A Standardized and Validated Protocol for Primitive Reflex Assessment: Reliable Measurements Across the Lifespan for Clinical and Research Practice

Abstract Primitive and transitional reflexes reflect central nervous system development, integrity and functional status across the lifespan, yet their assessment has remained largely qualitative and non-standardized. We developed and validated a comprehensive protocol to quantify 18 primitive and transitional reflexes using a standardized three-point ordinal scale. A total of 565 participants aged 3 to 92 years were assessed, including typically developing children, healthy older adults, individuals with dementia, and those with sensorimotor integration difficulties. Inter-rater reliability (N = 259; weighted Cohen’s κ = 0.912 to 1.000) and intra-rater reliability (N = 306; κ = 0.912 to 0.983) demonstrated excellent agreement, with narrow confidence intervals confirming statistical robustness. This is the first lifespan-validated reflex battery with established psychometric properties. By transforming reflex examination into a reproducible measurement framework, it enables systematic investigation of cortical inhibitory control and establishes primitive reflex profiling as a potential behavioral biomarker in neurodevelopmental and neurodegenerative research.