Spontaneous Swallowing Rates in Health and Stroke

Julie A. Theurer, Western University
K Czachorowski
S Stanbouly
A South
J Fisher
P Letsos

Abstract

Purpose Few studies have documented spontaneous dry (i.e., non-bolus) swallowing rates in patients with swallowing impairment. This study compared spontaneous dry swallowing rates in dysphagic stroke patients and healthy older adults.

Methods Spontaneous, dry swallows were recorded during a 5-min period in 19 dysphagic stroke patients (11 males; mean age = 67.4 years) and 18 healthy older adults (10 males; mean age = 73.4 years). Swallows were identified from a distinct pattern of laryngeal movement, associated with a transient respiratory apnea, recorded from the output of pressure transducers positioned around the subject's neck and ribcage, respectively. Spontaneous dry swallowing rates were calculated as number of swallows per minute. Group data (e.g., dysphagic stroke patients vs. healthy older controls) were analyzed using a Mann-Whitney U test.

Results Spontaneous dry swallowing rates ranged from 0.0 to 1.14 swallows/min in the dysphagic stroke patients, and 0.0 to 1.6 swallows/min in the older controls. Group comparison revealed that the median spontaneous dry swallowing rate among the dysphagic stroke patients was significantly lower than the spontaneous dry swallowing rate in healthy older adults (p = 0.013).

Conclusion Spontaneous dry swallowing rates vary substantially among individuals in both health and disease. Dysphagic stroke patients tend to demonstrate significantly lower dry swallowing rates than healthy older controls. Future research is required to (1) determine if swallowing rates calculated over short observation periods predict swallowing rates calculated over longer time periods, and (2) explore the potential relationships between spontaneous swallowing frequency, patterns of swallowing impairment, and responses to swallowing rehabilitation.