This randomized clinical trial of 711 patients with a diagnosis of dementia and/or Parkinson’s disease examined the immediate effects in the fluoroscopy suite of three compensatory interventions to prevent aspiration of thin liquids: (a) chin-down posture, (b) nectar-thickened liquids, and (c) honey-thickened liquids. These compensatory strategies were used because patients with dementia could not use therapy interventions that required the following of more complex directions.
Our major hypothesis, based on the existing published data at the time of project design, was that the chin-down posture would be most successful in eliminating aspiration on thin liquids. Based on the results of this study, this hypothesis must be rejected. During the radiographic study, each participant received all three interventions in random order. Results showed that the most frequently successful intervention to eliminate thin liquid aspiration immediately was the honey-thickened liquid, followed closely by the nectar-thickened liquid and then the chin-down posture. This was true for all three patient diagnostic groups. However, for about half the patients, there was at least one intervention that was consistently best; however, that intervention varied from patient to patient. This also means that about half of the patients received no benefit from any intervention, emphasizing the need to look for other interventions to eliminate aspiration. We did observe a significantly higher rate of benefit on at least one intervention for patients with Parkinson’s disease only compared with patients with dementia with or without Parkinson’s disease. Patients with most severe dementia exhibited least effectiveness on all interventions, probably reflecting greater physiologic abnormality in their swallows than patients with less severe dementia. In contrast, severity of Parkinson’s disease did not relate to success in the three interventions. Clinicians caring for patients similar to those in this study must examine the effectiveness of all three interventions for each patient, as this study reveals that aspiration of thin liquid could be eliminated with one or more of the three interventions in approximately half the patients. No assumptions can be made that any one of these interventions will be successful in all patients, even all of those with the same diagnosis. We also hypothesized that younger patients would be more successful with postural change, but, interestingly, the oldest patients (ages 80–95 years) were most successful in using the chin-down posture. This may relate to changes in the natural neck posture with age or in the way the size of their valleculae is changed by chin-down posture. We are examining these possible differences with age, and the results will be reported in a later article. Additionally, we found that older people were more successful on thickened liquids, particularly the honey, than younger patients.
The fact that our results indicate that honey-thickened liquid was least successful in eliminating aspiration when it was introduced last in the order of randomized techniques may reflect the effects of fatigue. Exercises to improve tongue strength in patients using the thickened liquids may be helpful (Robbins et al., 2005
). Clinicians need to be sure that older patients can sustain the increased muscle effort needed to swallow thicker liquids (Reimers-Neils et al., 1994
), particularly honey, over the length of drinking a cup of fluid or drinking fluids throughout or after eating a meal or throughout the day.
These results emphasize the importance of introducing the three strategies to eliminate aspiration on thin liquids to patients in the radiographic diagnostic study for oropharyngeal dysphagia or other instrumental diagnostic study in order to define which strategy or combination of strategies is effective for the individual patient. In this way, patients and families can be counseled about their choices for management of their aspiration. A radiographic study is also important prior to identifying a patient as aspirating. Three percent of our participants were identified as aspirating and yet exhibited no bedside symptoms of aspiration. Several studies have shown the difficulty in identifying aspiration using only a bedside examination (Logemann, 1998
; Splaingard, Hutchins, Sulton, & Chaudhuri, 1988
It is important to emphasize that in this study, the interventions were examined for their immediate effects. These immediate effects do not necessarily indicate the long-term effectiveness of the interventions. Extended follow-up is needed to define the long-term effectiveness of each of the interventions and their relationship to the development of changes in health status, including pneumonia. Studies of the long-term effects of thickened liquids should also assess their effects on hydration and nutrition. There is still an unanswered question regarding whether patients can remain hydrated on nectar or honey as their only liquid viscosity. In addition, when considering these three interventions, clinicians should realize the importance of monitoring the preparation of the consistencies to be sure that patients are receiving the appropriate viscosity if the best intervention for them is thickening liquid.
Data on our patient preferences were collected only from those with Parkinson’s disease without dementia. Patients with dementia were judged not to be reliable reporters. The data on preference in this study are similar to data collected by other investigators showing a dislike for the honey-thickened liquids as compared with the other options of thin liquids and nectar-thickened liquids. This result supports our hypothesis that patients would prefer chin-down posture to thickened liquids. Some patients also disliked the nectar but not as much as the honey. Patient preference is an important element in selecting an intervention and may affect the patient’s compliance with the intervention (Colodny, 2005
). Many patients or their families reject thickened liquids as an intervention and prefer to risk aspiration pneumonia rather than accept thickened liquids. This was true of the patients and their families in this study. Some patients would not participate in the study because they did not wish to take thickened liquids; this wish was sometimes stated in the advanced directives, even if thickened liquids might eliminate their aspiration as demonstrated on thin liquids. Patient choice is an important component of evidence-based practice (Logemann, 2004
It must be emphasized that this study looked only at the short-term, immediate effects of these three interventions on safety of swallow. Longer-term effects on swallow safety and their relationship to health outcomes must be considered. However, these results do indicate that all three interventions are effective at least in the short term with some patients, whereas only one or two interventions are effective with other patients. It is important that clinicians examine these three strategies with these patient populations and their effects on swallow safety before ordering one of the interventions. In addition, patient compliance, predicted perhaps by their preferences, must be considered when choosing an intervention (Colodny, 2005
This study illustrates the fact that no assumptions can be made about the uniform effectiveness of any one of these three interventions with a particular patient. Patients deserve the opportunity to display the effectiveness of strategies on their swallows rather than receiving an order to utilize any one of them with no careful assessment. One of the observations that we have made in this study is that some patients came to the radiographic study already placed on thickened liquids, yet they did not exhibit any aspiration on thin liquids during the radiographic study (Pulliza, Hind, & Robbins, 2000
). It is clear that clinicians will order thickened liquids for patients suspected of aspirating thin liquids, especially in patients who are being treated in locations where a radiographic study is not readily available. Unfortunately, this means that some of these patients are required to take thickened liquids with no objective evaluation of their effectiveness. It is clear from patient preference that the patients’ quality of life may be quite negatively affected. Therefore, confirmation or validation of effectiveness justifies fluoroscopic evaluation.
For some patients, this study shows that thickened liquids can be quite effective in either nectar or honey form in eliminating aspiration on thin liquids in the short term, but modification of other material properties may be needed for some patients. This study looked only at patients with dementia and/or Parkinson’s disease. Every diagnosis should be examined in this regard.
For patients with diagnoses that involve muscle weakness, swallowing thicker liquids may be more difficult because of the greater pressure required during swallow to clear them through the mouth and pharynx (Nicosia et al., 2000
; Reimers-Neils et al., 1994
). More research is needed on thickened liquids and other viscosities in relationship to their effectiveness with particular types of dysphagia. More investigations to identify additional interventions are also needed for various groups of patients. There were clearly a number of patients in this present study who did not benefit from any of the interventions examined. The introduction and assessment of treatment strategies for evaluation during the radiographic study can provide important information for patient management.