Walking speed and brain glucose uptake are uncoupled in patients with multiple sclerosis
Date
2015-02-02
Authors
Kindred, John H., author
Tuulari, Jetro J., author
Bucci, Marco, author
Kalliokoski, Kari K., author
Rudroff, Thorsten, author
Frontiers Media S. A., publisher
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Abstract
Motor impairments of the upper and lower extremities are common symptoms of multiple sclerosis (MS). While some peripheral effects like muscle weakness and loss of balance have been shown to influence these symptoms, central nervous system activity has not been fully elucidated. The purpose of this study was to determine if alterations in glucose uptake were associated with motor impairments in patients with multiple sclerosis. Eight patients with multiple sclerosis (4 men) and 8 sex matched healthy controls performed 15 minutes of treadmill walking at a self-selected pace, during which ≈ 322 MBq of the positron emission tomography glucose analogue [18F]-Fluorodeoxyglucose was injected. Immediately after the cessation of walking, participants underwent positron emission tomography imaging. Patients with MS had lower FDG uptake in ≈ 40% of the brain compared to the healthy controls (pFWE-corr > 0.001, qFDR-corr < 0.001, ke = 93851) and walked at a slower speed (MS, 1.1 (0.2), Controls 1.4 (0.1), m/sec, P = 0.014). Within the area of lower FDG uptake 15 regions were identified. Of these 15 regions, 13 were found to have strong to moderate correlations to walking speed within the healthy controls (r > -0.75, P < 0.032). Within patients with MS only 3 of the 15 regions showed significant correlations: insula (r = -0.74, P = 0.036), hippocampus (r = -0.72, P = 0.045), and calcarine sulcus (r = -0.77, P = 0.026). This data suggests that walking impairments in patients with MS may be due to network wide alterations in glucose metabolism. Understanding how brain activity and metabolism are altered in patients with MS may allow for better measures of disability and disease status within this clinical population.
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Subject
brain activity
walking
Multiple Sclerosis
glucose uptake
positron emission tomography
movement disorder