fNIRS-based cortical activation during swallowing-related tasks: implications for dysphagia rehabilitation-a scoping...

Swallowing is a complex sensorimotor function requiring coordinated cortical and subcortical control and is frequently impaired in neurological disorders. Functional near-infrared spectroscopy (fNIRS) has emerged as a promising non-invasive neuroimaging modality for investigating swallowing-related cortical activity; however, its application in dysphagia research remains methodologically heterogeneous. This scoping review aimed to map existing evidence on the use of fNIRS in swallowing and dysphagia rehabilitation and to identify prevailing concepts and knowledge gaps. The review followed the Joanna Briggs Institute methodology and PRISMA-ScR guidelines. Electronic searches of MEDLINE, Embase, Scopus, and Web of Science were conducted from database inception to September 2025. Studies involving adult participants and task- or intervention-based fNIRS assessment of swallowing-related cortical activity were included. Twenty-one studies involving healthy adults and patients with dysphagia met the inclusion criteria. Swallowing consistently activated a distributed fronto-sensorimotor cortical network, with activation patterns modulated by sensory stimulation, motor demands, and neuromodulation. Considerable heterogeneity was observed in study design, task paradigms, optode placement, and analytical approaches, limiting cross-study comparability. Overall, fNIRS demonstrates feasibility and sensitivity for assessing swallowing-related cortical activity in both experimental and clinical contexts. However, methodological variability and the limited inclusion of clinical populations restrict the interpretation and generalizability of current findings. The development of standardized protocols and clinically relevant outcome measures will be essential for translating fNIRS into routine dysphagia assessment and rehabilitation.