Parental symptom report and periodic limb movements of sleep in children

Abstract

Study Objectives: To examine the prevalence of raised periodic limb movements of sleep (PLMS) index in children referred for polysomnography (PSG) and whether parental report of symptoms correlates with objective measurement during PSG. Methods: Records of children undergoing PSG from January 2006 to July 2006 were retrospectively reviewed. At their initial sleep clinic visit, parents had been asked whether their child was restless or moved their legs excessively during sleep. Their response to these questions was compared to the child's PLMS index (number of periodic limb movements per hour) during a full PSG. PLMS were scored according to internationally accepted criteria. Results: Data were examined for 101 children (60 male) with mean age 6.5 years (range 1.2 to 17.6 years). Excessive leg movements were reported by parents in 50% and restlessness in 73%. A raised PLMS index (defined as ≥5 per hour) was noted in 10 cases (prevalence 10%). Asking parents about whether their child kicks their legs excessively in sleep had sensitivity 50%, specificity 51%, positive predictive value (PPV) 10%, negative predictive value (NPV) 90% and positive likelihood ratio (LR+) 1.02 when compared to objective analysis. Asking parents about whether their child is restless in sleep had sensitivity 70%, specificity 26%, PPV 9%, NPV 89% and LR+ 0.95. Conclusions: Asking parents about their child's symptoms is not an accurate predictor of raised PLMS index. We recommend that leg electromyography be used in all pediatric sleep studies to record PLMS. Keywords: Periodic limb movements of sleep; child; questionnaires; polysomnography; sensitivity and specificity; likelihood ratio. Citation: Martin BT; Williamson BD; Edwards N; Teng AY. Parental symptom report and periodic limb movements of sleep in children.