Cortical neuromodulation by vibration-induced illusion of movement is observed in older individuals, but not in individuals with acute stroke: a cross-sectional fNIRS study.
Léger B, Auzou P, et al. • Journal of neuroengineering and rehabilitation • 2026
Older adults exhibited more extensive bilateral activation in frontoparietal and sensorimotor cortices during vibration-induced illusion of movement compared with young adults, whereas individuals with acute stroke showed no significant task-related cortical activation and an overall reduction in cerebral activity, though neural efficiency in stroke participants was comparable to that of older adults.
Key Findings
Results
Older adults showed more extensive bilateral frontoparietal and sensorimotor cortical activation during vibration-induced illusion of movement compared with young adults.
Sample included 28 young adults, 30 older adults, and 23 individuals with acute stroke.
Vibration was applied at 80 Hz for six 15-second trials per condition to the distal tendon of the triceps brachii.
Cerebral hemodynamic activity was assessed using fNIRS through changes in (de)oxyhemoglobin concentrations.
The bilateral pattern of activation in older adults was interpreted as age-related changes in neural recruitment during proprioceptive processing.
Conditions included vibration with and without visual feedback of the vibrated arm.
Results
Individuals with acute stroke showed no significant task-related cortical activation during vibration-induced illusion of movement.
23 individuals with acute stroke received vibration applied to the paretic left arm.
Stroke participants displayed an overall reduction in cerebral activity compared with both healthy groups (young and older adults).
The absence of significant activation contrasted with the patterns seen in both young and older healthy participants.
Illusion intensity was quantified using the Standardized Kinesthetic Illusion Procedure scale in addition to fNIRS measures.
Results
Neural efficiency in participants with acute stroke was comparable to that observed in older participants, despite reduced overall cortical activation.
Neural efficiency metrics were derived from fNIRS-assessed cerebral hemodynamic activity within frontoparietal and sensorimotor areas.
This finding was described as suggesting that 'preserved compensatory mechanisms may still be engaged early after stroke.'
The comparable neural efficiency between stroke and older adult groups was observed even though the stroke group showed no significant task-related activation.
Activation profiles were established for each group and compared across groups.
Methods
Vibration-induced illusion of movement was administered to three distinct participant groups using a cross-sectional fNIRS study design.
Groups consisted of 28 young adults, 30 older adults, and 23 individuals with acute stroke.
Healthy participants received vibration bilaterally; stroke participants received vibration only to the paretic left arm.
Each condition consisted of six 15-second vibrations at 80 Hz, delivered with or without visual feedback.
The study was registered as NCT06218563, with registration date 2024-01-12.
Frontoparietal and sensorimotor areas were the primary cortical regions of interest assessed via fNIRS.
Discussion
The authors suggest vibration-induced illusion of movement has potential implications for limiting age-related proprioceptive decline and supporting early rehabilitation after stroke.
Stroke is described as 'frequently associated with sensorimotor impairments of the upper limb, including proprioceptive deficits, that substantially impair motor control and quality of life.'
The authors note that 'understanding how physiological aging and acute stroke affect proprioceptive processing is therefore crucial for developing targeted rehabilitation strategies.'
The presence of preserved neural efficiency early post-stroke was cited as supporting the plausibility of early vibration-based intervention.
The findings pertaining to older adults were interpreted as suggesting potential to limit age-related proprioceptive decline through vibration-based approaches.
What This Means
This research suggests that the brain responds very differently to a sensory illusion technique — vibration applied to a tendon that tricks the brain into feeling movement — depending on whether a person is a healthy older adult or has recently had a stroke. In healthy older adults, the brain activated a wider network of regions on both sides compared to younger adults, which the researchers interpreted as the older brain working harder or recruiting more resources to process the same sensory information. In contrast, people who had recently had a stroke showed no meaningful brain activation in response to the vibration at all, and their overall brain activity was lower than both healthy groups.
Despite this reduced brain activity after stroke, the researchers found that how efficiently the stroke-affected brain used whatever activity it did generate was similar to older adults. This is notable because it hints that even in the acute (early) phase of stroke recovery, some preserved brain mechanisms may still be functioning. The study used a non-invasive brain imaging method called fNIRS (functional near-infrared spectroscopy) to measure blood flow changes in the brain, and the illusion itself was rated using a standardized scale.
This research suggests that vibration-induced movement illusions could potentially be useful both as a tool to maintain or improve sensory function as people age, and possibly as an early rehabilitation approach after stroke. However, the fact that acute stroke patients showed no significant brain response to the technique raises important questions about timing and patient selection for such interventions, and further research would be needed to understand when and how this approach might be clinically beneficial.
Léger B, Auzou P, Fourdrinoy &, Sarrazin M, Celot S, Gay C, et al.. (2026). Cortical neuromodulation by vibration-induced illusion of movement is observed in older individuals, but not in individuals with acute stroke: a cross-sectional fNIRS study.. Journal of neuroengineering and rehabilitation. https://doi.org/10.1186/s12984-026-02129-w