The Influence of Strength and Skill Parameters on the Evolution of Dysphagia Post Stroke: A Prospective Study

The role of pathophysiological deficits in the evolution of dysphagia post-stroke is unclear. This observational, longitudinal study aimed to document the evolution and relationship between strength and precision of submental contraction, and swallowing outcomes at six months. Participants were recruited from a tertiary acute hospital after a first acute stroke. Sociodemographic data and stroke typology were documented. Outcome measures were collected five times across six months. These included: oral diet (FOIS, IDDSI), functional ingestion (TOMASS, TWST), self-reported swallowing-related quality of life (SWAL-QOL), and submental muscle strength and precision contraction as assessed using surface electromyography coupled with biofeedback during saliva swallowing and jaw-opening tasks. Mixed effects models and multiple regressions analyses were conducted. Participants (N = 22, mean age 73.9 ± 14.4 years, 9 males) were recruited at a mean time of 2.8 ± 1.5 days after stroke. Strength parameters (effortful swallow hit rate) improved between ten days and one month post-stroke (p = 0.04). Swallowing temporal precision improved significantly between one and six months (p < 0.01). At six months, participants with decreased swallowing precision also had decreased quality of life (p = 0.04) and increased ingestion time of fluids (p = 0.002). This study is a novel step in exploring the nature and evolution of strength and precision parameters of swallowing muscle activation, and their impact on dysphagia recovery. As swallowing precision was associated with poorer functional outcomes, further studies are warranted to improve early differential diagnosis of patients at risk of chronic dysphagia.