Validation of speech-language therapists’ perceptions of reflexive cough strength against objective measures of peak flow, pressure and acoustics (2020)
Type of ContentElectronic Thesis or Dissertation
Degree NameMaster of Science
PublisherUniversity of Canterbury
AuthorsChittleborough, Jennifershow all
Introduction: Clinicians routinely use subjective ratings of reflexive coughing strength to make judgements about an individual’s ability to protect their airway in the event of aspiration. It is therefore important to understand the accuracy of these judgements. This study investigated the validity of perception of strength of reflexive coughing as compared to objective coughing measures. Secondarily, reliability of speech-language therapist’s perceptual ratings of reflexive coughing strength was investigated.
Methods: Data from prior research (Mills, Jones, & Huckabee, 2017), in which participants underwent videotaped cough reflexive testing (CRT) with concurrent measurement of peak pressure, flow and acoustics, were used in this web-based study. This study included two online surveys, each comprising 36 videos of individuals undergoing CRT. Participants first viewed ‘very weak’ and ‘very strong’ reflexive cough examples to serve as perceptual anchors. Participants then provided ratings of reflexive coughing strength for each of 36 cough epochs using a visual analogue scale (VAS), which were used to evaluate inter-rater reliability. For intra-rater reliability, the same videos were rated in a re-randomised order after a minimum of 3 days. Reliability was calculated using Intraclass Correlation Coefficient (ICC). Correlations between the averaged VAS scores within a cough epoch and each physiological measure are reported.
Results: Eighty-two participants completed ratings for the analysis of inter-rater reliability and validity; 36 provided ratings for intra-rater reliability analysis. Moderate inter- and intra- rater agreements of perceptual ratings were calculated. There was no association between VAS score and peak flow and peak acoustic measures. A moderate positive association was present between VAS score and peak pressure (τb = 0.46, p <0.01). Participant experience level with CRT did not influence validity or reliability of reflexive coughing strength ratings.
Conclusions: Research findings suggest that clinician’s subjective judgments of reflexive coughing strength are not validated by objective measures of peak pressure, flow or acoustics. In addition, findings of only moderate reliability between clinicians’ perceptual judgements, supports the use of objective swallowing and reflexive coughing strength assessment to guide clinical dysphagia management and to accurately determine aspiration risk. Further research is indicated to determine the clinical utility and value of subjective assessment of reflexive coughing strength.