The Time Course of the Probability of Transition Into and Out of REM Sleep

Study objectives: A model of rapid eye movement (REM) sleep expression is proposed that assumes underlying regulatory mechanisms operating as inhomogenous Poisson processes, the overt results of which are the transitions into and out of REM sleep. Design: Based on spontaneously occurring REM sleep episodes ("Episode") and intervals without REM sleep ("Interval"), 3 variables are defined and evaluated over discrete 15-second epochs using a nonlinear logistic regression method: "Propensity" is the instantaneous rate of into-REM transition occurrence throughout an Interval, "Volatility" is the instantaneous rate of out-of-REM transition occurrence throughout an Episode, and "Opportunity" is the probability of being in non-REM (NREM) sleep at a given time throughout an Interval, a requisite for transition. Setting: 12:12 light:dark cycle, isolated boxes. Participants: Sixteen male Sprague-Dawley rats Interventions: None. Spontaneous sleep cycles. Measurements and Results: The highest leve

Envelope analysis of the airflow signal to improve polysomnographic assessment of sleep disordered breathing

Study Objectives: Given the detailed respiratory waveform signal provided by the nasal cannula in polysomnographic (PSG) studies, to quantify sleep breathing disturbances by extracting a continuous variable based on the coefficient of variation of the envelope of that signal. Design: Application of an algorithm for envelope analysis to standard nasal cannula signal from actual polysomnographic studies. Setting: PSG recordings from a sleep disorders center were analyzed by an algorithm developed on the Igor scientific data analysis software. Patients or Participants: Recordings representative of different degrees of sleep disordered breathing (SDB) severity or illustrative of the covariation between breathing and particularly relevant factors and variables. Interventions: The method calculated the coefficient of variation of the envelope for each 30-second epoch. The normalized version of that coefficient was defined as the respiratory disturbance variable (RDV). The method outcome wa

On-line analysis of biosignals for the automation of total and specific sleep deprivation in the rat

A computer-based system that automates sleep studies, including sleep deprivation paradigms, is described. The system allows for total or REM-specific sleep deprivation and is based on a reliable, fast-responding, on-line state detection algorithm linked to a dependable intervention device. Behavioral state detection is achieved by dimensión reduction of short-term EEG power spectrum. Interventions are made by serial outputs to servomotors that move a cage with different patterns and variable intensity. The system can adapt itself to individual characteristics and to changes in recording conditions. Customized protocols can be designed by defining the states or stages to be deprived, including scheduling temporal patterns. A detailed analysis of the relevant signáis during and after deprivation is readily available. Data is presented from two experimental designs in rats. One consisted of specific REM-sleep short-term deprivation and the other of 10-hour total sleep deprivation. An outline of conceptual and practical considerations involved in the automation of laboratory set-ups oriented to biosignal analysis is provided. Careful monitoring of sleep EEG variables during sleep deprivation suggests peculiarities of brain functioning in that condition. A corollary is that sleep deprivation should not be considered to be merely a forced prolonged wakefulness

Envelope analysis of electromyogram in rem sleep behavior disorder patients

Resumen de reuniónClinical manifestations of REM Behavior Disorder (BRD) include REM sleep without atonia (RWA) characterized by maintenance of muscle tonus associated to intense and frequent phasic motor events during REM sleep episodes. The diagnosis of RBD includes the enaction of dreams, i.e. the patient displays complex vocal and motor behaviors during REM sleep thatmay reflect dream content and the polisomnographic recording of RWA. There is a growing interest in RWA, as it has been considered a prodromal manifestation of neurodegenerative alpha-synucleinopathies such as Parkinson's disease. Current clinical diagnostic procedures include the visual inspection of polysomnographic record and categorization of electromyographic (EMG) events. Automated (computer based) strategies has been proposed to assist in EMG scoring to maximize diagnostic accuracy. Here we apply envelope analysis to EMG records obtained in healthy subjects and RBD patients. Envelope analysis give qualitative information regarding the underlying mechanism of signal generation. The mathematical properties of CVE distribution may help to obtain an unbiased scoring of electromyographic (EMG) events during sleep. The numeric value acquired by CVE is a reporter of the temporal structure of recorded elements, where phasic or pulsatile events adopt high CVE values and can be unequivocally discriminated from non pulsatile intervals. The amplitude of the envelope (AE) of EMG is directly related to muscle tonus. We propose that characterization CVE and AE may help to assist in identify RWA.Guillermo Puelma Foundatio

Melatonin relations with respiratory quotient weaken on acute exposure to high altitude

High altitude (HA) exposure may affect human health and performance by involving the body timing system. Daily variations of melatonin may disrupt by HA exposure, thereby possibly affecting its relations with a metabolic parameter like the respiratory quotient (RQ). Sea level (SL) volunteers (7 women and 7 men, 21.0 +/- 2.04 y) were examined for daily changes in salivary melatonin concentration (SMC). Sampling was successively done at SL (Antofagasta, Chile) and, on acute HA exposure, at nearby Caspana (3,270 rn asl). Saliva was collected in special vials (Salimetrics Oral Swab, United Kingdom) at sunny noon (SMCD) and in the absence of blue light at midnight (SMCN). The samples were obtained after rinsing the mouth with tap water and were analyzed for SMC by immunoassay (ELISA kit; IBL International, Germany). RQ measurements (n = 12) were realized with a portable breath to breath metabolic system (Oxicon (TM) Mobile, Germany), between 8:00 PM and 10:00 PM, once at either location. At SL, SMCD, and SMCN values (mean +/- SD) were, respectively, 2.14 +/- 1.30 and 11.6 +/- 13.9 pg/ml (p tightly correlate with RQ at SL (r = -0.79) and weaker at HA (r = -0.31). SMCN-SMCD, as well as, SMC values at SL, on the other hand, respectively, correlate with the corresponding values at HA (r = 0.71 and r = 0.85). Acute exposure to HA appears to loosen relations of SMC with RQ. A personal profile in daily SMC variation, on the other hand, tends to be conserved at HA.This study was supported by FONDECYT Chile ( Project No1100161) and Bundesministerium fur Bildung und Forschung (Project CHLI2Anb, Domeyko-Center) Germany is gratefully acknowledged