Hippocampal volume is related to cognitive decline and fornicial diffusion measures in multiple sclerosis

Abstract

Purpose: To assess for associations between hippocampal atrophy and measures of cognitive function, hippocampal magnetization transfer ratio (MTR), and diffusion measures of the fornix, the largest efferent white matter tract from the hippocampus, in patients with multiple sclerosis (MS) and controls.

Materials and methods: A total of 53 patients with MS and 20 age- and sex-matched healthy controls participated in cognitive testing and scanning including high spatial-resolution diffusion imaging and a T1-MPRAGE scan. Hippocampal volume and fornicial thickness measures were calculated and compared to mean values of fornicial transverse diffusivity, mean diffusivity, longitudinal diffusivity, fractional anisotropy, mean hippocampal MTR, and scores on measures of episodic memory, processing speed, and working memory tasks.

Results: In patients with MS, hippocampal volume was significantly related to fornicial diffusion measures (P<7×10(-4)) and to measures of verbal (P=0.030) and visual spatial (P=0.004) episodic memory and a measure of information processing speed (P<0.037).

Discussion: These results highlight the role of the hippocampus in cognitive dysfunction in patients with MS and suggest that measures of hippocampal atrophy could be used to capture aspects of disease progression.

Keywords: Atrophy; DTI; Episodic memory; Fornix; Hippocampus; Multiple Sclerosis.