Post-stroke dysphagia (a difficulty in swallowing after a stroke) is a common and expensive complication of acute stroke and is associated with increased mortality, morbidity, and institutionalization due in part to aspiration, pneumonia, and malnutrition. Although most patients recover swallowing spontaneously, a significant minority still have dysphagia at six months. Although multiple advances have been made in the hyperacute treatment of stroke and secondary prevention, the management of dysphagia post-stroke remains a neglected area of research, and its optimal management, including diagnosis, investigation and treatment, have still to be defined.

Individuals with dysphagia may be prescribed thickened fluids to promote a safer and more successful swallow. Starch-based thickening agents are often employed; however, these exhibit great variation in consistency. The aim of this study was to compare viscosity and the rheological profile parameters complex (G*), viscous (G″), and elastic modulus (G') over a range of physiological shear rates. UK commercially available dysphagia products at "custard" consistency were examined. Commercially available starch-based dysphagia products were prepared according to manufacturers' instructions; the viscosity and rheological parameters were tested on a CVOR Rheometer. At a measured shear rate of 50 s(-1), all products fell within the viscosity limits defined according to the National Dysphagia Diet Task Force guidelines. However, at lower shear rates, large variations in viscosity were observed. Rheological parameters G*, G', and G″ also demonstrated considerable differences in both overall strength and rheological behavior between different batches of the same product and different product types. The large range in consistency and changes in the overall structure of the starch-based products over a range of physiological shear rates show that patients could be receiving fluids with very different characteristics from that advised. This could have detrimental effects on their ability to swallow.

Starch‐based thickening agents may be prescribed for patients with dysphagia. Thickened fluids alter variables of the swallow reflex, allowing more time for bolus manipulation without compromising airway closure. This investigation explored the variation in viscosity and physical characteristics of thickened drinks prepared in different media under laboratory conditions and compared the results with those of thickened drinks presented to dysphagic patients in one hospital. The rheological characteristics were tested on a simple plastometer and a Bohlin CVOR rheometer (Malvern Instruments, Worcestershire, UK). Samples prepared to “syrup” consistency both in the laboratory and in the hospital were significantly different from each other (P < 0.0001). This was also the case for samples prepared to “custard” consistency. Differences existed not only in viscosity, but drinks prepared in different media produced different rheological matrices. This signifies different viscoelastic behaviors that may effect manipulation in the mouth. From this study, preparation of thickened drinks using starch‐based instant thickening powders appears to be a highly variable practice. PRACTICAL APPLICATIONS The research has highlighted differences in the preparation of thickened drinks for patients with dysphagia among guidelines, descriptors, manufacturers' instruction and actual preparation in the hospital setting. The differences in the final thickness and rheology produced when preparing drinks of different types and temperatures were significant and may have clinical consequences. The results can be used to provide advice and recommendations when preparing drinks in practice.

The international approach to the assessment and management of dysphagia in the acute phase post stroke is little studied. A questionnaire was sent to clinicians in stroke services that explored the current practice in dysphagia screening, assessment, and management within the acute phase post stroke. The findings from four (the UK, the US, Canada, and Australia) of the 22 countries returning data are analysed. Consistent approaches to dysphagia screening and the modification of food and liquid were identified across all four countries. The timing of videofluoroscopy (VFS) assessment was significantly different, with the US utilising this assessment earlier post stroke. Compensatory and Postural techniques were employed significantly more by Canada and the US than the UK and Australia. Only food and fluid modification, tongue exercises, effortful swallow and chin down/tuck were employed by more than fifty percent of all respondents. The techniques used for assessment and management tended to be similar within, but not between, countries. Relationships were found between the use of instrumental assessment and the compensatory management techniques that were employed. The variation in practice that was found, may reflect the lack of an available robust evidence base to develop care pathways and identify the best practice. Further investigation and identification of the impact on dysphagia outcome is needed.

Starch-based thickeners may be given to individuals with dysphagia to favourably alter variables of the swallow reflex (1) . These are prepared to different consistencies (syrup, custard and pudding), which correspond to different viscosity levels at a shear rate of 50 1/s, which is thought to represent "the average" shear rate operating in the mouth (2)(3)(4)(5) . The viscosity ranges were established by the American Dietetic Association for the National Dysphagia Diet task force (NDD) (6) . Starch-based pre-made beverages and instant thickeners were found to be shear thinning and to exhibit great variation in consistency, especially at lower shear rates as shown by simple viscosity and the rheological profile parameters complex (G*), viscous (G 00 ) and elastic modulus (G 0 ) over a range of physiological shear rates denoting the variation in structure and behaviour. At low shear rates, the large range of viscosity values for "Custard consistency" samples was found to be significant at P < 0.0001 (F = 77.56). At a shear rate of 50 1/s, the viscosity was reduced considerably and the range narrowed to allow all samples to fall within the NDD guidelines. However, the variation was still found to be significant at P < 0.0001 (F = 98.21) and was largely attributed to the considerable differences between the pre-thickened instantly thickened beverages. The rheological profile parameters (G*, G 0 and G 00 ) showed that all samples were found to have the characteristics of a weak viscoelastic "gel" network (7) . This was shown to be much weaker for the pre-thickened beverages denoting that they have a much looser structure and thus different behaviour. Large variations in viscosity values and rheological parameters were not only evident between premade and instantly thickened beverages but also between different batches of the same products.The 50 1/s shear rate chosen to classify the viscosity of the different consistency classes was originally based on studies from the late 1960s, where sensory panels were used to correlate perception of viscosity with actual viscosity measurements. Later investigations showed the range varied between about 1-1000 1/s, and in fact a shear rate of about 10 1/s was identified as a more "realistic" shear rate (2)(3)(4)(5) . These studies used healthy volunteers, usually staff and students, who were likely to be capable of developing higher shear rates than older, more fragile dysphagic patients. A recent study looking at computer simulation of pharyngeal transport of starch-thickened materials found that the shear rates generated were as low as 0.001 1/s. Therefore, if a shear rate of 50 1/s is generated and complete destruction of the samples is attained in the mouth, then all the products fall within the NDD guidelines, and patients are receiving what they have been assessed to receive. However, if the shear rate generated is lower, as seems reasonable, and the ability to manipulate boluses of different viscoelastic structures is considered, then patients may be receiving products wi...