Sleep plays a crucial role in brain development, sensory information processing, and consolidation. Sleep spindles are markers of these mechanisms as they mirror the activity of the thalamocortical circuits. Spindles can be subdivided into two groups, slow (10–13Hz) and fast (13–16Hz), which are each associated with different functions. Specifically, fast spindles oscillate in the high-sigma band and are associated with sensorimotor processing, which is affected by visual deprivation. However, how blindness influences spindle development has not yet been investigated. We recorded nap video-EEG of 50 blind/severely visually impaired (BSI) and 64 sighted children aged 5 months to 6 years old. We considered aspects of both macro- and micro-structural spindles. The BSI children lacked the evolution of developmental spindles within the central area. Specifically, young BSI children presented low central high-sigma and high-beta (25–30Hz) event-related spectral perturbation and showed no signs of maturational decrease. High-sigma and high-beta activity in the BSI group correlated with clinical indices predicting perceptual and motor disorders. Our findings suggest that fast spindles are pivotal biomarkers for identifying an early developmental deviation in BSI children. These findings are critical for initial therapeutic intervention.

Here, you can find raw EEG data in European data format (EDF) format. Descriptive and clinical data of the participants in the xlsx format. Columns report for each participant: code, group (blind/severely impaired, BSI or sighted, S), biological sex, age expressed in decimal years, visual impairment index (VII, 0 = sighted, 1 = severely visual impairment, 2 = blindness) diagnosis and clinical indices for BSI. For the latter, we reported the data for motor coordination impairment (MCI), hypotonia, social adaptation, spatial exploration, languages, and sound response classification (1 = not impaired, 2 = impaired). NA corresponds to undefined classification.