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.

Families with sleepwalking.

BACKGROUND: Studies on families with sleepwalking are uncommonly published but can give further information on the phenotype of patients with chronic sleepwalking. SUBJECTS AND METHODS: Out of 51 individuals referred for chronic sleepwalking during a 5-year period, we obtained sufficient information on 7 families with direct relatives who reported sleepwalking with or without sleep terrors. Among 70 living direct family members, we obtained questionnaire responses from 50 subjects and identified 34 cases with a history of sleepwalking. Of the 50 subjects, 16 completed only questionnaires, while all the others also completed a clinical evaluation and nocturnal sleep recordings. RESULTS: There was a positive history of sleepwalking on either the paternal or maternal side of the family over several generations in our 7 families. Thirty-three clinically evaluated subjects had evidence of sleep-disordered breathing (SDB), with associated craniofacial risk factors for SDB (particularly maxillary and/or mandibular deficiencies). There was a complete overlap with the report of parasomnias and the presence of SDB. In cases with current sleepwalking, treatment of SDB coincided with clear improvement of the parasomnia. CONCLUSION: All of our subjects with parasomnias presented with familial traits considered as risk factors for SDB. These anatomical risk factors are present at birth and even subtle SDB can lead to sleep disruption and instability of NREM sleep. The question raised is: are factors leading to chronic sleep disruption the familial traits responsible for familial sleepwalking?

Sleep terrors in children: a prospective study of twins.

OBJECTIVE: There is growing evidence that genetic factors are involved in the occurrence of sleep terrors. Twin studies provide invaluable information regarding genetic and environmental factors that can affect the manifestation of the disease; however, most previous twin studies on sleep terrors were performed retrospectively or with a sample that was too small to yield conclusive results. The aim of this large prospective study was to clarify the genetic and environmental contributions to sleep terrors in childhood. METHODS: In all, 390 pairs of monozygotic and dizygotic twins were recruited at birth for a longitudinal study. The prevalence and frequency of sleep terrors were assessed at 18 and 30 months of age with a questionnaire administered to the biological mother of the twins. Zygosity was determined by a questionnaire and genotyping. The prevalence and polychoric correlation for each type of twins were calculated. Structural-equation modeling was used to determine the proportion of variance attributable to additive genetic, shared, and nonshared environmental factors. RESULTS: The prevalence of sleep terrors was 36.9% at 18 months and 19.7% at 30 months; 49% of affected children were boys, and 51% were girls. At 18 months, the polychoric correlations were 0.63 for monozygotic and 0.36 for the dizygotic twins. These were 0.68 (monozygotic) and 0.24 (dizygotic) at 30 months. Our model-fitting analysis showed that sleep terrors were explained by a 2-component model at 18 months (43.7% additive genetic effects and 56.3% nonshared environment) and at 30 months (41.5% additive genetic effects and 58.5% nonshared environment). CONCLUSIONS: These results strongly support the heritability of sleep terrors. There also seems to be continuity in genetic effects with the persistence of sleep-terror symptoms.