Reduced Cingulate Grey Matter Mediates Dual-Task Gait and Dementia Onset in MCI

Overview

In individuals with mild cognitive impairment (MCI), a high dual-task gait cost (≥20% slowing) is linked to a threefold increased risk of progressing to dementia. This study identifies reduced grey matter volume in the right anterior and middle cingulate cortices as a key mediator of this association, highlighting a neural substrate underlying cognitive-motor decline.

Background

Mild cognitive impairment is a transitional state with heterogeneous risk for progression to dementia. Dual-task gait testing, which assesses walking speed while performing a cognitive task, has emerged as a promising functional biomarker for dementia risk. Prior studies have linked high dual-task cost (DTC) to brain structural changes, but the specific cortical regions mediating the relationship between DTC and incident dementia remain unclear. Understanding these neural mechanisms could improve early detection and intervention strategies.

Data Highlights

Key Findings

• High dual-task gait cost during counting backwards by ones and naming animals is associated with smaller grey matter volume in multiple brain regions.
• Higher choline-to-creatine ratio in the primary motor cortex correlates with increased dual-task cost during serial sevens subtraction.
• Individuals with high dual-task cost have a threefold increased risk of progressing to dementia over 9 years.
• Grey matter volume loss in the right anterior and middle cingulate cortices mediates 48% of the relationship between dual-task cost and incident dementia.
• No mediation effect was observed from grey matter loss in other brain regions or motor cortex metabolite levels.

Clinical Implications

Dual-task gait testing, particularly counting backwards by ones and naming animals while walking, can serve as a practical motor biomarker to identify MCI patients at elevated risk for dementia. The identification of the right anterior and middle cingulate cortices as mediators suggests potential targets for therapeutic interventions aimed at preserving grey matter volume to delay or prevent dementia onset. Incorporating dual-task gait assessments into routine clinical evaluations may enhance early detection and monitoring of cognitive decline.

Conclusion

Reduced grey matter volume in the right anterior and middle cingulate cortices partially explains the link between impaired dual-task gait performance and dementia onset in MCI. These findings advance understanding of the neural mechanisms underlying cognitive-motor interactions in dementia progression and support the clinical utility of dual-task gait as a biomarker.

References

1. Montero-Odasso et al. 2024 -- Reduced cingulate grey matter as a mediator in the link between dual-task gait performance and the onset of dementia