White matter integrity and cognitive dysfunction: Radiological and neuropsychological correlations

Abstract

Cerebral white matter (WM) is comprised of nerve fibers interconnecting neurons in the cerebral cortex or the deep structures. With advancing age, WM frequently shows hyperintense lesions in T2-weighted or fluid-attenuated inversion recovery images in both the periventricular and deep WM. Patients with these WM lesions might manifest a variety of symptoms, such as parkinsonism, cognitive impairment, depression and apathy, when these WM lesions become sufficiently confluent and diffuse. However, there are inconsistencies with respect to their clinical significance, because patients with extensive WM lesions might remain asymptomatic. The present review focuses on the pathological mechanism underlying why the loss of integrity of nerve fibers in the WM induces neuropsychological symptoms.