Background: Dysphagia has been reported in up to 70% of patients with stroke, predisposing them to aspiration and pneumonia. Despite this, the mechanism for aspiration remains unclear.
Aims: To determine the relationship between bolus flow and laryngeal closure during swallowing in patients with stroke and to examine the sensorimotor mechanisms leading to aspiration.
Methods: Measures of swallowing and bolus flow were taken from digital videofluoroscopic images in 90 patients with stroke and 50 healthy adults, after repeated volitional swallows of controlled volumes of thin liquid. Aspiration was assessed using a validated Penetration–Aspiration Scale. Oral sensation was also measured by electrical stimulation at the faucial pillars.
Results: After stroke, laryngeal ascent was delayed (mean (standard deviation (SD)) 0.31 (0.06) s, p<0.001), resulting in prolongation of pharyngeal transit time (1.17 (0.07) s, p<0.001) without a concomitant increase in laryngeal closure duration (0.84 (0.04) s, p = 0.9). The delay in laryngeal elevation correlated with both the severity of aspiration (r = 0.5, p<0.001) and oral sensation (r = 0.5, p<0.001).
Conclusions: After stroke, duration of laryngeal delay and degree of sensory deficit are associated with the severity of aspiration. These findings indicate a role for sensorimotor interactions in control of swallowing and have implications for the assessment and management of dysphagia after stroke.
- LCD, laryngeal closure duration
- OLE, onset of laryngeal elevation
- OTT, oral transit time
- PAS, Penetration–Aspiration Scale
- PTT, pharyngeal transit time
- SRT, swallow response time
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Published Online First 29 September 2006
Funding: This study was supported by the MRC, the Health Foundation and the Stroke Association.
S H was funded by an MRC Clinician Scientist Award.
Competing interests: None.