Conclusion: In spite of no clinical signs of facial paresis, a pathological lip force (LF) will strongly influence swallowing capacity (SC). Stroke patients with impaired SC suffer a subclinical facial paresis. The results support earlier findings that LF training can be used to treat dysphagia.
Objectives: Lip muscle training with an oral screen can improve both LF and SC in stroke patients, irrespective of the presence or absence of facial palsy. The aim was therefore to study the influence of LF on SC.
Methods: This prospective study included 22 stroke patients, aged 38–90 years, with dysphagia, 12 with initial unilateral facial paresis and 45 healthy subjects, aged 25–87 years. All were investigated with a Lip Force Meter (LF100), and with an SC test.
Results: A significant correlation was found between LF/SC (p = 0.012) in stroke patients but not in healthy subjects. LF/SC was not age-related in stroke patients. LF was not age-dependent in healthy subjects, but SC decreased with increasing age (p < 0.0001). However, SC did not reach a pathological value and a regression analysis showed that 73% of the variation in SC is attributable to LF and age.