Low- and high-tech AAC approaches in severe acquired brain injury: an exploratory pilot study

Acquired brain injury (ABI) is a major cause of long-term cognitive and communication impairments and is frequently associated with complex communication needs. Augmentative and alternative communication (AAC) interventions are commonly used to support communication in individuals with severe acquired brain injury (SABI), yet evidence regarding their cognitive and neurophysiological effects remains limited. This pilot feasibility and exploratory study examined preliminary effects of low- and high-tech AAC interventions on cognitive, communicative, functional, and neurophysiological outcomes in individuals with SABI. Twenty participants were quasi-randomly assigned to an experimental group (EG) receiving high-tech AAC (Grid 3) or a control group (CG) receiving low-tech AAC. Cognitive functioning, functional independence, communication abilities, and P300 event-related potential latency were assessed at baseline and post-intervention. Non-parametric statistics were applied due to the small sample size. Within-group changes were examined using Wilcoxon signed-rank tests, and exploratory between-group comparisons were conducted using Mann-Whitney U tests. Effect sizes with 95% confidence intervals were calculated, and Bonferroni correction was applied. Both groups showed significant within-group improvements in functional communication (EG p = 0.007, CG p = 0.014). The EG demonstrated significant gains in cognitive functioning (p = 0.005) and reduced P300 latency (p = 0.003), whereas no significant changes were observed in the control group. Changes in functional independence were modest and not statistically significant in either group. These findings support the feasibility of AAC interventions in SABI and suggest potential benefits for communication and selected cognitive processes. Larger randomised studies are needed to clarify comparative effects and mechanisms.