- Email: [email protected]
Sleep and mood disorders in epilepsy
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Abstracts / Sleep Medicine 14S (2013) e165–e238
Results: Sub-C inhibition markedly influenced REM sleep and cataplexy. Compared to saline, Sub-C inhibition increased REM sleep amounts by increasing both the number (p = 0.001) and duration of REM episodes (p<0.0001). This intervention also triggered increases in basal levels of muscle tone during REM sleep, i.e., it blocked REM sleep paralysis (p<0.05). Silencing Sub-C cells also lead to marked sleep fragmentation by increasing the number of NREM to REM transitions. Sub-C inhibition lead to an 88% decrease (p = 0.04) in time spent in cataplexy as well as 75% fewer cataplexy episodes (p = 0.025). There were no measureable changes in the duration of cataplectic events (p > 0.05 for all variables). Conclusion: Pharmacogenetic manipulation of the Sub-C influences REM sleep expression as well as cataplexy expression in narcoleptic mice. At first glance, these preliminary data suggest that REM sleep paralysis and cataplexy may be mediated by a similar neural mechanism. http://dx.doi.org/10.1016/j.sleep.2013.11.553
Association between the amount of daytime sleep variability and cognitive flexibility in older adults S. Reyes 1, C. Algarín 1, D. Bunout 2, P. Peirano 1 1 Sleep Lab, INTA, University of Chile, Chile 2 Aging Lab, INTA, University of Chile, Chile
Introduction: Disrupted sleep patterns are commonly referred in the older population. They are often manifested by decreased total sleep time, increased waking after sleep onset, and napping. Napping may also be associated with increased risk of cognitive impairment, particularly compromised executive function, like cognitive flexibility. Recent evidence showed that variability in nap duration from day to day was predictive of greater medical morbidity. The aim of the study is to assess the association between variability in the amount of daytime and nighttime sleep and cognitive flexibility in older adults. Materials and methods: Participants were 76 subjects: 72% were women and mean age was 75.4 3.9 years (1). Motor activity was recorded continuously for a week with actigraphs (Actiwatch-16/ 64) worn in the nondominant wrist, yielding estimates of the amount of daytime and nighttime sleep. The variability of daytime and nighttime sleep amounts were calculated by dividing the standard deviation of sleep amounts within the week by the square root of the number of data points. Participants also performed the Stroop test: the words red, blue and green and a string of Xs were displayed on a monitor in red, blue, or green color. Three keys from the computer keyboard were covered by corresponding color patches, and the participants were told to press the key corresponding to the color of the target. The color words served as stimuli in the incongruent condition (e.g., the word red displayed in blue color), and was considered as the cognitive flexibility. We obtained the reaction time (RTI) and percentage of correct responses (PCI) for incongruent stimuli. 1. Reyes S, Algarín C, Bunout D, Peirano P. Sleep/wake patterns and physical performance in older adults. Aging Clin Exp Res 2013;25:175–181. Results: The logistic regression model showed that subjects with greater variability in the amount of daytime sleep were more likely to have longer RTI (OR = 1.07, p < 0.05) and lower PCI (OR = 1.08, p < 0.05). Variability in the amount of nighttime sleep showed no significant associations. Analyses were adjusted by gender and age. Conclusion: Our results show an association between daytime sleep amount variability and cognitive flexibility in older subjects. They provide support to the hypothesis relating sleep patterns and cognitive functioning, and suggest the relevance of daytime duration regularity for cognitive performance.
Acknowledgements: Support: FONIS SA06I20038/Fondecyt 1110513; (*) CONICYT, PhD program fellowship. http://dx.doi.org/10.1016/j.sleep.2013.11.554
The effectiveness of a community pharmacist-led intervention to improve screening for sleep apnea in primary care – A cohort study C. Perraudin Centre de Recherches Médecine Sciences Santé Mentale Société (CERMES3), UMR 8211 - INSERM U 988
Introduction: Despite the high prevalence and major public health ramifications, obstructive sleep apnea syndrome (OSAS) remains underdiagnosed. In many developed countries, because community pharmacists (CP) are easily accessible, they have been developing additional clinical services that integrate the services of and collaborate with other healthcare providers (general practitioners (GPs), nurses, etc.). Alternative strategies for primary care screening programs for OSAS involving the CP are discussed. Objectives: We aimed to determine whether the involvement of a CP in the care pathway of a patient at risk for OSAS, through the implementation of a GP-CP collaborative intervention, was effective that is to say if it improved the detection rate and diagnosis of the disease in this population. Materials and methods: Setting: 31 community pharmacies in 5 regions in France. Participants: Patients at risk for OSAS, i.e taking 1 or more anti- hypertensive drugs, being overweight (BMI > 25), snoring nearly every night. Intervention: The CP intervention consisted in (i) a discussion with the patient on the risks and comorbidities associated with untreated OSAS, (ii) guiding the patient to fill in the Berlin Questionnaire and the Epworth Sleepiness Scale and (iii) encouraging the patient to consult his/her referent GP with the questionnaires results and urging the doctor, in a letter written to his/her intention, to continue investigations. Measurement: Proportion of patients who had performed a diagnostic test for OSAS. Results: 782 Patients were analysed (88 patients exposed and 694 patients unexposed). After a 6 months follow-up, the number of patients who had performed a diagnostic test for OSAS was significantly higher in the exposed group compared to the unexposed group (22.7% versus 11.4%, p = 0.003). Being exposed to the CP intervention was associated with a higher chance of having a diagnostic test for OSAS, (adjusted OR: 2.34 [1.26–4.35]). Conclusion: These findings provide arguments for the implementation of a CP-GP collaborative OSAS screening intervention in community pharmacy routine practice. Future research should focus on potential economic benefits of such an intervention. Acknowledgements: We would like to thank the Ordre National des Pharmaciens and all the community pharmacists who participated in this study for their support in this new adventure. http://dx.doi.org/10.1016/j.sleep.2013.11.555
Sleep and mood disorders in epilepsy M. Pereira 1, L. Zuccolo 2, S. Cieza Ortiz 1, E. Urrestarazu Bolumburu 1, J. Iriarte Franco 1,2 1 Clínica Universidad de Navarra 2 Higa san martin la plata
Introduction: Epilepsy has a prevalence of 1% in general population, sleep disorders are common complications. Determine the fre-
Abstracts / Sleep Medicine 14S (2013) e165–e238
quency of sleep disorders (SD) and excessive daytime sleepiness (EDS) in patients with epilepsy and to identify the factors that are related to those described. Materials and methods: The factors analyzed included age, sex, type of epilepsy, duration of epilepsy disease, nocturnal seizures, frequency of seizures, electroencephalogram (EEG) interictal pathological, altered brain MRI, antiepileptic drug (AED) used; sleep quality, daytime sleepiness and mood disorders. Results: 58 patients were evaluated by interview and questionnaires on sleep quality (Pittsburgh scale), the degree of EDS (Epworth scale) and anxiety-depression (hospital depression and anxiety (HAD). The rest of the data were obtained from medical history. SD among patients with epilepsy studied had a prevalence of 55%. Significant differences were found between patients with sleep disorders versus (vs) patients with normal sleep in the following variables: frequency of difficulty (1 attacks/month: 8 (25%) vs 1 (4%): p 0.03), EDS (Epworth scale) 8 (25%) vs 1 (4%): p 0.03), presence of anxiety (HAD scale) 11 (22%) vs 3 (6%): p 0.001; presence of depression (HAD scale) 1 (4%) vs 10 (20%): p 0003. No significant differences between epileptic patients with and without sleep disorders when analyzing the rest of the variables. Conclusion: Sleep disorders are common among patients with epilepsy and are associated with a higher frequency of daytime sleepiness, anxiety and depression. It was shown that epileptic patients with sleep disorders showed a significant difference in seizure frequency of 1 time/month. However, this difference was not observed with a lower seizure frequency, possibly due to insufficient sample size. This would also explain the lack of association of other variables such as temporal lobe epilepsy, interictal EEG, AED disease and sleep disorders. While it is known the deleterious effect of epilepsy on sleep architecture, it is important to consider mood disorders predisposing factors of such alterations. Acknowledgements: Laura Zuccolo. http://dx.doi.org/10.1016/j.sleep.2013.11.556
Circadian and homeostatic processes influence daytime nap architecture S. Pereira, F. Beijamini, R. Spada, F. Menon, J. Clementin, F. Louzada Universidade Federal do Paraná, Brazil
Introduction: Besides being a useful tool for coping with sleep deprivation, naps can reduce sleepiness and improve cognitive performance. However, few studies so far have examined what factors regulate its structure. Therefore, we aimed to investigate if circadian preference influences daytime nap architecture. Materials and methods: Following a week of actigraphy monitoring of the sleep/wake cycle, a total of 43 healthy young adults (19 females, 22.16 (3.82) years) filled out the Morningness–Eveningness Questionnaire (MEQ) and took a 90 min polysomnographyrecorded nap. MEQ score, nocturnal sleep data and minutes of prior wakefulness were correlated with nap sleep variables. Results: There is a negative correlation between MEQ Score (47.93 (10.93)) and Slow Wave Sleep% (SWS) (r = .364, p = .044) and a positive correlation with Stage N1% (r = .371, p = .014), meaning that morning preference is associated with increased SWS and decreased N1 in a daytime nap. No correlations were found between MEQ Score and total sleep time (nap or nocturnal, for either the previous night or the mean 5 previous nights), Stage N2%, or REM%. The mean 5 previous nights bedtime (r = .381, p = .038) and wake time (r9 = .362, p = .049) were also negatively correlated with SWS, whereas the previous night bedtime (r = .375, p = .013) and wake time (r = .302, p = .049) were positively correlated with N1, that is, going to bed
e231
and waking up earlier predicted greater SWS% and smaller N1%, supporting MEQ Score correlations. To rule out homeostatic sleep drive as an explanation for increased nap SWS in individuals with a morning preference, minutes of prior wakefulness were correlated with nap sleep data. No association was found between homeostatic sleep drive and SWS (r = 0,244, p > 0.05). However, increasingly amounts of N1 were associated with less time between waking and napping (r = 0.370, p = 0.015). Conclusion: Morningness is associated with increased SWS in a daytime nap and prior wakefulness predicts time spent in N1, in healthy young adults. It is possible that this is because the scheduled nap timing was more suitable for individuals with a morning preference. Both components (circadian and homeostatic) should be taken into account when prescribing naps to ensure maximal restorative effects. Acknowledgements: Supported by grants from CAPES and CNPq. We would like to thank all the subjects that volunteered for this study. http://dx.doi.org/10.1016/j.sleep.2013.11.557
Determining the efficacy of temporary mandibular advancement splint in mild to moderate obstructive sleep apnea patients at baseline polysomnography W. Phuapradit 1, P. Mahakit 2 1 Phramongkutklao Hospital, Dental Department 2 Phramongkutklao Hospital, Otolaryngology Department
Introduction: Mandibular advancement splint (MAS) have become increasingly popular as alternatives to continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea (OSA). However, the acceptance of MAS is limited to the efficacy rate of 50–70% and inability to predict which patients will respond to this treatment. To overcome this limitation, the temporary mandibular advancement titration was performed in mild to moderate OSA patients dsuring baseline polysomnography (PSG) Objective: To determine the efficacy of temporary mandibular advancement splint in mild to moderate OSA patients during baseline polysomnography (PSG). Materials and methods: This pilot study consisted of ten undiagnosed subjects with OSA symptoms. The Temporary mandibular advancement splint, fabricated at 50% and 70% of maximum jaw protrusion, had been delivered to all subjects before each subject underwent baseline PSG. After the first half of the night, five subjects had severe OSA (AHI > 30) and CPAP titration was performed in this group,four subjects had mild to moderate OSA (AHI 5–30) and temporary mandibular advancement splint titration was performed in this group, one subjects was normal (AHI < 5) and no any device was performed on this subject. Results: Mean apnea–hypopnea index (AHI) was significantly reduced from 20.60(SD 8.28) to 5.65(SD 4.49) after treatment with Temporary mandibular advancement splint (p < 0.05). Three patients were considered treatment success and one patient was considered treatment failure as defined by AHI < 5. Conclusion: This pilot study shows that it is possible to utilize temporary mandibular advancement splint titration in mild to moderate OSA patients during baseline PSG and these results suggest that temporary mandibular advancement splint can be used as a tool in predicting treatment response in terms of efficacy piro to oral appliance therapy by means of using mandibular advancement splint in treating OSA. Acknowledgements: This study is granted by dental department,Phramongkutklao hospital, Bangkok, Thailand. http://dx.doi.org/10.1016/j.sleep.2013.11.558
Abstracts / Sleep Medicine 14S (2013) e165–e238
Results: Sub-C inhibition markedly influenced REM sleep and cataplexy. Compared to saline, Sub-C inhibition increased REM sleep amounts by increasing both the number (p = 0.001) and duration of REM episodes (p<0.0001). This intervention also triggered increases in basal levels of muscle tone during REM sleep, i.e., it blocked REM sleep paralysis (p<0.05). Silencing Sub-C cells also lead to marked sleep fragmentation by increasing the number of NREM to REM transitions. Sub-C inhibition lead to an 88% decrease (p = 0.04) in time spent in cataplexy as well as 75% fewer cataplexy episodes (p = 0.025). There were no measureable changes in the duration of cataplectic events (p > 0.05 for all variables). Conclusion: Pharmacogenetic manipulation of the Sub-C influences REM sleep expression as well as cataplexy expression in narcoleptic mice. At first glance, these preliminary data suggest that REM sleep paralysis and cataplexy may be mediated by a similar neural mechanism. http://dx.doi.org/10.1016/j.sleep.2013.11.553
Association between the amount of daytime sleep variability and cognitive flexibility in older adults S. Reyes 1, C. Algarín 1, D. Bunout 2, P. Peirano 1 1 Sleep Lab, INTA, University of Chile, Chile 2 Aging Lab, INTA, University of Chile, Chile
Introduction: Disrupted sleep patterns are commonly referred in the older population. They are often manifested by decreased total sleep time, increased waking after sleep onset, and napping. Napping may also be associated with increased risk of cognitive impairment, particularly compromised executive function, like cognitive flexibility. Recent evidence showed that variability in nap duration from day to day was predictive of greater medical morbidity. The aim of the study is to assess the association between variability in the amount of daytime and nighttime sleep and cognitive flexibility in older adults. Materials and methods: Participants were 76 subjects: 72% were women and mean age was 75.4 3.9 years (1). Motor activity was recorded continuously for a week with actigraphs (Actiwatch-16/ 64) worn in the nondominant wrist, yielding estimates of the amount of daytime and nighttime sleep. The variability of daytime and nighttime sleep amounts were calculated by dividing the standard deviation of sleep amounts within the week by the square root of the number of data points. Participants also performed the Stroop test: the words red, blue and green and a string of Xs were displayed on a monitor in red, blue, or green color. Three keys from the computer keyboard were covered by corresponding color patches, and the participants were told to press the key corresponding to the color of the target. The color words served as stimuli in the incongruent condition (e.g., the word red displayed in blue color), and was considered as the cognitive flexibility. We obtained the reaction time (RTI) and percentage of correct responses (PCI) for incongruent stimuli. 1. Reyes S, Algarín C, Bunout D, Peirano P. Sleep/wake patterns and physical performance in older adults. Aging Clin Exp Res 2013;25:175–181. Results: The logistic regression model showed that subjects with greater variability in the amount of daytime sleep were more likely to have longer RTI (OR = 1.07, p < 0.05) and lower PCI (OR = 1.08, p < 0.05). Variability in the amount of nighttime sleep showed no significant associations. Analyses were adjusted by gender and age. Conclusion: Our results show an association between daytime sleep amount variability and cognitive flexibility in older subjects. They provide support to the hypothesis relating sleep patterns and cognitive functioning, and suggest the relevance of daytime duration regularity for cognitive performance.
Acknowledgements: Support: FONIS SA06I20038/Fondecyt 1110513; (*) CONICYT, PhD program fellowship. http://dx.doi.org/10.1016/j.sleep.2013.11.554
The effectiveness of a community pharmacist-led intervention to improve screening for sleep apnea in primary care – A cohort study C. Perraudin Centre de Recherches Médecine Sciences Santé Mentale Société (CERMES3), UMR 8211 - INSERM U 988
Introduction: Despite the high prevalence and major public health ramifications, obstructive sleep apnea syndrome (OSAS) remains underdiagnosed. In many developed countries, because community pharmacists (CP) are easily accessible, they have been developing additional clinical services that integrate the services of and collaborate with other healthcare providers (general practitioners (GPs), nurses, etc.). Alternative strategies for primary care screening programs for OSAS involving the CP are discussed. Objectives: We aimed to determine whether the involvement of a CP in the care pathway of a patient at risk for OSAS, through the implementation of a GP-CP collaborative intervention, was effective that is to say if it improved the detection rate and diagnosis of the disease in this population. Materials and methods: Setting: 31 community pharmacies in 5 regions in France. Participants: Patients at risk for OSAS, i.e taking 1 or more anti- hypertensive drugs, being overweight (BMI > 25), snoring nearly every night. Intervention: The CP intervention consisted in (i) a discussion with the patient on the risks and comorbidities associated with untreated OSAS, (ii) guiding the patient to fill in the Berlin Questionnaire and the Epworth Sleepiness Scale and (iii) encouraging the patient to consult his/her referent GP with the questionnaires results and urging the doctor, in a letter written to his/her intention, to continue investigations. Measurement: Proportion of patients who had performed a diagnostic test for OSAS. Results: 782 Patients were analysed (88 patients exposed and 694 patients unexposed). After a 6 months follow-up, the number of patients who had performed a diagnostic test for OSAS was significantly higher in the exposed group compared to the unexposed group (22.7% versus 11.4%, p = 0.003). Being exposed to the CP intervention was associated with a higher chance of having a diagnostic test for OSAS, (adjusted OR: 2.34 [1.26–4.35]). Conclusion: These findings provide arguments for the implementation of a CP-GP collaborative OSAS screening intervention in community pharmacy routine practice. Future research should focus on potential economic benefits of such an intervention. Acknowledgements: We would like to thank the Ordre National des Pharmaciens and all the community pharmacists who participated in this study for their support in this new adventure. http://dx.doi.org/10.1016/j.sleep.2013.11.555
Sleep and mood disorders in epilepsy M. Pereira 1, L. Zuccolo 2, S. Cieza Ortiz 1, E. Urrestarazu Bolumburu 1, J. Iriarte Franco 1,2 1 Clínica Universidad de Navarra 2 Higa san martin la plata
Introduction: Epilepsy has a prevalence of 1% in general population, sleep disorders are common complications. Determine the fre-
Abstracts / Sleep Medicine 14S (2013) e165–e238
quency of sleep disorders (SD) and excessive daytime sleepiness (EDS) in patients with epilepsy and to identify the factors that are related to those described. Materials and methods: The factors analyzed included age, sex, type of epilepsy, duration of epilepsy disease, nocturnal seizures, frequency of seizures, electroencephalogram (EEG) interictal pathological, altered brain MRI, antiepileptic drug (AED) used; sleep quality, daytime sleepiness and mood disorders. Results: 58 patients were evaluated by interview and questionnaires on sleep quality (Pittsburgh scale), the degree of EDS (Epworth scale) and anxiety-depression (hospital depression and anxiety (HAD). The rest of the data were obtained from medical history. SD among patients with epilepsy studied had a prevalence of 55%. Significant differences were found between patients with sleep disorders versus (vs) patients with normal sleep in the following variables: frequency of difficulty (1 attacks/month: 8 (25%) vs 1 (4%): p 0.03), EDS (Epworth scale) 8 (25%) vs 1 (4%): p 0.03), presence of anxiety (HAD scale) 11 (22%) vs 3 (6%): p 0.001; presence of depression (HAD scale) 1 (4%) vs 10 (20%): p 0003. No significant differences between epileptic patients with and without sleep disorders when analyzing the rest of the variables. Conclusion: Sleep disorders are common among patients with epilepsy and are associated with a higher frequency of daytime sleepiness, anxiety and depression. It was shown that epileptic patients with sleep disorders showed a significant difference in seizure frequency of 1 time/month. However, this difference was not observed with a lower seizure frequency, possibly due to insufficient sample size. This would also explain the lack of association of other variables such as temporal lobe epilepsy, interictal EEG, AED disease and sleep disorders. While it is known the deleterious effect of epilepsy on sleep architecture, it is important to consider mood disorders predisposing factors of such alterations. Acknowledgements: Laura Zuccolo. http://dx.doi.org/10.1016/j.sleep.2013.11.556
Circadian and homeostatic processes influence daytime nap architecture S. Pereira, F. Beijamini, R. Spada, F. Menon, J. Clementin, F. Louzada Universidade Federal do Paraná, Brazil
Introduction: Besides being a useful tool for coping with sleep deprivation, naps can reduce sleepiness and improve cognitive performance. However, few studies so far have examined what factors regulate its structure. Therefore, we aimed to investigate if circadian preference influences daytime nap architecture. Materials and methods: Following a week of actigraphy monitoring of the sleep/wake cycle, a total of 43 healthy young adults (19 females, 22.16 (3.82) years) filled out the Morningness–Eveningness Questionnaire (MEQ) and took a 90 min polysomnographyrecorded nap. MEQ score, nocturnal sleep data and minutes of prior wakefulness were correlated with nap sleep variables. Results: There is a negative correlation between MEQ Score (47.93 (10.93)) and Slow Wave Sleep% (SWS) (r = .364, p = .044) and a positive correlation with Stage N1% (r = .371, p = .014), meaning that morning preference is associated with increased SWS and decreased N1 in a daytime nap. No correlations were found between MEQ Score and total sleep time (nap or nocturnal, for either the previous night or the mean 5 previous nights), Stage N2%, or REM%. The mean 5 previous nights bedtime (r = .381, p = .038) and wake time (r9 = .362, p = .049) were also negatively correlated with SWS, whereas the previous night bedtime (r = .375, p = .013) and wake time (r = .302, p = .049) were positively correlated with N1, that is, going to bed
e231
and waking up earlier predicted greater SWS% and smaller N1%, supporting MEQ Score correlations. To rule out homeostatic sleep drive as an explanation for increased nap SWS in individuals with a morning preference, minutes of prior wakefulness were correlated with nap sleep data. No association was found between homeostatic sleep drive and SWS (r = 0,244, p > 0.05). However, increasingly amounts of N1 were associated with less time between waking and napping (r = 0.370, p = 0.015). Conclusion: Morningness is associated with increased SWS in a daytime nap and prior wakefulness predicts time spent in N1, in healthy young adults. It is possible that this is because the scheduled nap timing was more suitable for individuals with a morning preference. Both components (circadian and homeostatic) should be taken into account when prescribing naps to ensure maximal restorative effects. Acknowledgements: Supported by grants from CAPES and CNPq. We would like to thank all the subjects that volunteered for this study. http://dx.doi.org/10.1016/j.sleep.2013.11.557
Determining the efficacy of temporary mandibular advancement splint in mild to moderate obstructive sleep apnea patients at baseline polysomnography W. Phuapradit 1, P. Mahakit 2 1 Phramongkutklao Hospital, Dental Department 2 Phramongkutklao Hospital, Otolaryngology Department
Introduction: Mandibular advancement splint (MAS) have become increasingly popular as alternatives to continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea (OSA). However, the acceptance of MAS is limited to the efficacy rate of 50–70% and inability to predict which patients will respond to this treatment. To overcome this limitation, the temporary mandibular advancement titration was performed in mild to moderate OSA patients dsuring baseline polysomnography (PSG) Objective: To determine the efficacy of temporary mandibular advancement splint in mild to moderate OSA patients during baseline polysomnography (PSG). Materials and methods: This pilot study consisted of ten undiagnosed subjects with OSA symptoms. The Temporary mandibular advancement splint, fabricated at 50% and 70% of maximum jaw protrusion, had been delivered to all subjects before each subject underwent baseline PSG. After the first half of the night, five subjects had severe OSA (AHI > 30) and CPAP titration was performed in this group,four subjects had mild to moderate OSA (AHI 5–30) and temporary mandibular advancement splint titration was performed in this group, one subjects was normal (AHI < 5) and no any device was performed on this subject. Results: Mean apnea–hypopnea index (AHI) was significantly reduced from 20.60(SD 8.28) to 5.65(SD 4.49) after treatment with Temporary mandibular advancement splint (p < 0.05). Three patients were considered treatment success and one patient was considered treatment failure as defined by AHI < 5. Conclusion: This pilot study shows that it is possible to utilize temporary mandibular advancement splint titration in mild to moderate OSA patients during baseline PSG and these results suggest that temporary mandibular advancement splint can be used as a tool in predicting treatment response in terms of efficacy piro to oral appliance therapy by means of using mandibular advancement splint in treating OSA. Acknowledgements: This study is granted by dental department,Phramongkutklao hospital, Bangkok, Thailand. http://dx.doi.org/10.1016/j.sleep.2013.11.558