Training with and without a cane under visual deprivation: Effects on body schema and perceived reachability in young...

Tool use can modify body-related representations, but it remains unclear whether such changes are specific to the limb using the tool, whether they generalize to other body parts, and whether their expression differs across healthy aging under visual deprivation. We examined 43 younger and older adults during three blindfolded training conditions adapted from Sun and Tang (2019): Object Search Training (object search with a cane), Walking/Navigation Training with Cane, and Walking Training Without Cane. Body schema-related recalibration was assessed using tactile distance judgment (TDJ) at the right hand, forearm, shin, and foot, while perceived reachability was assessed using reaching distance estimation (RDE) before and after the two cane use conditions. For TDJ, estimation error was averaged across four tactile separations and analyzed as post-minus-pre change. Across all three conditions, TDJ change did not differ significantly by training condition, and neither Condition × Limb nor Age Group × Condition × Limb interactions were significant. Instead, a significant Age Group × Limb interaction indicated that younger and older adults differed in the relative pattern of recalibration across body limbs, without evidence for a single selectively affected limb. RDE likewise showed no significant Condition or Age Group × Condition effect. Older adults exhibited a reliable within-group shift toward greater underestimation of reachability following object search with the cane, but this change did not differ significantly from that observed in younger adults or from the walking-with-cane condition. Together, these findings challenge a simple limb-specific tool-embodiment account by showing that short-term blindfolded cane training did not produce robust condition-specific recalibration, while age differences emerged primarily in the relative pattern of change across body limbs. Because training duration differed between age groups and no sighted control condition was included, age- and vision-related interpretations remain cautious.