Sarah Joy Gallardo, Eli Rudnisky, Robert J Coni
The phenomenon of lucidity refers to transient episodes of cognitive clarity in individuals with advanced and irreversible neurological impairment, typically coupled with late-stage illness. Although there have been strides spanning the course of decades to understand what a lucid episode (LE) truly entails, research regarding this topic remains in its infantile stages. Using a hybrid narrative-systematic-based literature approach, this review aims to review the existing body of literature and provide between-group qualitative comparisons of LEs from family members and healthcare workers to identify shared characteristics, observer-related differences, and potential predictors of lucidity. A variety of sources were vetted for inclusion, including interviews, surveys, case reports, and observational analyses in patients with severe neurological diseases. Between-group similarities included the characterization and duration of LEs, while notable differences included potential triggers and the emotional appraisal of these episodes. Limitations of the study, such as heterogenous definitions, retrospective reporting, various forms of bias, inconsistent assessment tools, and the absence of neurobiological measures, appear to be reflective of the early stages of research regarding lucidity. Therefore, future research should prioritize conceptual refinement through a standardized definition and exclusion criteria, prospective study designs, and the integration of physiological and neurological monitoring in this patient population. The improved recognition and understanding of lucidity may enhance clinician education, caregiver guidance, and ethical decision-making in palliative and hospice care settings.