Motor network degeneration in amyotrophic lateral sclerosis: a structural and functional connectivity study.
BACKGROUND
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by motor neuron degeneration. How this disease affects the central motor network is largely unknown. Here, we combined for the first time structural and functional imaging measures on the motor network in patients with ALS and healthy controls.


RESULTS
Structural measures included whole brain cortical thickness and diffusion tensor imaging (DTI) of crucial motor tracts. These structural measures were combined with functional connectivity analysis of the motor network based on resting state fMRI. Focal cortical thinning was observed in the primary motor area in patients with ALS compared to controls and was found to correlate with disease progression. DTI revealed reduced FA values in the corpus callosum and in the rostral part of the corticospinal tract. Overall functional organisation of the motor network was unchanged in patients with ALS compared to healthy controls, however the level of functional connectedness was significantly correlated with disease progression rate. Patients with increased connectedness appear to have a more progressive disease course.


CONCLUSIONS
We demonstrate structural motor network deterioration in ALS with preserved functional connectivity measures. The positive correlation between functional connectedness of the motor network and disease progression rate could suggest spread of disease along functional connections of the motor network.
Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, Utrecht, The Netherlands.
Esther
E
Verstraete
Martijn P
MP
van den Heuvel
Jan H
JH
Veldink
Niels
N
Blanken
René C
RC
Mandl
Hilleke E
HE
Hulshoff Pol
Leonard H
LH
van den Berg
D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology*; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000473:pathology*