Motor proficiency composite scores as a novel biomarker for Alzheimer's disease. (31st December 2021)

• Record Type: Journal Article
• Authors: Koppelmans, Vincent; Ruitenberg, Marit F.L.; Van der Geest, Jos; Duff, Kevin M.
• Is Part Of: Alzheimer's & dementia. Volume 17(2021)Supplement 5
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-31
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.050315
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are associated with various motor impairments in ambulatory and manual measures that involve speed, force, and precision. Prior studies suggest that such motor impairments are an early disease marker and predict AD progression. A composite motor score that combines motor measures spreading the breadth of motor domains could be a stronger predictor than individual motor measures. Here, we evaluate associations of motor composite scores with existing AD biomarkers in a combined group of individuals with MCI and AD, and cognitively normal individuals. Method: All participants, who were classified by ADNI‐2 criteria, completed the following motor measures: 1) grip strength using a hand‐dynamometer; 2) general motor reaction time assessed as the time between the visualization of stimuli on a computer screen and pressing a button; 3) psychomotor speed using the Trail Making Test Part A; 4) unimanual and bimanual finger tapping speed using a keyboard; and 5) drawing speed and accuracy using the computerized Archimedes spiral tracing test. Motor composite scores were defined as the sum of the z‐transformed raw measures. Additionally, participants underwent APOE genotyping to determine the presence of e4 alleles, amyloid PET imaging to quantify amyloid deposition, and structural MRI scanning to obtain hippocampal volume. Correlational analysis was used to test the association between motor composite score and AD biomarkers. Result: To date, 5 cognitively normal, 7 MCI, and 9 AD subjects completed all assessments. Motor composite scores were significantly and strongly associated with AD biomarker scores (p<.05 and Cohen's d>.8 for all outcomes; see Figure 1). Individuals with more APOE e4 alleles had worse motor composite scores (Rho=‐0.43). Higher amyloid burden was related to worse motor composite scores (r=‐0.51). Larger volume of the left hippocampus correlated with better motor composite scores (r=0.51). Conclusion: Motor proficiency, as reflected in composite scores, is strongly associated with established markers of AD. Ongoing work focuses on expanding our sample size to allow for statistical correction for potential confounders such as age, stratify the sample to study potential sex differences, and compare motor scores to neuropsychological test scores collected in this sample.