O maior receio dos profissionais que atendem pacientes com queixa de disfagia é a dificuldade em diagnosticá-la, durante a avaliação clínica, principalmente quando os mesmos não apresentam sinais clínicos sugestivos de penetração e/ou aspiração laringotraqueal. Portanto, o objetivo deste estudo foi comparar a avaliação clínica da deglutição ao resultado da videofluoroscopia e à filmagem da videofluoroscopia, buscando identificar sinais comuns que sugiram e comprovem a aspiração silente. Foi realizado um estudo observacional e prospectivo com 49 pacientes adultos com diagnóstico de Acidente Vascular Cerebral. Uma anamnese foi realizada para coleta de informações. A avaliação clínica, incluiu a avaliação estrutural e funcional. Houve monitoração do paciente através da oximetria de pulso e a observação da ausculta cervical e sinais clínicos. Na videofluoroscopia, o paciente manteve-se monitorado pela oximetria e parâmetros clínicos foram analisados. Durante a videofluoroscopia o paciente foi filmado por uma câmera para posterior análise clínica. Em ambas as avaliações foi oferecido ao paciente a consistência líquida no volume de 100 ml no copo. As avaliações foram realizadas por profissionais distintas, ambas cegas uma na avaliação da outra. Dos pacientes avaliados 46 (94%) indivíduos apresentaram diagnóstico de Acidente Vascular Cerebral isquêmico. Do total, sete apresentaram aspiração, sendo que seis foram silente. A alteração da ausculta cervical na avaliação clínica e a presença de resíduo oral na filmagem se associaram a aspiração silente detectada na videofluoroscopia. Não foi observado relação entre alteração de saturação de oxigênio e aspiração silente. / The greatest fear of the professionals who attend patients with complaints of dysphagia is the difficulty in diagnosing it during the clinical evaluation, especially when they do not present clinical signs suggestive of laryngotracheal penetration and / or aspiration. Therefore, the objective of this study was to compare the clinical evaluation of swallowing to the videofluoroscopic result and videofluoroscopic filming, in order to identify common signs that suggest and prove the silent aspiration. An observational and prospective study was conducted with 49 adult patients with a diagnosis of stroke. An anamnesis was performed to collect information. Clinical evaluation included structural and functional assessment. There was patient monitoring through pulse oximetry and observation of cervical auscultation and clinical signs. In videofluoroscopic, the patient was monitored by oximetry and clinical parameters were analyzed. During the videofluoroscopic the patient was filmed by a camera for further clinical examination. In both evaluations was offered 100 ml of the liquid in the cup. The evaluations were performed by distinct professionals, both blinded one in the evaluation of the other. Of the patients evaluated, 46 (94%) individuals had a diagnosis of ischemic stroke. Of the total, seven had aspiration, six of which were silent. Alteration of the cervical auscultation in clinical evaluation and presence of oral residue in filming were associated with silent aspiration detected in videofluoroscopic. No relation between alteration of oxygen saturation and silent aspiration was observed.

O maior receio dos profissionais que atendem pacientes com queixa de disfagia é a dificuldade em diagnosticá-la, durante a avaliação clínica, principalmente quando os mesmos não apresentam sinais clínicos sugestivos de penetração e/ou aspiração laringotraqueal. Portanto, o objetivo deste estudo foi comparar a avaliação clínica da deglutição ao resultado da videofluoroscopia e à filmagem da videofluoroscopia, buscando identificar sinais comuns que sugiram e comprovem a aspiração silente. Foi realizado um estudo observacional e prospectivo com 49 pacientes adultos com diagnóstico de Acidente Vascular Cerebral. Uma anamnese foi realizada para coleta de informações. A avaliação clínica, incluiu a avaliação estrutural e funcional. Houve monitoração do paciente através da oximetria de pulso e a observação da ausculta cervical e sinais clínicos. Na videofluoroscopia, o paciente manteve-se monitorado pela oximetria e parâmetros clínicos foram analisados. Durante a videofluoroscopia o paciente foi filmado por uma câmera para posterior análise clínica. Em ambas as avaliações foi oferecido ao paciente a consistência líquida no volume de 100 ml no copo. As avaliações foram realizadas por profissionais distintas, ambas cegas uma na avaliação da outra. Dos pacientes avaliados 46 (94%) indivíduos apresentaram diagnóstico de Acidente Vascular Cerebral isquêmico. Do total, sete apresentaram aspiração, sendo que seis foram silente. A alteração da ausculta cervical na avaliação clínica e a presença de resíduo oral na filmagem se associaram a aspiração silente detectada na videofluoroscopia. Não foi observado relação entre alteração de saturação de oxigênio e aspiração silente. / The greatest fear of the professionals who attend patients with complaints of dysphagia is the difficulty in diagnosing it during the clinical evaluation, especially when they do not present clinical signs suggestive of laryngotracheal penetration and / or aspiration. Therefore, the objective of this study was to compare the clinical evaluation of swallowing to the videofluoroscopic result and videofluoroscopic filming, in order to identify common signs that suggest and prove the silent aspiration. An observational and prospective study was conducted with 49 adult patients with a diagnosis of stroke. An anamnesis was performed to collect information. Clinical evaluation included structural and functional assessment. There was patient monitoring through pulse oximetry and observation of cervical auscultation and clinical signs. In videofluoroscopic, the patient was monitored by oximetry and clinical parameters were analyzed. During the videofluoroscopic the patient was filmed by a camera for further clinical examination. In both evaluations was offered 100 ml of the liquid in the cup. The evaluations were performed by distinct professionals, both blinded one in the evaluation of the other. Of the patients evaluated, 46 (94%) individuals had a diagnosis of ischemic stroke. Of the total, seven had aspiration, six of which were silent. Alteration of the cervical auscultation in clinical evaluation and presence of oral residue in filming were associated with silent aspiration detected in videofluoroscopic. No relation between alteration of oxygen saturation and silent aspiration was observed.

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.

One of the most elusive challenges in the diagnosis and treatment of dysphagia is the reliable identification of silent aspiration (aspiration in the absence of cough). The citric acid inhalation cough challenge offers potential for aiding in identification of silent aspiration; however clinical application of this technique is currently problematic due to an absence of normative data. Therefore, this study aimed to establish a normative data set for the Citric- Acid Inhalation Cough Challenge, as administered with facemask method. 80 healthy subjects will participate in this study, constituting 2 age groups: above and below 60 years, with equal gender representation. On 3 separate trials, they will be asked to passively inhale, via a facemask, nebulised citric acid of concentrations ranging from 08M to 2.6M with placebo interspersed. ‘Natural cough thresholds’ (NCT) and ‘Suppressed Cough Thresholds’ (SCT) will be reached when subjects cough on at least 2 out of 3 trials. The majority (92.5%) of participants reached Natural Cough Threshold by 0.8M, with 68% demonstrating Suppressed Cough Threshold also at this concentration. There were no significant differences found between males and females (p<0.05) for either NCT (p=0.9885) or SCT (p=0.44). Whilst no difference was found between youngers and elders for NCT (p=0.7254), there was a significant difference for SCT (p=0.018), with youngers better able to suppress cough. Over 90% of healthy people were found to elicit cough at 0.8M, inferring that this level would be an adequate guide for use by clinicians testing for presence/absence of cough.

Silent aspiration is associated with pneumonia and mortality, and is poorly identified by traditional clinical swallowing evaluation (CSE). Currently, there is no reliable test for detecting silent aspiration during CSE. There is, however, increasing evidence for the validity of cough reflex testing (CRT) for identifying silent aspiration. This test has the potential to significantly improve clinical assessment of dysphagia. The aim of this research programme was to further investigate the validity, reliability and clinical utility of CRT for identifying patients at risk of silently aspirating. Several aspects of CRT were explored during this research programme. Two correlational studies were conducted to validate CRT for identifying silent aspiration against videofluoroscopic swallowing study (VFSS) and flexible endoscopic evaluation of swallowing (FEES). Cough reflex threshold testing was completed on 181 patients using inhaled, nebulised citric acid. Within one hour, 80 patients underwent VFSS and 101 patients underwent FEES. All tests were recorded and analysed by two researchers blind to the result of the alternate test. Significant associations between CRT result and cough response to aspiration on VFSS (p = .003) and FEES (p < .001) were identified. Sensitivity and specificity were optimised at 0.6mol/L in patients undergoing VFSS (71%, 60% respectively) and at 0.4mol/L in patients undergoing FEES (69%, 71% respectively). A concentration of 0.8mol/L had the highest odds ratio (OR) for detecting silent aspiration (8 based on VFSS, 7 based on FEES). Coughing on lower concentrations of citric acid (0.4mol/L compared with 1.2mol/L) was a better predictive measure of silent aspiration. Diminished cough strength has also been associated with aspiration and increased risk of pneumonia. Reflexive cough is our primary defensive mechanism against aspiration and a measure of reflexive cough strength therefore holds greater relevance than one of voluntary cough strength. Despite common use and clinical applicability, the reliability of subjective cough judgements has received little attention. The inter- and intra-rater reliability of subjective judgements of cough in patients following inhalation of citric acid was assessed. Forty-five speech-language therapists (SLTs) were recruited to the first study. Of these, 11 SLTs were currently using CRT in their clinical practice (experienced raters) and 34 SLTs reported no experience with CRT (inexperienced raters). Participants provided a rating of strong, weak or absent to ten video segments of cough responses elicited by inhalation of nebulised citric acid. The same video segments presented in a different sequence were re- evaluated by the same clinicians following a 15-minute break. Inter-rater reliability for experienced raters was calculated with a Fleiss’ generalised kappa of .49; intra-rater reliability was higher with a kappa of .70. Inexperienced raters showed similar reliability with kappa values for inter-rater and intra-rater reliability of .36 and .62, respectively. SLTs demonstrated only fair to moderate reliability in subjectively judging a patient’s cough response to citric acid. Experience in making cough judgements did not improve reliability significantly. In a second study, specific training in cough physiology and cough judgement was provided to 58 trained SLTs. Inter-rater reliability of subjective judgements of cough in patients following inhalation of citric acid was assessed. Participants provided a rating of present or absent, and if present then a rating of strong or weak, to ten video segments of cough responses. Inter-rater reliability for cough presence was calculated with a Fleiss’ generalised kappa of .71 and cough strength was calculated at .61. Years of clinical experience did not improve inter-rater reliability significantly. Experience in using CRT did improve inter-rater reliability. Further validity and reliability research would be beneficial for guiding clinical guidelines and training programmes. By identifying patients at risk of silent aspiration, more informed management decisions can be made that consequently lead to a reduction in preventable secondary complications such as pneumonia. The clinical utility of CRT for reducing pneumonia in acute stroke patients was assessed through a randomised, controlled trial. Three hundred and eleven patients referred for swallowing evaluation were assigned to either 1) a control group receiving standard evaluation or 2) an experimental group receiving standard evaluation with CRT. Participants in the experimental group were administered nebulised citric acid with test results contributing to clinical decisions. Outcomes for both groups were measured by pneumonia rates at three months post stroke and other clinical indices of swallowing management. Analysis of the data identified no significant differences between groups in pneumonia rate (p = .38) or mortality (p = .15). Results of CRT were shown to influence diet recommendations (p < .0001) and referrals for instrumental assessment (p <.0001). Despite differences in clinical management between groups, the end goal of reducing pneumonia in post stroke dysphagia was not achieved. Through this research, the characteristics and outcomes associated with dysphagia secondary to stroke in New Zealand were identified. Baseline characteristics of 311 patients with dysphagia following acute stroke were collected during their hospital stay and outcomes were measured at three months post stroke. Mortality rates were 16% and pneumonia rates 27%. Mean length of stay was 24 days and only 45% of patients were in their own home at three months post stroke. Pneumonia was significantly associated with mortality and increased length of stay. Only 13% of patients received referral for instrumental assessment of swallowing. These data are discussed in reference to the National Acute Stroke Services Audit 2009 and internationally published data. The outcomes for stroke patients with dysphagia in New Zealand are poor with a high risk of pneumonia and long hospital stays when compared internationally. In summary, this research programme has contributed to our understanding of the use of CRT in patients with dysphagia. The addition of a measure of reflexive cough strength may add to clinical assessment but specific training is required to reach adequate reliability. CRT results are significantly associated with aspiration response on instrumental assessment and lower concentrations of citric acid provide a better predictive measure of silent aspiration. CRT can be standardised and therefore is not as susceptible to interpretative variance that plagues much of CSE. Sensitivity and specificity values using this CRT methodology are adequate for CRT to be incorporated into clinical protocols. Inclusion of CRT alone was not shown to be sufficient to change clinical outcomes however integration of CRT into clinical pathways may prove more successful. Further research evaluating the addition of CRT to a comprehensive CSE would add greatly to the field of dysphagia assessment.

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