The researchers note that people with lower-limb amputation often experience balance and gait impairments due to missing somatosensory feedback from prostheses. Recent neuroprostheses can partially restore such sensations by electrically stimulating sensory nerves in the residual limb or spinal cord, but whether the restored sensations are intuitive and integrate seamlessly into the sensorimotor network has been difficult to quantify. The CCE task had been proposed for upper-limb amputees; this study is the first to extend it to the lower limb. The authors emphasize that external factors affecting the CCE must be identified before the task can be applied to lower-limb amputees.
Crossmodal Congruency Test Tells Sensory Feedback Types Apart at the Knee but Not the Foot
Summary
A University of Pittsburgh team (Bose et al.) tested the crossmodal congruency effect (CCE) task in 15 able-bodied volunteers to see whether it can quantify how intuitive lower-limb sensory feedback feels. At the knee, the task distinguished more natural pneumatic stimulation from less natural electrical stimulation; at the foot, it could not tell the same stimuli apart. The study was posted to bioRxiv on August 10, 2026. Lower-limb amputees often have balance and gait problems because their prostheses give no somatosensory feedback; electrical-stimulation neuroprostheses can partly restore sensation, but there has been no way to quantify how intuitive that sensation is. The authors stress that external factors affecting the CCE must be identified before it can be used with amputees.
Why it matters
The first extension of the CCE task, commonly used for the upper limb, to lower-limb sensory feedback shows its discriminating power depends on body site, working at the knee but not the foot, so neuroprosthetics will need site-specific assessment methods to measure how intuitive restored sensation is for amputees.
Compiled by BCIwiki from public sources
Sources · 1
biorxiv.org 2026-08-10