Sleep Characteristics in Children with Attention Deficit Hyperactivity Disorder: Systematic Review and Meta-Analyses.

STUDY OBJECTIVES: Sleep disturbances have been associated with attention deficit hyperactivity disorder (ADHD), but such relationship is still unclear. The results from the studies conducted do not provide enough evidence to support a sleep physiology inherent to ADHD. This study tries to determine if that sleep physiology really exists by comparing children with ADHD and control children in some sleep parameters. METHODS: A search was conducted in several databases (Web of Science, Scopus, Pubmed and PsycINFO), and a manual search, to retrieve all the articles available from 1987 until March 2014. Of 8,678 non-duplicate studies retrieved, 11 studies met the inclusion and methodological quality criteria. Two meta-analyses were performed with eight of those studies, depending on data provided by them: polysomnographic or actigraphic. A fixed-effects model, and the standardized mean difference (SMD) as the index of effect size, were used in both meta-analyses. RESULTS: Significant differences were found only in the meta-analysis with polysomnography as outcome. Children with ADHD were found to spend more time in stage 1 sleep than controls (pooled SMD = 0.32, 95% CI = 0.08-0.55, p value = 0.009). CONCLUSIONS: Although few differences in sleep between children with ADHD and controls have been found in this review, further studies are required on this matter. Those studies should consider some variables discussed in this review, in order to obtain useful and reliable conclusions for research and clinical practice. Particularly, the influence of assessment criteria and ADHD subtypes in the sleep characteristics of children with ADHD should be addressed.

Tool for Semiautomatic Labeling of Moving Objects in Video Sequences: TSLAB.

An advanced and user-friendly tool for fast labeling of moving objects captured with surveillance sensors is proposed, which is available to the public. This tool allows the creation of three kinds of labels: moving objects, shadows and occlusions. These labels are created at both the pixel level and object level, which makes them suitable to assess the quality of both moving object detection strategies and tracking algorithms. The labeling can be performed easily and quickly thanks to a very friendly graphical user interface that allows one to automatize many common operations. This interface also includes some semiautomatic advanced tools that simplify the labeling tasks and drastically reduce the time required to obtain high-quality results.

Polysomnographic and subjective sleep markers of mild cognitive impairment.

STUDY OBJECTIVES: Growing evidence suggests that sleep disturbances precede by years the clinical onset of Alzheimer disease (AD). The goal of the current study is to determine whether changes in polysomnographic (PSG) sleep patterns accompany subjective sleep complaints in patients with mild cognitive impairment (MCI). We further examine whether meaningful changes in objective sleep physiology are predicted by self-reported sleep measures in MCI patients, and whether incipient neurodegeneration contributes to exacerbate sleep misperception. DESIGN SETTING AND PARTICIPANTS: Overnight PSG recordings and self-reported sleep measures were obtained from 25 healthy elderly (HE) subjects and 25 patients with MCI at the sleep laboratory. RESULTS: Both PSG and self-reported sleep measures confirmed that sleep is altered in patients with MCI. Whereas subjective sleep responses predicted fragmentation of slow wave sleep (SWS) in HE individuals, this relationship was not evident in MCI patients. Furthermore, patients with MCI showed significant discrepancies in the estimation of sleep onset latency when compared with HE subjects. CONCLUSIONS: Sleep is significantly impaired in patients with mild cognitive impairment at both the objective and subjective level, which may be used as a surrogate marker of preclinical Alzheimer disease. Taken together, these findings aid in the development of novel therapeutic strategies devoted to improve sleep in the elderly population at risk of developing Alzheimer disease.

Disturbed sleep patterns in elders with mild cognitive impairment: the role of memory decline and ApoE ε4 genotype.

Sleep disturbances are prevalent in patients with Alzheimer' disease (AD), being one of the most troubling symptoms during the progression of disease. However, little research has been made to determine if impaired sleep patterns appear years before AD diagnosis. This study tries to shed light on this issue by performing polysomnographic recordings in healthy elders and patients with mild cognitive impairment (MCI). We further investigated whether changes in sleep patterns parallel memory decline as well as its relationship with the Apolipoprotein E (ApoE) ɛ4 genotype. Results showed a significant shortening of rapid eye movement (REM) sleep together with increased fragmentations of slow-wave sleep in MCI patients relative to healthy elders. Interestingly, we further showed that reduction of REM sleep in MCI patients with ApoE ɛ4 was more noticeable than in ɛ4 non-carriers. Contrary to our initial hypothesis, changes in sleep patterns were not correlated with memory performance in MCI patients. Instead, increased REM sleep accompanied enhanced immediate recall in MCI ɛ4 non-carriers. Taken together, these results suggest that sleep disruptions are evident years before diagnosis of AD, which may have implications for early detection of dementia and/or therapeutic management of sleep complaints in MCI patients.

Role of tau protein on neocortical and hippocampal oscillatory patterns.

Tau is a neuronal microtubule-associated protein implicated in microtubules stabilization, axonal establishment and elongation during neuronal morphogenesis. Because of its elevated expression in neocortical regions and hippocampus, tau might play a role in sculpting collective neural responses underlying slow and fast brain oscillations and/or long-range synchronization patterns between hippocampus and neocortex. To test this hypothesis, local field potentials were recorded in tau-deficient (tau(-/-) ) and wild-type mice from different neocortical regions and from the hippocampus during spontaneous motor exploratory behavior. We found that tau(-/-) mice showed hippocampal theta slowing and reduced levels of gamma long-range synchronization involving the frontal cortex. We hypothesize that the lack of normal phosphorylated tau during early stages of development might influence the maturation of parvalbumin interneurons affecting the spatiotemporal structure of long-range gamma synchronization. Also, the proper functioning of gap-junction channels might be compromised by the absence of tau in hippocampal networks. Altogether, these results provide novel insights into the functional role of tau protein in the formation of collective neural responses and emergence of neocortical-hippocampal interactions in the mammalian brain.

Tau protein role in sleep-wake cycle.

Evidence has shown that the lack of tau produces subtle changes in neuronal structure and modest impairment in complex behaviors, suggesting compensatory mechanisms carried out by other neuronal microtubule-associated proteins. Here we show major abnormalities in sleep-wake cycle of tau-deficient animals including increased wakefulness duration and decreased non-rapid eye movement (NREM) sleep time, a higher number of state transitions between NREM and wake, and shortened sleep bouts. Altered sleep structure in tau-/- mice was accompanied by a significant decline in delta power together with an enhanced spectral density of sleep spindles during NREM sleep. No significant differences were observed in rapid eye movement (REM) sleep between the two mouse strains. Taken together, these results suggest that tau indirectly participates in the regulation of the sleep-wake cycle modulating not only the control and maintenance of global brain states but also the cerebral oscillatory patterns underlying sleep-wake states.

External sense organs in freshwater oligochaetes (Annelida, Clitellata) revealed by scanning electron microscopy.

Freshwater oligochaetes have at least two kinds of external sense organs: multiciliate organs of short cilia (also present in earthworms) and sense organs with one to three long cilia (unknown in earthworms and possibly acting as rheoreceptors). Ciliate sense organs of freshwater oligochaetes are distributed over their entire body surface, including the clitellum. They are scattered on the prostomium and pigidium and are arranged into a transversal chaetal row and dispersed or forming a few other discrete transversal rows on chaetal segments. Three species display very prominent sense organs (sensory buds in Protuberodrilus tourenqui and papillae in Ophidonais serpentina and Spirosperma velutinus). The number of cilia per organ at the prostomium of freshwater families appears to be fewer than that of terrestrial ones. It is suggested that the total number of cilia at the prostomium of the freshwater species could be related to their habitat, evolving from an epibenthic to an endobenthic way of life.