Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1015_Библиотеки_им_академика_М_И_Перельмана

swallow trials performed, in the bolus consistencies and bolus volumes, or in the clinical cut-off points (e.g. wet voice, coughing, aspiration, or unsafe swallow as judged by the clinician during the vid­eofluoroscopy). Many studies do not explain how the recordings have been assessed. A single expert or clinician can make the assessment during a patient’s visit to an outpatient clinic for dysphagia. But the assessment could also be performed afterwards by a panel of blinded expert raters. Using panel ratings, one can gather information about the intra- and inter-rater reliability of scoring visuoperceptual variables in videofluoroscopic or fibre-optic endo­scopic recordings of swallowing. The limited comparability may reflect the diversity of assessment protocols, in the absence of universal standardiza­tion. Furthermore, the frequent use of unvalidated or unreliable instruments or questionnaires may gener­ate data that can neither be interpreted adequately nor make any useful contribution to formal assess­ment. Another issue is the enormous variation in the duration of therapies as found in the literature. Quite a few studies claim significant, usually short-term improvement after a single treatment session, such as when using postural adjustments or bolus modification. In contrast, other studies describe long series of therapy sessions. Very few trials have described any long-term treatment effects. The generalizability or comparability of effect data may be another problem. Treatment techniques that have been found effective in a specified patient population may not have the same positive therapy outcome when applied in a different group of dysphagic subjects with other etiological problems or patient characteristics, such as differences in age, severity of the dysphagic symptoms or underlying diseases, or motivation for therapy. Some studies use very small patient populations or restrict the number of thera­pists involved in treatment, thus introducing bias when no therapy effects may be found. The absence of significant therapy effects may be the result of a noneffective swallowing intervention. But if too few subjects or therapists have been included, the absence of clear effects may also be due to an underpowered study design or a clinician lacking sufficient expertise. A further methodological issue concerns blinding of the assessors or raters to the