To investigate cerebral structural signatures of the bulbar-and spinal-onset amyotrophic lateral sclerosis(ALS)using voxel-based morphometry on magnetic resonance imaging.Methods The MR structural images of the brain were obtained from 65 ALS patients(15 bulbar-onset,50 spinalonset)and 65 normal controls(NC)on a 3.0T MRI system.Gray matter(GM)volume changes were investigated by voxel-based morphometry,and the distribution of the brain regions with volume changes was compared between ALS and normal controls,as well as between bulbar-onset and spinal-onset ALS based on Neuromorphometrics atlas.Results On voxel-level the decreased volume of brain regions in ALS patients was located in the right precentral gyrus(rPrcGy)and right middle frontal gyrus compared with that in NC.The bulbar-onset ALS presented extramotor cortex atrophy(fronto-temporal pattern),including left medial orbital gyrus,left inferior temporal gyrus and right middle temporal gyrus;the spinal-onset ALS suffered from motor cortex atrophy(rPrcGy dominance)and extra-motor cortex atrophy(fronto-temporal and extra-fronto-temporal pattern)compared with NC.The spinal-onset ALS featured by GM volume loss of left postcentral gyrus and bulbar-onset ALS featured by GM volume loss of left middle temporal gyrus compared with each other.Conclusions The asymmetric GM atrophy of the motor cortex and extra-motor cortex represents the common MRI structural signatures of spinal-onset ALS,and sole extra-motor cortex atrophy represents the structural signatures of bulbar-onset ALS.The present study also demonstrated that the pattern of GM damage is likely to distribute wider in spinal-onset ALS than in bulbar-onset ALS.
Objective To study the activation changes of the brain in patients with amyotrophic lateral sclerosis (ALS) while executing sequential finger tapping movement using the method of blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI). Methods Fifteen patients with definite or probable ALS and fifteen age and gender matched normal controls were enrolled. MRI was performed on a 3.0 Tesla scanner with standard headcoil. The functional images were acquired using a gradient echo single shot echo planar imaging (EPI) sequence. All patients and normal subjects executed sequential finger tapping movement at the frequency of 1-2 Hz during a block-design motor task. Structural MRI was acquired using a three-dimensional fast spoiled gradient echo (3D-FSPGR) sequence. The fMRI data were analyzed by statistical parametric mapping(SPM). Results Bilateral primary sensorimotor cortex (PSM), bilateral premotor area (PA), bilateral supplementary motor area (SMA), bilateral parietal region (PAR), contralateral inferior lateral premotor area (ILPA), and ipsilateral cerebellum showed activation in both ALS patients and normal controls when executing the same motor task. The activation areas in bilateral PSM, bilateral PA, bilateral SMA, and ipsilateral cerebellum were significantly larger in ALS patients than those in normal controls (P<0.05). Extra activation areas including ipsilateral ILPA, bilateral posterior limb of internal capsule, and contralateral cerebellum were only detected in ALS patients. Conclusions Similar activation areas are activated in ALS patients and normal subjects while executing the same motor task. The increased activation areas in ALS patients may represent neural reorganization, while the extra activation areas in ALS patients may indicate functional compensation.
