Swallowing Abnormalities after Acute Stroke: A Case Control Study

Abstract.

Dysphagia is a common and potentially fatal complication of acute stroke. However, the underlying pathophysiology, especially the relative importance of motor and sensory dysfunction, remains controversial. We conducted a case control study of 23 acute stroke patients (mean age = 72 yr) at a median of 6 days poststroke and 15 healthy controls (mean age = 76 yr). We used novel methods to assess swallowing in detail, including a timed videoendoscopic swallow study and oral sensory threshold testing using electrical stimulation. Vocal cord mobility and voluntary pharyngeal motor activity were impaired in the stroke group compared with the controls (p= 0.01 and 0.03). There was a delay during swallowing in the time to onset of epliglottic tilt in the stroke group, particularly for semisolids (p= 0.02) and solids (p= 0.01), consistent with a delay in initiation of the swallow. Sensory thresholds were not increased in the stroke group compared with controls. We conclude that pharyngeal motor dysfunction and a delay in swallow initiation are common after acute stroke. Vocal cord mobility is reduced, and this may result in reduced airway protection. We found no evidence to support the hypothesis that oropharyngeal sensory dysfunction is common after acute stroke.