Impact of ageing on the brain regions of the schizophrenia patients: an fMRI study using evolutionary approach

Abstract

Schizophrenia is a mental disorder that results in adverse functional and biochemical changes in the brain. Although normal ageing significantly affects the brain of a person structurally as well as functionally, the functional activation pattern in the brain of a schizophrenia patient may change differentially with age. To the best of our knowledge, this is the first of its kind fMRI-based study to find the functional changes in the brain of schizophrenia patients associated with ageing. In this study, we aim to compare the age-related variations in the functional activation pattern in the brain of schizophrenia patients vis a vis the healthy controls. For this study, we have used 1.5T fMRI data of 60 subjects and 3T fMRI data of 50 subjects, having an equal number of schizophrenia and healthy subjects. We have split this dataset into multiple age-groups. We applied a three-stage methodology comprising the application of the general linear model, followed by statistical hypothesis testing, and a finally bi-objective NSGA-II algorithm for selection of relevant voxels. The proposed methodology yielded a set of relevant voxels in the brain that demonstrate the age related variations in activation patterns. Specifically, it revealed increased functional activations in elderly patients suffering from schizophrenia in multiple brain regions, mostly located in areas like frontal lobe, temporal lobe and parietal lobe as compared to the young schizophrenic patients. These findings may help in making decisions for differential clinical management of younger patients as compared to the elderly ones.