EPISONO is an epidemiological sleep study that
EPISONO is an epidemiological sleep study that was performed with a sample representing the São Paulo population in 2007. All volunteers were submitted to a single night polysomnography on sleep laboratory and to complete questionnaires before and after exam, one of these questionnaire was about SB history. The all methods of EPISONO study are described in Santos-Silva et al., 2009 .
Whole-night PSG was performed using a digital system (EMBLA (R) S7000, Embla System, Inc., Broomfield, CO., USA) in a sleep laboratory, at the usual sleep time. Physiological variables were simultaneously and continuously monitored: four buspirone hcl for electroencephalography (EEG); two channels for electrooculography (EOG); five channels for EMG (submental area, tibialis anterior muscle, masseter and temporal areas, and seventh intercostal space); one channel for electrocardiography (ECG); two channels for air flow, through thermostat and nasal pressure; chest and abdominal respiratory effort through inductance plethysmography, snoring and body position; oxyhemoglobin saturation and heart rate . Sleep staging was previously performed , as were the scoring of arousals , leg movements  and respiratory events (apnea was classified according to the recommended rules and hypopnea according to the alternative rules) .
Analysis of SB was performed by right masseter muscle (alternative option) according to the AASM , the audiovisual monitoring was not performed. The burst was defined as the twice of the baseline amplitude, and the events were classified in phasic, at least three bursts of 0.25 to 2s; tonic, bursts with durations longer than 2s; or mixed, a combination of the two. An interval of at least three seconds was being necessary to distinguish successive events.
An automatic report was generated and printed after each scoring; the report had separate presentations for each type of bruxism event (phasic, tonic or mixed), total duration of events per night (sum of all events), duration of the shortest and longest event and index. Following data collection, Kendall Tau correlation was used to evaluate the interobserver concordance relative to the abovementioned variables in each detected event; the significance level was p<0.05.
Results The sample was composed of 56 volunteers, the descriptive values (mean±SD) and correlations between Dentist 1 and Dentist 2 are described in Table 1. There was a high concordance between dentists, T>0.47.
Discussion Few studies have assessed the variability in SB (20–25%) [10,12]. In addition, there are variability between clinical report and diagnosis based in PSG (Maluly et al., 2013). However, our study support that this variability is intrinsic to SB and not be related to the EMG scoring. As a part of their study protocol, Dutra et al. performed two different scoring of SB records according to the research criteria formulated by Lavigne et al.  (using the masseter) and in association with audiovisual records. In confirmation of our results, those authors found a high degree of interobserver concordance, although Spindle performed audiovisual monitoring and used a criterion different from that formulated by AASM (2007). Carra et al. (2014) found a good concordance of bruxism score between with and without audio–video and found a good correlation intra-examiner in score bruxism without audio–video. In our study, we found the good concordance between differents examiners.
Introduction Chronic Fatigue Syndrome (CFS) is a multisystem illness, associated with disabling fatigue, cognitive dysfunction and sleeping disturbances. In 1992 the WHO approved the term “Chronic Fatigue Syndrome” and recognized this disorder as a neurological disease (WHO ICD-10 G93.3). CFS is characterized by persistent and relapsing fatigue, post exertional malaise (both physical and mental), cognitive and mood changes, and gastrointestinal disturbance and food intolerances. In addition, sleep disturbances and unrefreshing sleep are commonly reported by these patients . While there are now internationally recognized criteria for diagnosing this disorder, the cause (or causes) remains elusive .