Background: Cough Reflex Testing (CRT) has been shown to be useful in the challenging task of
identifying silent aspiration (aspiration without a cough response). With the emergence of the routine
clinical use of CRT in the acute stroke population, the following clinical conundrum often arises:
Does passing a previously failed CRT mean the risk of silent aspiration has resolved? The purpose of
this study was to evaluate the association between change in laryngeal cough threshold sensitivity and
change in PAS (Penetration Aspiration Scale) score within the acute stage post-stroke. Methods: This was a prospective longitudinal pilot study of 20 acute stroke patients utilizing a
Cough Reflex Threshold Test (CRTT) at 0.4M, 0.6M and 0.8M citric acid concentrations and
Fiberoptic Endoscopic Evaluation of Swallowing (FEES). A cough response threshold was obtained
from the CRTT and a PAS (penetration aspiration scale) score from FEES. Inclusion criteria required
a PAS score of 4 or above on preliminary FEES or impaired CRT threshold as defined by weak or
failed cough test result at 0.8M citric acid concentration. Both test methods were repeated every four
days for 20 days or until the participant no longer aspirated/penetrated and had a normal result on
CRTT on two consecutive assessment sessions. Agreement between changes in the two tests was
evaluated using the Cohen’s Kappa statistic.
Results: Eighteen of the twenty participants in this study aspirated on initial assessment, ten of which
were silent. One participant continued to aspirate at study completion. On initial assessment eleven
participants had a C2 response threshold at 0.4M citric acid concentration and three participants failed
to reach threshold at 0.8M citric acid concentration. At study completion, 18 participants had a C2
response threshold at 0.4M citric acid concentration and one participant failed to reach threshold at
0.8M citric acid concentration. During the study, sixty-six re-assessments took place; there were
fifteen incidences of improved cough response threshold on re-assessment and thirty-one incidences
of improved PAS score. There was no significant agreement between improved laryngeal cough reflex threshold and improved PAS score during the acute stage Kappa = 0.0598 (p <.0.574), 95% CI (-
0.1496- 0.2692).
Conclusion: Significant limitations of this study included small data set and potential flooring effect
of the CRT. Due to the limitations of this study, no conclusions can be made as to the appropriateness
of reinstating oral intake based on passing a previously failed CRT.
| Identifer | oai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/10734 |
| Date | January 2013 |
| Creators | McFarlane, Mary |
| Publisher | University of Canterbury. Speech and language science |
| Source Sets | University of Canterbury |
| Language | English |
| Detected Language | English |
| Type | Electronic thesis or dissertation, Text |
| Rights | Copyright mary mcfarlane, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml |
| Relation | NZCU |
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