Spontaneous swallowing frequency in the evaluation of swallowing function

Oropharyngeal dysphagia (OD) is a common but underdiagnosed condition associated with serious complications such as malnutrition, aspiration pneumonia, and increased mortality. Spontaneous swallowing frequency (SSF) has recently emerged as a potential noninvasive biomarker for dysphagia screening.

This narrative review explores the current state of knowledge on SSF in both healthy individuals and patients with OD, including stroke, Parkinson's disease, head and neck cancer, and cerebral palsy. The review discusses the physiological and neurological bases of SSF, summarizes the available measurement techniques (such as acoustic, electromiography, accelerometry), and examines its diagnostic and therapeutic implications. The literature search was conducted in PubMed, Scopus, and Web of Science, without publication date restrictions; studies included were published between 1965 and 2023. Literature was selected based on relevance, novelty, and methodological robustness, focusing on recent clinical studies and technical advances.

SSF holds promise as a clinical tool to assess brainstem function and detect dysphagia, particularly when integrated with AI-based systems. However, standardization of methods and large-scale validation are essential for its widespread implementation. In the future, SSF may complement existing assessments, enabling earlier and more precise management of OD.