Using functional Magnetic Resonance Imaging to differentiate between Healthy Aging subjects, Mild Cognitive Impairment, and Alzheimer's Patients

Back ground: Alzheimer''s disease is the most common form of dementia which is still difficult to be differentiated from other types of brain disorders. Moreover, Mild Cognitive Impairment refers to the presence of cognitive impairments that is not severe enough to meet the criteria of dementia, and its diagnosis in early stages is so critical. There is currently no distinct method available for diagnosing Alzheimer''s or Mild Cognitive Impairment, and their diagnosis needs a combination of different methods and assessments. Our goal in this study was to evaluate the effectiveness of fMRI imaging in differentiating between Alzheimer''s, Mild Cognitive Impairment (MCI) and Healthy Aging. To prove fMRI''s ability, we compared resting-state brain activation patterns between these three groups of subjects using Independent Component Algorithm (ICA). We examined 40 age- and sex-matched subjects, 15 elderly, 11 MCI and 14 Alzheimer''s subjects. The results show that during a certain resting-state session, healthy aging brain benefits from larger area and greater intensity of activation (compared with MCI and Alzheimer''s group) in Posterior Cingulate Cortex (PCC) region of the brain, as part of Default Mode Network. This difference in activation pattern can be used as a diagnostic criterion in using fMRI for differentiating between Alzheimer''s disease (AD), MCI and Healthy Aging.