Self-reported traumatic brain injury and in vivo measure of AD-vulnerable cortical thickness and AD-related biomarkers in the ADNI cohort

Abstract

In this study, we aimed to investigate whether self-reported mild traumatic brain injury (mTBI) was associated with decreased AD-vulnerable cortical thickness, and to assess the relationship between AD-vulnerable cortical thickness and AD-related biomarker in the Alzheimer's Disease Neuroimaging Initiative subjects. We identified 45 self-reported mTBI subjects, who had structural MRI, 18F-AV45 PET, and cerebrospinal fluid (CSF) data. Of them, eight subjects were normal; ten were preclinical AD; seventeen were MCI due to AD; ten were AD. Additional demographics-controlled 45 subjects were included. Cortical thickness of eight AD-vulnerable regions, mean AD-vulnerable cortical thickness, 18F-AV45 PET mean amyloid SUVR, CSF Aβ42, CSF total tau (T-tau), and CSF phosphorylated tau (P-tau) were compared between mTBI and non-TBI groups. Correlational analysis was done to investigate the relationship between mean AD-vulnerable cortical thickness and mean amyloid SUVR, CSF Aβ42, CSF T-Tau, CSF P-Tau. Our study revealed that preclinical AD subjects with self-reported mTBI had smaller cortical thickness in mean and three AD-vulnerable cortical regions than non-TBI subjects (P<0.05). The mean AD-vulnerable cortical thickness was correlated with CSF T-tau (r=-0.81, P=0.001). There was no statistical difference in the comparison of normal, MCI due to AD, and AD groups. Our study indicated that among individuals with preclinical AD, but not normal, MCI due to AD and AD subjects, self-reported mTBI was associated with more decreased AD-vulnerable cortical thickness which was related to CSF tau pathology, suggesting the possible early involvement of tau pathology in the decreased AD-vulnerable cortical thickness of self-reported TBI subjects.

Keywords: Alzheimer’s disease; Beta-amyloid; CSF biomarkers; Cortical thickness; Tau; Traumatic brain injury.