Differed brain spontaneous neural activity between limb-onset and bulbar-onset amyotrophic lateral sclerosis patients

To investigate the differences in brain spontaneous neural activity between limb-onset and bulbar-onset amyotrophic lateral sclerosis (ALS-L and ALS-B, respectively) patients using resting-state functional MRI (rs-fMRI) with amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo).

The rs-fMRI data were collected from 41 ALS patients (11 ALS-B and 30 ALS-L) and 25 healthy controls (HC). ALFF and ReHo values were calculated, and group differences were assessed using one-way ANCOVA and two-sample t-tests. Correlation analyses with clinical measures were conducted. Support vector machine (SVM) analysis was performed to distinguish ALS subtypes.

Compared with ALS-L, ALS-B showed increased ALFF values in the right gyrus rectus/ orbital part of right middle frontal gyrus, orbital part of left middle frontal gyrus and left dorsolateral superior frontal gyrus/ left medial superior frontal gyrus and decreased ALFF values in the left superior occipital gyrus (FDR-corrected, P < 0.05). Both ALS subtypes demonstrated distinct ALFF alterations compared to HC. Differences in ReHo values were only found between ALS-B and HC. Correlation analyses revealed associations between ALFF in specific brain regions and ALS clinical scores. SVM analysis achieved an accuracy of 90.2 %, with an AUC of 0.909 in differentiating ALS-B and ALS-L.

ALS-B and ALS-L patients had distinct alterations in brain spontaneous neural activity, which could serve as potential biomarkers for accurately distinguishing these two subtypes. Our findings offer a new insight into the neural mechanism of ALS, underscoring the importance of personalized diagnostic approaches for this complex neurological disorder.