A Systematic Review on the Effects of Speech and Language Therapy in Patients with Dementia

Background/Objectives: Dementia is a progressive neurocognitive disorder characterized by decline in cognitive, communicative, and functional abilities. Speech and language therapists (SLTs) play a role in managing communication and cognitive–linguistic impairments while supporting families and caregivers. However, evidence regarding the effectiveness of speech and language therapy interventions remains heterogeneous, and evidence has not integrated cognitive–linguistic and caregiver-related outcomes. This systematic review aimed to synthesize recent evidence regarding the effects of speech and language therapy interventions on cognitive–linguistic functioning in individuals with dementia and caregiver-related outcomes. Methods: The review followed PRISMA guidelines. Studies were retrieved from Google Scholar, PubMed, and ScienceDirect using search terms including “speech therapy,” “language therapy,” and “dementia.” Eligible studies included those published within the last ten years that examined speech and language therapy interventions in individuals with dementia and reported cognitive-linguistic and/or caregiver-related outcomes. Methodological quality was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Tools. Findings were synthesized narratively due to heterogeneity in study designs, interventions, and outcome measures. Twelve studies met the inclusion criteria. Results: The included studies generally reported improvements in cognitive–linguistic and communicative functioning following speech and language therapy interventions. Fewer studies reported performance stabilization, while none reported deterioration. Several studies also reported positive effects on caregiver communication confidence and interaction quality. Conclusions: Speech and language therapy appears to improve cognitive–linguistic functioning and support caregiver communication and engagement. However, the evidence remains limited due to small sample sizes, heterogeneous intervention protocols, and variability in outcome measures, highlighting the need for further high-quality research.