Marie-Hélène Pennestri

Nocturnal blood pressure changes in patients with restless legs syndrome

Objectives: To assess heart rate (HR) and blood pressure (BP) changes associated with periodic leg movements during sleep (PLMS) with or without EEG signs of arousal in subjects with primary restless legs syndrome (RLS). Methods: Ten patients with RLS (4 women, aged 47.3 ± 13.5 years) underwent one night of polysomnography along with noninvasive beat-to-beat BP monitoring. Ten PLMS with microarousals (PLMS-MA) and 10 PLMS without microarousals (PLMS-noMA) were analyzed in each subject. Systolic and diastolic BP (SBP, DBP) were measured within a 25-beat temporal window comprising 10 beats before and 15 beats after onset of each movement. PLMS-related BP changes were assessed by repeated measures one-way analysis of variance. BP changes associated with PLMS-MA and PLMS-noMA were compared by paired t-tests. Pearson correlation coefficients were used to assess the relationship between cardiovascular changes and clinical and polysomnographic variables. Results: BP increased significantly in association with all PLMS (on average, SBP 22 mm Hg, DBP 11 mm Hg). BP changes associated with PLMS-MA were greater vs those associated with PLMS-noMA (p < 0.05). SBP and DBP changes increased with age and the duration of illness. Conclusions: Periodic leg movements–related repetitive nocturnal blood pressure fluctuations could contribute to the risk of cardiovascular diseases in patients with restless legs syndrome, especially in the elderly.

Periodic leg movements during sleep and wakefulness in narcolepsy.

The objectives of the study were to measure the prevalence of periodic leg movements during NREM and REM sleep (PLMS) and while awake (PLMW) and to assess the impact of PLMS on nocturnal sleep and daytime functioning in patients with narcolepsy. One hundred and sixty‐nine patients with narcolepsy and 116 normal controls matched for age and gender were included. Narcoleptics with high and low PLMS indices were compared to assess the impact of PLMS on sleep and Multiple Sleep Latency Test (MSLT) variables. More narcoleptics than controls had a PLMS index greater than 5 per hour of sleep (67% versus 37%) and an index greater than 10 (53% versus 21%). PLMS indices were higher both in NREM and REM sleep in narcoleptic patients, but the between‐group difference was greater for REM sleep. A significant increase of PLMS index was also found with aging in both narcoleptic patients and controls. PLMW indices were also significantly higher in narcoleptic patients. Patients with an elevated index of PLMS had a higher percentage of stage 1 sleep, a lower percentage of REM sleep, a lower REM efficiency and a shorter MSLT latency. The present study demonstrates a high frequency of PLMS and PLMW in narcolepsy, an association between the presence of PLMS and measures of REM sleep and daytime functioning disruption. These results suggest that PLMS represent an intrinsic feature of narcolepsy.

Blood pressure changes associated with periodic leg movements during sleep in healthy subjects

BACKGROUND AND OBJECTIVES Periodic leg movements during sleep (PLMS) are associated with important blood pressure (BP) increases in restless legs syndrome (RLS) patients. These movements also are highly prevalent in the healthy elderly population. The aims of our study were to evaluate if heart rate (HR) and BP changes associated with PLMS are present in healthy subjects with no report of health concerns and to compare the amplitude of cardiovascular changes in healthy subjects to that of RLS subjects. METHODS Fourteen healthy subjects (six men, eight women; 46.6±9.7 y) and 14 RLS subjects (six men, eight women; 47.6±11.8 y) matched for age and gender participated in our study. Beat-to-beat noninvasive BP was continuously recorded during one night of polysomnography. HR, systolic BP (SBP) and diastolic BP (DBP) were measured for 10 beats before and 15 beats after onset of PLMS with and without microarousals (MA). RESULTS PLMS were associated with sudden and significant increases of HR, SBP and DBP in both groups; however, cardiovascular increases were more pronounced in RLS subjects than in healthy subjects. CONCLUSIONS Because PLMS index increases with age in healthy subjects and aging is associated with higher cardiovascular risk, further studies should investigate the impact of PLMS-related BP changes on the development of cardiovascular diseases in healthy elderly populations.

Childhood sleepwalking and sleep terrors: a longitudinal study of prevalence and familial aggregation

IMPORTANCE Childhood sleepwalking and sleep terrors are 2 parasomnias with a risk of serious injury for which familial aggregation has been shown. OBJECTIVES To assess the prevalence of sleepwalking and sleep terrors during childhood; to investigate the link between early sleep terrors and sleepwalking later in childhood; and to evaluate the degree of association between parental history of sleepwalking and presence of somnambulism and sleep terrors in children. DESIGN, SETTING, AND PARTICIPANTS Sleep data from a large prospective longitudinal cohort (the Quebec Longitudinal Study of Child Development) of 1940 children born in 1997 and 1998 in the province were studied from March 1999 to March 2011. MAIN OUTCOMES AND MEASURES Prevalence of sleep terrors and sleepwalking was assessed yearly from ages 1 1/2 and 2 1/2 years, respectively, to age 13 years through a questionnaire completed by the mother. Parental history of sleepwalking was also queried. RESULTS The peak of prevalence was observed at 1 1/2 years for sleep terrors (34.4% of children; 95% CI, 32.3%-36.5%) and at age 10 years for sleepwalking (13.4%; 95% CI, 11.3%-15.5%). As many as one-third of the children who had early childhood sleep terrors developed sleepwalking later in childhood. The prevalence of childhood sleepwalking increases with the degree of parental history of sleepwalking: 22.5% (95% CI, 19.2%-25.8%) for children without a parental history of sleepwalking, 47.4% (95% CI, 38.9%-55.9%) for children who had 1 parent with a history of sleepwalking, and 61.5% (95% CI, 42.8%-80.2%) for children whose mother and father had a history of sleepwalking. Moreover, parental history of sleepwalking predicted the incidence of sleep terrors in children as well as the persistent nature of sleep terrors. CONCLUSIONS AND RELEVANCE These findings substantiate the strong familial aggregation for the 2 parasomnias and lend support to the notion that sleepwalking and sleep terrors represent 2 manifestations of the same underlying pathophysiological entity.

Attachment disorganization among children in Neonatal Intensive Care Unit: Preliminary results

BACKGROUND Preterm children have been reported to be at higher risk to develop attachment insecurity. AIMS The present study aimed to investigate potential differences in attachment security between newborns who were sent to Neonatal Intensive Care Unit (NICU) and those who were not, in a population of full-term children. STUDY DESIGN Participants (162 mother-child dyads) were part of a longitudinal study (MAVAN). Twenty-three of these children received special care at birth (NICU group). Attachment security was assessed at 36 months with the Strange Situation Procedure. Socio-economic status (SES), birth weight, maternal mood, maternal sensitivity, mental/psychomotor developmental indexes, Apgar scores, presence of complications during delivery and infant general health were assessed. RESULTS In the No-NICU group, 55.4% of children were securely attached, 24.5% were insecure and 20.1% were disorganized. However, in the NICU group, 43.5% of children were securely attached, 8.7% were insecure and 47.8% were disorganized (χ(2)=9.0; p=.01). The only differences between the 2 groups were a lower Apgar, more respiratory infections and more visits to walk-in clinic/hospital (ps<.05) and a trend for lower SES and more ear infections in the NICU group. Logistic regressions revealed an odds ratio of 6.1 (p=.003) of developing a disorganized attachment after a stay in NICU, when controlling for these confounding variables. CONCLUSION Newborns who were admitted to NICU have an odds ratio of about 6 to develop a disorganized attachment at 36 months. These preliminary results support the importance of supportive parental proximity and contact with the infant in the NICU and possible after-care.

Effects of Genotype and Sleep on Temperament.

BACKGROUND AND OBJECTIVES: Sleep problems are frequent in young children; however, children vary in the degree to which they are affected by poor sleep quality. We investigated whether a polymorphism in the serotonin transporter gene, which is linked to emotional function, is a potential moderator of the influences of sleep duration on infant temperament using longitudinal data. METHODS: We examined the interactive effects of average sleep duration between 6 and 36 months of age and the 5-HTTLPR genotype on negative emotionality/behavioral dysregulation at 36 months in 209 children recruited into a longitudinal birth cohort study. Triallelic genotyping of 5-HTTLPR was performed by looking at SLC6A4 genotype, focusing on the serotonin transporter-linked polymorphic region (5-HTTLPR) including the SNP polymorphism (rs23351). Child sleep habits were assessed with a maternal self-report questionnaire. RESULTS: After controlling for demographics and both previous and concurrent maternal depression, multiple linear regression analyses revealed a significant interaction effect of average sleep duration for the first 3 years of life and 5-HTTLPR genotype on child negative emotionality/behavioral dysregulation such that the effects were exclusive to those with low-expressing 5-HTTLPR genotypes. CONCLUSIONS: The results suggest differential susceptibility to the effect of sleep duration early in life, which reiterates that the short allele of the 5-HTTLPR represents a marker of increased environmental sensitivity regarding emotional development. Differential susceptibility theory posits that certain factors may increase an individual’s susceptibility to the environment, in either a positive or negative fashion.

Establishment and consolidation of the sleep-wake cycle as a function of attachment pattern

The development of sleep-wake regulation in infants depends upon brain maturation as well as various environmental factors. The aim of the present study was to evaluate sleep duration and quality as a function of child attachment to the mother. One hundred and thirty-four mother–child dyads enrolled in the Maternal Adversity, Vulnerability and Neurodevelopment (MAVAN) project were included in this study. Attachment was assessed with the Strange Situation procedure at 36 months and maternal sleep reports were collected at 6, 12, 24 and 36 months. Differences in sleep characteristics were assessed with mixed models with one factor (attachment group) and one repeated measure (age). Children classified as disorganized had a significantly lower duration of nocturnal sleep, went to bed later, signaled more awakenings, had shorter periods of uninterrupted sleep (only at 12 months) and had shorter periods of time in bed (only at 6 months) than children classified as secure and/or ambivalent (p < 0.05). This is the first study to show that children with insecure disorganized attachment present a distinct sleep pattern in comparison with those with secure or ambivalent attachment between 6 and 36 months of age. Sleep disturbances could exacerbate difficulties in these families that are already considered vulnerable.

Poor Quality of Sleep in Foster Children Relates to Maltreatment and Placement Conditions

This exploratory study investigated child sleep in a sample of maltreated children living in foster care and examined its associations with placement conditions and history of maltreatment. Participants included 25 foster children and their foster caregiver. Children were on average 60.24 months of age (SD = 18.70). Foster mothers completed questionnaires assessing parenting stress and quality of child sleep while maltreatment/placement history was retrieved from children Child Protection Services (CPS) records. Shorter nocturnal sleep duration and parasomnias were related to placement at a younger age. The non-restorative sleep index was significantly related to time spent in the foster home and parenting stress and marginally related to number of placements and sexual abuse and neglect. Poor sleep was associated with past experience of sexual abuse and neglect and parenting stress. No relationships were found between sleep characteristics and past experiences of physical abuse or type of foster family. These findings provide an opportunity to uncover how foster children experiences are related to sleep disturbances.

Maternal characteristics and behavioural/emotional problems in preschoolers: how they relate to sleep rhythmic movements at sleep onset

Sleep rhythmic movements have been speculated to be a form of self‐soothing. While this sleep‐related movement has been associated with lower socioeconomic status, psychopathologies and maternal characteristics, prospective studies with sizeable sample and objective measurements are lacking. The objectives were: (a) to identify maternal characteristics predicting sleep rhythmic movements in children; and (b) to document behavioural/emotional problems in preschoolers with sleep rhythmic movements. Participants were mother–child dyads (N = 529) from the Adversity: Maternal Adversity, Vulnerability and Neurodevelopment cohort. Questionnaires evaluating socioeconomic status (prenatal), maternal depressive symptoms (prenatal, 48 months), sleep rhythmic movements (12, 18, 24, 36, 48 months), maternal anxiety trait (24 months) and childrens behavioural/emotional problems (48 months) were used. Maternal sensitivity (accuracy and appropriateness of mothers responses to her babys needs) was assessed objectively with a filmed mother–infant interaction (6 months). Generalized estimating equation was used to investigate associations between sleep rhythmic movements and maternal characteristics (depression, anxiety and sensitivity). Linear regressions were used to assess associations between sleep rhythmic movements and behavioural/emotional problems in children. Lower maternal sensitivity, higher maternal depressive symptoms and lower socioeconomic status predicted sleep rhythmic movements in children (p < 0.05). To our knowledge, this is the first study showing that sleep rhythmic movements are associated with lower maternal sensitivity, measured objectively. This study also builds on previous reports, by documenting an association between sleep rhythmic movements and behavioural/emotional problems even in preschoolers. The presence of psychosocial factors in sleep rhythmic movements aetiology should be considered in treatment.

Heart rate variability of typically developing and autistic children and adults before, during and after sleep

INTRODUCTION Studies suggest a sympathetic-parasympathetic disequilibrium in children with autism spectrum disorder (ASD), compared to typically developing (TD) children. The autonomic nervous system (ANS) shows profound modification with age but studies in ASD adults are lacking. The ANS is also influenced by vigilance states such as wakefulness and sleep. The aim of this study is to explore differences in ANS activity in typically developing (TD) and ASD individuals during sleep and wakefulness, as a function of age. METHODS Four groups of participants (17 adults with ASD, 16 TD adults, 13 children with ASD and 13 TD children) were recorded for two consecutive nights in a sleep laboratory. Electrocardiogram (ECG) was sampled during wakefulness (before and after sleep) and during stage N2 and REM sleep. Groups were compared on their heart rate variability parameters (LFnu, HFnu, LF/HF ratio) in each vigilance state. RESULTS Results show that ASD adults had lower HFnu in the morning than TD adults (p < 0.05). During REM sleep, adults had higher LF/HF ratio than children, regardless of their clinical status (p < 0.05). CONCLUSIONS Results of this study show autonomic distinctiveness during wakefulness specifically in ASD adults, suggesting a lower parasympathetic activity in the morning. Whether this characteristic represents a developmental feature or is related to lower sleep quality remains to be clarified.