Dysphagia Screening Measures for Use in Nursing Homes: A Systematic Review

Dysphagia can be life threatening, particularly in frail, older adults. It is one of the major health care problems leading to aspiration pneumonia which is the second most common infection found in nursing home (NH) residents[1, 2]. Swallowing difficulty increases with age. Such impairment is a major health problem in NHs. Dysphagia is found in 52.7% of NH residents in Korea[3] and in 40% to 60% of institutionalized older adults in the United States[4].

In NHs, many professionals are involved in dysphagia assessment and management. Although speech-language specialists have taken a leadership role in dysphagia management in most western countries[5], there is little speech-pathology service for NHs in Asian countries like Korea. In addition, the omission of nurses has been central to malpractice issues related to dysphagia in NHs[2]. Awareness of dysphagia in older people, diagnostic procedures, and treatment options available should be increased among health care professionals, including nurses[1]. Nurses are the primary and often sole professional provider employed by NHs and are responsible for directing and evaluating the work of licensed and unlicensed assistance staffs[6]. Nurses play an important role in the identification, assessment, management, and prevention of complications related to dysphagia[7]. They are the professionals most often present at the bedside, particularly during mealtimes and while administering medications, and are the first members of the health care team to notice any signs and symptoms of dysphagia[8, 9]. Most patients with dysphagia can be identified with various tools, through systematic interviews, observation of signs & symptoms and trial swallows[8]. Dysphagia screening measurements have been developed and used by various health professionals. Videofluoroscopic swallowing study (VFSS) and fiberoptic endoscopic evaluation of swallowing (FEES) are administered by speechlanguage pathologists (SLPs). Although these invasive methods provide dynamic imaging of the swallowing function, it is inappropriate to be feasibly and repeatedly administered because these require special equipment and skilled personnel[8]. There are various non-invasive bedside screening measurements such as trial swallows, oximetry, and even simple questionnaires for self-report of dysphagia[8]. The trial swallows use diverse amount and viscosities of swallowing materials resulting in varying degree of psychometric properties[8]. However, there is no universal agreement on which of these are reliable tools that can be applied to NH residents easily by nurses. Therefore, we performed a systematic review to identify the instruments screening and/or assessing dysphagia in older adults, to evaluate their measurement properties, and to assess the feasibility of their use in order to identify the 'right tool' for nurses to use in NHs.

Of the 348 articles identified, after eliminating duplicates, 265 abstracts were reviewed by two independent reviewers (HKC, HLB) to determine whether the study was eligible for inclusion. 89 full-text articles were reviewed. Most of the studies excluded had an irrelevant study population with different study purposes or did not have validated instruments that were available in English or Korean. Finally, 31 articles met the inclusion criteria yielding 29 dysphagia screening tools for review. The search process is presented as a flow diagram in Figure 1. Results of the methodological quality for the included studies are presented in Table 1. Most of the studies were rated 'good' or 'fair' on methods and data analysis, except for 4 studies in which the method was not clearly explained and for 9 studies in which the description of the data analysis was not sufficiently rigorous.

Figure 1
Flowchart of document identification and selection process.

• Click for larger image

In this review, we evaluated the quality and the feasibility of dysphagia screening tools that could be used by nurses in NHs. Although a multidisciplinary approach is needed in managing dysphagia, nurses have a crucial role in detecting and managing swallowing difficulty because they are available in NHs 24 hours a day[8]. VFSS is known as the gold standard for dysphagia diagnosis, and FEES is as valuable in that these tests are considered comparably important for the detection of swallowing difficulty[18]. However, VFSS is expensive and requires radiological support and entails radiation exposure[19], and FEES requires experts such as SLPs to perform the test[18]. In addition to the availability of VFSS and FEES, there are limitations imposed by patient cooperation[20]. Because NH residents usually do not have access to these tests and lack the personnel or equipment to perform these tests, it is important to develop tools for detecting swallowing difficulties in the absence of VFSS and FEES[8]. Thus, alternative screening methods have been reviewed to determine which ones could be performed easily at bedside in NHs. Screening by nurses and staff other than physicians and SLPs are also recommended in international guidelines[21, 22]. Our search process resulted in profuse studies using a variety of screening methods with different populations, various materials and procedures, and diverse levels of psychometric properties.

GUSS and SSA were identified as feasible tools with acceptable psychometric quality for dysphagia screening among NH residents that could be routinely used by nurses, according to our evaluation criteria. GUSS and SSA had high sensitivity. When evaluating the psychometric properties of diagnostic measurements, using the diagnostic odds ratio is recommended as it measures the discriminatory performance of a test, rather than sensitivity and specificity values[8]. However, we decided to evaluate sensitivity / specificity because when screening for dysphagia, it is desirable that tools have high sensitivity so that the chance for missing a patient with dysphagia resulting in serious adverse events is low[8, 11]. If a diagnostic test has high sensitivity, there is a trade-off with specificity, such that the number of false-positives could increase[12]. Such is the case with GUSS having a sensitivity of 100% with a specificity of 63%. However, it is preferable to have high sensitivity to identify as many cases as possible and to prevent adverse events like aspiration[12]. CFS-D and The Massey Bedside Swallowing Screen (Massey BSS) had 100% sensitivity and 100% specificity, but the methodological quality of the study was questionable because of the biased and small sample size.

Various choices of materials and volumes were used during the trial swallows. While many screening tools used water for swallowing trials, significant differences were observed in how much liquid was given and how it was given. Some tests such as 3-oz Water Swallow Test (3-oz WST) require a large amount of water which is not easy to swallow continuously for patients with swallowing difficulty[23]. Water was used at the first phase of most of the dysphagia screenings. SSA used water only. Testing with water showed a higher sensitivity in detecting problems in laryngeal protection, and testing with semisolids was more sensitive for functionally analyzing dysphagia itself[16]. However, swallowing liquids had more problems than semisolid textures among patients in clinical observations[24]. GUSS starts with swallowing semisolid food and proceeds to water and solid food in a stepwise manner in order to minimize the risk of aspiration during the test. Although GUSS is criticized as being less feasible than tests using water only[8], the risk of aspiration during the test has been reduced to a minimum by starting with semisolid textures[24]. Both water and semisolid materials should be used routinely in swallowing screening because the risk of aspiration can be evaluated with water, whereas testing with semisolid food can safely guide the patient to the reintroduction of food[16].

For feasible use by nurses in NHs, the tools need to be simple with less items that do not require lengthy training[25]. Identifying simpler methods will enhance better implementation of dysphagia screening and improve dysphagia management effectively in NH practices. SSA is simple and involves general assessment and trial swallows. Clinical signs such as voice quality and coughing are recorded during trial swallows by sipping water from a spoon and drinking from a glass[25]. GUSS consists of 2 subsets: indirect assessment without swallowing and direct assessment with trial swallows. Voice change, drooling, coughing and delayed swallowing are noted. Simple instructions are provided in SSA and GUSS that can guide nurses to perform the test and to make referrals to SLPs or to modify diet appropriately. Simply comparing the changes in GUSS scores to previous scores makes it easy to understand the changes in swallowing difficulty and aspiration risk. In addition, GUSS classifies the severity of dysphagia into 4 codes that enable the assessment of the extent of risk for aspiration and allow nurses to determine the appropriate nursing intervention according to the severity level.

Screening and assessment were used interchangeably in the studies while Perry & Love[19] and Logemann et al.[26] distinguished screening and assessment as two different procedures. Generally, screening tests are administered noninvasively, and the patient is exposed to minimum risk while identifying dysphagia symptoms which entail profound diagnostic assessment[26]. Although the tools reviewed in this study used the term assessment and screening interchangeably, the tools mainly screened for the risk of dysphagia and aspiration. In terms of screening for dysphagia in NHs, GUSS and SSA were chosen based on our criteria with high psychometric quality, especially with a high sensitivity. They are easy to use and intelligible to the nurses who will be carrying out the screening and acceptable in terms of resource use, such as time and equipment in NHs.

We believe that this is the first systematic review on the properties of dysphagia screening tests that can be used in NHs by nurses. Other reviews were not systematic[27], or were limited to studies on patients with neurological disorders or stroke[8, 12, 15, 20]. Conforming to our findings, other reviewers also reported the difficulty in making a comparative analysis because of the variety of tests. Bours et al.[8] concluded in their review that as a screening tool, a water test combined with pulse oximetry produces the most satisfactory results. However, using oximetry scored a minus point in our review because oximetry is not commonly available in Korean NH settings, making it less feasible as a screening tool.

Our results have implications in the implementation of dysphagia screening in NHs by identifying the right screening tool for use by nurses. GUSS and SSA can be feasibly used in NHs with a high prevalence of swallowing difficulty; however, the resources and staffing to screen and manage the problem are limited. Further research is needed to standardize the implementation of screening tools in routine NH care, and to take into account the special circumstances of NH where cognitive problems abound.

This study has a few limitations. We used the method by Hawker et al.[10] for the critical appraisal of studies because our review was not limited only to the primary diagnostic accuracy studies. If the review was to focus on evaluating diagnostic accuracy, it would be desirable to use QUADAS-2[28], a tool for the quality assessment of diagnostic accuracy studies, and to include only the studies that compared the results with VFSS or FEES, the gold standards of dysphagia measurement. Although we focused on searching for tests to detect swallowing difficulty in NH residents, the majority of the tests found were used with stroke patients in an acute setting without presenting measurement properties in different target populations, such as NH residents. As dysphagia recovers within 2 to 4 weeks of stroke onset in more than 80% of patients[29], and dysphagia of NH residents could be caused by reasons other than stroke[3], the results of our review should be generalized with caution. Further research on NH residents applying the recommended instruments is necessary according to the study purpose, and also to validate the use of the screening tools. Despite many studies being identified by our review, we cannot be certain that we did not omit any. We used search terms to retrieve as many relevant studies as possible and performed a hand search after reading the studies thoroughly. The restriction to English and Korean journals could be another limitation. Also, the recommended instruments should be tested in certain languages because measurement properties are not mechanically constant throughout diverse languages or cultures.

The review showed that GUSS and SSA are the right tools for detecting dysphagia with high psychometric properties and feasibility that can be administered by nurses in NHs. More research is needed to identify efficient ways to incorporate the implementation of screening procedures especially in NHs with limited staffing and resources. In addition, we recommend developing a standardized protocol for referring NH residents with risk of aspiration to a doctor or SLPs for further evaluation.