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Summary Acoustic stimulation synchronized to slow oscillations in scalp electroencephalograms has been shown to enhance sleep features, which makes it promising in boosting cognitive functions as well as in the treatment of some sleep disturbances. Nevertheless, scalp electrode sensors are resource intensive and poorly tolerated by sleeping patients. The aim of this study was to investigate the potential usability of in‐the‐ear electroencephalography to implement auditory closed‐loop stimulation during sleep. For this, we evaluated the agreement between slow oscillation recordings obtained through the in‐ear sensor and those obtained simultaneously from standard scalp electrodes during naps of 13 healthy subjects. We found that in‐ear activity provided enough information to automatically detect sleep slow oscillations in real‐time. Based on this, we successfully enhanced scalp slow oscillations using auditory single‐cycle closed‐loop brain‐state‐dependent stimulation based on in‐ear signals acquired in 11 further subjects. We conclude that in‐ear sensors provide a feasible technology for the enhancement of sleep patterns, and could pave the way for new clinical applications in the near future.

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El artículo presenta un estudio de caso de la Unidad Académica de Comunicación contra la Violencia en Chihuahua (México), como respuesta a las dificultades que presentan los medios de comunicación y periodistas en el contexto de violencia sistemática, producido por el narcotráfico y corrupción en el territorio. Así mismo, se aborda la implementación de esta misma estructura académica en Bogotá (Colombia), en el contexto actual del postconflicto, con un énfasis especial en la búsqueda de la verdad y la no-repetición.

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Closed loop acoustic stimulation (CLAS) during sleep has shown to boost slow wave (SW) amplitude and spindle power. Moreover, sleep SW are suggested to be classified based on different processes of neuronal synchronization. Following this, different types of SW events may have distinct functional roles and be differentially affected by external stimuli. However, the SW synchronization processes affected by CLAS are not well understood. Here, we studied the effect of CLAS on the dissociation of SW events based on two features of neuronal synchronization in the EEG (topological spread and wave slope). We evaluated and classified individual SW events of fourteen healthy subjects during a CLAS stimulated (STM) and a control night (CNT). Three main categories of SW events were found denoting (C1) steep-slope SW with global spread, (C2) flat-slope waves with localized spread and homeostatic regulation, and (C3) multipeaked flat-slope events with global spread. Comparing between conditions, we found a consistent increase of event proportion and trough amplitudes for C1 events during the time of stimulation. Furthermore, we found similar increases in post-stimulus spectral power in θ, β and σ frequencies for CNT vs STIM condition independently of sleep stage or SW categories. However, topological analysis showed differentiated spatial dynamics in N2 and N3 for SW categories and the co-occurrence with spindle events. Our findings reveal the nature of post-stimulus SW and suggest that CLAS boosts SW amplitudes by increasing neuronal synchronization of wave troughs, leading thus the post-stimulus SW-spindle co-occurrence.