of patients with Alzheimer's disease (AD), a non-synucleinopathy. Methods: We recruited 105 clinically probable AD patients. Fifteen clinically probable AD patients with suspected RBD underwent a video-polysomnography (vPSG) examination. Results: Five patients with probable AD exhibited RBD. One of the patients performed repeated touching of the head and the face with his hands and flailed his arms. Three patients exhibited hand twisting, exploring, prominent limb kicking, and jerking. The fifth patient exhibited all of the characteristics of RBD (he recalled a dream about fighting animals), and his wife was awakened by his screaming. Of these five patients, one patient took the acetylcholinesterase inhibitor drug donepezil. The patients with AD + RBD demonstrated increases in both tonic and phasic electromyography activity during REM sleep, but sleep architecture did not differ between the AD + RBD and AD-alone groups. Conclusion: RBD can occur in patients with AD. The occurrence of RBD does not change the sleep architecture of AD patients. [ABSTRACT FROM AUTHOR]

Summary: Seizures, namely in certain epileptic conditions, may be precipitated by sleep. Nocturnal frontal lobe epilepsy seizures, characterized by bizarre motor behaviour and autonomic activation, appear almost exclusively during sleep. The differential diagnosis between this condition and sleep-related non-epileptic paroxysmal motor phenomena, in particular the parasomnias, is arduous. Moreover, accepted criteria for the diagnosis of nocturnal frontal lobe seizures are lacking and even ictal scalp EEG recording could fail to disclose paroxysmal abnormalities. The clinical and polygraphic features of the different types of seizures in nocturnal frontal lobe epilepsy and of the more common non-epileptic paroxysmal events during sleep are described. The main differentiating features characterizing nocturnal frontal seizures are: onset at any age, several attacks per night at any time during the night, brief duration (s) with stereotyped motor pattern. As video-polysomnographic recordings of the attack, the gold-standard for diagnosis, are expensive and not readily available everywhere, home-made video recordings may be helpful. Further investigations on pathophysiology, genetics and epidemiology are needed to clarify the relationship between epileptic and non-epileptic sleep related paroxysmal phenomena. [Copyright &y& Elsevier]