Journal Article

Increased functional connectivity common to symptomatic amyotrophic lateral sclerosis and those at genetic risk

Benatar, Michael, Proudfoot, Malcolm, Andersen, Peter M, Turner, Martin R, Talbot, Kevin, Menke, Ricarda A L, Wuu, Joanne

2016

Overview

ObjectiveTo discern presymptomatic changes in brain structure or function using advanced MRI in carriers of mutations predisposing to amyotrophic lateral sclerosis (ALS).MethodsT1-weighted, diffusion weighted and resting state functional MRI data were acquired at 3 T for 12 asymptomatic mutation carriers (psALS), 12 age-matched controls and affected patients with ALS. Cortical thickness analysis, voxel-based morphometry, volumetric and shape analyses of subcortical structures, tract-based spatial statistics of metrics derived from the diffusion tensor, and resting state functional connectivity (FC) analyses were performed.ResultsGrey matter cortical thickness and shape analysis revealed significant atrophy in patients with ALS (but not psALS) compared with controls in the right primary motor cortex and right caudate. Comparison of diffusion tensor metrics showed widespread fractional anisotropy and radial diffusivity differences in patients with ALS compared to controls and the psALS group, encompassing parts of the corpus callosum, corticospinal tracts and superior longitudinal fasciculus. While FC in the resting-state sensorimotor network was similar in psALS and controls, FC between the cerebellum and a network comprising the precuneus, cingulate & middle frontal lobe was significantly higher in psALS and affected ALS compared to controls.ConclusionsRather than structural brain changes, increased FC may be among the earliest detectable brain abnormalities in asymptomatic carriers of ALS-causing gene mutations. With replication and significant refinement, this technique has potential in the future assessment of neuroprotective strategies.

• Publisher: BMJ Publishing Group LTD,BMJ Publishing Group
• Subject: Adult / Aged / Alzheimer's disease / Amyotrophic lateral sclerosis / Amyotrophic Lateral Sclerosis - diagnostic imaging / Amyotrophic Lateral Sclerosis - genetics / Amyotrophic Lateral Sclerosis - physiopathology / Asymptomatic / Biomarkers / Brain - diagnostic imaging / Brain - physiopathology / C9orf72 Protein / Cerebellum - diagnostic imaging / Cerebellum - physiopathology / Cerebral Cortex - diagnostic imaging / Cerebral Cortex - physiopathology / Cohort Studies / Cone-Beam Computed Tomography / Corpus Callosum - diagnostic imaging / Corpus Callosum - physiopathology / Diffusion Magnetic Resonance Imaging / Disease prevention / Female / Frontal Lobe - diagnostic imaging / Frontal Lobe - physiopathology / Genetic Carrier Screening / Genetic Predisposition to Disease - genetics / Gyrus Cinguli - diagnostic imaging / Gyrus Cinguli - physiopathology / Humans / Image Interpretation, Computer-Assisted / Magnetic Resonance Imaging / Male / Middle Aged / Nerve Net - diagnostic imaging / Nerve Net - physiopathology / Neurodegeneration / Parietal Lobe - diagnostic imaging / Parietal Lobe - physiopathology / Pathology / Proteins - genetics / Pyramidal Tracts - diagnostic imaging / Pyramidal Tracts - physiopathology / Registration / Superoxide Dismutase-1 - genetics / Volumetric analysis / Young Adult