Improvements in Cognitive Function and Quantitative Sleep EEG in OSA after Six Months of CPAP Treatment

Study Objectives Untreated obstructive sleep apnea (OSA) is associated with cognitive deficits and altered brain electrophysiology. We evaluated the effect of continuous positive airway pressure (CPAP) treatment on quantitative sleep electroencephalogram (EEG) measures and cognitive function. Methods We studied 162 OSA patients (age 50±13, AHI 35.0±26.8) before and after 6 months of CPAP. Cognitive tests assessed working memory, sustained attention, visuospatial scanning and executive function. All participants underwent overnight polysomnography at baseline and after CPAP. Power spectral analysis was performed on EEG data (C3-M2) in a sub-set of 90 participants. Relative delta EEG power and sigma power in NREM and EEG slowing in REM were calculated. Spindle densities (events p/min) in N2 were also derived using automated spindle event detection. All outcomes were analysed as change from baseline. Results Cognitive function across all cognitive domains improved after six months of CPAP. In our sub-set, increased relative delta power (p<0.0001) and reduced sigma power (p=0.001) during NREM were observed after the 6-month treatment period. Overall, fast and slow sleep spindle densities during N2 were increased after treatment. Conclusions Cognitive performance was improved and sleep EEG features were enhanced when assessing the effects of CPAP. These findings suggest the reversibility of cognitive deficits and altered brain electrophysiology observed in untreated OSA following six months of treatment.

Questionnaire measures of adult attachment correlate with frontal hemispheric asymmetry in sleep spindle activity

Introduction: Attachment anxiety and neuroticism were proposed to be associated with relative right frontal neural activity. Since sleep spindles are argued to reflect enhanced offline neuroplasticity, higher spindle activity measured over the right frontal areas relative to the corresponding left frontal ones could index higher attachment anxiety and neuroticism.Methods: 34 healthy subjects (male = 19; Mage = 31.64; SDage = 9.5) were enrolled in our preliminary study. Second night EEG/polysomnography records and questionnaire measures of personality (Zuckermann-Kuhlman Personality Questionnaire) and adult attachment (Relationship Scales Questionnaire) were collected. Frontal slow sleep spindles were measured by the Individual Adjustment Method (IAM), whereas hemispheric asymmetry indexes of spindle occurrence rate, duration and amplitude were derived as normalized left-right differences (electrode pairs: Fp1-Fp2, F3-F4 and F7-F8).Results: Relative right lateralization of frontolateral and frontopolar slow sleep spindle density and mid-frontal slow spindle duration were associated with attachment anxiety, but spindle lateralization was less closely related to neuroticism. The relationships between frontal slow spindle laterality and attachment anxiety remained statistically significant even after controlling for the effect of neuroticism. The attachment “relationship” dimension (need for close relationships) was related to relative left dominance of frontal slow spindle activation, whereas attachment independence was not correlated with frontal slow spindle lateralization.Conclusion: Right frontal lateralization of slow sleep spindle activity can potentially serve as a marker for attachment anxiety.

Electrical Status Epilepticus during Sleep and Evaluating the Electroencephalogram

Electrical status epilepticus during sleep (ESES) is an age-related, self-limited epileptic encephalopathy characterized by heterogeneous clinical manifestations and a specific electroencephalographic pattern of continuous spikes and waves during slow sleep. The etiology of ESES is not completely clear, although structural brain lesions, abnormal immunological markers, and genetic mutations have been associated with the syndrome. ESES was first described in 1971 and since then, the diagnostic criteria have changed multiple times. Additionally, inconsistency between authors in how to record and evaluate the electroencephalogram also leads to variability between studies. These inconsistencies hamper objectivity, comparison, and generalization. Because of this, one of the first priorities of physicians treating this condition should be defining the parameters of this disease so that cooperative building can occur.

Differential Functional Changes of Nav1.2 Channel Causing SCN2A-Related Epilepsy and Status Epilepticus During Slow Sleep

Background: Nav1.2 encoded by the SCN2A gene is a brain-expressed voltage-gated sodium channel known to be associated with neurodevelopment disorders ranging from benign familial neonatal infantile seizures (BFIS) to developmental and epileptic encephalopathy (DEE) and autism spectrum disorder. Interestingly, status epilepticus during slow sleep (ESES), which aggravates cognitive impairment, has been found in SCN2A-related epilepsy. However, the functional features and the relationship between SCN2A and ESES have not been researched.Method: We herein investigated the functional consequences of an unpublished de novo V911A and the other two published variants in patients with SCN2A-related disorder and ESES by whole-cell patch-clamp studies in transfected HEK293T cells.Results: The unpublished V911A and published K1933M variants detected in patients with DEE exhibited a profound gain-of-functional (GOF) change. Another published BFIS variant S863F significantly reduced current density as a loss-of-functional (LOF) change. The refractory epilepsy in the patient with V911A was controlled by using the precise treatment of oxcarbazepine (OXC) since the age of 3 months. ESES was found at 18 months during the seizure-free period. We finally chose an aggressive treatment for eliminating ESES by using methylprednisolone combined with levetiracetam and nitrazepam instead of the precise treatment of OXC.Conclusion: Both GOF and LOF variants in the SCN2A gene can lead to ESES among the phenotypes of DEE and BFIS. We should monitor the electroencephalogram regularly in the patients with SCN2A-related epilepsy even during their seizure-free period.

The Biophysical Modeling of the Sleep Regulation in the Human Organism

A seventy-year-old human spends approx. twenty years, or one-third of their life, asleep. During sleep, their connection with the outside world is more or less lost, but in the meantime they experience exciting dreams that are difficult for rational thinking to grasp. Analysis of EEG recordings revealed that sleep can be divided into two sharply separated states: one is the so-called slow wave sleep; the other is the so-called paradoxical sleep (REM), e.g. characterized by strong eyeball movement. The slow sleep period can be divided into 4 periods based on the EEGs, and these follow each other in a well-defined order, then comes the paradoxical sleep and the whole thing is repeated; during a full sleep of approx. 4–6 times. The duration of paradox sleep depends on the individual, but it lasts for approx. 6–15 minutes. Compared to the literature, one of the significances of this article is also that we wrote a mathematical model of the sleep. This model also allows us to characterize different forms of particular sleep.

Impact of Multimodal Cognitive Training on Cognitive Traits of Children: A Multicentric Interventional Study

In this article, we evaluate the hypothesis that a multimodal cognitive training (MCT) program, the Brighter Minds, can enhance certain inherent traits of a child and thus bring changes in the external behavior. For the study, 186 children (randomized to 93 each in intervention and control group) aged 10-15 years were enrolled from three different locations. Psychometric tests, parental/caregiver interviews and EEG (electroencephalography) tests were conducted before and after the program. Intervention group showed strong statistical significance for improvements in Mini Mental Status Examination (MMSE) (P<0.01) but no significance for Raven’s Standard Progrssive Matrices (SPM) or Susan Harter’s test. The parental/caregiver reported satistically significant improvements in focus (P<0.05), empathy (P<0.05), intuition (P<0.05), comprehension (P<0.05) and understanding of abstract concepts (P<0.05) for the intervention group. For the control, Power Spectral Density (PSD) of the baseline eyes-closed (EC) EEG recording, the spectrum below 20Hz exhibited the characteristic “1/f” spectral scaling of the power-law. This signature matches prior reported evidence in literature of those in wakeful state with EC. The intervention group EC PSD, however, exhibited a signature similar to those in a slow sleep state; reflective of the possible transfer effect of the training on other skills like relaxation. We used unsupervised learning methods with dice distance, on the psychometric and interview data, to show the effect of location and the exposure of a few control children to the program.