Sleep cyclic alternating pattern in normal school-age children Oliviero Bruni a, * , Raffaele Ferri b , Silvia Miano a , Elisabetta Verrillo a , Elena Vittori a , Giacomo Della Marca c , Benedetto Farina c , Gioacchino Mennuni c a Department of Developmental Neurology and Psychiatry, Center for Pediatric Sleep Disorders, University of Rome ‘La Sapienza’, Via dei Sabelli 108, 00185 Rome, Italy b Sleep Research Center, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy c Sleep Medicine Unit, Catholic University, S.C., Rome, Italy Accepted 2 August 2002 Abstract Objectives: To evaluate cyclic alternating pattern (CAP) in sleep of school-age children in order to obtain a standardized database for CAP parameters in this age range. Methods: CAP parameters were quantified in 10 normal healthy subjects (6 males and 4 females, mean age 8.3 years; range 6–10 years). All subjects underwent polysomnography recordings for two consecutive nights in a standard laboratory setting. Sleep data were stored on computer using a 16-channel polysomnography digital system. Sleep macrostructure was visually scored according to the criteria by Rechtschaffen and Kales (Brain Information Service/Brain Research Institute, University of California, Los Angeles, 1968); CAP was visually scored following the criteria by Terzano et al. (Sleep Med 2 (2001) 537). Results: CAP rate showed a progressive increase with the deepness of sleep, with high values during slow wave sleep (SWS). CAP time showed its longest duration during non-REM (NREM) sleep stage 2 (S2), followed by SWS and sleep stage 1 (S1). No differences across NREM sleep stages were found for CAP cycle and phase B mean duration; on the contrary, phase A showed longer duration during SWS than in S1 and S2. Phases A1 were the most numerous (84.45%) followed by A3 (9.14%) and by A2 (6.44%). The distribution of phases A subtypes across NREM stages showed significant differences for the A1 subtypes that occurred more frequently during SWS than in S2 and S1 (and during S2 than in S1). Subtypes A3 were more frequent during S1 than SWS while no differences were found for subtype A2. The analysis of A1 interval distribution showed a log-normal-like distribution with a peak around 25 s for the A1 phases and no clear peak for A2– A3 phases. Conclusions: The analysis of CAP in school-age children is characterized by an increase of CAP rate during SWS and a high percentage of A1 phases. The distribution of interval between consecutive A1 phases showed a peak around 25 s. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Cyclic alternating pattern; Sleep; Polysomnography; Arousal; Children 1. Introduction In recent years, increasing emphasis has been put on the analysis of phasic aspects of sleep, based on the evidence that frequent brief arousals, even without affecting the sleep macrostructure, may impair the restorative value of sleep. Cyclic alternating pattern is the translation into English of the French term ‘trace ´ alternant’. This term was used to describe the periodic discontinuity of quiet sleep (equivalent to NREM sleep) recorded in premature and newborn babies after 37 weeks conceptional age and is characterized by bursts of 1–3 Hz, 50–150 mV activity mixed with faster lower-amplitude waves, interrupted by intervals of lower amplitude (25–50 mV) 4–7 Hz waves (Curzi-Dascalova and Mirmiran, 1996). The trace ´ alternant represents a modi- fication of the discontinuous electroencephalogram (EEG) pattern recorded at 32–36 weeks conceptional age, repre- sented by high-voltage delta bursts of variable duration (2–8 s) interrupted by short periods of very low voltage EEG activity (less than 15 s), and generally disappears between 3 and 4 weeks after birth. The disappearance of the trace ´ alternant and the appearance of K complexes and sleep spindles lead to the individuation of the NREM sleep stage 2 and reflect the maturation of the thalamo-cortical pathways and rostro-caudal pons-thalamus connections (Louis, 1998). Even if there is no demonstration that the trace ´ alternant Clinical Neurophysiology 113 (2002) 1806–1814 1388-2457/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S1388-2457(02)00265-1 www.elsevier.com/locate/clinph CLINPH 2002537 * Corresponding author. Tel.: 139-6-4471-2257; fax: 139-6-4957-857. E-mail address: oliviero.bruni@uniroma1.it (O. Bruni).