Using Longitudinal Variance Components Models to Assess Hyper-connectivity in Severe Traumatic Brain Injury Patients

Keyvan Olazadeh; Nasrin Borumandnia; Mahin Habibi; Hamid Alavi Majd

doi:10.32598/bcn.2022.3796.1

Using Longitudinal Variance Components Models to Assess Hyper-connectivity in Severe Traumatic Brain Injury Patients

Basic Clin Neurosci. 2024 Jul-Aug;15(4):509-518. doi: 10.32598/bcn.2022.3796.1. Epub 2024 Jul 1.

Authors

Keyvan Olazadeh¹, Nasrin Borumandnia², Mahin Habibi³, Hamid Alavi Majd¹

Affiliations

¹ Department of Biostatistics, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
² Urology and Nephrology Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
³ Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.

Abstract

Introduction: Traumatic brain injury (TBI) is one of the leading causes of death globally and one of the most important diseases indicated by the World Health Organization (WHO). Several studies have concluded that brain damage can dramatically increase functional connectivity (FC) in the brain. The effects of this hyper-connectivity are not yet fully understood and are being studied by neuroscientists. Accordingly, this study identifies areas of the brain where, after brain injury, an acute increase in FC in such areas is observed.

Methods: The data used in this study were downloaded from the accessible open functional magnetic resonance imaging (fMRI) site. The data included fMRI of 14 patients with severe TBI and 12 healthy individuals. The longitudinal model of variance components investigated the difference between FC in the baseline effect and the longitudinal trend between the TBI and control groups.

Results: After fitting the longitudinal model of variance components, no difference was observed between the FC of the two groups due to the baseline effect. However, in the longitudinal trend of FC, there was a statistically significant difference between the three pairs of cerebellum left, cerebellum right, superior frontal gyrus left, superior frontal gyrus right, thalamus left, and thalamus right in the TBI group compared to the control group.

Conclusion: The results showed that FC was sharply increased in 3 pairs of areas in people with TBI. This hyper-connectivity can affect individuals' cognitive functions, including motor and sensory functions. The exact extent of this effect is unclear and requires further investigation by neuroscientists.

Keywords: Cognitive function; Functional magnetic resonance imaging (fMRI); Hyper-connectivity; Longitudinal model of variance components; Traumatic brain injury (TBI); neuroimaging.