Abnormal dynamic brain activity and functional connectivity of primary motor cortex in blepharospasm

Area of Science:

• Neuroscience
• Medical Imaging
• Neurology

Background:

• Static and dynamic brain activity measures (sALFF/dALFF, sFC/dFC) offer distinct insights into brain function.
• Dynamic measures may be crucial for detecting subtle functional abnormalities in neurological diseases.

Purpose of the Study:

• To investigate the utility of dynamic amplitude of low-frequency fluctuations (dALFF) and dynamic functional connectivity (dFC) in detecting functional brain abnormalities in blepharospasm.
• To compare dynamic measures with static measures (sALFF, sFC) in patients with blepharospasm.

Main Methods:

• Resting-state fMRI data were acquired from 46 patients with blepharospasm, 46 with hemifacial spasm (HFS), and 46 healthy controls (HCs).
• Intergroup differences in sALFF and dALFF were examined.
• Seed-based sFC and dFC analyses were performed focusing on regions with altered dALFF in blepharospasm patients.

Main Results:

• Blepharospasm patients showed increased sALFF in the left primary motor cortex (PMC) and increased dALFF variance in the right PMC compared to HCs.
• No significant differences were observed between HFS patients and HCs.
• Blepharospasm patients exhibited decreased dFC strength between the right PMC and ipsilateral cerebellum, without changes in sFC, compared to HCs and HFS patients.

Conclusions:

• Dynamic measures (dALFF, dFC) are complementary to static measures (sALFF, sFC) and enhance the detection of functional brain abnormalities in blepharospasm.
• Blepharospasm appears to be a network disorder affecting the cortico-ponto-cerebello-thalamo-cortical circuit.