Traumatic brain injury (TBI), Alzheimer's disease and related dementias (ADRD) have an extremely high occurrence and a dizzying array of associated biological changes that arguably make them the most important cause of neurodegeneration and impairment requiring rehabilitation. Sleep disorders (SD) often occur in conjunction with TBI and ADRD and have long been connected to adverse brain health outcomes. The predisposition to these adverse outcomes depends on age, concomitant disorders (i.e., comorbidities), and a variety of factors including gender, race, socioeconomic status which makes it difficult to treat these diseases. My research program aims to address the challenge of inequity by focusing on how SD and TBI affect brain health of people and communities. I use various analytical methods including hypothesis-driven approaches and non-hypothesis-driven techniques to thoroughly investigate and understand complex clinical and functional data, and to capture the risk and protective factors that interact across a person's lifespan to affect the person, family, clinical and functional, and policy-relevant outcomes. My research examines the dynamic interactions between exposure variables and outcomes at various stages of life.