Sensory substitution and augmentation are pivotal concepts in multi-modal perception, particularly when confronting the challenges associated with impaired or missing sense rehabilitation. The present systematic review investigates the role of haptics for the hearing impaired in training or gamified activities. We applied a set of keywords to the Scopus® and PubMed® databases, obtaining a collection of 35 manuscripts spanning 23 years. Each article has been categorized following a documented procedure and thoroughly analyzed. Our findings reveal a rising number of studies in this field in the last five years, mostly testing the effectiveness of the developed rehabilitative method (77.14%). Despite a wide variety in almost every category we analyzed, such as haptic devices, body location, and data collection, we report a constant difficulty in recruitment, reflected in the low number of hearing-impaired participants (mean of 8.31). This review found that in all six papers reporting statistically significant positive results, the vibrotactile device in use generated vibrations starting from a sound, suggesting that some perceptual aspects connected to sound are transmittable through touch. This fact provides evidence that haptics and vibrotactile devices could be viable solutions for hearing-impaired rehabilitation and training.
