General Purpose Haptic/Biometric-Based Dynamic Difficulty Adjustment for Post-Stroke Upper-Limb Rehabilitation Games.

Rehabilitation therapy can be more effective and engaging when interactive technologies are involved. To enhance this experience, we integrated a haptic/biometric-based (HBB) Dynamic Difficulty Adjustment (DDA) system into the enAblegames ${}^{\text {TM}}$ platform, which already uses body tracking for therapeutic gaming. This system adapts game and haptic difficulty in real time based on each patient's biometric data and performance, making therapy more personalized. We tested this system with 11 participants, comparing their experiences with and without DDA. The results were promising-36% preferred DDA-enhanced games, compared to just $\mathbf{7 \%}$ for non-DDA, and in a single-game scenario, preference for DDA increased by 50 %. These early findings suggest that HBB-DDA can make rehabilitation more engaging and tailored to individual needs. While more research is needed to understand its full impact, this system has the potential to improve patient experience and therapy outcomes.