Premotor cortex and frontal eye field region metabolite alteration in human amyotrophic lateral sclerosis patients: A quantitative survey

Abstract

Introduction

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive upper and lower motor neuron degeneration, leading to muscle weakness, respiratory failure, and mortality. The premotor cortex (PMC), including the frontal eye field (FEF), shows greater resistance, with limb function declining earlier than eye movement. This study utilizes magnetic resonance spectroscopy (MRS) to investigate metabolite ratio changes in these regions for potential early ALS diagnosis.

Methods and Materials

Fourteen ALS patients and healthy controls underwent MRS to assess neurometabolite levels, including N-acetyl aspartate (NAA), creatine (Cr), myo-inositol (mIns), and choline (Cho) in the PMC and FEF. ELISA measured superoxide dismutase-1 (SOD1) enzyme levels. Group differences were analyzed statistically using t-tests to evaluate significant variations.

Result

In ALS patients, a significant decrease in NAA/Cr (p = .045) and an increase in mIns/Cr (p < .0001) concentrations were observed in the PMC. No significant differences in Cho/Cr (p = .215) were detected between the FEF and PMC regions in ALS patients. Compared to the control group, NAA/Cr levels in the PMC and FEF regions of ALS patients were significantly lower (p = .004, .001), while mIns/Cr values were significantly higher (p = .001). However, no significant changes were observed in the Cho/Cr ratio in the FEF between ALS patients and controls. Additionally, SOD1 enzyme levels were significantly reduced in ALS patients (p < .0001).

Conclusion

The findings suggest that neurometabolites levels in the PMC and FEF may be a promising candidate for clinical and pathological changes in ALS.