DeGennaro_Children&Adolescents

30 children and adolescents (9–14 years old) were involved in the study.Participants with developmental dyslexia were recruited at the Child and Adolescents Neuropsychiatric Unit of the Bambino Gesù Children’s Hospital, while control subjects were recruited through advertisements in the community.Before entering the study, all participants were assessed for intelligence, reading abilities, psychiatric and sleep comorbidities by means of a screening test battery.The absence of intellectual disabilities was assessed through Raven’s Matrices (colored or standard based on age) or Wechsler Intelligence Scale for Children Fourth Edition (WISC-IV): none of the participants had an IQ score below 85. For reading abilities, the text reading test (MT-2) and the word and non-word reading tests (DDE-2) were administered. In order to exclude the presence of psychiatric comorbidities and sleep problems, the Child Behavior Checklist (CBCL) and the Sleep Disturbance Scale for Children were filled out by parents. All participants were free of any medication for the week preceding the experimental night.Participants and their parents were informed about the procedure and the aims of the study and gave their written informed consent.Participants who fulfilled the inclusion/exclusion criteria required for participation in the study underwent a complete PSG recording of a nocturnal sleep, performed at the Sleep Psychophysiology Laboratory of the Department of Psychology (Sapienza, University of Rome).During the week preceding the experimental night, participants were asked to fill out sleep diaries every morning within 15 min after awakening in order to monitor the regularity of the sleep-wake cycle. They were asked to avoid naps in the day of the experimental night. Each participant took part in the experimental session alone and each on a different day. Participants arrived at the sleep lab between 17:00 and 19:00. After the application of the PSG, participants had a light dinner. Sleep PSG recordings started between 21:00 and 23:00, according to the habitual bedtime of the participants, and finished after 10 h of sleep or with the spontaneous awakening of the subjects. In the morning, the subjects filled out a sleep and dream diary. Data recordings were conducted on weekends or free-school days. Environmental influences that could disturb sleep (light, noise, temperature) were controlled.  

Language: Italian  

-DREAM categorization procedure--  

2 = Experience or Experience without recall (in the dream diary subjects report the feeling of having had a dream but he/she does not remember the content), and 0 = No dream (in the dream diary subject report no recall or "I don't know" response without any clear feeling of having had a dream) -

--Technical details--- N/A N/A--

Data acquisition-- 

The PSG recordings were acquired in a sound-proof, temperature-controlled room, with a Brain Amp MR plus system (Brain Products GmbH, Gilching, Munich, Germany).The 28 unipolar EEG derivations of the international 10-10 system (C3, C4, Cp1, Cp2, Cp5, Cp6, Cz, F3, F4, F7, F8, Fc1, Fc2, Fc5, Fc6, Fp1, Fp2, Fz, O1, O2, Oz, P3, P4, P7, P8, Pz, T7, T8) were recorded from scalp electrodes (Ag/AgCl). EEG signals were acquired with a sampling rate of 250 Hz and bandpass filtered at 30 Hz. Electrode impedance was kept below 5 kΩ. The electrooculogram (EOG) electrodes were placed about 1 cm from the lateral canthi up for the right eye and down for the left eye and were recorded with a time constant of 1 s. Submental electromyogram (EMG) was recorded with a time constant of 0.03 s. All channels were referenced to the average of the two mastoids (A1 and A2). 

--Data preprocessing-- N/A