Identification of the most significant electrode positions in electromyographic evaluation of swallowing-related movements in humans.

Surface electromyography (sEMG) is a well-established procedure for recording swallowing-related muscle activities. Because the use of a large number of sEMG channels is time consuming and technically sophisticated, the aim of this study was to identify the most significant electrode positions associated with oropharyngeal swallowing activities. Healthy subjects (N = 16) were tested with a total of 42 channels placed in M. masseter, M. orbicularis oris, submental and paralaryngeal regions. Each test subject swallowed 10 ml of water five times. After having identified 16 optimal electrode positions, that is, positions with the strongest signals quantified by the highest integral values, differences to 26 other ones were determined by a Mann-Whitney U test. Kruskal-Wallis H test was utilized for the analysis of differences between single subjects, subject subgroups, and single electrode positions. Factors associated with sEMG signals were examined in a linear regression. Sixteen electrode positions were chosen by a simple ranking of integral values. These positions delivered significantly higher signals than the other 26 positions. Differences between single electrode positions and between test subjects were also significant. Sixteen most significant positions were identified which represent swallowing-related muscle potentials in healthy subjects.

[Validation of the German short version of the Murray Secretion Rating Scale]. / Validierung der deutschen Kurzversion der Sekretbeurteilungsskala nach Murray.

OBJECTIVE: Accumulation of secretions in hypopharynx, aditus vestibule, and trachea is often found in cases of severe dysphagia and is considered a cardinal trait of high clinical and therapeutic importance. For the graduation of the severity level of accumulated secretions, a short version of the 4-point Murray secretion scale is available, which is also integrated into the protocol of the fiberoptic endoscopic evaluation of swallowing (FEES) according to the Langmore standard. This study aimed at the validation of the German translation of this short version in order to facilitate a uniform, standardized evaluation of the accumulation of secretions in dysphagic patients in the German language area. MATERIAL AND METHODS: For the examination of reliability and validity, a reference standard was defined by 2 dysphagia experts on the basis of 40 video files of the FEES examination, 10 videos for each of the severity grades. Afterwards, these videos were rated independently by 4 raters and re-rated in a new randomized order 2 weeks later. RESULTS: Both the intra-rater reliability (τ>0,830***) and the inter-rater reliability (Kendalls W>0,890***) were highly significant and can be considered good. The same is valid for the correlation of ratings with the reference standard (τ=0,969***). CONCLUSIONS: The German translation of the short version of the 4-point Murray secretion scale is recommendable as a reliable and valid instrument for the graduation of the cardinal trait of oropharyngeal dysphagia and also as an evidence-based instrument for standardized use in the German language area.

[Quality Assurance in the Endoscopic Evaluation of Swallowing (FEES)]. / Qualitätssicherung der endoskopischen Schluckdiagnostik (FEES).

BACKGROUND: A fiberoptic endoscopic evaluation of swallowing (FEES) is well established internationally as gold standard of the instrument-based diagnostics if it is performed according to the Langmore-protocol. For the quality assurance of FEES, videotaping is recommended. However, often no videotaping is carried out due to a limited availability of portable recording systems, for instance, in the bedside diagnostics. This study aimed at the comparison of FEES quality assurance with and without videotaping by rating of the main finding in swallowing disorders, the penetration and aspiration, as defined in the penetration-aspiration scale by Rosenbek. MATERIAL AND METHODS: An examination of agreement of penetration and aspiration ratings with the defined reference standard was conducted by means of 80 videotaped recordings. The ratings were carried out independently by 4 raters in 2 settings: A) "real time" and B) "frame-by-frame". RESULTS: As far as the interrater- and intrarater-reliability is concerned, the association between the ratings in the rating setting B were higher than those in the rating setting A. Furthermore, examination of the validity showed higher correlation in setting B than in setting A. The difference between correlations was significant in favor of setting B (videotaped FEES). CONCLUSION: The results of the present study, namely better rating reliability and validity in case of the penetration and aspiration, emphasize the importance of the videotaping of the FEES diagnostics, at least for the evaluation of penetration or aspiration.

[Secretion scale by Murray et al. for FEES®: comparison of reliability and validity of the German long and short version]. / Sekretbeurteilungsskala nach Murray et al. für FEES(®) : Reliabilitäts- und Validitätsvergleich der deutschen Lang- und Kurzversion.

BACKGROUND: Accumulation of secretions in the hypopharynx, aditus laryngis and trachea constitute a cardinal trait of oropharyngeal dysphagia. For the evaluation of the degree of severity a 4-point secretion scale by Murray et al. is used internationally in a long and a short version. However, a validated German translation of the long version of this scale does not yet exist. Also, it has not yet been scientifically proven that both versions of the scale are equally valid. OBJECTIVES: This study aimed at the validation of the German translation of the long version of the secretion scale by Murray et al. and at a comparison of reliability and validity of the short and long versions. MATERIAL AND METHODS: A total of 40 videos of fiberoptic endoscopic evaluation of swallowing (FEES(®)), 10 for each severity level, were rated by 4 otorhinolaryngologists (ENT specialists) independently and with different randomizations for examination of the reliability and validity. Two rating sessions for each of the scale versions were conducted. Intrarater and interrater reliability as well as the agreement of the ratings with a reference standard were analyzed. RESULTS: Both the intrarater reliability (Spearman correlations: ρs > 0.840***) and the interrater reliability (Krippendorff's alpha: α > 0.850) yielded very good results and the concurrent validity was highly significant (ρs > 0.981***). DISCUSSION: The German translation of the secretion scale by Murray et al. can be considered reliable and valid, with comparable test accuracy of the short and long versions. Hence, the scale can be recommend for the graduation of pharyngolaryngotracheal secretions and should be integrated into the standardized evaluation of FEES(®) diagnostics for clinical and scientific purposes.

[Penetration-Aspiration Scale according to Rosenbek. Validation of the German version for endoscopic dysphagia diagnostics]. / Penetrations-Aspirations-Skala nach Rosenbek. Validierung der deutschen Version für die endoskopische Dysphagiediagnostik.

BACKGROUND: The Penetration-Aspiration Scale was developed by Rosenbek et al. to enable standardized documentation of this cardinal symptom of a swallowing disorder. OBJECTIVES: The objective was to create and validate a German version of the Penetration-Aspiration Scale according to the guidelines governing the translation of foreign language measurement tools. MATERIALS AND METHODS: Both reliability and validity were examined based on the ratings of 80 randomized endoscopically evaluated swallows, 10 for each severity level. Ratings were carried out by four independent raters: two with more than 3 years' experience with dysphagia and a further two with less than 3 years' experience. The swallows were rerated after 4 weeks. RESULTS: Both intrarater (Kendall's Tau: τs > 0.643; median 0.773; ps < 0.001) and interrater reliability were highly significant (two-way mixed single ICC coefficient of 0.799 for the first rating session and 0.728 for the second session; ps < 0.001). Results from the raters with less than 3 years' experience were significantly different from the reference standard in three out of four cases, whereas this was not the case for the more experienced raters. However, for each film, the median of the individual ratings from all four raters correlated almost perfectly with the reference standard (first rating session: τ = 0.894; second rating session: τ = 0.843; ps < 0.001). CONCLUSION: The German version of the Penetration-Aspiration Scale according to Rosenbek presented here was demonstrated to be both reliable and valid. Despite its dependency on the raters' experience, it can therefore be used as a graduation instrument for swallowing disorders in German-speaking countries and make an important contribution to evidence-based medicine in dysphagiology for both clinical and scientific use.