Sensory substitution under passive guidance: Effects on proprioceptive acuity and motor performance

Sensory substitution devices (SSDs) offer a unique framework for investigating attention, perception, and sensorimotor interactions. While previous studies have examined how the type of stimuli provided by an SSD and the exploration strategy applied during active manipulation affect perception, proprioception, and motor-exploratory performance, these factors have not been explored in the context of passive guidance through an SSD. In this study, we examined how the type of stimuli (modality-specific vs. cross-modal stimuli) and the exploration strategy used to passively guide participants (micro-scanning (MIC) vs. macro-scanning (MAC)) influence the perception of two-dimensional shapes during passive guidance through an SSD. We also assessed changes in proprioceptive acuity after passive guidance, and evaluated motor-exploratory performance in a subsequent tracing task. Overall, MIC was more effective than MAC for shape recognition during passive guidance. This superiority of MIC over MAC was observed across all sessions and was particularly marked in the group receiving MIC with cross-modal stimulation. Proprioceptive acuity and tracing performance were also higher following MIC training, especially with cross-modal stimuli. These findings offer new insights into multisensory processing, proprioceptive calibration, and sensorimotor transfer following passive-guided sensory substitution, highlighting the joint influence of exploration strategy and sensory feedback. They suggest an association between perceptual performance during passive guidance training and proprioceptive improvements, and open avenues for investigating its influence on subsequent motor-exploratory behavior. Data supporting this study are publicly available in a French national research data repository and include all measures needed for replication.