PICoS: photorealistic immersion for cognitive stimulation on virtual reality

Abstract Virtual reality (VR) has established itself as a promising technology for cognitive stimulation and intervention in children with special educational needs. This paper presents PICoS, a photorealistic VR immersion system designed to support cognitive therapies using digitized scenarios of real spaces. The system combines 3D reconstruction of the environment from 360 $$^\circ $$ images with optimization using 3D Gaussian Splatting, generating visually realistic and interactive digital twins integrated into Unity. Within this environment, PICoS incorporates an intelligent conversational avatar connected to a language model, capable of guiding therapy, regulating turns, and implementing immediate feedback tailored to the user’s profile. To validate its technical and clinical feasibility, two Go/No-Go activities were designed–taking turns selecting objects and collaboratively building a tower–aimed at training inhibitory control, sustained attention, and social synchronization. An experimental study was conducted with two contrasting groups: children with Down syndrome and gifted children, following a 2D pre-test protocol, VR session, and 2D post-test. Participant ratings showed high enjoyment, with four of five children selecting the highest enjoyment category, and all five expressing a willingness to use the system again. Three of five participants selected the highest comprehension category. However, two participants reported dizziness, indicating that tolerability requires more systematic assessment in future studies. Overall, these preliminary results suggest that PICoS is a realistic and usable platform for immersive cognitive interventions, opening the door to personalized VR-based therapies with conversational agents in clinical and educational contexts .