Altered volume and microstructural integrity of hippocampus in NMOSD.

OBJECTIVE: To assess whole and subfield volume and microstructural integrity of the hippocampus in patients with neuromyelitis optical spectrum disorder (NMOSD), and whether these alterations are correlated with expanded disability status scale (EDSS), anxiety score and depression score.

METHODS: The volume of the hippocampus and twelve hippocampal subfields, together with fractional anisotropy (FA) and mean diffusivity (MD) were measured in thirty patients with NMOSD and twenty-six healthy controls. EDSS score, anxiety score and depression score were measured in all participants. The relationships between whole hippocampal volume, subfield volume, hippocampal microstructural integrity and clinical and behavioral test scores were investigated.

RESULTS: Significantly decreased total volume, decreased FA and increased MD were observed in the hippocampus bilaterally in NMOSD. The reductions in left presubiculum, subiculum, CA1, CA4, GC-DG, molecular layer and right presubiculum (p < .004) remained significant after Bonferroni correction. Hippocampal volume reductions, FA reductions and MD increases were correlated with anxiety and depression scores.

CONCLUSIONS: This study reveals that patients with NMOSD have decreased volume and altered microstructural integrity of the hippocampus. Furthermore, certain of these alterations are correlated with severity of anxiety and depression. Further investigation of these findings may provide insight to improve clinical management and treatment of NMOSD patients with mood disorders.