Normative values of polysomnographic parameters in childhood and adolescence: quantitative sleep parameters.

OBJECTIVE: To provide normative values for sleep macroarchitecture of healthy children aged 1-18 years using the AASM sleep scoring criteria, assessing the effects of gender, age, and Tanner pubertal stage. METHODS: One-night polysomnography was performed at subjects' habitual bedtimes in 16 laboratories on 209 healthy German children. RESULTS: Normal values of sleep macrostructure show significant age dependencies (p<0.05). Increasing with age: awakening index, R latency (RL), sleep efficiency (SE) (total sleep time (TST)/sleep period time (SPT)) and SE (TST/time in bed), stage N2, mean sleep cycle duration, number of stage shifts. Decreasing with age: TST, SPT, wake after sleep onset, stage N3, stage R, movement time (MT), number of sleep cycles. The following sleep parameters show a dependency on Tanner stages as well as corresponding age (p<0.05):TST, SPT, awakening index, R latency, stage N2, stage N3, MT, number of sleep cycles, mean sleep cycle duration. No gender dependencies were found. CONCLUSION: The given study, considering AASM rules, shows the development of sleep in normal children ages 1-18. Subject selection criteria and other factors influencing sleep as well AASM guideline modifications including scoring arousals in N2 and scoring MT as a measure of sleep fragmentation are discussed.

Infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1).

Autosomal recessive spinal muscular atrophy with respiratory distress type 1 (SMARD1) is the second anterior horn cell disease in infants in which the genetic defect has been defined. SMARD1 results from mutations in the gene encoding the immunoglobulin micro-binding protein 2 (IGHMBP2) on chromosome 11q13. Our aim was to review the clinical features of 29 infants affected with SMARD1 and report on 26 novel IGHMBP2 mutations. Intrauterine growth retardation, weak cry, and foot deformities were the earliest symptoms of SMARD1. Most patients presented at the age of 1 to 6 months with respiratory distress due to diaphragmatic paralysis and progressive muscle weakness with predominantly distal lower limb muscle involvement. Sensory and autonomic nerves are also affected. Because of the poor prognosis, there is a demand for prenatal diagnosis, and clear diagnostic criteria for infantile SMARD1 are needed. The diagnosis of SMARD1 should be considered in infants with non-5q spinal muscular atrophy, neuropathy, and muscle weakness and/or respiratory distress of unclear cause. Furthermore, consanguineous parents of a child with sudden infant death syndrome should be examined for IGHMBP2 mutations.