Sleep characteristics in children with specific language impairment: macrostructure and microstrucrure analysis

Abstract

Introduction Sleep is important for learning, memory and underlying neural plasticity. Studies support that children utilize a dual memory system when acquiring and integrating new vocabulary, and sleep (especially sleep spindles, slow waves sleep and REM sleep) is important for this process. We aimed to describe sleep characteristics in children with diagnosis of Specific Language Impairment because sleep disruption, especially of the microstructure, could have an important role in the development and evolution in these patients. Materials and methods 30 children (24 boys and 6 girls) with 3–5 years old, diagnosed of specific language impairment (development quotient ⩾ 70 in Brunet-Lezine Scale), normal MRI, without epileptiform discharges in EEG, no hearing impairment, no other disorders and with parents in medium–high sociocultural level. Children participated in a polysomnographic (PSG) sleep recording. Sleep disorders like Obstructive Sleep Apnea Pediatric (OSAP), Periodic Limb Movement Disorder (PLMD) and parasomnias, and sleep characteristics like sleep stages percentage, spindles characteristics, presence of significant alpha rhythm during sleep (alpha-delta sleep), microarousal index, sleep efficiency and awakenings episodes were analyzed. Results In our sample, we found OSAP only in one patient, and parasomnias in 2 patients. However, data about PLMD was relevant, 93.3% present this disorder with an average index of 9.316 ± 6.11 . We found an average of 4.073 % ± 3.41 of stage 1, 40.76 ± 8.89 of stage 2, 25.381 ± 6.91 of stage 3, 25.587 ± 6.91 of stage REM, 112.76 ± 25.65 of body movements, 3.10 ± 1.6 awakening episodes ⩾ 5 min, 85.14 ± 9.07 of sleep efficiency, 37.556 ± 9.6 of microarousal index (83.4% with microarousal index ⩾ 30 ), 80% present significant percentage of alpha rhythm during sleep and 66.7% presented unsuitable spindles. Conclusion We observed that although the sleep architecture in terms of the macrostructure, like time spent in the different stage of sleep, appears to not be consistently altered in relation with normal values, it is very important the analysis of sleep microstructure because specific features would be altered in these patients and could be related to the problem of language skills. Treatment for specific sleep disorders and treatment to stabilize sleep structure, could improve the symptomatology in these patients.