Reach-to-grasp kinematics and kinetics with and without visual feedback in early-stage Alzheimer's disease.
Jianhong Zhang, Yunling Xiao, Zong-Ming Li and 3 others
PMID 36357939WHAT IT FOUND
People with early-stage Alzheimer's disease reached and grasped objects more slowly and less accurately than healthy adults.
These differences were most pronounced when they could not see their own hands, suggesting they rely heavily on visual feedback to compensate for motor control deficits.
Key findings
01Patients with early-stage AD took significantly longer to complete a reach-to-grasp task than healthy controls, especially when visual feedback of their hand was blocked.
02Without visual feedback, AD patients showed greater errors in grasping accuracy and longer preload times compared to controls.
03Kinematic and kinetic deficits in AD patients correlated with scores on standard cognitive tests like the MMSE and MoCA.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The sample size was small (17 per group), which limits the generalizability of the findings. The study was cross-sectional and case-control, so it cannot establish causality or track progression. The participants were from a single center in China, and the results may not apply to other populations. The study excluded patients with other neurological or musculoskeletal conditions, so findings do not apply to AD patients with comorbidities like stroke or Parkinson's disease. The task was a simple precision grip; it may not reflect complex, multi-step functional activities.
Declared interests
The study was funded by the Key Research & Development Programs of Guangdong Province, the National Key Research and Development Program, the National Natural Science Foundation of China, and the Key Research & Development Programs of Shandong Province. The authors declared no conflicts of interest.
The easy way to misread this
Do not interpret these findings as evidence that visual feedback alone can correct motor deficits in AD. The study shows that AD patients rely on vision to compensate for underlying sensorimotor degradation, but it does not test whether training visual strategies improves functional outcomes or slows disease progression.