- Top of page
- Research questions
- Specific hypotheses
- Appendix 1
Dysphagia has been defined as ‘eating and drinking disorders which may occur in the oral, pharyngeal and oesophageal stages of deglutition. Subsumed in this definition are problems positioning food in the mouth and in oral movements, including suckling, sucking, mastication and the process of swallowing’ (Royal College of Speech and Language Therapists, Communicating Quality 3, 2006).
Dysphagia is a significant problem for people with intellectual disabilities (ID) (Chadwick & Jolliffe 2009). Dysphagia puts people with ID at risk of discomfort, poor nutritional status, dehydration, aspiration, choking and reduced quality of life (Helfrich-Miller et al. 1986; Wood 1994; Kennedy et al. 1997; Kerr 1998; Aziz & Cambell-Taylor 1999; Chadwick et al. 2003, 2006; Samuels & Chadwick 2006). Many of these problems can be life threatening or can lead to other life threatening problems, for example, aspiration leading to upper respiratory infections (Helfrich-Miller et al. 1986) and choking leading to asphyxia (Dupont & Mortenson 1990; Samuels & Chadwick 2006). The National Patient Safety Agency identified dysphagia as one of the five key risk areas for people with ID (NPSA 2004) and its importance is further highlighted by the MENCAP report ‘Death by Indifference’ (MENCAP 2007) as swallowing difficulties were a contributing factor in all of the case studies contained in the report.
Dysphagia is managed by a range of rehabilitative and direct and indirect compensatory strategies, dependent upon the underlying aetiology (Groher 1987). Consistency modification is one such strategy and incorporates modification of the consistency of both food and drinks; in this study we are focussing particularly on the thickening of fluids. Referring to modification of both food and drinks, Logemann (1999) stated that consistency modification should be the last compensatory strategy examined, unless other strategies, for example altering posture or using techniques to help to protect their airway, such as the effortful swallow or the Mendelsohn Maneuve (Logemann 1999), are not feasible as is often the case with adults with ID and other neurological or degenerative conditions.
In an American survey of Speech and Language Pathologists, 84.6% indicated that they considered thickening of thin fluids to be an effective management technique for dysphagia (Garcia et al. 2005). Modifying the consistency of food and drinks has been found to delay bolus transit through the mouth and pharynx, reduce the speed of tongue peristalsis, extend the duration of pharyngeal peristalsis and prolong upper oesophageal opening, reducing avoidance of food and drinks, coughing and choking (Griggs et al. 1989; Reimers-Neils et al. 1994). However, Langmore (1999) highlights the need for more research into the use of modified consistencies to manage dysphagia in different populations. There is no strong clinical research evidence supporting modification of food and drinks as an effective management strategy specifically for adults with dysphagia and ID. However, in the general research literature, of the different dysphagia management strategies used, consistency modification has the strongest evidence supporting its efficacy (Groher 1987; Griggs et al. 1989; Reimers-Neils et al. 1994).
Consistency modification is commonly used in the management of dysphagia for people with ID, with Speech and Language Therapists (SLTs) typically training caregivers to modify food and drinks to a consistency appropriate for the individual based on clinical and videofluoroscopic assessments (Chadwick et al. 2002, 2003). A recent study by Ball et al. (2012) found that 25% of adults with ID who required mealtime support had fluid consistency modified. People with ID and dysphagia who are receiving modified food and drinks have a dependence on the skills and knowledge of the caregiver and in particular, the modification of fluids using powdered thickener, relies on carers achieving the correct consistency through correct instruction and adequate guidelines (Harding & Halai 2009). It is important that fluids are thickened to the appropriate consistency specific to the individual so as to facilitate comfortable safe oral transit and deglutition and reduce the risk of aspiration. In a study of inadequate fluid intake in dysphagic acute stroke patients, Whelan (2001) found that the use of powder thickeners resulted in less than 50% of patients receiving fluids thickened to the correct consistency. Moreover, caregivers modifying consistently is dependent on appropriate training by professionals and worryingly, professionals have been found to have difficulty being consistent when modifying liquids (Glassburn & Deem 1998).
An investigation into the barriers caregivers experience in managing dysphagia for adults with ID found that caregivers often found food and drink modification one of the most challenging aspects of management. In circumstances where the person with ID had a history of choking on unmodified food or drinks caregivers in residential and day settings found modification and management stressful, often worrying about whether they had achieved the appropriate consistency (Chadwick et al. 2006). Crawford et al. (2007) in an investigation of caregiver compliance with dysphagia recommendations in day centres, found that ‘food provision’ guidelines were reported to be difficult to follow and highlighted the need for training in the area of food modification. These studies suggest that although training can increase accuracy of fluid modification (Chadwick et al. 2003) that mealtime support staff can still have difficulties achieving a safe, appropriate fluid consistency (Chadwick et al. 2006; Crawford et al. 2007), recommending additional support for caregivers supporting people with ID and dysphagia, at least until they feel fully confident modifying fluids.
This investigation will add to the small number of studies focusing on dysphagia intervention by exploring the efficacy of training caregivers to modify fluids. The study was prompted by the concerns of a group of clinicians [dietitians, Speech & SLTs, Occupational Therapists (OTs) and community nurses] regarding the management of dysphagia for adults with ID living in the community. They observed that caregivers were sometimes unable to reliably and accurately modify fluids to the prescribed consistency. In considering how to overcome this difficulty the group of clinicians developed a visual tool which could serve as a comparator and a memory aid when people are modifying fluids. The Thickness Indicator Model (TIM) was developed comprising a series of fluid filled tubes, which have been used in this study. Harding & Halai (2009) identified visual demonstration as a way of enabling people to gain a clear understanding of the liquid thickness required and concluded that research needs to focus on the training methods used to support staff.
Typically, training with regard to modifying food and drinks to a safe consistency, incorporates the provision of written information describing the consistencies, discussing modification, modelling how to modify food and drinks to appropriate consistencies, watching caregivers modify meals and drinks and providing feedback on the results (Chadwick et al. 2002). This study focuses on fluid modification and will compare the efficacy of this typical model of training intervention for fluid modification with the provision of written guidance alone. The study also aims to evaluate the benefits of using a visual model (the TIM tubes) to support training and act as a comparator, thus reducing the reliance on memory when modifying fluids. Given the prior literature and clinical experience suggesting that training can improve accuracy but that additional support is required to overcome modification errors, we hypothesised that the training should improve accuracy and that the addition of the TIM tubes should enhance fluid modification accuracy further. Thus we developed the followed research questions and hypotheses prior to commencement of the study.
- Top of page
- Research questions
- Specific hypotheses
- Appendix 1
In this study we aimed to evaluate the efficacy of typical fluid consistency modification training and of the training combined with the use of the TIM tubes by comparing these two forms of intervention with the provision of written guidance alone post-training and at 3–10-month follow-up. We investigated four hypotheses and the results were analysed using mean observed accuracy scores across time, intervention group (see Table 4).
Accuracy improved following all types of training and then reduced at the 3–10-month follow-up but not to the original pre-intervention level. The increase and subsequent decline were more marked for the two interventions involving training and the greatest observed accuracy was among the Typical Training and TIM tube group.
With regard to the specific hypotheses, the results supported hypothesis 1 and partially supported hypothesis 2. We found, in line with hypotheses 1 and 2 that the two types of Training (Typical Training alone & Typical Training and the TIM tubes) resulted in significantly greater accuracy in fluid modification than written guidance alone immediately post-training. The Typical Training and Typical Training plus TIM tube groups did not significantly differ in accuracy immediately post intervention; therefore this aspect of hypothesis 2 was not supported.
In line with hypothesis 4, Typical training and using the TIM tubes together did result in greater accuracy post-training and at 3–10 months than Written Guidance and Typical Training alone. However, this increase in accuracy was only statistically significant compared with the Written Guidance alone group so this hypothesis was only partially supported. The difference hypothesised between the TIM tube and Typical Training group and the Typical Training group at 3–10-month follow-up was not found, thus we cannot accept this aspect of hypothesis 4. Though more accurate, the accuracy of the Typical Training group was not significantly greater than that of the Written Guidance group at 3–10-month follow-up and so hypothesis 3 is not supported here.
Thus hypothesis 1 was supported, hypotheses 2 and 4 were partially supported and hypothesis 3 was not supported. The non-significant difference between the two groups involving Typical Training may be because of the relatively small sample size for this study. It may also indicate that the TIM tubes may have more utility as a reference tool to aid caregivers at the point of thickening fluids rather than being a training aid. This warrants further study but would mean that caregivers supporting people with fluid modification needs will need one in the kitchen at all times.
There are very few studies looking at dysphagia in people with an intellectual disability and fewer still investigating the efficacy and effectiveness of clinical interventions for this population. This study demonstrates the efficacy of training in improving caregiver accuracy in modifying liquids. This links to previous studies which have recognised the importance of training to enable caregivers to follow dysphagia management plans accurately (Chadwick et al. 2002, 2003, 2006; Crawford et al. 2007). The two groups that received training were significantly more accurate at modifying fluids immediately post-training compared with the Written Guidance group. However, there was a decline in accuracy from post-training to 3–10-month follow-up.
In clinical practice fluid modification would be carried out routinely as prescribed for individual patients. However, it was a requirement of the study that caregivers had not worked with people with dysphagia previously. As a result they did not practice modifying fluids during the intervening 3–10 months between the first and second appointments. The decline in accuracy after 3–10 months is not therefore unexpected as there had been no opportunity for knowledge to be embedded through practice. If carers had been using their training daily, one would expect better maintenance of accuracy. However, it may be that training effects wear off over time irrespective of use, this is a question for future research. An effectiveness study would capture these long-term gains in modification accuracy by comparing carers utilising their fluid modification training over time with a control group of carers who are not.
Despite the decline in accuracy, the group trained using the TIM tubes were the most accurate at modifying fluids at 3–10-month follow-up being 41.82% more accurate than they were prior to training. This may suggest that use of the TIM tubes could reduce the amount of top-up or repeat training sessions required by caregivers. The utility of the TIM tubes could also be generalised to other client groups requiring fluid modification as part of their health care, including other groups who commonly present with dysphagia, for example those who have had a stroke, Parkinson's disease and older adults.
Attempts were made to ensure consistency across trainers and raters, in their ability to modify and to identify specific consistencies, prior to beginning the study. However, during the study no checks of the consistency accuracy of the modelled liquids prepared by the trainers was conducted during the study. This is an oversight considering the finding that professionals are not always consistent in their attempts to modify liquids (Glassburn & Deem 1998), and should be addressed into future effectiveness investigations. The use of a viscometer in future studies would alleviate concerns about professional rater accuracy.
At present there are no agreed viscosity measurements for different consistencies of fluid modification. The National Descriptors were developed in response to requests from SLTs and dietitians to provide a common language to describe consistency modification as clearly as possible (BDA/RCSLT 2002). Although food descriptors have been updated, the fluid descriptors have not been updated since 2002 and many practitioners have developed their own terminology in an attempt to clarify their recommendations. In the absence of any other guidelines, the descriptors were used as the basis for the development of the TIM tubes. The National Descriptors were also used within the study as part of the training and the written information given to participants. The TIM tubes provide the first visual representation of different fluid consistencies and this study has shown that the presence of a visual aid can improve modification accuracy.
The use of the TIM tubes also paves the way for subsequent avenues of research to promote effective support for people with dysphagia. An effectiveness study in a clinical setting would be beneficial to confirm the effect of training and TIM tubes under more ecologically valid circumstances. This investigation into the efficacy of training should therefore be viewed as a precursor to an effectiveness study to determine the effectiveness of training and the use of TIM tubes in the field. Given the qualified success of training and of the TIM tubes in improving accuracy of modification of fluids subsequent effectiveness research is warranted. As noted above the TIM tubes could also be used with other client groups, a future effectiveness study could encompass a broader group of care givers supporting people with dysphagia rather than simply being restricted to those supporting people with ID.
There are many clinical implications from this study. First, dysphagia training appears to be efficacious in enabling carers to more accurately modify fluids. The combination of training and use of TIM tubes increased the accuracy of consistency modification and, if used more widely, may result in improved compliance with prescribed dysphagia management strategies. Incorrectly thickened drinks can have negative implications for patient health and well-being. Being able to achieve the correct consistency at the first attempt will limit wastage of both time and thickening product.
With the presence of a TIM tube, any visiting health professional can monitor the accuracy of the consistency offered to the patient so that inaccuracies can be identified and rectified quickly, thus potentially improving patient safety. By giving the patient ownership of the TIM tube we could also increase their involvement and control over their own care.
The TIM tubes may also enable caregivers to more accurately cascade the information about individual management strategies for people requiring modification of liquids which may also help caregivers to more consistently modify fluids accurately over time. This is particularly important in situations where people are reliant on multiple caregivers and where frequent staff changes occur. Improved ability for caregivers to cascade training to one another may also help to reduce the frequency of training required to be provided by professionals.
This study has demonstrated the efficacy of typical training and the use of TIM tubes in helping caregivers to accurately modify fluids to accurate safe consistencies. The TIM tubes appear to be a useful tool supporting accurate long term management of dysphagia. Further effectiveness work is needed to confirm their utility.