Sleep Deprivation, Decision Fatigue, and Clinical Performance in Medical Training: A Narrative Review and Perspective on Neurophysiological Monitoring.

Sleep deprivation and decision fatigue are important but often under-recognized determinants of daytime clinical performance. In medical training environments, these state-dependent factors may impair attention, executive control, and decision-making, complicating the interpretation of observed competence during wakefulness. This narrative review and perspective synthesizes evidence from sleep science, neurophysiology, psychology, and medical education to examine how sleep loss and decision fatigue shape clinical performance and how non-invasive monitoring approaches may help contextualize this variability. Attention is given to electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) as candidate research tools for characterizing fatigue-related changes in cognitive workload and vigilance. The reviewed literature supports strong links between sleep loss, fatigue, and impaired neurocognitive functioning, but the use of real-time neurophysiological monitoring for actionable readiness assessment in medical training remains conceptual and requires empirical validation. We propose the CBME-BCI-Fatigue framework as a hypothesis-generating perspective model for integrating physiological state information with competency-based assessment, while emphasizing limitations related to construct validity, incremental value, individual variability, feasibility, and governance. This framework may inform future simulation-based and low-stakes research on fatigue-aware feedback and learner support in sleep-vulnerable clinical training environments.