An evaluation on changes in hippocampus size for cognitively normal, mild cognitive impairment, and Alzheimer’s disease patients using fuzzy membership function

Alzheimer’s disease (AD) is a neurological disorder where the hippocampus, an essential part of the limbic system in the brain, gets affected severely. The transition from cognitively normal (CN) to AD has one intermittent stage, popularly known as mild cognitive impairment (MCI). Since physical changes in the human brain may occur during aging, sometimes it is challenging to predict dementia stages based on the hippocampus size. To solve this uncertainty, the concept of the fuzzy membership function has been used in this study, where all the data are acquired from the online public dataset “Alzheimer’s disease neuroimaging initiative” and found that the average difference in the hippocampus size between CN and MCI is 17.05%, between CN and AD is 31.90%, and between MCI and AD is 18.24%. The average atrophy per year in the hippocampus is 4.62% for AD, 2.33% for MCI, and 1.10% for CN subjects. From the study, it is also observed that, for AD patients, hippocampus atrophy is the highest, and hence they experience the highest memory loss, followed by the MCI and CN patients.