Abstract TP37: Brain Activity During Cognitive-motor Balance Dual-tasking Among Healthy Older Adults and People With Subcortical Stroke: A Cross-sectional Study
Bibliographic record
Abstract
Introduction: Prefrontal cortex (PFC) has long been thought to be involved in dual-tasking, and is also found to be associated with areas involved in motor control (supplementary motor area (SMA), premotor cortex). Functional near-infrared spectroscopy (fNIRS), a non-invasive neuroimaging technology, allows measurement of cortical activity during dual-tasking. This study aimed to compare cognitive-motor interference and brain activity between people with subcortical stroke and their healthy counterparts. Methods: People with subcortical chronic stroke and their healthy counterparts (N=25/group; aged ≥ 50 years old, Montreal Cognitive Assessment score ≥ 22 points, Mini Balance Evaluation Systems Test score ≥16 points) were included. Each participant performed tasks in random order including: (1) single-task maintaining balance in standing position under vibration disturbance, (2) single-task serial-7-subtractions/clock test (while standing), and (3) dual-task maintaining balance in standing position in conjunction with a serial-7-subtractions/clock test. Participants were instructed to maintain balance as fast as they could safely while generating as many correct answers as possible during dual-task balance maintenance. Oxyhemoglobin (HbO) changes in bilateral PFC and SMA were measured with 46 channels of a continuous-wave system in fNIRS (ETG-4000, Hitachi). Path length of center of gravity was monitored by DynSTABLE system for postural sway. For both HbO and postural sway, dual-task cost was calculated as (dual-task performance-single-task performance) × 100%) / (single-task performance). Results: People with subcortical stroke had greater dual-task cost for postural sway during dual-task serial-7-subtractions than their healthy counterparts ( P <0.001). However, the dual-task cost for HbO changes was not significantly different between the two groups. There was moderate correlation of changes in oxyhemoglobin (HbO) in non-lesion hemisphere of PFC and postural sway during dual-task serial-7-subtractions among people with subcortical stroke (r = 0.538, P = 0.005). Conclusions: PFC plays an important role in dual-task balance tests. People with subcortical stroke have similar brain activation compared to healthy older adults, but with worse dual-task performance. Dual-task serial-7-subtractions may serve as a better assessment to discriminate dual-task performance between people with subcortical stroke and their healthy counterparts compared to dual-task clock test.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".