Bridging Reduced Grip Strength and Altered Executive Function: Specific Brain White Matter Structural Changes in Patients with Alzheimer’s Disease

Abstract

Objective

To investigate the correlation between specific fiber tracts and grip strength and cognitive function in patients with Alzheimer’s disease (AD) by fixel-based analysis (FBA).

Methods

AD patients were divided into AD with low grip strength (AD-LGS, n=29) and AD without low grip strength (AD-nLGS, n=25), along with 31 normal controls (NC). General data, neuropsychological tests, grip strength and cranial magnetic resonance imaging (MRI) scans were collected. FBA evaluated white matter (WM) fiber metrics, including fiber density (FD), fiber cross-sectional (FC), and fiber density and cross-sectional area (FDC). The mean fiber indicators of the fiber tracts of interest (TOI) were extracted in cerebral region of significant statistical differences in FBA to further compare the differences between groups and analyze the correlation between fiber properties and neuropsychological test scores.

Results

Compared to AD-nLGS group, AD-LGS group showed significant reductions in FDC in several cerebral regions. In AD patients, FDC values of bilateral uncinate fasciculus and left superior longitudinal fasciculus were positively correlated with Clock Drawing Test scores, while FDC of splenium of corpus callosum, bilateral anterior cingulate tracts, forceps major, and bilateral inferior longitudinal fasciculus were positively correlated with the Executive Factor Score of Memory and Executive Screening scale scores.

Conclusion

Reduced grip strength in AD patients is associated with extensive impairment of WM structural integrity. Changes in FDC of specific WM fiber tracts related to executive function play a significant mediating role in the reduction of grip strength in AD patients.

Keywords:

• Alzheimer disease
• grip strength
• white matter
• fixel-based analysis
• cognition function

Data Sharing Statement

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

Ethical Approval

The study was performed in accordance with the guidelines of the 1964 Declaration of Helsinki and was approved by the ethics committee of the Second Affiliated Hospital of Soochow University (JD-LK-2021-049-01). All patients provided written informed consent prior to the study.

Acknowledgments

We would like to thank all the participants and their relatives, and the staff of the Second Affiliated Hospital of Soochow University for their cooperation and assistance. Shan-wen Liu and Xiao-ting Ma contributed equally to this work and shared the first authorship.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no competing interests relevant to the content of this work.

Additional information

Funding

This work was supported by Application of Clinical Technology in Elderly Health Research Project in Jiangsu Province (LD2021031); Suzhou Science and Technology Plan Medical and Health Care Science and Technology Innovation Applied Basic Research (SKY2022161); Research Project of Neurological Diseases in the Second Affiliated Hospital of Suzhou University, Research Center (ND2023A01); Jiangsu Provincial Medical Key Discipline for the 14th Five-Year Plan (ZDXK202217). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.