1.1 Disease Burden and Epidemiology

A systematic review and meta-analysis including 27 articles reported that the global prevalence was 43.8% 1. The global prevalence of dysphagia ranges between 2% to 20% 2. As per global statistics, the prevalence of oropharyngeal dysphagia is between 2.3 and 16%. Its prevalence is high with predisposing conditions, such as aging and stroke, with a prevalence of 26.19% in the elderly 3, 8.1-80% in stroke patients 4, and 21.9-69.5% in patients taking antipsychotic drugs 5.

Currently, there is limited data regarding the prevalence of dysphagia etiologies in India. In a study conducted in North India, the distribution of dysphagia cases among males and females was 63.6% and 36.4%, respectively. Amongst the important causes of dysphagia, malignancy was identified as an important cause of dysphagia, the total percentage being 35% 6. A study from central India has shown that the maximum cases of dysphagia in that study were due to carcinoma oesophagus (47%) 7. Krishnamurthy R et al. have reported in their systematic review and meta-analysis that the pooled prevalence of dysphagia and pneumonia for patients with stroke in India was reported to be 47.71% and 20.43%, respectively 8.

Dysphagia is commonly related to several diseases, such as cerebrovascular accidents, amyotrophic lateral sclerosis, Parkinson's disease, myasthenia gravis, and tardive dyskinesia. However, the elderly are at increased susceptibility to the development of dysphagia due to illnesses that affect the swallowing mechanism. Compared to community-dwelling elderly, the prevalence of dysphagia in the elderly is even higher in those living in assisted living facilities and nursing homes 9.

1.2 Causes of dysphagia in India

Dysphagia is classified into four categories depending on the site of swallowing impairment: oropharyngeal, oesophageal, esophagogastric, and paraesophageal. These four types of dysphagia occur in four different continuous anatomic regions. Table 1 enumerates the causes of dysphagia and the associated disorders.

• Oropharyngeal dysphagia: It is caused when there is difficulty in emptying the food bolus from the oral cavity to the cervical oesophagus. Symptoms of this condition may include the sensation and occurrence of food sticking in the oral cavity or neck region and symptoms of pulmonary aspiration. Neuromuscular conditions account for almost 75 to 85% of causes leading to this type of dysphagia. Impairment of the upper oesophageal sphincter may be the most common cause of oropharyngeal dysphagia 10.

• Oesophageal dysphagia: This type of dysphagia occurs when there is difficulty with the movement of solid or fluid through the oesophagus, especially in the area between the upper and lower oesophageal sphincter. Abnormal motility or physical impairment to passage could lead to this condition. The symptoms depend on the etiology of the oesophageal disturbance. In the case of motility disorders, symptoms include spasms and chest pain. In contrast, in the case of physical obstruction, the swallowing difficulty is greater and occurs earlier for solids than fluids 10.

Various grades of dysphagia have been provided:

• Normally eating

• Swallows meal with liquid

• Swallows semisolids

• Liquid alone

• Saliva alone

• Unable to swallow saliva

1.3 Challenges and complications with dysphagia

Dysphagic symptoms are driven by abnormalities in the rate of food consumption, mastication, bolus transfer, respiration, and swallow initiation 11. The symptoms are characterized by difficulties in the passage of food or liquid from the mouth through the pharynx, oesophagus, and stomach.

Dysphagia has a negative impact on the quality of life and reduces work productivity. It is the 10^th leading cause of ambulatory care visits in the US among gastrointestinal symptoms, with more than 6 lakh annual visits 12, 13.

Dysphagia is associated with choking, abnormalities in bolus transfer, aspiration pneumonia, respiratory insufficiency, abnormalities in bolus transfer, reduced quality of life due to reliance on alternative feeds for years, intake disorders of water and nutrition, pulmonary contamination by swallowed material, malnutrition, neurogenic dysphagia, severe obstruction, aspiration of gastric contents, cardiac arrest, and regurgitation.

Dysphagia significantly increases the risk of malnutrition, aspiration pneumonia, and choking, varying in severity across individuals 14. Choking incidents could be distinguished into five types depending on the results of clinical assessments: bradykinetic, dyskinetic, fast eating syndrome, paralytic, and medical 15. Dysphagia is one of the most important risk factors in the development of pneumonia, and the incidence of pneumonia was higher among patients with dysphagia compared with those without dysphagia. Post-stroke dysphagia frequently results in poor nutritional status, aspiration pneumonia leading to prolonged hospital stay, poor functional capacity, poor prognosis, and increased mortality 16.

Dysphagia can be associated with considerable morbidity and mortality. When untreated, dysphagia may cause dehydration, malnutrition, respiratory infections, and death. Patients with symptoms of dysphagia are more prone to the risk of complications of dysphagia, including aspiration pneumonia. Patients with dysphagia are subject to substantial social and psychological burdens related to the associated symptoms such as swallowing, anxiety during meals, or avoidance of eating with others 6. Community-acquired pneumonia is a significant cause of morbidity and mortality in the elderly. and the leading cause of fatality among residents of nursing homes. One of the primary factors causing pneumonia in the elderly is oropharyngeal aspiration. It has also been shown that the occurrence of cerebrovascular and degenerative neurologic diseases increases with aging, which is in turn associated with dysphagia and impaired cough reflex with raised chances of oropharyngeal aspirations 17.

1.4 Risk factors causing Dysphagia

Swallowing function is affected by certain issues, such as loss of muscle mass, changes in the cervical spine, impaired dental status, and decreased saliva production. In the case of oropharyngeal dysphagia, aging, neurological diseases such as Parkinson’s dementia, multiple sclerosis, stroke, head and neck cancer, neck surgery, traumatic brain injury, and chronic obstructive pulmonary disease act as causative factors 1.

In elderly patients, identifying the risk factor becomes the driving factor for identifying, assessing, and controlling these risks. Age; comorbid conditions such as stroke, Parkinson’s disease, multiple sclerosis, head and neck cancer, and skeletal muscle; surgical and other therapeutic factors are common risk factors causing dysphagia in the elderly 18.

1.5 Rationale and objective of the consensus

The aims of developing the clinical consensus are: (1) to establish how dysphagia should be diagnosed and assessed, (2) to suggest how to manage dysphagia caused by different etiologies, including oropharyngeal, oesophageal, and structural disorders, and (3) to provide a systematic approach to manage nutrition in dysphagia patients.

3.1 The approach to dysphagia assessment

Dysphagia detection is an important contributor to earlier management, prevention of comorbidities, and improving the quality of life. It is also important to assess the severity and the progression of dysphagia. Patients who are asymptomatic but at risk of dysphagia must be screened to detect early symptoms or swallowing dysfunction and identify those that need more comprehensive and definitive swallowing assessment for appropriate management 21.

Patients with dysphagia may present with multiple complaints, but the most common symptoms include coughing, choking, or the abnormal sensation of food sticking in the back of the throat or upper chest while attempting to swallow. The approach to evaluating dysphagia follows the steps given in Figure 1.

3.2 Clinical History

A focused history and an examination of the site of swallowing difficulty will help in distinguishing dysphagia from alternate diagnoses that are not true dysphagia. A careful history also distinguishes oesophageal from oropharyngeal dysphagia, whether the dysphagia is experienced when swallowing solids and liquids or only solids, whether it is progressive, and whether there are other associated symptoms such as pain on swallowing or regurgitation 22. Box 1 shows a few important questions that must be included in the history taking 22.

3.3 Aspiration Screening

Aspiration screening is important to rapidly and reliably identify patients at risk of aspiration to initiate prophylactic measures and further assessment. It is important to ensure that the screening procedures are designed in a way that they can be carried out following appropriate training by different healthcare workers, even if they have not received dysphagia-specific training. It is also worth mentioning that a large proportion of the test protocols that have been published are assessed in stroke patients. However, some are also evaluated in mixed cohorts of dysphagia patients. In the absence of evidence evaluating the optimal test in all dysphagia patients, there are no standardized test approaches suggested so far 23, 24.

The screening methods are divided into three categories: water swallowing tests, multi-consistency tests, and swallow provocation tests 25. Pulse oximetry for aspiration detection is considered to be of low sensitivity despite its use in several test protocols, as studies have shown that a reduction in oxygen saturation of more than 3% was neither predictive nor sensitive for aspiration 26.

The water swallowing test usually assesses whether the patient can drink a defined amount of water without clinical signs of aspiration. The results of the water swallowing test are always binary; either the patient has clinical signs of aspiration requiring nil per os and results in a more refined diagnostics, or the test is inconspicuous, following which oral intake is possible. The Water Swallowing test is considered when assessment of swallowing safety is important and further assessment of swallowing function can be conducted rapidly.

Besides this, multi-consistency tests like the Gugging Swallowing Screen or the Volume Viscosity Test assess whether other fluids can be swallowed. These tests are intended for a stepwise classification of swallowing impairment and the addition of dietary recommendations to their risk assessments 25. In the case of patients who are non-cooperative and cannot receive an oral bolus, the Swallow Provocation Test is used to examine the involuntary swallowing reflex. It hence focuses on the pharyngeal phase of deglutition 25. The multi-consistency test is recommended if, along with the safety of swallowing, swallowing efficiency also needs to be evaluated, and a more differentiated swallowing assessment for determining the optimal oral diet is not available within a reasonable time 27.

In case of negative screening results, further dysphagia assessment is recommended in stroke patients if the patient presents with other risks of dysphagia, such as a severe neurological deficit, severe dysarthria or aphasia, or severe facial palsy. This additional assessment is also recommended in patients with a high risk of silent aspiration, such as Parkinson’s disease 28.

Aspiration screening in patients with neurogenic dysphagia has been significant, especially in patients with acute stroke. Prospective observational studies have shown that evaluation of aspirations screening was related to a reduction of infectious complications 29. In another prospective, multicentre observational study, it was seen that a formal aspiration screening showed significantly reduced pneumonia and mortality rates 30. A pre-post comparison revealed that implementing a nurse-based aspiration screening led to a 50% reduction in pneumonia rates in stroke survivors 31. A large retrospective registry involving over 60,000 patients also showed that performing an aspirations screening after stroke was reported to be time critical. The risk of developing pneumonia increased from just over 3% with prompt clinical examination to almost 4.5% when testing was conducted later than 24 hours 32. Similar associations between delayed performance of aspiration screening and increased risk of pneumonia were also seen in other studies 33.

3.4 Dysphagia Assessment

Clinical Swallowing Examination (CSE) should be carried out by trained speech and language therapists (SLTs). CSE provides an accurate evaluation of the severity and phenomenological pattern of the swallowing impairment to allow for further diagnostic assessments, dietary recommendations, and treatment planning. Even though it is widely used in everyday clinical practice, its validity is restricted. It was reported in a cohort of acute stroke patients that CSE has a comparatively good sensitivity of 86% for the determination of aspiration risk. Still, since it has a specificity of just 30%, no reliable conclusions can be drawn about the presence of a disturbance in the swallowing act. A comparative study between CSE and VFSS showed that the use of CSE could only assess laryngeal elevation while failing to assess other parameters of swallowing physiology, such as oral transit, swallowing reflex latency, and total duration of swallowing 34.

During the initial two weeks after stroke, a significant improvement of dysphagia is seen in a high number of patients, especially those with supratentorial lesions 35, 36, 37, 38. However, in the case of stroke recurrence, a worsening of swallowing function could be seen 39. Hence, a regular dysphagia assessment is necessary in acute stroke patients. In a randomized controlled study, it was seen that early behavioral swallowing intervention was linked to a considerable decrease in infectious complications and an increase in the proportion of patients regaining swallowing function 40.

Flexible Endoscopic Evaluation Swallowing : In many parts of the world and several guidelines, Flexible Endoscopic Evaluation Swallowing (FEES) has been established as the diagnostic standard for the assessment of swallowing. FEES provides comprehensive information about the pharyngeal phase of swallowing and enables the identification of impairment within the oral and oesophageal phases. It aims to identify pathological movement patterns, assess the effectiveness and safety of swallowing, assess suitable food consistencies and feeding strategies, and guide the use of therapeutic maneuvers for individual patients. The standard FEES protocol consisted of the following steps, including anatomical-physiological examination, swallowing without and with defined test boli, and an evaluation of the efficacy of the therapeutic methods 25. As per ASHA clinical guidance, FEES may be recommended irrespective of treatment setting, used without concerns of radiation exposure, and can be used within the frames of diagnostic and therapeutic contexts 41. The scales available for evaluating the salient endoscopic findings are the penetration aspiration scale, according to Rosenbeck 42, the Yale Residue scale 43, the Secretion Severity Scale 44, and the Scale for Quantification of Premature Spillage 45. Other than the standard FEES protocol, several other specific examination protocols have been developed and validated for different clinical conditions: FEES Tensilon-Test and Fatiguable Swallowing Test for the detection and assessment of myasthenia dysphagia, FEES-L-Dopa Test for assessment of L-Dopa-sensitive dysphagia in patients with Parkinson’s syndrome, FEDSS for the classification and management of stroke-related dysphagia, and decannulating algorithm to examine the feasibility of decannulation in tracheotomized intensive care patients 46.

Following the FEES test, the patients should be referred for consultation by an otolaryngologist or phoniatrician. In a study, it was shown that FEES was performed safely and well tolerated by all the patients with dysphagia, especially stroke, Parkinson’s disease, critical illness polyneuropathy, motor neuron disease, dementia, myasthenia gravis, and myopathies. It also led to a significant impact on dysphagia management 47. Considering FEES results, over 40% of the patients were able to achieve a more liberal oral diet, while more than 10% needed a more careful nutritional approach. Among the tracheotomized patients, decannulation was possible in over 25% of the cases based on FEES results. The results of a retrospective study showed that following the implementation of bedside FEES service in a stroke unit, pneumonia rates were significantly reduced from 12% to 7%. Besides this, dependent on FEES results, patients had increased chances of receiving a regular diet at discharge, while the duration of non-oral nutrition and the duration of hospital stay increased 48.

Video Fluoroscopic Evaluation of Swallowing: The Video Fluoroscopic Swallowing Study (VFSS) or the modern digital method (Digital Fluoroscopic Swallowing Study, DFSS) is a radiological examination of the entire swallowing act, including oral, pharyngeal, and oesophageal stages. VFSS distinguishes between dysphagia symptoms such as aspiration, residues, and underlying pathomechanisms 25. It also offers quantitative measures such as the oral onset time, the oral transit time, the pharyngeal transit time, the anterior-superior movement of the hyoid, the duration and size of the velopharyngeal closure and the duration and width of the opening of the upper oesophagus sphincter. Studies have shown that the specific VFSS parameters are linked to penetration and aspiration 49, 50. VFSS results also serve as indicators for the recovery of swallowing function after stroke 51 or for patient response to dysphagia swallowing interventions 52. Several scores available that can characterize dysphagia severity have also been devised, including the Modified Barium Swallow Study Impairment Profiles, the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST), and the Parkinson Disease VFSS Scale (PDVFS) scale. The MBSImP has been used to characterize dysphagia in COPD patients 53, the DIGEST score has been used in patients with oculopharyngeal muscular dystrophy and amyotrophic lateral sclerosis 54, 55, and the PDVFS is a disease-specific score to detect the risk of aspiration pneumonia 56. In stroke patients with dysphagia, VFSS may bring about a safe change in the route of feeding from artificial enteral nutrition through an NG tube to an oral diet 57. VFSS enables the detection and comprehensive description of the complex pathomechanisms of swallowing disorders affecting laryngopharyngeal and -oesophageal interactions. It also offers the advantage of capturing the entire swallowing act, including the oral phase, pharyngeal constriction, epiglottic inversion, hyolaryngeal elevation, upper oesophageal sphincter function and the oesophageal phase in high resolution 25.

Manometry: Manometry, especially high-resolution manometry (HRM), allows the endoluminal pressure conditions in the pharynx and esophagus to be measured during the swallowing act. It is of significant importance to prove relaxation disorders of the UES and motility disorders of the esophagus (achalasia, diffuse oesophagospasm) 58. The parameters that are assessed during manometry are resting pressure, the opening of the upper and lower oesophageal sphincters as well as peristalsis, pressure, and amplitudes of the tubular oesophagus 59. HRM has been used for the assessment of oesophageal motility in patients with neurological diseases such as Parkinson syndromes 60, inflammatory myopathies 61, and Morbus Huntington 62. HRM is useful in neurology, especially in patients with opening disorders of the UES as a result of myopathies or strategic brainstem infarctions 63. Pharyngeal HRM is used in many neurological diseases, such as stroke 64, Parkinson’s disease 65, and inflammatory and genetically determined myopathies 66, to describe the pattern of swallowing impairment.

Even though manometry is a good choice to complement FEES and VFSS, pharyngeal manometry is still not integral to routine dysphagia diagnostics.

The Table 4 provides instrument-wise guidance for various indications 25.

3.5 Assessment of malnutrition

Assessing malnutrition in individuals with dysphagia (swallowing difficulties) involves a multi-faceted approach that considers both the impact of swallowing problems on nutritional intake and the overall nutritional status of the individual.

3.6 Dysphagia management

The therapeutic techniques in dysphagia management are divided into those used as compensatory strategies and exercises and those used as both compensatory strategies and/or exercises 67. The choice of therapy or treatment approach in a dysphagia patient is dependent on the assessment and evaluation of the patient. The execution of the treatment approach depends on the available evidence from published literature, patient choice, and guideline-based treatments or standard protocols 67.

3.7 Malnutrition risk in dysphagia patients

Malnutrition may be present in almost 24% of stroke patients, with studies reporting prevalence between the range of 8 to 48% depending on patient cohort and assessment technique 68. Malnutrition in stroke patients can lead to a severe impact as it improves functional results and poor quality of life. There is an association between dysphagia and increased dehydration as well as malnutrition in the first 7 days after stroke. This is a reason for an increased duration of hospital stay, greater chances of institutionalization following discharge, increased mortality, and poor functional outcomes. Nutritional deficit is also linked to worsening quality of life in stroke patients. Hence, nutritional assessment must be undertaken in all patients after a stroke 69.

In a systematic review, it was seen that dysphagia is an important complication in chronic patients after stroke. Early identification of this condition through screening tools with adequate diagnostic accuracy (such as volume-viscosity swallow test) is crucial 70. A study has shown that almost half of the patients with head and neck cancer present with a high risk of malnutrition. Screening can identify head and neck cancer patients who are at risk of malnutrition and eventually require a dietitian for nutritional assessment and support, irrespective of BMI 71.

While no studies support the fact that nutritional support will reduce adverse events or mortality, there is a strong recommendation in favour of nutritional intervention based largely on clinical and expert opinion and that the benefit of the intervention outweighs the risk 69.

3.8 Rehabilitation

Rehabilitation intervention is aimed at enabling patients to swallow safely. Physical rehabilitation relies on strengthening hyoid musculature, including tongue strengthening exercises, the Shaker maneuver, and Chin Tuck Against Resistance to improve swallowing. Tongue-strengthening exercises have shown benefits in dysphagia patients.

Exercises and maneuvers may be considered to be the most widespread treatment approach for patients with neurogenic dysphagia. Tongue and pharyngeal muscle strengthening exercises are an important treatment method for dysphagia. Strengthening exercises are frequently used for better lingual and pharyngeal strength and improvement in swallowing ability 72. These exercises intend to raise the diameter of the upper oesophageal sphincter opening and reduce post-deglutitive aspiration and dysphagic symptoms 73.

Restorative techniques are aimed at restoring impaired swallowing functions or promoting residual functions through pre-swallow stimulation (e.g., thermal stimuli), mobilization techniques (e.g., tongue pressing against resistance), and specific motor exercises (e.g., Shaker exercise, Masako maneuver, EMST) 25.

Swallowing exercises are used to treat dysphagia to alter the swallowing physiology and encourage long-term changes. Exercises are classified as compensatory and rehabilitative. Both compensatory and rehabilitative techniques are effortful swallow, supraglottic swallow, super-supraglottic swallow, and the Mendelsohn maneuver. Other exercises to improve swallowing physiology include the Shaker and Masako maneuvers 67. About 12 randomized controlled trials assessed whether strengthening exercises for the tongue and laryngeal muscles were effective in improving the swallowing function and decreasing the occurrence of aspiration pneumonia. These randomized controlled trials were conducted on patients with brain lesions and head and neck cancer applying rehabilitative techniques, such as head lift exercise, Shaker exercise, Mendelsohn Maneuver, and muscle strengthening exercises of the tongue and larynx 74. An RCT conducted by Kang and Kim showed that in dysphagia patients with stroke, a significant improvement in neck strength and swallowing function was seen when head lift exercises were performed for 30 minutes, 5 times a week for 6 weeks 75. The results of two other randomized controlled trials by McCullough et al. 76 and McCullough and Kim 77 revealed that the 2 weeks of the Mendelsohn method training improved hyoid anterior and superior movements and raised UES opening and swallow physiology in 18 patients with stroke and dysphagia. Kotz et al. showed that patients with head and neck cancer patients who performed swallowing exercises (five exercises, including effortful swallowing, super-supraglottic swallowing, tongue hold, tongue retraction, and Mendelsohn maneuver, 10 times per day, and three times per day) experienced better swallowing outcomes than those who did not perform exercises at 3 and 6 months after the treatment 78. In another study by Lazarus et al., it was seen that tongue-strengthening exercises improved swallowing function in 12 patients with oropharyngeal cancer who underwent radiotherapy compared to those who were given only conventional treatment 73.

In an ideal scenario, based on the physiologic impairment identified through FEES or VFSS, a combination of compensatory and rehabilitative strategies could be adopted for the management of dysphagia symptoms and improve swallowing physiology. In stroke patients with dysphagia, the treatment goal, irrespective of the etiology, is to identify and treat the physiologic impairments, thereby improving outcomes and alleviating symptoms 67.

3.9 Enteral nutrition

In many cases, enteric feeding is the only way to ensure nutritional and hydration intake and to allow medication administration 79. Guidelines across the world recommend enteral nutrition by NGT as soon as possible following a stroke, with recommendations varying from the first 24 hours, 80 the first 3 days,81, 82, 83 or the first 7 days 84, 85, 86. Hence, enteral nutrition support is indispensable for patients who cannot achieve a full supply of nutritional and energy requirements. An appropriate and timely nutritional intervention plays a crucial role in preventing malnutrition and promoting recovery 87.

However, there is no clear evidence that states which stroke patients will benefit from tube feeding. Stroke patients and those with severe pre-existing malnutrition and with a decreased level of consciousness, severe dysphagia, or severe palsy are considerably impaired in their food intake and are at high risk for malnutrition. These patients are likely to benefit from tube feeding.

The results of the FOOD trial, involving 859 stroke patients, revealed a tendency towards a decrease in mortality in dysphagia stroke patients by 5.8% (p=0.09) in the group with early tube feeding initiated within 7 days after stroke. While the results of the study indicated a potential benefit of early initiation of tube feeding in patients, a prominent limitation of the study is that it only included patients when the attending physician was unsure about adequate nutrition therapy 88, 89.

No significant difference between percutaneous endoscopic gastrostomy (PEG)and nasogastric tube (NGT), with regard to mortality and pneumonia, has been noted. A small randomized controlled trial of a moderate quality study conducted in 104 dysphagic stroke patients showed that, even though a nasal bridle considerably increased the amount of enteral nutrition and fluid delivered, ameliorated electrolyte disturbances, and decreased NGT failure, no differences were seen in terms of mortality, morbidity, PEG placement, functional outcomes or duration of hospital stay at 3 months. The intervention period was limited to 2 weeks 90. A two-year follow-up study comparing percutaneous endoscopic gastrostomy and nasogastric feeding in 160 patients with swallowing disturbances showed that both techniques are safe and effective in the short term. However, when needed for long-term management, PEG is shown to be superior to NGT feeding in improving nutrition and preventing common challenges for patients with swallowing disturbances 91. A study by Chang et al. showed that PEG is a better choice than NGT feeding due to the reduction in risk of pneumonia needing hospital admission, especially in patients with abnormal volumes of pooling secretions collection in the pyriform sinus or leak into the laryngeal vestibule 92. In a study aimed to assess the role of oropharyngeal dysphagia in older patients on long-term enteral feeding for risk stratification of pneumonia requiring hospitalization, it was reported that PEG is a better choice than NGT. 93 The results of a systematic review showed that percutaneous gastrostomy and NGT have equivalent outcomes in terms of weight management in patients with head and neck cancer. However, considering the evidence available, it is premature to conclude that PEG is advantageous over NGT feeding 94. The results of the systematic review by Gomes CAR et al. favored PEG compared with NGT owing to the fact that it is associated with a lower probability of intervention failure. However, there is no significant difference in mortality rates between comparison groups or in adverse events, including aspiration pneumonia 95. A systematic review by JAAFAR et al. showed that definitive conclusions could not be drawn about whether PEG feeding is beneficial over NGT in older patients with non-stroke dysphagia. The pooled analysis results indicated no significant difference in the risk of pneumonia and overall complications between PEG and NG feeding. However, from the studies included in the systematic review, three studies suggested improved mortality outcomes with PEG feeding, but two out of three studies showed that PEG feeding was better from a nutritional perspective 96.

Patients with difficulty in swallowing are at a high risk of aspiration and aspiration pneumonia and developing malnutrition. While aspiration pneumonia cannot be prevented by tube feeding in the acute phase after stroke 88 the rate of aspiration risk does not increase during enteral nutrition 25, 96, 97, 98. It is recommended to feed patients at risk of prolonged dysphagia via a tube to avoid the risk of malnutrition, thereby malnutrition 99, 100.

Evidence-based practice guidelines by the Dieticians Association of Australia command that the goals of nutritional intervention in head and neck cancer patients undergoing chemo-radiation therapy are to ‘reduce a decline in nutritional status/weight to maintain quality of life and symptom management 101.

The results of a meta-analysis have shown that nutritional support through intermittent tube feeding can ensure the nutritional support of the patients, encourage the recovery of swallowing function, and reduce the incidence of aspiration-related pneumonia, providing optimized nutritional support for stroke patients with dysphagia 102. In Nakajima’s study, it was found that intermittent oral-to-oesophageal (IOE) tube feeding was one of the options for continuous nasogastric tube feeding in acute stroke patients with severe dysphagia 103. In a meta-analysis, it was proven that IOE can better improve the nutritional level of patients and reduce the incidence of complications. The findings showed that IOE tube feeding could improve the nutritional levels of patients better than a nasogastric tube, reduce the incidence of aspiration pneumonia, and improve swallowing function 104. Intermittent tube feeding can considerably improve the nutritional status on the basis of encouraging the recovery of swallowing function. Intermittent tube feeding has a similar food intake per time to normal people 105.

Long-term indwelling gastric tube leaves a passive effect on the throat reflex, which fails to achieve the effect of training the swallowing function and disuse dysphagia, and patients may need nasal feeding for life 106. Intermittent tube feeding avoids oesophagus, gastric mucosal damage, and digestive ulcers caused by indwelling a gastric tube, ensures normal digestion and absorption of the digestive tract, and promotes the absorption of nutrients 107.

It has been shown that dysphagia and malnutrition are frequently found together in stroke patients 107, 108. Dysphagia is a strong predictor of malnutrition in stroke patients during the rehabilitation period 109. While it may not be practically feasible to initiate tube feeding on the first day of treatment in most patients, early initiation of enteral nutrition in acute disease does have several benefits, including fewer infectious complications with tube feeding compared to parenteral nutrition 110, 111.

In the “Early versus Avoid trial” of the FOOD study, where tube feeding was started as early as possible versus delayed placement of the tube, it was seen that the group of patients that started enteral nutrition within 7 days of admission had a reduction in mortality by 5.8%, which was not significant. Considering the proportion of patients surviving with poor outcomes was higher in the group with early nutrition, it could be suggested that these patients with an ‘impaired outcome’ would not have survived with a delayed start of nutrition 88, 89. Hence, enteral nutrition may play an important role.

Prehabilitation nutrition is known to decrease the rate of serious complications significantly 112. In post-traumatic conditions, amino acids are important for supporting the immune system and promoting tissue repair. 113, 114 Prehabilitation nutrition is important in managing the nutritional deficits resulting from the disease 112. Nutritional support, along with psychoeducation, considerably lowered the overall mortality rate in head and neck cancer patients 112.

3.10 Compensatory techniques

Compensatory techniques are rehabilitative strategies employed for dysphagia management. Several compensatory techniques, such as head flexion, head turn, head tilt, bolus viscosity, texture, and volume modifications, are used for managing dysphagia. The compensatory swallowing techniques target to keep patients safe when swallowing and encourage temporary stability without changing the swallowing mechanism. These techniques include chin tuck, chin down, head extension, head rotation, effortful swallow, Mendelsohn maneuver, tongue-hold maneuver, or Masako maneuver, supraglottic swallow, and super-supraglottic swallow.

Compensatory methods are used during the swallow to allow effective and safe deglutition despite functional impairments. There are two distinct techniques: postural maneuvers (e.g., chin-tuck or head-turn maneuvers) and special swallowing techniques (e.g., supraglottic swallowing) 25.

The Table 7 provides details about different compensatory techniques 67.

It was seen in an observational study that compensatory swallowing techniques like chin-down posture, head turned posture, and a hyperextended head posture led to safe swallowing in 88% of patients with dysphagia 115. It has been seen that the effect of both chin tuck and chin down maneuvers was advantageous in swallowing function 116, 117. There is currently no or weak evidence supporting the effect of effortful swallowing, Mendelsohn maneuver, or tongue hold maneuver.

A study has reported that super-supraglottic swallowing changed airway closure and hyoid-larynx movement 118, while another revealed that supraglottic swallowing does not alter the propelling pressure of food lumps 119.

3.11 Bolus viscosity, texture, and volume modifications

In patients with dysphagia, swallowing, and respiration do not have tight temporal coordination. Hence, fluid kinematics or dynamics to evaluate the food bolus flow properties are an important tool to assess swallowing disorders.

Texture-modified food and thickened liquid is a common therapeutic strategy to manage neurogenic dysphagia. It is believed that modifying the properties of normal food and liquids will transform them into a form that is easier and safer to swallow 120.

3.12 Solid and semisolid foods

It is recommended to use modified solid and semisolid foods to promote safe swallowing and adequate nutrition in dysphagia patients. The texture of these is suited to a patient's swallowing ability and palatability. The International Dysphagia Diet Standardization Initiative (IDDSI) has developed global standardized terminology and definitions for texture-modified food and thickened liquids for individuals of all ages, in all care settings, and in all ethnicities and cultures 121.

Clinical or technical assessment should form the basis for recommendation of suitable consistency. Based on the type and severity of the swallowing dysfunction, food should be offered in various consistencies, from pureed to soft textures. Dry, stringy, or crumbly foodstuff should be avoided as they disturb bolus formation. Two-phase food has been seen to increase the risk of aspiration 122. Nectar- or honey-thickened consistency of fluids may assist in the prevention of aspiration 118. The results of a systematic review showed that nutritional status can be improved by specially made and nutritionally enriched, texture-modified foods (pureed and minced) and thickened fluids (nectar, honey, and pudding consistency) are recommended for elderly persons with chronic dysphagia 123. It becomes important to define grades of thickened liquids for dysphagia management. Standardization of thickened liquids used in dysphagia includes the dysphagia phenotype, age, gender, detailed rheological characterization, measurement protocol, and preparation protocol. In a consensus by Krishnamurthy et al., the changes in the food texture have been suggested by the expert committee 123.

Table 8 provides the properties of food texture recommended as the most significant in the modification of solid and semi-solid foods for Indian dysphagia patients 124, 123.

Several studies have shown that increasing bolus viscosity from liquid to pudding considerably reduces the prevalence of laryngeal penetration and aspiration in 98.9% of patients. Changing the characteristics of solid food by dicing, chopping, mincing, or pureeing is frequently employed to make these materials easier for oral processing and swallowing 87. A study has also shown that the minimal massive intervention (MMI) employed through thickening powders reduced hospital readmissions, respiratory infections, and increased survival after the follow-up period.

If seven days have elapsed without the patient achieving an adequate oral intake or if the patient cannot take at least 60% of the estimated daily nutrient demands, it is suggested in the UK national clinical guidelines for diagnosis and initial management of acute stroke and transient ischemic attack that nutritional support with modified texture products should be initiated immediately 80.

Currently, there is a lack of substantial evidence to support the role of texture-modified diets, either alone or along with ONS or enteral tube feeding, in maintaining or improving the nutritional status of dysphagic stroke patients.

In a small study in stroke patients, Diniz et al. showed that modification of diet texture and thickening of fluids can prevent aspiration in stroke patients 125. However, patients on texture-modified diets may have reduced nutrient intakes than patients on a normal diet 126, 127.

A study has shown that semi-solid nutrients significantly reduce the risk of gastroesophageal reflux and the dwell time in the stomach in adult patients 128. A systematic review by Wu et al. suggested that texture modified diet led to a positive effect on nutritional status and mealtime satisfaction of nutritional fortification. A few modifications of diet texture may be significant for individuals at the highest risk of choking on food 129. A review has suggested that food thickening to a certain degree can decrease the complications of choking, aspiration, reflux, and other complications in patients with dysphagia and also reduce the social disorder, anxiety, and other psychological problems caused by catheterization and surgery. 130 Using thickeners to improve bolus viscosity in post-stroke oral dysphagia patients has been claimed to be a countervailing clinical technique against aspiration 131.

Modified diets are believed to minimize the risk of choking and the need for chewing or oral food processing 132. Food thickeners play a relevant role in texture-modified food while swallowing, slowing down the flow of liquids and stopping them from being aspired through the airway 133.

The results of a systematic review showed a reduction in the risk of penetration-aspiration with liquids as they move from the thin to the very thick end of the viscosity continuum 120. It was seen in a study that the use of texture-modified diets along with high-energy, high-protein supplements improved functional and nutritional status in hospital patients with dysphagia 134. Three studies included in the systematic review found significant weight or BMI improvement with texture modified diet 135, 136, 137.

However, there is a lack of well-defined boundaries among texture-modified food using rheological measurements and sensory analyses. This has an impact on the treatment of dysphagia since there is a lack of uniform understanding about the texture differences in the food. The results of a meta-analysis including 30 studies concluded that thickening liquids reduce the risk of aspiration in different patient groups. The whole continuum covering the spectrum of viscosity values, from ‘thin,’ ‘nectar,’ and ‘honey,’ to ‘spoon thick,’ a dose-response characteristic was seen with thicker liquids being safer than thinner liquids 137. A few studies have also reported that thickened liquids may lead to oral and/or pharyngeal residues with ultra-thick liquids 25.

3.13 Thickened liquids

The primary aim for prescribing thickened liquids for dysphagia patients is to maintain sufficient hydration and prevent aspiration during swallowing. By enhancing the consistency of the bolus, the flow behaviour of the bolus and the physiology of swallowing in dysphagia patients is improved. The use of thickening agents helps dysphagia patients manipulate the bolus properly and makes way for enough time for laryngeal vestibule closure, thus improving airway protection 87.

An article by Newman et al. (2016) showed that increased viscosity from a thin liquid to spoon-thick viscosity significantly reduces laryngeal penetration and aspiration prevalence. However, evidence is lacking to establish the optimal viscosity of boluses ensuring safe swallowing for different dysphagia severity, phenotype, and different swallowing dysfunctions 137. Besides bolus viscosity, bolus volume also plays a significant role in the safety of swallowing. In the case of patients with pyriform sinuses, an increase in bolus volume leads to a higher chance of overspill into the airway, leading to increased post-swallow residue 138.

3.14 Thickening powders

Thickening powders are used in dysphagia management to slow bolus flow speed during swallowing. With the use of thickening powders, the thickened fluids could be prepared in a simple manner, with convenience, and at a reasonable cost. Thickening agents are notably beneficial for dysphagic patients with delayed swallow, owing to the reduced velocity of bolus flow in comparison to thin liquid 87.

Acknowledgment

The authors would like to appreciate and acknowledge Shivshankar Timmanpyati for his Guidance, support and inputs in the entire process of developing the consensus. Ms. Pooja S Banerjee for her literature search and medical writing support in developing the consensus statement.