Mitochondrial Function and Metabolomic Profile in Alzheimer's Disease and Related Dementias

This study investigates how the mitochondria (the energy-producing parts of cells) function differently in people with Alzheimer's disease and other types of dementia. Researchers will study energy metabolism and biological markers in the blood and spinal fluid to better understand what drives these conditions at a cellular level. **You may be eligible if:** - You have a cognitive disorder (memory or thinking problems) that has been present or reported for at least 6 months - Your diagnosis is being evaluated according to current medical guidelines - You have had cerebrospinal fluid (spinal fluid) biomarker testing done at the study center and agreed to provide biological samples **You may NOT be eligible if:** - Your cognitive symptoms have only recently started (less than 6 months) - You have not had the required diagnostic workup - You are unwilling to undergo the biological sample collection procedures - You have a condition that prevents safe spinal fluid collection Talk to your doctor to see if this trial is right for you.