Evidence of Altered Corticomotor System Connectivity in Early-Stage Alzheimer's Disease
- 1 March 2012
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Neurologic Physical Therapy
- Vol. 36 (1), 8-16
- https://doi.org/10.1097/npt.0b013e3182462ea6
Abstract
Background and Purpose: There is increasing evidence for subtle motor dysfunction early in Alzheimer disease (AD), including common motor behaviors that were once considered unaffected early in the disease process. Our objective was to assess whether functional neural networks underlying motor behavior are altered by AD. Methods: We investigated AD-related differences in regional brain activation during motor performance. Nine older adults with early-stage AD and 10 without dementia underwent functional magnetic resonance imaging while performing a visually directed simple motor task (hand squeeze). Results: Despite some similarity in brain activation during motor performance, we found that individuals without dementia exhibited greater activation in accessory motor regions, supplementary motor area, and cerebellum compared with those with AD. We also assessed disease-related differences in regions where activity was functionally integrated with primary motor cortex. Using a psychophysiological interaction analysis, we found that those with AD displayed increased coactivation with primary motor cortex of bilateral motor and visual regions. Discussion and Conclusions: These AD-related differences in regional coactivation during motor execution may represent inefficiency in the motor network as a consequence of the disease process. Alternatively, they may represent compensatory activation. These findings provide further evidence that in early stages of AD, neuromotor function is altered even during simple motor behaviors. The results may have implications for performance of more complex tasks and may be associated with the well-characterized decline in dual-task performance in those with AD.Keywords
This publication has 59 references indexed in Scilit:
- Default mode network connectivity in stable vs progressive mild cognitive impairmentNeurology, 2011
- Structural MRI biomarkers for preclinical and mild Alzheimer's diseaseHuman Brain Mapping, 2009
- Detection of PCC functional connectivity characteristics in resting-state fMRI in mild Alzheimer’s diseaseBehavioural Brain Research, 2009
- Staging Dementia Using Clinical Dementia Rating Scale Sum of Boxes ScoresArchives of Neurology, 2008
- Cardiorespiratory fitness and brain atrophy in early Alzheimer diseaseNeurology, 2008
- Selective changes of resting-state networks in individuals at risk for Alzheimer's diseaseProceedings of the National Academy of Sciences of the United States of America, 2007
- Relationship of fMRI activation to clinical trial memory measures in Alzheimer diseaseNeurology, 2007
- Voxel-based homogeneity probability maps of gray matter in groups: assessing the reliability of functional effectsNeuroImage, 2004
- Neuropathological stageing of Alzheimer-related changesActa Neuropathologica, 1991
- Clinical diagnosis of Alzheimer's diseaseNeurology, 1984