The importance of ultrasonography in the evaluation of swallowing function in hemiplegic patients and investigation of its correlation with videofluoroscopy

This study was funded by Scientific Research Projects Coordination Unit of Bezmialem Vakıf University. Project number: 20200801 Introduction and Aim: The aim of this study is to evaluate the effectiveness of ultrasonography in measuring the distance between the thyroid (T) and hyoid (H), the approximation rate, the thickness of the tongue (TT) in the resting position, and the anterior and superior displacement distance of the hyoid bone in stroke patients diagnosed with dysphagia, and to compare the data with stroke patients without dysphagia and healthy participants. Additionally, to investigate the correlation between the performance of ultrasonographic methods in evaluating dysphagic patients and videofluoroscopic swallowing study (VFSS). Materials and Method 25 patients who developed hemiplegia due to cerebrovascular events and diagnosed with dysphagia using a bedside screening test, 25 stroke patients without swallowing complaints, and 25 healthy volunteers without a history of stroke and without swallowing complaints were included in the study. These participants were recruited from the Physical Medicine and Rehabilitation and Neurology clinics of Bezmialem Vakıf University Medical Faculty Hospital. Demographic characteristics and medical histories of the patients were recorded. Patients identified as having unsafe swallowing via the bedside swallowing test underwent a videofluoroscopic swallowing study (VFSS) and were evaluated using the penetration-aspiration scale (PAS). Measurements included the thyroid-hyoid distance and approximation percentage, hyoid displacement distance, and the duration between junction opening and closing during rest and swallowing. The thyroid-hyoid distance and approximation percentage, hyoid displacement distance, and tongue thickness were measured using ultrasonography (USG) in all participants during rest and dry swallowing. Results: Hyoid anterior movement: There is a statistically significant difference between the dysphagic stroke group and the non-dysphagic stroke group (p<0.001) as well as between the dysphagic stroke group and the control group (p<0.001). Cut-off value of <11 mm (Sen:%84, Spe:%68, AUC:0,8) was determined. Hyoid Superior Movement: A statistically significant difference was found between the dysphagic stroke group and the control group (p<0.01). Cut-off value of <7 mm (Sen:%60, Spe:%76, AUC:0,725) was determined. Absolute Distance of Hyoid Movement: The differences between the dysphagic stroke group and the non-dysphagic stroke group (p<0.001) and between the dysphagic stroke group and the control group (p<0.001) were statistically significant. Cut-off value of <14,4 mm (Sen:%72, Spe:%84, AUC:0,827) was determined.Thyroid-Hyoid Resting Distance: There was no statistically significant difference between the groups (p=0.654). Shortest Distance between Thyroid-Hyoid: The difference between the dysphagic stroke group and the control group was statistically significant (p<0.05). Thyroid-Hyoid Approximation Distance: Statistically significant differences were found between the dysphagic stroke group and the control group (p<0.001) and between the control group and the non-dysphagic stroke group (p<0.01). Cut-off value of <6 mm (Sen:%96, Spe:%64, AUC:0,82) was determined.Thyroid-Hyoid Approximation Ratio: There were statistically significant differences between the control group and the dysphagic stroke group (p<0.001) and between the control group and the non-dysphagic stroke group (p<0.05). Cut-off value of <%36 (Sen:%80, Spe:%80, AUC:0,856) was determined. Tongue Thickness: There were no statistically significant differences between the groups in the statistical analysis of tongue thickness data (p>0.05). Correlation between USG and VFSS Values: A positive moderate correlation was found between the two methods (p<0.01; Pearson's r=0,56) when examining the Thyroid-Hyoid approximation ratios in the dysphagic stroke group. Conclusions: Ultrasonography is a convenient and accessible method for assessing both the oral and pharyngeal phases of swallowing. For patients with dysphagia, USG can provide clinicians with additional data on swallowing function, aiding in the accurate management of the condition. Although there are positional measurement differences between USG and videofluoroscopic swallowing study (VFSS) values, a correlation was found between the two methods regarding the Thyroid-Hyoid approximation ratios. The use of USG in dysphagic stroke patients can serve as a complementary method to VFSS in analyzing oropharyngeal movement and evaluating oropharyngeal function. Specifically, it has been found to correlate with dynamic examination videofluoroscopy, described as the Thyroid Hyoid Approximation Ratio, and it can be practically used in the evaluation of swallowing. Extensive studies are needed due to the importance of this measurement for the assessment of dysphagia and the follow-up of the rehabilitation process. Keywords: Dysphagia, stroke, ultrasonography, videofluoroscopy, dysphagia measurement