Immersive AOT: Multisensory Stimulation and Neurophysiological Correlates - A Pilot Study

The discovery of the Mirror Neuron System (MNS) has promoted the development of rehabilitation techniques such as Action Observation Treatment (AOT) and Motor Imagery (MI). These are based on the principle that neural circuits active during execution, also activate during the observation or imagination of movements. These techniques have been found to be effective in several clinical populations including children with Cerebral Palsy (CP), the most common childhood-onset motor disorder. We hypothesize that a multimodal version of AOT, integrating not only visual stimuli (standard practice) but also auditory and tactile stimuli, could further enhance the activation of the MNS. In fact, everyday actions naturally involve multiple sensory channels, and evidence indicate that audio-visual action observation activates the MNS more intensely than visual stimuli alone, thus offering a potential improvement for CP rehabilitation.

The primary aim of this observational pilot study, conducted at IRCCS Fondazione Stella Maris, is to verify whether a multisensory (=immersive) AO session - combining visual, auditory, and tactile stimuli - produces greater activation of the MNS, than a traditional session (visual AO alone). Neural correlates will be measured through high-density Electroencephalography (hdEEG), with a specific focus on the modulation of the sensorimotor mu rhythm. Twenty children and adolescents with CP, aged 7-25 years, and 20 typically developing (TD) aged-matched peers will be recruited in the study. The study also aims to assess the level of participants' attention during stimuli presentation through eye tracking, and to verify whether immersive AO can influence MI abilities, measured through specific tasks and questionnaires (i.e., Motor Imagery Questionnaire for Children (MIQ-C, aged 7-12) and the Motor Imagery Questionnaire - 3 (MIQ-3) for adolescent). In an initial phase of the study both questionnaires will be the validated in a separate sample of 120 TD Italian children and 120 Italian adolescents or adults. The absence of intellectual disability will be assessed using the age-appropriate version of Raven's Progressive Matrices test.

Each participant will undergo two EEG sessions: the immersive session will consist of watching first-person videos accompanied by auditory stimuli consistent with the action and tactile stimuli provided by TouchDIVER Pro haptic gloves (Weart, CE-marked device), suitably adapted for the paediatric population. The traditional session will consist of watching videos without sounds or any tactile additional stimulus. The two sessions will be performed in a in random order. In both sessions, after the observation phase, participants will be asked to perform or imagine the same actions presented in the videos. During observation, eye movements and gaze behavior will be monitored using an eye tracking system. Throughout each session, cortical activity will be recorded using a 128-channel hdEEG net. The sessions will be video-recorded to accurately monitor participants motor behavior, response times, and compliance with the protocol.

At the end of each EEG session, participants will be administered the MIQ-C or MIQ-3 questionnaire and a short task to assess MI abilities. In this task, participants will watch some of the videos previously used during the EEG session and will then be asked to imagine the same action. In this case, their imagery will be interrupted at specific time points, and they will be asked to select, from two images, the moment of the action corresponding to the point at which they were interrupted.

Data analysis will examine within- and between-groups differences for the immersive AO vs the traditional AO. Correlation analysis will be also performed between neurophysiological data, attentional data, questionnaires, MI responses and standardized clinical assessments ( for the CP group), in order to understand how the participants' motor and cognitive abilities influence the activation of the circuits involved in the experimental tasks.