Bridging dream and wake states: a new tool for consciousness research.

In this study, the Consciousness States Comparison Scale: REM Version (CSCS-REM) was developed as a self-report instrument to assess dream consciousness during REM sleep in comparison with waking consciousness. Existing instruments capture only limited aspects of phenomenology and provide few opportunities for systematic cross-state evaluation. By anchoring waking consciousness as a reference point, the CSCS-REM quantifies relative differences in phenomenological experience and serves as a tool for empirically testing the predictions of the continuity and discontinuity hypotheses in consciousness research. The item pool was derived from a systematic review, expert evaluations, and preliminary studies, with content validity ensured through expert panels. After pilot testing, the 63-item draft was administered online, and data from 432 participants were analyzed using exploratory factor analysis. The final version consisted of 35 items across eight subscales: Metacognitive Awareness, Cognitive Fluency, Memory, Temporal Awareness, Spatial Awareness, Emotional Awareness, Perceptual and Bodily Senses, and Interoceptive and Chemical Senses. This structure accounted for 56.04% of the variance, with Cronbach's α ranging from .736 to .915 and McDonald's ω from .639 to .901. Confirmatory factor analysis in an independent sample (n = 211) demonstrated excellent fit indices (Comparative Fit Index = .986, Tucker-Lewis Index = .984, Root Mean Square Error of Approximation = .059). Subscales of the CSCS-REM showed small to moderate, yet significant, correlations with the Bodily Self-Consciousness in Dreams Questionnaire and the Dream Reflective Awareness Questionnaire, supporting convergent validity. In conclusion, while subject to some limitations, the CSCS-REM is a psychometrically reliable and valid instrument that enables systematic comparison of REM dream consciousness and waking consciousness across shared phenomenological dimensions.