Investigating the impact of the years of blindness on sleep rhythms, dream patterns, and spatial abilities: The BLINDREAM protocol.

Sleep health is a topic of great interest in recent years. However, it is still often undervalued in vulnerable populations, such as those with sensory disorders. A higher percentage of blind individuals experience circadian disorders, and their dreams have different sensory contents. However, many questions remain unanswered regarding the impact of blindness on overall sleep structure and how circadian desynchronization may influence them. Additionally, understanding how changes in the dream sensory contents and sleep alterations may affect daily life skills, such as spatial cognition which tends to be more challenging in blind individuals, is relevant for further comprehension of the vision role on our perception. The BLINDREAM protocol aims to investigate the interrelationships of all these aspects. We aim to collect one week of data from 20 blind adults and 20 sighted age-matched controls. Participants' sleep and circadian rhythm will be assessed through one-night home polysomnography, melatonin sampling, one-week actigraphy monitoring, and questionnaires. Dream activity will be measured through a one-week voice-recorded dream diary and questionnaires. Finally, a neuropsychological assessment of spatial cognition will be conducted. Capturing the dynamics of subjective experiences phase-locked to neural and physiological evaluation both between and within individuals, this approach can contribute to our understanding of the impact of blindness on sleep processes.