MAPT and Alzheimer disease: AD is an irreversible neurodegenerative disorder characterized by a progressive decline in memory and other neurocognitive functions, including visual–spatial skills, attention, executive function, decision-making ability, language ability, personality and behavioral abnormality, etc. (29) Classical cerebrospinal fluid biomarkers of AD, such as increased tau proteins, reduced β-amyloid42, and elevated lactate levels, were demonstrated in the cerebrospinal fluid of individuals with OSA (30, 31).