APP and Cognitive impairment: Intra-axonal upregulation of the amyloid precursor protein (APP) and increased processing of the protein resulting in diffuse Aβ plaque deposition occurs quickly after TBI and notably, studies in long-term survivors have revealed that axonal degeneration persists and mature Aβ plaques and tau pathology develops, which is associated with cognitive impairment (Johnson et al., 2011).