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144 DOES SLEEP DEPRIVATION INFLUENCE THE OCCURRENCE OF FALLS IN CHILDREN?
Abstracts of 3rd International Congress of the Association of Sleep Medicine (WASM) / Sleep Medicine 10, Suppl. 2 (2009) S1–S83
amount of time spent sleeping (60%-80%), the impact of GER episodes on sleep has never been investigated. The role of vigilance states in the physiopathology of GER has also largely been ignored in neonates. The aim of this study was to analyze the effect of GER on sleep and the influence of vigilance states on GER in neonates. Methods: Esophageal impedance-pH monitoring was performed during nocturnal polysomnography in 24 infants (post-conception age: 40.8±3.5 weeks, body weight: 3.6±1.2 kg) hospitalized for suspicion of GER disease. According to the frequency and duration of acid, weak acid and non-acid reflux episodes, 8 infants were considered normal, without GER (control group), and 16 infants were considered pathologic (GER group). Results: No difference in sleep parameters (total sleep time, mean duration and frequency of sleep stages, and relative duration of active (AS) and quiet sleep (QS)) was observed between the two groups. Interestingly, an influence of vigilance states on GER episodes was observed. Out of 612 reflux episodes in the GER group, 60±29% were observed in wakefulness (W) and 35±23% in AS. These percentages were significantly (p<0.001) higher than the percentage of GER episodes in QS (5±6%). The occurrence of GER episodes was significantly (p<0.01) higher in W (0.16±0.17 min-1) than in AS (0.04±0.03 min-1) and QS (0.01±0.02 min-1). The difference between occurrences in AS and QS was also significant (p=0.001). The mean duration of GER episodes was higher in AS (0.20±0.14 min) than in QS (0.13±0.05 min, p=0.09). This parameter was 0.15±0.06 min in W. As a consequence, the relative time duration of GER episodes was significantly higher in W (2.6±3.2%) than in AS (0.8±0.8%) and QS (0.2±0.3%); all differences were significant (p<0.01). Conclusion: Gastroesophageal reflux disease does not seem to induce sleep disruption in neonates. Interestingly, GER episode characteristics are vigilance state dependent. They are more frequent in W and AS than in QS. The mechanisms explaining the effects of vigilance state on the characteristics of GER episodes in W, AS and QS remain to be determined.
142
SOCIO-CULTURAL ASPECTS OF PARENTING STYLE CONCERNING THE SLEEP OF QUEBEC CHILDREN
T.C.B.C. de Araújo, Y. Leanza, S. Salazar. Université Laval, Québec, Canada Introduction: Research on sleep is becoming increasingly relevant, especially since sleep disorders in children are more and more frequent (Tse & Hall, 2007). For some authors, the hectic life conditions in highly urbanized societies explain sleep problems in children. Considering sleep as a good strategy for monitoring children’s psychological development, a global comprehensive understanding (LeVine, 1974) is required in order to better comprehend sleep, its manifestations, as well as the parenting styles related to it. Objectives: This study explores parenting in relation to children’s sleep in Quebec, Canada. It aims to improve understanding of the socio-cultural aspects of parents’ perceptions and interventions in the sleep arrangements of their children in a French-Canadian society. Methods: A structured interview divided into four main themes (place of sleep; night feeding; sleep routines; and difficulties associated with sleep) was used. Collaborating parents were primarily middle-class and of Quebec origin only, with no immigrants in the family for the past three generations. Ninety-five interviews were analyzed quantitatively (SPSS) and qualitatively (Merleau-Ponty’s phenomenology method) concerning the reading of the parents’ interventions in their children’s sleep world. Results: Most of the Quebec children slept in their parents’ room until 5 months of age. After that, they began to sleep in their own room for the parents’ comfort and the children’s autonomy. Night feeding was mainly breast and bottle feeding. Most of the parents did not leave the bottle in their children’s cribs. Bedtime was guided by a well-established routine, conducted by both parents, usually with an equitable sharing of tasks and a fixed time to go to sleep. The majority of Quebec children had a transitional object and did not present difficulties associated with sleep. The Quebec parents, in general, accepted and/or sought parenting advice regarding the sleep of their children; however, they preferred to act according to their own intuition or their own childhood experiences. Conclusion: The Quebec parenting style confirms the North-American individualist norms and values, focusing on children’s development of psychological autonomy and early individuation, in a balanced family environment. Concerning their children’s sleep, Quebec parents prefer to portray themselves as autodidactic, self-reliant and independent, adapting their parenting skills to their children’s needs.
143
S39
CHARACTERIZATION OF THE SLEEP/WAKE CYCLE IN PRESCHOOL CHILDREN IN A PUBLIC SCHOOL
A.S. Belísio 1 , F.F. Kolodiuk 1 , D.N.S. Bezerra 1 , I.C. Sousa 1 , F.M. Louzada 2 , C.V.M. Azevedo 1 . 1 UFRN; 2 UFPR Introduction: The sleep/wake cycle during infancy is marked by biological and social changes that alter the pattern of child’s sleep. These changes are compensated by behaviors usually performed before bedtime (rituals before bedtime) trying to help children adapt to sleeping alone providing a better quality of sleep. Objective: To characterize the sleep/wake cycle and the influence of the social factors on the sleep/wake cycle in preschool children in a public school in Natal/RN. Methods: Subjects were 29 children that attended school in the morning (18 girls and 11 boys), aged 4-6 years. The research was conducted in two stages. First: meeting with parents, delivery of the consent forms and characterization of the habits of sleep, with the application of sleep habits questionnaire and economic classification. Second: characterization of patterns of sleep by sleep log during seven days and observation of the behavior in the classroom during five days (first observation: 07:35-08:20 a.m.; second observation: 09:45-10:35 a.m.). The frequency of yawning, rubbing the eyes, stretching and stooping on the desk were recorded. The questionnaires were filled by the parents. Results: The behavior most often performed by children before sleep was going to the bathroom (70.4%), requiring parental presence (40.7%) and taking an object to bed, as a toy or a blanket (40.0%). Moreover, most of them shared a room with siblings (55.0%) and parents (45.8%) (Qui-square, p<0,05). During the school days the sleep duration decreased and the children woke up earlier than on weekends (t-test, p<0.05). The frequency of yawns and stretches was higher during the first interval of observation (Wilcoxon, p<0.05). Conclusion: From the preliminary results, we suggest that the children performed rituals before bedtime. Also, the preschool children showed signs of partial sleep deprivation associated to the pattern of extension and reduction of sleep frequently reported in adolescents that attend to school on the morning. However, is necessary to extend the sample to confirm this hypothesis.
144
DOES SLEEP DEPRIVATION INFLUENCE THE OCCURRENCE OF FALLS IN CHILDREN?
L. Boto 1 , J. Crispim 1 , C. Juvandes 2 , I. Melo 2 , T. Rodrigues 3 , L. Nicolau 3 , P. Azeredo 2 , R. Ferreira 1 . 1 Department of Pediatrics, Hospital Santa Maria; 2 Department of Pediatrics, Hospital Garcia de Orta; 3 Biostatistics Laboratory, Faculdade de Medicina de Lisboa Introduction: Accidents are the main cause of death for children over 12 months of age in developed countries. While the relationship between sleep deprivation and accident risk is well-documented in adults, there have been few similar studies that have focused on this relationship in children. The demonstration of this relationship in children has crucial importance for the development of preventive actions. The aim of this study was to determine if there was an association between sleep deprivation and the risk of accidental fall (AF) in children over one year of age. Methods: Over a one-year period, a specifically designed questionnaire was given to children belonging to one of two different groups of children: G1, which included all children between the ages of 1 to 14 years old who sought care in the pediatric ER of a secondary care hospital for an AF; and G2, which included children who attended regular health visits (HV) at a healthcare center and who did not experience an AF. The relevant data that was collected included demographic characteristics, past medical history and drug exposure, previous week sleep pattern (PWSP), and the sleep duration (SD) and sleep pattern (SP) during the 24 hours that preceded the AF or HV. In addition, the cause of the fall and the severity of the injury were also included for children in group G1. Children with acute or chronic disease or exposure to drugs that are known to influence sleep or motor skills were excluded. Simplistic statistical methods were used for a comparative exploratory analysis of the data. For the non-parametric tests (α=5%), the children were stratified by sex and age. Results: A total of 2066 questionnaires were obtained, with 1789 representing G1 and 277 representing G2. The G1 group was 57.6% male, with a median age of 6.19 y [IQR 2,9;10,5], and 874 G1 members provided information on
S40
Abstracts of 3rd International Congress of the Association of Sleep Medicine (WASM) / Sleep Medicine 10, Suppl. 2 (2009) S1–S83
SP. PWSP was <8 h in 10.4%, 8-10 h in 55.5% and >10 h in 34.1%. The SD median for the previous 24 hours was 10 h [IQR 9;11,5], and SD was lower than PWSP in 12.8%of the G1 group members. The G2 group was 50.2% male, with a median age of 4.88 y [IQR 2,1;8,1], with a total of 267 completed questionnaires. PWSP was <8 h in 3.1%, 8-10 h in 55.5% and > 10 h in 41.2%. The SD median for the previous 24 hours was 10.5 h [IQR 9,5;12], and SD was lower than PWSP in 7.7% of the G2 group members. A significant association was found between the occurrence of an AF and a shorter-than-usual SD during the previous 24 hour period (p=0.025). In the 1-3 and 3-6 age groups, the rate of AF was significantly lower in those children who had daytime naps (p=0.002 and 0.04, respectively). There was no significant association between SD and the occurrence of AF. Conclusions: This study provides evidence of a relationship between acute sleep deprivation and AF in children and also indicates that daytime naps have a protective effect against AF in younger children. The level of sleep duration itself does not seem to have an influence on the occurrence of AF.
145
SLEEP-WAKE PATTERNS IN OVERWEIGHT PREPUBERTAL CHILDREN
R.A. Chamorro 1 , C. Algarín 1 , S. Reyes 1 , S. Durán 1 , M. Garrido 1 , B. Lozoff 2 , P. Peirano 1 . 1 INTA, University of Chile; 2 CHGD, University of Michigan Introduction: Increasing evidence supports the role of sleep in the regulation of body weight. An inverse relationship between sleep amount (SA) and body mass index (BMI) has been reported. However, most studies have used self-reported SA data. Objective: To study the relationship between objectively measured sleepwake patterns (SWP) and nutritional status in prepubertal children. Methods: We studied 171 preadolescents, mean age 10.2±0.2 yr, 60% males. Motor activity was evaluated by actigraphic recordings (Actiwatch-16/64) during 3 weekdays in the home. The SWP variables of interest were: total SA (sum of all nocturnal sleep episodes), nocturnal sleep episodes duration (NS), number of nocturnal awakenings (NA), and the latency to the first nocturnal waking episode (defined as the time elapsed from sleep onset until the first awakening lasting ≥5 min.). Also, the relationship of SA to BMI was studied by dichotomizing SA into ≤9 and >9 hours/night. Weight and height were measured in the laboratory, and BMI was calculated and classified as normal (BMI p≥10 and p<85) or overweight (BMI ≥ p85), according to age and sex. Results: SA was lower in overweight children (8.9±1.1 vs. 9.6±1.4 hours in normal-weight children, p<0.001). SA was negatively associated with BMI (r= -0.30, p<0.001). Children sleeping ≤9 h/night showed higher BMI than those sleeping >9 h/night (p<0.04). Sleeping ≤9 h/night was also associated with overweight status (p<0.05). In particular, children who slept ≤9 h/night showed shorter NS (p<0.0001), higher NA (p<0.05), and shorter latency to the first nocturnal waking episode (p<0.05). Finally, this group had 1.8 times more risk for being overweight (p<0.06) compared with those sleeping >9 h/night. Conclusions: These results support current evidence regarding SA and overweight in otherwise healthy prepubertal children. The nocturnal sleep fragmentation in the overweight group suggests a reduced ability to consolidate sleep in an uninterrupted episode throughout the night. We emphasize the relevance of nocturnal sleep as a contributing factor for body weight regulation in prepubescents. Support: Fondecyt 1070668 and NIH HD33487.
146
DISTURBANCES OF THE AUTONOMIC NERVOUS SYSTEM PRECEDE GASTROESOPHAGEAL REFLUX IN NEONATES DURING WAKEFULNESS AND SLEEP
D. Djeddi 1 , G. Kongolo 2 , M. Ammari 3 , A. Léké 1 , S. Delanaud 3 , E. Stéphan-Blanchard 3 , F. Telliez 3 . 1 PERITOX Laboratory, Pediatric Department, Amiens Hospital, France; 2 GRAMFC, Pediatric Department, Amiens Hospital, France; 3 PERITOX Laboratory, Medical Faculty Background: In adults, parasympathetic activity disturbances seem to be involved in the impaired function of the antireflux barrier and, therefore, could be the origin of gastroesophageal reflux (GER) episodes. The aim of the present study was to determine whether a dysfunction of the autonomic nervous system (ANS) is associated with GER disease in neonates. Sleep stages were considered because they influence ANS activity.
Methods: Esophageal impedance/pH monitoring was performed during a nocturnal polysomnography in 22 infants (post-conceptional age: 40.6±4.7 weeks; body weight: 3.1±0.8 kg) who were hospitalized on the suspicion of GER disease. According to the frequency and duration of acid and non-acid reflux episodes, eight infants were considered normal (control group) without GER, and 14 infants were considered pathologic (GER group). The time and frequency domain analyses of heart rate variability (HRV), which characterizes the functional state of the ANS, were investigated on successive 3-min slices of data. With respect to the frequency domain, the low frequency (LF) and high frequency (HF) band powers were used to characterize the sympathetic and parasympathetic activities, respectively. Sympathovagal balance was expressed as LF/HF. Results: Whatever the vigilance states, no difference was observed in the ANS status between the control and GER groups., Of the 612 reflux episodes that occurred in the GER group, 60±29% of the reflux episodes were observed during wakefulness (W), 35±23% during active sleep (AS) and 5±6% during quiet sleep (QS). Interestingly, transitory modifications of HRV occurred just before the onset of the reflux episodes. In the period preceding the reflux, an increase in LF/HF was observed during W (p=0.04) and in QS (p=0.06). This observation could be explained by a decrease in the normalized value of HF and an increase in the normalized value of LF during W (both p=0.04) and QS (both p=0.06). Although the same pattern was observed during AS, the values did not reach statistical significance. Conclusion: Strikingly, the major modification in HRV occurs during the period that precedes the reflux episodes. In neonates, the increase in sympathovagal balance could be considered to be a primary factor that contributes to the physiopathological mechanism of reflux.
147
VIGILANCE STATES INFLUENCE THE RELATIONSHIP BETWEEN HEART RATE VARIABILITY LEVELS AND SYMPATHOVAGAL BALANCE IN NEONATES
D. Djeddi 1 , G. Kongolo 2 , M. Ammari 3 , A. Léké 1 , S. Delanaud 3 , E. Stéphan-Blanchard 3 , F. Telliez 3 . 1 PERITOX Laboratory, Pediatric Dept., Amiens Hospital, France; 2 GRAMFC-Medical Faculty, Pediatric Dept., Amiens Hospital, France; 3 PERITOX Laboratory, Medical Faculty, Amiens, France Background: Heart rate variability (HRV) characterizes the functional state of the autonomic nervous system (ANS). During neonatal maturation of the ANS, HRV is increased and accompanied by a pronounced increase in parasympathetic activity. HRV is vigilance-state dependent and is higher in walkfulness (W) and in active sleep (AS) than in quiet sleep (QS). Aim: The aim of this study was to investigate the influence of vigilance state on the relationship between the HRV level and sympathovagal balance in neonates. Methods: Nightime video polysomnography (EEG, EOG, cardiorespiratory signals) was recorded in 27 neonates (gestational age: 36.4±4.6 weeks, postconceptional age: 42.1±5.2 weeks). The time and frequency domain (fast fourier transform) of HRV were investigated during the entire night on successive 3-min slices of data. In the frequency domain, we calculated the low frequency (LF) and high frequency (HF) band powers that characterized the sympathetic and parasympathetic activities, respectively. Sympathovagal balance was expressed as the LF/HF ratio. Results: As previously observed, the levels of HRV in both the time and frequency domains were significantly higher in W and AS than in QS. A negative relationship was observed between the level of HRV parameters and sympathovagal balance in wakefulness and in AS. This was observed over time as in frequency domain analyses. In W and AS, higher LF, HF and total variability, was inversley proportional to lower LF/HF (r2 between 44-58%, p<0.001 for all parameters tested). Strikingly, these relationships were not observed in QS. Despite the LF/HF great inter-individual variability in QS, the level of HRV remained within a low range of values. No relationships with gestational or post-conceptional age was found. Conclusion: The results suggested that the relationship between HRV level and sympathovagal balance is vigilance state dependent. In AS and wakefulness, when neonates were characterized by a high level of HRV, the sympathovagal balance decreased. This was not the case in QS. It remains to be determined whether the physiological significance of this result is related to the effect of maturation on HRV level.
amount of time spent sleeping (60%-80%), the impact of GER episodes on sleep has never been investigated. The role of vigilance states in the physiopathology of GER has also largely been ignored in neonates. The aim of this study was to analyze the effect of GER on sleep and the influence of vigilance states on GER in neonates. Methods: Esophageal impedance-pH monitoring was performed during nocturnal polysomnography in 24 infants (post-conception age: 40.8±3.5 weeks, body weight: 3.6±1.2 kg) hospitalized for suspicion of GER disease. According to the frequency and duration of acid, weak acid and non-acid reflux episodes, 8 infants were considered normal, without GER (control group), and 16 infants were considered pathologic (GER group). Results: No difference in sleep parameters (total sleep time, mean duration and frequency of sleep stages, and relative duration of active (AS) and quiet sleep (QS)) was observed between the two groups. Interestingly, an influence of vigilance states on GER episodes was observed. Out of 612 reflux episodes in the GER group, 60±29% were observed in wakefulness (W) and 35±23% in AS. These percentages were significantly (p<0.001) higher than the percentage of GER episodes in QS (5±6%). The occurrence of GER episodes was significantly (p<0.01) higher in W (0.16±0.17 min-1) than in AS (0.04±0.03 min-1) and QS (0.01±0.02 min-1). The difference between occurrences in AS and QS was also significant (p=0.001). The mean duration of GER episodes was higher in AS (0.20±0.14 min) than in QS (0.13±0.05 min, p=0.09). This parameter was 0.15±0.06 min in W. As a consequence, the relative time duration of GER episodes was significantly higher in W (2.6±3.2%) than in AS (0.8±0.8%) and QS (0.2±0.3%); all differences were significant (p<0.01). Conclusion: Gastroesophageal reflux disease does not seem to induce sleep disruption in neonates. Interestingly, GER episode characteristics are vigilance state dependent. They are more frequent in W and AS than in QS. The mechanisms explaining the effects of vigilance state on the characteristics of GER episodes in W, AS and QS remain to be determined.
142
SOCIO-CULTURAL ASPECTS OF PARENTING STYLE CONCERNING THE SLEEP OF QUEBEC CHILDREN
T.C.B.C. de Araújo, Y. Leanza, S. Salazar. Université Laval, Québec, Canada Introduction: Research on sleep is becoming increasingly relevant, especially since sleep disorders in children are more and more frequent (Tse & Hall, 2007). For some authors, the hectic life conditions in highly urbanized societies explain sleep problems in children. Considering sleep as a good strategy for monitoring children’s psychological development, a global comprehensive understanding (LeVine, 1974) is required in order to better comprehend sleep, its manifestations, as well as the parenting styles related to it. Objectives: This study explores parenting in relation to children’s sleep in Quebec, Canada. It aims to improve understanding of the socio-cultural aspects of parents’ perceptions and interventions in the sleep arrangements of their children in a French-Canadian society. Methods: A structured interview divided into four main themes (place of sleep; night feeding; sleep routines; and difficulties associated with sleep) was used. Collaborating parents were primarily middle-class and of Quebec origin only, with no immigrants in the family for the past three generations. Ninety-five interviews were analyzed quantitatively (SPSS) and qualitatively (Merleau-Ponty’s phenomenology method) concerning the reading of the parents’ interventions in their children’s sleep world. Results: Most of the Quebec children slept in their parents’ room until 5 months of age. After that, they began to sleep in their own room for the parents’ comfort and the children’s autonomy. Night feeding was mainly breast and bottle feeding. Most of the parents did not leave the bottle in their children’s cribs. Bedtime was guided by a well-established routine, conducted by both parents, usually with an equitable sharing of tasks and a fixed time to go to sleep. The majority of Quebec children had a transitional object and did not present difficulties associated with sleep. The Quebec parents, in general, accepted and/or sought parenting advice regarding the sleep of their children; however, they preferred to act according to their own intuition or their own childhood experiences. Conclusion: The Quebec parenting style confirms the North-American individualist norms and values, focusing on children’s development of psychological autonomy and early individuation, in a balanced family environment. Concerning their children’s sleep, Quebec parents prefer to portray themselves as autodidactic, self-reliant and independent, adapting their parenting skills to their children’s needs.
143
S39
CHARACTERIZATION OF THE SLEEP/WAKE CYCLE IN PRESCHOOL CHILDREN IN A PUBLIC SCHOOL
A.S. Belísio 1 , F.F. Kolodiuk 1 , D.N.S. Bezerra 1 , I.C. Sousa 1 , F.M. Louzada 2 , C.V.M. Azevedo 1 . 1 UFRN; 2 UFPR Introduction: The sleep/wake cycle during infancy is marked by biological and social changes that alter the pattern of child’s sleep. These changes are compensated by behaviors usually performed before bedtime (rituals before bedtime) trying to help children adapt to sleeping alone providing a better quality of sleep. Objective: To characterize the sleep/wake cycle and the influence of the social factors on the sleep/wake cycle in preschool children in a public school in Natal/RN. Methods: Subjects were 29 children that attended school in the morning (18 girls and 11 boys), aged 4-6 years. The research was conducted in two stages. First: meeting with parents, delivery of the consent forms and characterization of the habits of sleep, with the application of sleep habits questionnaire and economic classification. Second: characterization of patterns of sleep by sleep log during seven days and observation of the behavior in the classroom during five days (first observation: 07:35-08:20 a.m.; second observation: 09:45-10:35 a.m.). The frequency of yawning, rubbing the eyes, stretching and stooping on the desk were recorded. The questionnaires were filled by the parents. Results: The behavior most often performed by children before sleep was going to the bathroom (70.4%), requiring parental presence (40.7%) and taking an object to bed, as a toy or a blanket (40.0%). Moreover, most of them shared a room with siblings (55.0%) and parents (45.8%) (Qui-square, p<0,05). During the school days the sleep duration decreased and the children woke up earlier than on weekends (t-test, p<0.05). The frequency of yawns and stretches was higher during the first interval of observation (Wilcoxon, p<0.05). Conclusion: From the preliminary results, we suggest that the children performed rituals before bedtime. Also, the preschool children showed signs of partial sleep deprivation associated to the pattern of extension and reduction of sleep frequently reported in adolescents that attend to school on the morning. However, is necessary to extend the sample to confirm this hypothesis.
144
DOES SLEEP DEPRIVATION INFLUENCE THE OCCURRENCE OF FALLS IN CHILDREN?
L. Boto 1 , J. Crispim 1 , C. Juvandes 2 , I. Melo 2 , T. Rodrigues 3 , L. Nicolau 3 , P. Azeredo 2 , R. Ferreira 1 . 1 Department of Pediatrics, Hospital Santa Maria; 2 Department of Pediatrics, Hospital Garcia de Orta; 3 Biostatistics Laboratory, Faculdade de Medicina de Lisboa Introduction: Accidents are the main cause of death for children over 12 months of age in developed countries. While the relationship between sleep deprivation and accident risk is well-documented in adults, there have been few similar studies that have focused on this relationship in children. The demonstration of this relationship in children has crucial importance for the development of preventive actions. The aim of this study was to determine if there was an association between sleep deprivation and the risk of accidental fall (AF) in children over one year of age. Methods: Over a one-year period, a specifically designed questionnaire was given to children belonging to one of two different groups of children: G1, which included all children between the ages of 1 to 14 years old who sought care in the pediatric ER of a secondary care hospital for an AF; and G2, which included children who attended regular health visits (HV) at a healthcare center and who did not experience an AF. The relevant data that was collected included demographic characteristics, past medical history and drug exposure, previous week sleep pattern (PWSP), and the sleep duration (SD) and sleep pattern (SP) during the 24 hours that preceded the AF or HV. In addition, the cause of the fall and the severity of the injury were also included for children in group G1. Children with acute or chronic disease or exposure to drugs that are known to influence sleep or motor skills were excluded. Simplistic statistical methods were used for a comparative exploratory analysis of the data. For the non-parametric tests (α=5%), the children were stratified by sex and age. Results: A total of 2066 questionnaires were obtained, with 1789 representing G1 and 277 representing G2. The G1 group was 57.6% male, with a median age of 6.19 y [IQR 2,9;10,5], and 874 G1 members provided information on
S40
Abstracts of 3rd International Congress of the Association of Sleep Medicine (WASM) / Sleep Medicine 10, Suppl. 2 (2009) S1–S83
SP. PWSP was <8 h in 10.4%, 8-10 h in 55.5% and >10 h in 34.1%. The SD median for the previous 24 hours was 10 h [IQR 9;11,5], and SD was lower than PWSP in 12.8%of the G1 group members. The G2 group was 50.2% male, with a median age of 4.88 y [IQR 2,1;8,1], with a total of 267 completed questionnaires. PWSP was <8 h in 3.1%, 8-10 h in 55.5% and > 10 h in 41.2%. The SD median for the previous 24 hours was 10.5 h [IQR 9,5;12], and SD was lower than PWSP in 7.7% of the G2 group members. A significant association was found between the occurrence of an AF and a shorter-than-usual SD during the previous 24 hour period (p=0.025). In the 1-3 and 3-6 age groups, the rate of AF was significantly lower in those children who had daytime naps (p=0.002 and 0.04, respectively). There was no significant association between SD and the occurrence of AF. Conclusions: This study provides evidence of a relationship between acute sleep deprivation and AF in children and also indicates that daytime naps have a protective effect against AF in younger children. The level of sleep duration itself does not seem to have an influence on the occurrence of AF.
145
SLEEP-WAKE PATTERNS IN OVERWEIGHT PREPUBERTAL CHILDREN
R.A. Chamorro 1 , C. Algarín 1 , S. Reyes 1 , S. Durán 1 , M. Garrido 1 , B. Lozoff 2 , P. Peirano 1 . 1 INTA, University of Chile; 2 CHGD, University of Michigan Introduction: Increasing evidence supports the role of sleep in the regulation of body weight. An inverse relationship between sleep amount (SA) and body mass index (BMI) has been reported. However, most studies have used self-reported SA data. Objective: To study the relationship between objectively measured sleepwake patterns (SWP) and nutritional status in prepubertal children. Methods: We studied 171 preadolescents, mean age 10.2±0.2 yr, 60% males. Motor activity was evaluated by actigraphic recordings (Actiwatch-16/64) during 3 weekdays in the home. The SWP variables of interest were: total SA (sum of all nocturnal sleep episodes), nocturnal sleep episodes duration (NS), number of nocturnal awakenings (NA), and the latency to the first nocturnal waking episode (defined as the time elapsed from sleep onset until the first awakening lasting ≥5 min.). Also, the relationship of SA to BMI was studied by dichotomizing SA into ≤9 and >9 hours/night. Weight and height were measured in the laboratory, and BMI was calculated and classified as normal (BMI p≥10 and p<85) or overweight (BMI ≥ p85), according to age and sex. Results: SA was lower in overweight children (8.9±1.1 vs. 9.6±1.4 hours in normal-weight children, p<0.001). SA was negatively associated with BMI (r= -0.30, p<0.001). Children sleeping ≤9 h/night showed higher BMI than those sleeping >9 h/night (p<0.04). Sleeping ≤9 h/night was also associated with overweight status (p<0.05). In particular, children who slept ≤9 h/night showed shorter NS (p<0.0001), higher NA (p<0.05), and shorter latency to the first nocturnal waking episode (p<0.05). Finally, this group had 1.8 times more risk for being overweight (p<0.06) compared with those sleeping >9 h/night. Conclusions: These results support current evidence regarding SA and overweight in otherwise healthy prepubertal children. The nocturnal sleep fragmentation in the overweight group suggests a reduced ability to consolidate sleep in an uninterrupted episode throughout the night. We emphasize the relevance of nocturnal sleep as a contributing factor for body weight regulation in prepubescents. Support: Fondecyt 1070668 and NIH HD33487.
146
DISTURBANCES OF THE AUTONOMIC NERVOUS SYSTEM PRECEDE GASTROESOPHAGEAL REFLUX IN NEONATES DURING WAKEFULNESS AND SLEEP
D. Djeddi 1 , G. Kongolo 2 , M. Ammari 3 , A. Léké 1 , S. Delanaud 3 , E. Stéphan-Blanchard 3 , F. Telliez 3 . 1 PERITOX Laboratory, Pediatric Department, Amiens Hospital, France; 2 GRAMFC, Pediatric Department, Amiens Hospital, France; 3 PERITOX Laboratory, Medical Faculty Background: In adults, parasympathetic activity disturbances seem to be involved in the impaired function of the antireflux barrier and, therefore, could be the origin of gastroesophageal reflux (GER) episodes. The aim of the present study was to determine whether a dysfunction of the autonomic nervous system (ANS) is associated with GER disease in neonates. Sleep stages were considered because they influence ANS activity.
Methods: Esophageal impedance/pH monitoring was performed during a nocturnal polysomnography in 22 infants (post-conceptional age: 40.6±4.7 weeks; body weight: 3.1±0.8 kg) who were hospitalized on the suspicion of GER disease. According to the frequency and duration of acid and non-acid reflux episodes, eight infants were considered normal (control group) without GER, and 14 infants were considered pathologic (GER group). The time and frequency domain analyses of heart rate variability (HRV), which characterizes the functional state of the ANS, were investigated on successive 3-min slices of data. With respect to the frequency domain, the low frequency (LF) and high frequency (HF) band powers were used to characterize the sympathetic and parasympathetic activities, respectively. Sympathovagal balance was expressed as LF/HF. Results: Whatever the vigilance states, no difference was observed in the ANS status between the control and GER groups., Of the 612 reflux episodes that occurred in the GER group, 60±29% of the reflux episodes were observed during wakefulness (W), 35±23% during active sleep (AS) and 5±6% during quiet sleep (QS). Interestingly, transitory modifications of HRV occurred just before the onset of the reflux episodes. In the period preceding the reflux, an increase in LF/HF was observed during W (p=0.04) and in QS (p=0.06). This observation could be explained by a decrease in the normalized value of HF and an increase in the normalized value of LF during W (both p=0.04) and QS (both p=0.06). Although the same pattern was observed during AS, the values did not reach statistical significance. Conclusion: Strikingly, the major modification in HRV occurs during the period that precedes the reflux episodes. In neonates, the increase in sympathovagal balance could be considered to be a primary factor that contributes to the physiopathological mechanism of reflux.
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VIGILANCE STATES INFLUENCE THE RELATIONSHIP BETWEEN HEART RATE VARIABILITY LEVELS AND SYMPATHOVAGAL BALANCE IN NEONATES
D. Djeddi 1 , G. Kongolo 2 , M. Ammari 3 , A. Léké 1 , S. Delanaud 3 , E. Stéphan-Blanchard 3 , F. Telliez 3 . 1 PERITOX Laboratory, Pediatric Dept., Amiens Hospital, France; 2 GRAMFC-Medical Faculty, Pediatric Dept., Amiens Hospital, France; 3 PERITOX Laboratory, Medical Faculty, Amiens, France Background: Heart rate variability (HRV) characterizes the functional state of the autonomic nervous system (ANS). During neonatal maturation of the ANS, HRV is increased and accompanied by a pronounced increase in parasympathetic activity. HRV is vigilance-state dependent and is higher in walkfulness (W) and in active sleep (AS) than in quiet sleep (QS). Aim: The aim of this study was to investigate the influence of vigilance state on the relationship between the HRV level and sympathovagal balance in neonates. Methods: Nightime video polysomnography (EEG, EOG, cardiorespiratory signals) was recorded in 27 neonates (gestational age: 36.4±4.6 weeks, postconceptional age: 42.1±5.2 weeks). The time and frequency domain (fast fourier transform) of HRV were investigated during the entire night on successive 3-min slices of data. In the frequency domain, we calculated the low frequency (LF) and high frequency (HF) band powers that characterized the sympathetic and parasympathetic activities, respectively. Sympathovagal balance was expressed as the LF/HF ratio. Results: As previously observed, the levels of HRV in both the time and frequency domains were significantly higher in W and AS than in QS. A negative relationship was observed between the level of HRV parameters and sympathovagal balance in wakefulness and in AS. This was observed over time as in frequency domain analyses. In W and AS, higher LF, HF and total variability, was inversley proportional to lower LF/HF (r2 between 44-58%, p<0.001 for all parameters tested). Strikingly, these relationships were not observed in QS. Despite the LF/HF great inter-individual variability in QS, the level of HRV remained within a low range of values. No relationships with gestational or post-conceptional age was found. Conclusion: The results suggested that the relationship between HRV level and sympathovagal balance is vigilance state dependent. In AS and wakefulness, when neonates were characterized by a high level of HRV, the sympathovagal balance decreased. This was not the case in QS. It remains to be determined whether the physiological significance of this result is related to the effect of maturation on HRV level.