Could assessment of upper limb motor function help identify cognitive impairment and dementia?
Background
Motor biomarkers such as gait help identify people at higher risk of developing dementia and cognitive impairment. Upper limb motor function (ULMF) is emerging as a new and more accessible motor biomarker, but it remains unclear which assessment methods to use. This knowledge gap hinders developing and including ULMF protocols in cognitive clinics. The aim of this study was to determine what ULMF assessment methods (including tests, recruitment settings and conditions causing cognitive impairment) have been used and to describe the associations found between ULMF and cognitive impairment.
Methods
A scoping review of all published study types was conducted using PubMed, CINAHL, and Web of Science. A systematic search using JBI guidelines was undertaken, including synonyms for key concepts ‘upper limb’, ‘motor function’ and ‘cognitive impairment’. Selection criteria included dynamic and volitional tests of ULMF in adults. Analysis was by narrative synthesis.
Results
Sixty papers published between 1995 and 2022, comprising 41,800 participants, were included. The most common ULMF assessment tasks were finger tapping, Purdue Pegboard Test and functional tasks such as drawing and grasping an object. Methods of measurement were diverse, ranging from visually counting repetitions during a defined period to more detailed quantification of speed and rhythm using advanced motion capture systems. Participants were mostly recruited from clinical settings. Alzheimer’s Disease was the most studied cause of cognitive impairment. Generally, slower speed, lower frequency, more errors, and greater variability in ULMF movement measures was associated with cognitive impairment, but results were mixed.
Discussion/Conclusion
This review maps the methods used in assessing ULMF and summarises the available evidence on how ULMF associates with cognitive impairment. It identifies research gaps and may help guide ULMF protocols for future cognitive clinics and research. There is potential for ULMF to be used in clinical assessments of dementia and cognitive impairment.
