Investigation of Pharyngeal Swallow Function of Healthy Older Adults Using Visual Analysis of Swallowing Efficiency and Safety Scale

Abstract

To assess the pharyngeal swallow function of older adults in terms of safety and efficiency using the VASES scale. Twenty healthy individuals aged 60–80 years were included. They were evaluated using the EAT-10 K and VVST, followed by the FEES assessment. VASES was used to assess the residue in the oropharynx, hypopharynx, Epiglottis, Laryngeal vestibule, Vocal folds, and Sub glottis, and the aspiration and penetration during swallowing. Residue was present in the oropharynx, hypopharynx, epiglottis, and laryngeal vestibule for 95%, 85%, 45%, and 15% of the swallowing trials. The median residue amount was found to be 2% in the oropharynx and 1% in the hypopharynx. 70% of swallows yielded a score of PAS score of 1, followed by PAS 3 for 20% and PAS 2 for 10%. VASES facilitated the quantification of the residue across anatomical sites. Older adults did have compromised swallow safety and efficiency.

Introduction

Structural and physiological changes occur in the swallowing mechanism as age increases, which is unavoidable. The following changes have been reported in the pieces of literature: reduced tongue muscle strength and endurance, [1–6] decreased pharyngeal pressure due to pharyngeal muscular atrophy [7], decreased laryngeal elevation or laryngohyoid excursion [8], and reduced upper esophageal sphincter pressure [9]. Characteristic changes in the swallowing physiology of an older adult who is otherwise healthy is defined as presbyphagia [8]. The changes mentioned earlier may affect the safety and efficiency of swallowing.

FEES (Fiberoptic Endoscopic Evaluation of Swallowing) and VFSS (Video Fluro Scopy Swallow Study) are the instruments used to assess the swallow safety and efficiency. Emerging evidence suggests that FEES yields better visualization of pharyngeal residue [10–12] and airway invasion than VFSS. There are many scales to assess swallow safety and efficiency in terms of penetration, aspiration, and residue. These scales are based on either the anatomically defined residue estimation method or the bolus clearance estimation method. Yale Pharyngeal Residue Severity Scale [13], the Pooling score [14], the Boston Residue and Clearance Scale [15], and the Mansoura Fiberoptic Endoscopic Evaluation of Swallowing Residue Rating scale [16] and Penetration Aspiration Scale (PAS) [17] are based on the anatomically defined residue estimation method. Dynamic Imaging Grade of Swallowing Toxicity for Flexible Endoscopic Evaluation of Swallowing (DIGEST-FEES) [18] is based on bolus clearance and anatomically defined residue estimation methods. The scales mentioned above use a categorical rating system to quantify the residue. However, they vary regarding the outcome measured (i.e., vallecular, pyriform residue), the number of categories, and the definitions associated with each severity category. Additionally, due to their inability to capture relatively minor unit variations, categorical rating scales for FEES are less sensitive and reliable than the visual analog scales. Emerging research has indicated that a visual analog scale, which is incorporated in the Visual analysis of swallowing efficiency and safety scale (VASES) [19] may be more reliable and sensitive and can capture relatively minor variations than the categorical rating scales [20–22].

Furthermore, the studies assessing pharyngeal swallow function using FEES in healthy older adults are limited; most studies have used categorical rating methods to quantify the residue. Moreover, there is no consensus across the study findings. Kelly et al. 2008 investigated the pharyngeal residue and penetration aspiration in healthy young and older adults using FEES, and they found that elderly individuals showed marginally less residue than younger individuals [23]. Garand et al. 2019 studied the airway invasion of bolus using the Penetration aspiration score scale during videofluroscopy in the healthy cohorts across the three age groups (21–39, 40–59, 60 years, and older). The results revealed no significant differences across the age groups in the PAS score [24]. These study findings are contradicted by the following studies by Butler et al. 2009, Butler et al. 2010, De Lima Alvarenga et al. 2018, and Jardine et al. 2020 [25–28]. Overall, the studies on the impact of aging on swallowing are less conclusive. Also, studies exploring swallowing physiology in older adults have been done outside India utilizing FEES. However, it is impossible to extrapolate these findings to the older population of India due to pronounced disparities in culture, lifestyle habits, nutrition, healthcare services, and practices. Considering these facts, the present study aimed to assess the pharyngeal swallow function of older adults using the VASES scale.

Method

Participants

Twenty older adults participated in the study. The mean age range of the participants was 70.1 ± 5 years. Seven females and 13 males participated in this study. Informed consent was obtained from all the participants. Battery for cognitive communication Disorders – Kannada [29] was used to screen their cognitive function. Eating Assessment Tool-10 – Kannada (EAT-10 K) [30] and Volume viscosity swallow test (VVST) [31] were used to screen their swallowing function. The participants with no history of speech and swallowing disorders with intact cognitive function, and no history of having a neurological disorder were included. Those with EAT-10 K score above 3, inadequate safety /efficacy of swallowing during trials of VVST, intake of alcohol during the time of evaluation of FEES, history of stroke, neurodegenerative disease, head and neck cancer, structural changes to the larynx, pharynx, oral structures, palate, orofacial pain, trigeminal neuropathy, facial palsy, and history of medication that affects swallowing function were excluded.

Instrument

The ATMOS FEES portable mobile swallowing diagnostics by Medizing Technik, Germany, which incorporates a flexible chip-on-tip endoscope and a tablet PC with the appropriate software for video storage and reporting, was used for the study.

Procedure

The study procedures were approved by the institutional review board (No.DOR.9.1/Ph.D/SP/PR35/2022–2023, dated 26.09.2023). All the participants underwent the FEES procedure when they were seated in an upright position. The flexible thin scope was passed trans nasally by the otolaryngologist. Laryngeal sensory testing was carried out during FEES using touch method. Pre-swallow exams included velopharyngeal closure assessment, pharyngeal squeeze, and vocal fold adduction. After the pre-swallow examination, the test boluses were administered, and the swallows of bolus trials were video-recorded for later analysis. The bolus was given in the order of liquid consistency (5 ml, 10 ml milk), thick liquid (5 ml curd), semisolid (15 ml chopped banana), and solid (1/2 cookie). All the boluses were colored with green food dye for better visualization, and the boluses were administered when the subject was seated in a neutral head position.

Investigation of Swallow Function Using VASES

VASES was used to evaluate the swallow safety and efficiency in terms of residue, aspiration, and penetration. It is a newly developed and validated scale by Curtis et al. 2021. VASES is based on the continuous percentage method, while other scales are based on the categorical rating method. It uses a 100-point visual analog scale to quantify the residue in six anatomical areas: Oropharynx, Hypopharynx, Epiglottis, Laryngeal vestibule, Vocal folds, and Subglottis. VASES scale was used to analyze for each swallowing trial: (i) the presence and amount of residue for each anatomical site and (ii) the penetration and aspiration scale score.

Analysis of Residue

For each swallow trial, visual perceptual estimates of the amount of residue filling(oropharynx, hypopharynx) or covering (epiglottis, vestibule, vocal folds, subglottis) in each of the six anatomic structures were estimated using the VASES percentage-based rating system by the speech-language pathologist. A residue rating of 0% meant that the residue was “absent,” whereas a residue rating of > 0% meant that the residue was “present.” Higher residue ratings indicated greater percentages of an anatomic structure filled or coated by residue. The amount of residue was determined after the swallow. The amount of residue in the subglottis, vocal folds, and laryngeal vestibule was assessed before a cough or throat clearing.

PAS Score

The PAS [17] is an 8-point ordinal rating scale used to appreciate the depth of the airway invasion of the food particles. A PAS score of 1 indicates that the material does not enter the airway. A PAS score of 2–3 indicates that the material enters the laryngeal vestibule but not the vocal folds. A PAS score of 4–5 indicates material on the vocal folds, not below the vocal folds (Sub glottis). A PAS score of 6–8 indicates that material enters below the vocal folds.

Data Analysis

FEES videos were recorded individually for each participant. All the videos were digitally stored and analysed. A total of 100 swallow trials were analysed.

Statistical Analysis

All the data were statistically analysed using IBM SPSS Statistics Version 26. Descriptive statistics were used to characterize VASES outcome measures. Frequency distribution was used for the PAS score. Descriptive statistics for the residue ratings included the proportion of swallows when residue was absent (0%) and the mean, median, minimum, maximum, standard deviation, and interquartile range of residue ratings when residue was present (> 0%).

Results

Twenty participants participated in this study. The mean age range of the participant is 70.1 +_ 5 yrs. Each participant completed five swallow trials. The study yielded a total of 100 swallow trials for analysis.

Residue Ratings

Oropharyngeal Residue

The percentage of the swallow trials that had residue across different bolus types in the oropharynx is displayed in Fig. 1. The residue was present for 85% of the 5 ml liquid, 70% of the 10 ml liquid, 95% of thick liquid, 50% of semisolid, and 75% of solid swallow trials. Table 1 presents the mean, standard deviation (SD), median, and interquartile range (IQR) of the amount of oropharyngeal residue (VASES score) across bolus types. When oropharyngeal residue was analysed for liquid, the median amount of residue was estimated to be 1% (IQR:1) and 1% (IQR:2) for 5 ml and 10 ml liquids. The median amount of the residue for thick liquid was estimated to be 3% (IQR: 2). Residue was absent for 15%, 30%, 5%, 50%, and 25% of swallow trials for 5 ml liquid, 10 ml liquid, thick liquid, semisolid, and solid respectively.

Fig. 1.

Percentage of swallow trials that had residue across different bolus types in the oropharynx. Note 5 ml L- 5 ml liquid; 10 ml L-10 ml liquid

Table 1.

Mean, Standard deviation (SD), median, and interquartile range (IQR) of the amount of oropharyngeal residue (VASES score) across bolus type

Bolus type	Mean (SD)	Median, IQR	Min, Max
5 ml Liquid	1.40 (1.14)	1, 1	0,5
10 ml Liquid	1.60 (2.25)	1,2	0,10
Thick Liquid	2.70 (3.13)	2,2	0,15
Semisolid	0.80 (1.28)	0, 1	0,5
Solid	1.65 (1.38)	1,2	0,5

Note SD- Standard deviation IQR- Intra quartile range Min- Minimum Max- Maximum

Hypopharyngeal Residue

The percentage of the swallow trials that had residue across different bolus types in the oropharynx is displayed in Fig. 2. The residue was present for 75% of the 5 ml liquid, 70% of the 10 ml liquid, 85% of thick liquid, 35% of semisolid, and 40% of solid swallow trials. Table 2 shows the mean, standard deviation (SD), median, and interquartile range (IQR) of the amount of hypopharyngeal residue (VASES score) across bolus types. When hypopharyngeal residue was analysed for liquid, the median amount of residue was estimated to be 1% (IQR:2) and 1% (IQR: 2) for 5 ml and 10 ml. The median amount of the residue for thick liquid was estimated to be 1% (IQR: 1). Residue was absent for 25%, 30%, 15%, 65%, and 60% of swallow trials for 5 ml liquid, 10 ml liquid, thick liquid, semisolid, solid respectively.

Fig. 2.

Percentage of swallow trials that had residue across different bolus types in the hypopharynx. Note 5 ml L- 5 ml liquid; 10 ml L-10 ml liquid

Table 2.

Mean, Standard deviation (SD), median, and interquartile range (IQR) of the amount of hypopharyngeal residue (VASES score) across bolus type

Bolus type	Mean (SD)	Median, IQR	Min, Max
5 ml Liquid	1.10 (0.91)	1, 2	0,3
10 ml Liquid	1.40 (2.21)	1,2	0,10
Thick Liquid	1.50 (1.39)	1,1	0,5
Semisolid	0.45 (0.826)	0, 1	0,5
Solid	0.65 (0.875)	0,1	0,3

Note SD- Standard deviation IQR- Intra quartile range Min- Minimum Max- Maximum

Epiglottis Residue

The percentage of the swallow trials that had residue across different bolus types in the epiglottis is displayed in Fig. 3. The residue was present for 5% of 5 ml liquid, 20% of 10 ml liquid, 45% of thick liquid, 5% of semisolid, and 20% of solid swallow trials. Residue was absent for 95%, 80%, 55%, 95%, and 80% swallow trials of 5 ml liquid, 10 ml liquid, thick liquid, semisolid, and solid, respectively.

Fig. 3.

Percentage of swallow trials that had residue across different bolus types in the epiglottis. Note 5 ml L- 5 ml liquid, 10 ml L- 10 ml liquid

Laryngeal Vestibule Residue

The percentage of the swallow trials that had residue across different bolus types in the laryngeal vestibule is displayed in Fig. 4. The residue was present for 5% of 5 ml liquid, 15% of 10 ml liquid, and 5% of thick liquid swallow trials. The residue was absent for 95%, 85%, and 95% of swallow trials for 5 ml liquid, 10 ml liquid, and thick liquid, respectively. No residue was observed for semisolid and solid swallow trials.

Fig. 4.

Percentage of swallow trials that had residue across different bolus types in the laryngeal vestibule. Note 5 ml L- 5 ml liquid, 10 ml L- 10 ml liquid

Vocal Fold Residue

The percentage of the swallow trials that had residue across different bolus types in the vocal fold is displayed in Fig. 5. The residue was present for 5% of the swallow trials and absent for 95% of the swallow trials only with 10 ml liquid.

Fig. 5.

Percentage of swallow trials that had residue across different bolus types in the vocal fold. Note 10 ml L- 10 ml liquid

Subglottic Residue

There was no residue present in the subglottis.

PAS Score

70% of the persons swallow yielded a score of PAS 1, followed by PAS 3 for 20% and PAS 2 for 10%, respectively.

Discussion

The present study aimed to investigate the oropharyngeal swallow function of older adults using VASES. The results revealed that residue was present in the oropharynx, hypopharynx, epiglottis, laryngeal vestibule, and vocal fold for 95%, 85%, 45%,15%, and 5% of the swallowing trials. The median residue amount was 2% for thick liquid, 1% for 10 ml liquid, and 1% for semisolid. 70% of swallows yielded a score of PAS 1, followed by PAS 3 for 20% and PAS 2 for 10% of swallows. This study’s findings were consistent with those of a previous study done by Butler et al. 2009, Butler et al. 2010 and Butler et al. 2011 [11, 25, 26].

These findings of the proportion of swallow trials that have residue reveal that food residue is predominantly present in older adults. This may be due to reduced pharyngeal driving pressures and reduced swallowing efficiency [26, 32, 33]. Consequently, residue was high in the oropharyngeal and hypopharyngeal regions. It suggests that the process of aging in the oropharynx and hypopharynx is more pronounced. Food residue in older adults indicates the presence of primary Presbyphagia, or surrogacy of dysphagia, which could be a consequence of reduced tongue retraction, pharyngeal constriction, hyolaryngeal elevation, and reduced swallow trigger. When these structures are unable to move fully, the bolus cannot be evacuated completely from the hypopharynx into the esophagus [34].

The residue was frequently present for thick liquids, followed by thin liquids, and the median amount of residue was higher for thick liquids (2%) than for other bolus consistencies. This finding indicates that thick liquid will reduce the risk of aspiration, but the residue will be higher.

Moreover, the pharyngeal residue was present in almost three-fourths of the participants’ swallow trials, though it was not found through swallow screening tools such as EAT-10 and VVST. This suggests that FEES detected three-fourths of the participants with a risk of having dysphagia. To investigate the pharyngeal residue and penetration aspiration, FEES should be performed with different consistencies of foods. In this study, residue in older adults would have been unnoticed if FEES had not been performed.

Some studies also have indicated that the prevalence of Presbyphagia is as high as 63–72% [35, 36], which is highly alarming. The presbyphagia can also transition towards dysphagia if no rehabilitative measures are instituted. Conservative estimates suggest that dysphagia rates may range from 13 to 38% among elderly individuals who are living independently [37, 38].

Additionally, at a pace of around 3% annually, the population of adults 60 and older is increasing. There were 962 million people in the globe who were 60 years of age or older in 2017, which is predicted to increase to 1.4 billion by 2030, 2.1 billion by 2050, and even 3.1 billion by 2100 [39]. With a growing population of older people worldwide, the percentage of persons with presbyphagia also might increase. It is essential to take adequate steps to prevent it so that its consequences on nutrition, hydration, pulmonary function, reduced activities of daily living, and overall swallow safety are prevented.

Strengths and Limitations

This study is the first to investigate the pharyngeal swallow function in older adults using FEES and VASES in India, while other studies have been conducted outside India. This study adds to the growing body of literature that documents functional disruption of swallowing in healthy aging and emphasizes the importance of routinely screening healthy seniors for swallowing difficulties to prevent aspiration and maximize the future nutrition and hydration outcomes in this population. Of course, the present study has some limitations: (1) Small sample size – only 20 people included in this study. (2) Gender Bias- Female participants were lesser in number (3) Inter-rater reliability and intra-rater reliability were not assessed. Future studies can be conducted with a greater sample size and address all these limitations. Also, the comparison of this scale with the other categorical rating scales can be carried out.

Conclusion

The use of VASES facilitated the quantification of the residue across different anatomical sites. The findings showed the presence of residue and penetration in older adults when the FEES was done, though it was not identified through the swallow screening tools. Healthcare providers should be aware that certain persons, apparently older adults, may have swallowing difficulties without clinical complaints and that a screening test for swallowing assessment may not be sufficient to predict presbyphagia. Age itself appears to be a potential risk factor for inefficient swallowing. A good physical reserve can be built up by maintaining a level of physical fitness in the years leading up to older age with regular exercise and strength training.

Funding

There is no funding associated with the work featured in this article.

Declarations

Conflict of Interest

No potential conflict of interest.