Treatment approach and outcomes to severe and chronic dysphagia in lateral medullary syndrome: A case series

ABSTRACT

Introduction:

Dysphagia is more profound in lateral medullary syndrome (LMS) patients. LMS patients are susceptible to be dependent on tube feeding for months to years post stroke. The objectives of this study are to characterize and understand the extent of functional impairment in the swallowing phases, to strategize the noninvasive methods as per the deficits present, and to document swallowing outcomes of severe and chronic dysphagia following rehabilitation in patients with LMS.

Materials and Methods:

This is an ambispective observational study on chronic LMS (≥1 year) patients with complete dependency on tube feeding. Dysphagia was assessed with clinical bedside swallowing examination and video fluoroscopy swallowing study (VFSS), penetration-aspiration scale (PAS), dysphagia severity rating scale (DSRS), bolus residue scale (BRS), and functional oral intake scale (FOIS).

Results:

Six patients were included in our study for the final analysis. Initial VFSS was done at FOIS level 1 and a DSRS score of 12. The BRS and PAS score of all patients at this stage was 6. The second VFSS was done when patients achieved FOIS level ≥2 and a DSRS score of ≤10. At this stage, BRS was 4 ± 0.8, while PAS improved to 4 at the interval of 8 ± 3 weeks following rehabilitation. Final VFSS was performed at FOIS level ≥4 and DSRS ≤3. BRS and PAS at this stage were ≤2. This was achieved in 20.8 ± 8.3 weeks from the onset of rehabilitation.

Conclusion:

Chronic and severe dysphagia in LMS has a favorable recovery prospects. In our study, patients resumed complete oral feeding following dysphagia rehabilitation.

Introduction

Dysphagia is a patient’s inability to swallow food and occurs due to neurological or mechanical disorders and is clinically relevant because of its association with aspiration pneumonia, malnutrition, increased mortality, and poor quality of life. Usually mild or transient in nature, it is seen in 51-94% of lateral medullary syndrome (LMS). LMS, also called Wallenberg’s syndrome, is caused by occlusion of vertebral artery or posterior inferior cerebellar artery leading to ischemia of the lateral part of medulla oblongata.[1] It is a posterior circulation stroke with 20–25% incidence,[2] which may damage the structures present in lateral medulla. Vertigo, dizziness, nystagmus, ataxia, nausea, hiccups vomiting, dysphagia, headache, and sensory signs (facial numbness) are common neurological manifestations of this damage, which sometimes is also linked with dysarthria, facial paresis, diplopia, skew deviation, and gaze deviation. Dysphagia is more profound in LMS patients as it affects nucleus ambiguous (NA) and nucleus of tractus solitarius (NTS) like neural structures, which helps in the passage of food bolus from mouth to stomach via pharynx and esophagus. Thus, lesions in this area interfere with the mechanism of swallowing and pharyngeal and esophageal phases. Abnormality in upper esophageal sphincter (UES) functioning, pharyngeal pooling, and increased risk of aspiration are some well-documented features of dysphagia in patients with LMS.

Dysphagia is known to recover within 3 months of stroke onset, and patients resume complete independence in oral diet, with or without intervention. However, 10% of LMS patients continues to be dependent on tube feeding after months to years post stroke.[1]

Delayed or no recovery of dysphagia may occur for several reasons, often linked to the underlying cause of the condition, the patient’s overall health, and the rehabilitation process. In India, healthcare facilities are often concentrated in urban centers, with rural areas lacking access to specialized care. Diagnostic tools like FEES or VFSS and therapies required for managing dysphagia are often unavailable in remote locations. As a result, dysphagia may be left untreated or mismanaged. Failure to initiate early and consistent swallow rehabilitation can delay recovery. Dysphagia requires skilled approaches to re-educate the brain in swallowing function. Without structured, consistent therapy, recovery can stall and as the time passes, the brain’s ability to reorganize itself (neuroplasticity) may decrease. This, in turn, can exacerbate the problem, and patients may reach to a point where they believe that now recovery is impossible.

Literature reporting on the prognosis of LMS patients with persistent severe and chronic dysphagia is scant, which points to a lacuna in the field. There are noninvasive modalities (swallowing rehabilitation, EMG biofeedback, neuromuscular electrical stimulation, transcranial magnetic stimulation, and transcranial direct current stimulation) and invasive techniques (botulinum toxin injection, balloon catheter dilatation, myotomy of relaxation of cricopharyngeal muscle) which have been tried for dysphagia treatment.[1] Our study aims is to characterize and understand the extent of functional impairment in the swallowing phases, to strategize the noninvasive methods as per the deficits present, and to document swallowing outcomes of severe and chronic dysphagia following rehabilitation in patients with LMS.

Materials and Methods

This is an ambispective observational study done at a tertiary care center from June 2015 till July 2023. It was approved by the institutional ethics committee. Patients with LMS who presented with the clinical picture of inability to swallow (level 1 on functional oral intake scale) were enrolled. All patients enrolled were conscious, oriented, and able to follow verbal commands irrespective of motor deficits.

Inclusion criteria

• Chronic dysphagia, post LMS >1 year.

• No surgical intervention for dysphagia is performed.

• Functional oral intake scale (FOIS) <2.

Exclusion criteria

• Unable to comprehend.

• Tracheostomized patients.

• Lost to follow-up.

Outcome measures

• FOIS was used to determine the degree of oral diet independence and freedom from using a feeding tube.[3]

• Dysphagia severity rating scale (DSRS) is used in our study at the time of patient enrolment and subsequently scored to estimate the swallowing functionality. It grades the severity of clinical dysphagia by quantifying modification required in the diet along with level of supervision for safe oral intake. It comprises three subscales that are totalled to give us a score ranging from 0 (best) to 12 (worst).[4]

• Penetration Aspiration score (PAS) is rated on the scale of 1–8 (where 8 implies severity of score). PAS is a rank ordered scale that classifies the depth of penetrated or aspirated material and the patient’s response to airway invasion.[5]

• Bolus residue scale (BRS) is used for the quantification of the pharyngeal residue. It is scored from 1 to 6 (where 1 implies no residue and 6 implies residue in vallecula and posterior pharyngeal wall and piriformis sinus).[6]

• Video Fluoroscopy Swallowing Study (VFSS), also called modified Barium swallow study, is a radiographic procedure that provides a direct, dynamic view of oral, pharyngeal, and upper esophageal functions (Logemann 1986) along with aspiration.[7,8] It was done thrice, at level 1, level 2, and level ≥4 of FOIS, and quantified with outcome measures like DSRS, PAS, and BRS.

• Criteria for laryngeal elevation (Daniel MMT).

  1. F: Larynx elevated at least 20 mm in most people. The motion is quick and controlled.

  2. WF: Laryngeal excursion may be normal or slightly limited. The motion is sluggish and may be irregular.

  3. NF: Excursion is perceptible but less than normal. Aspiration may occur.

  4. 0: No laryngeal elevation occurs (aspiration will occur in this event).

Therapeutic tools

• Surface electromyographic biofeedback (EMG) was used for pharyngeal strengthening.[9]

• Neuromuscular electrical stimulation (NMES) was used as an intervention in the facilitation and strengthening phases of the swallowing. (Device details: Neurotrac Myoplus 4 Pro model from Verity medical UK, CE certified).[10]

• Traditional therapy for swallowing includes breathing exercises, resistive tongue and jaw exercise, shaker exercise, sensory stimulation, and compensatory and postural maneuvers.[10]

• The International Dysphagia Diet Standardization Initiative (IDDSI) is used to classify the degree of dietary modifications necessary for safe and efficient oral intake.[11,12]

Dysphagia was assessed with clinical bedside swallowing examination and VFSS. Based on the evaluation, swallowing rehabilitation was started with the intent of establishing an efficient swallowing function. Swallowing rehabilitation or dysphagia management protocol included traditional swallow therapy, NMES, and biofeedback. The study end point was made when the patient’s swallowing function reached a level of FOIS ≥4, DSRS ≤3, and PAS score ≤2 (on thin or mildly thick liquids, IDDSI ≤2) and became eligible for the removal of feeding tube (nasogastric tube [NGT] or percutaneous endoscopic gastrostomy [PEG]) [Figure 1].

Figure 1.

Methodology

Results

Our study included 6 patients (all males), mean age 53.3 years (range, 30–64 years). Four patients had right-sided lesion of lateral medulla, while two had left-sided lesion. All the patients were dependent on non-oral feeding methods (4 with PEG and 2 with NGT) [Table 1]. Initial VFSS was done at FOIS level 1. The DSRS score was 12, whereas the BRS and PAS score of all patients was 6. The second VFSS was done when patients achieved FOIS level ≥2. At this stage, the average DSRS score reduced to ≤10, and BRS was 4 ± 0.89, while PAS improved to 4. The time duration was between 3 weeks and 12 weeks from the onset of swallowing rehabilitation (8.1 ± 3.06). Final VFSS was performed when the patient reached FOIS level ≥4. DSRS improved to ≤3; BRS and PAS at this stage were between 1 and 2 (1.5 ± 0.54). This was achieved in approximately 20.8 (±8.35) weeks of time from the onset of rehabilitation [Table 2].

Table 1.

Epidemiology and clinical profile of patients

Patient	Gender	Age at the time of stroke	Age when the patient came for intervention	Lateralization	FOIS	Initial diet
1	Male	49	51	Right	1	PEG
2	Male	61	63	Right	1	PEG
3	Male	63	64	Left	1	NGT
4	Male	47	54	Left	1	PEG
5	Male	29	30	Right	1	NGT
6	Male	57	58	Right	1	PEG

PEG: Percutaneous endoscopic gastrostomy, NGT: Nasogastric tube, FOIS: Functional oral intake scale

Table 2.

Swallowing outcomes at different phases of recovery

	VFSS at FOIS=1					VFSS at FOIS ≥2						VFSS at FOIS ≥4
	EP	LE	DSRS	BRS	PAS	EP	LE	DSRS	BRS	PAS	T	EP	LE	DSRS	BRS	PAS	T
1	(–)	NF	12	6	6	++	WF	9	4	4	7	+++	F	2	1	2	13
2	(–)	WF	12	6	6	+	WF	8	5	4	9	+++	F	2	2	1	28
3	(–)	0	12	6	6	+	WF	9	5	4	12	+++	F	3	2	2	32
4	(–)	0	12	6	6	++	WF	9	3	4	10	+++	F	0	1	1	24
5	(–)	0	12	6	6	++	WF	8	4	4	8	+++	F	0	1	1	16
6	(–)	NF	12	6	6	++	WF	8	3	4	3	+++	F	3	2	2	12

EP: esophageal passage, (–) restricted passage, (+) minimal passage, (++,+++) significant passage, LE: laryngeal elevation, WF: weak functional, NF: not functional, F: functional, 0: absent, BRS: bolus residual scale, PAS: penetration aspiration scale, DSRS: dysphagia severity rating scale, FOIS: functional oral intake scale , VFSS: videofluoroscopy swallowing study, T: time duration (in weeks) to achieve outcomes

Discussion

Case vignette

Case 1

A 51-year-old male, k/c/o hypertension, presented with severe dysphagia and was dependent on PEG tube for 14 months after right-sided lateral medullary syndrome. Examination showed dysarthria, decreased pain, and temperature in the right upper limb and lower limb with gait ataxia. Dysphagia assessment showed no laryngeal elevation (Grade NF) with inability to swallow his own saliva. VFSS showed normal oral phase, delayed pharyngeal phase with poor contraction on swallowing, and inability of food bolus to pass beyond UES. Penetration aspiration was also seen (PAS 6). The patient was able to take oral feed independently (functional swallowing score of FOIS >4, DSRS <3, PAS <2) in 13 weeks following rehabilitation.

Case 2

A 63-year-old male, k/c/o hypertension, presented with severe dysphagia and was dependent on PEG tube for 18 months after right-sided lateral medullary syndrome. Mild dysarthria and wide-based gait were diagnosed upon examination. Dysphagia assessment showed no laryngeal elevation, Grade 0. VFSS showed negligible pharyngeal peristalsis and almost complete residue over PFS and vallecula (BRS 6) with aspiration penetration (PAS 6). DSRS for swallowing impairment was 12. Functional swallowing was achieved in nearly 28 weeks.

Case 3

A 64-year-old male presented with severe dysphagia, dependent on Ryle’s tube for 13 months after left-sided lateral medullary syndrome. There was decreased pain and temperature in the left upper limb and lower limb along with wide-based gait. Dysphagia assessment showed no laryngeal elevation, Grade 0. The patient achieved functional swallowing in 32 weeks.

Case 4

A 54-year-old male presented with severe dysphagia, dependent on PEG tube for 7 years after left-sided lateral medullary syndrome. He was independent for ADLs. Primary examination showed mild loss of temperature and pain sensations on the left side of the body and total pharyngeal palsy with no laryngeal elevation, Grade 0. Functional swallowing was seen in 24 weeks.

Case 5

A 30-year-old male presented with severe dysphagia, dependent on Ryle’s tube for 12 months after right-sided lateral medullary syndrome. The examination showed dysarthria, decreased pain, and temperature sensations in the left upper limb and lower limb. Dysphagia assessment showed no laryngeal elevation, Grade 0. Functional swallowing was seen in 16 weeks.

Case 6

A 58-year-old male presented with severe dysphagia, dependent on PEG tube for 12 months after right-sided lateral medullary syndrome. There was decreased pain and temperature sensations in the left upper limb and lower limb. Dysphagia assessment showed mild laryngeal elevation, Grade NF. Functional swallowing was seen in 12 weeks.

In our study, we have described the clinical course and prognosis of patients with severe and chronic dysphagia post stroke, precisely LMS. On enrolment, the severity of dysphagia was seen with VFSS findings which suggested poor laryngeal excursion with impaired pharyngeal peristalsis and relaxation or opening of UES. According to the deficits, swallowing rehabilitation was designed and was primarily focused on pharyngeal functioning, Figure 2.

Figure 2.

A schemata of the study/clinical pathway

Mechanism of swallowing

The process of swallowing is divided into oral, pharyngeal, and esophageal phases. Neural structures involved in the pharyngeal phase are in lateral medulla and are located on both sides in the medulla oblongata of the brainstem (NA, NTS, spinal trigeminal nucleus, vagal dorsal motor nuclei), which are interconnected. Due to this, unilateral lesion can cause severe dysphagia. These neural structures are responsible for coordinated functioning of the muscles of soft palate, pharynx, larynx, and UES. The opening of UES is associated with good pharyngeal and laryngeal muscle strength. Appropriate relaxation of the cricopharyngeal muscle and movement of the larynx (upward and forward) during pharyngeal swallowing induces UES opening and allows smooth passage of food bolus beyond PFS to the esophagus. Laryngeal elevation represents the pharyngeal phase of swallowing. Weak pharyngeal muscles and UES closure during swallowing interferes with the movement of food bolus through pharynx; this residual or pooled food is then easily aspirated during inhalation after a swallowing attempt, as reported in a case study by Kunieda et al.,[13] Bian et al.,[14] and Logemann.[15] Pharyngeal pooling and absence of UES relaxation is thus a typical feature of dysphagia due to LMS, as seen in our study also.[16]

Intervention

In our study, we found most of the patients were having poor pharyngeal contraction with minimal or no laryngeal elevation at the time of presentation [Figure 3a]. Hence, we divided our patients into two groups based on the degree of laryngeal elevation and pharyngeal contraction. We started with the facilitation phase, where there was no or minimal pharyngeal constriction, observed clinically as well as in VFSS. This phase was followed by a strengthening phase, where we aimed to increase the strength of pharyngeal muscles [Figure 2].

Figure 3.

(a) Initial VFSS (lateral view). Presence of a severe bolus residue in the pyriform sinus, valleculae, and posterior pharyngeal wall owing to poor pharyngeal constriction and an impaired UES relaxation (arrowhead at C-6 level), (b) VFSS at FOIS ≥2 (lateral view). Some portion of food bolus is passing through beyond UES (arrowhead), (c) VFSS at FOIS ≥4 (lateral/oblique view). Aspiration visible at the level of glottis (arrowhead). (d) VFSS at FOIS ≥4 (lateral view). Almost complete passage of contrast beyond PFS to esophagus with good pharyngeal constriction, and (e) No aspiration is noted and post swallow contrast pooling in pyriform sinus was minimal (BRS ≤3)

Facilitation phase (Grading ≤ NF)

The initial goal was to elicit swallowing reflex and to initiate hyo-laryngeal movement. The documented laryngeal elevation in normal adults is approximately 0–2.50 cm or 20 mm.[12] Therapy commenced after familiarizing patients with the treatment protocol which included traditional swallow therapy in combination with NMES. Each patient underwent 1-hour therapy session (including 45 minutes of NMES) 5 times per week until some improvement was seen in their laryngeal elevation (Grading ≥ WF).

Traditional therapy comprises breathing exercises, sensory tactile stimulation, shaker exercises, resistive tongue and jaw exercises, and hyoid lift maneuver. This regimen was structured for home programs also, except NMES, which is reported to excite the sensory and motor fibers of pharyngeal muscles after stroke in conjunction with traditional therapy for better outcome.[17]

Strengthening phase (Grading ≥ WF)

In this phase, treatment focus was on the strengthening of pharyngeal muscles. The exercise regimen, in addition to traditional therapy and NMES, included pharyngeal strengthening maneuvers like Masako and effortful swallow, which were combined with EMG biofeedback training also for a better performance.[18]

However, the frequency of NMES was reduced to three sessions per week in this phase and two sessions of NMES per week were replaced with EMG biofeedback training. Sessions included 30-minute subsection of traditional swallow therapy and a 30-minute subsection of pharyngeal strengthening maneuvers with biofeedback.

Masako or effortful swallow has been an effective maneuver to improve pharyngeal strength as it increases the oral and pharyngeal swallow pressure and augments posterior motion of the tongue base. Surface electromyography (sEMG) biofeedback uses specialized equipment to convert subconscious physiologic information into visual or auditory signals, helping patients to sense their deglutition and manipulate physiological changes to improve their performance. Electrodes are placed on the skin and detect motor unit action potentials generated by muscle contraction. With increasing force of muscle contraction, there is successive activation of motor units and an increase in the firing rate of all motor units recruited, leading to an increase in the amplitude of the sEMG signal, which can be displayed graphically. By using this feedback, patients can work to increase muscle activity. Limited research has been conducted on biofeedback-assisted pharyngeal strengthening.[19,20,21,22]

Along with this, swallowing trials were initiated using desired food bolus and IDDSI consistency between 4 and 6 keeping all safety measures. This food group is assumed to have minimal risk of aspiration and was compliant to patients to allow multiple swallow trials with the single bolus before having an ultimate need to clear pharynx through coughing and spitting it out. Esophageal passage of food was observed in 6–8 weeks after rehabilitation was initiated. This was correlated using VFSS and indicates potential for further recovery over time. As evidenced in literature, some esophageal passage could be seen in approximately 5 weeks following acute onset of LMS.[23] This becomes a point of reference for both the patient and therapist to continue the rehabilitative process [Figure 3b].

The patient improved on IDDSI food group (4–6) implying complete ingestion of food bolus without coughing or spitting it out. Further, swallowing training with liquids was initiated progressing from high-viscosity to low-viscosity liquids (IDDSI group 3 to 0). Advancement to different consistency in food training was made only when the patient stopped exhibiting the signs of penetration and aspiration on a particular consistency. Subsequently, caregivers were trained for the same when the risk of aspiration was nil on a particular consistency of food. Kim et al.[22] reported 11 patients with severe dysphagia after LMS, in whom VFSS was performed every 2 weeks and improvement was seen at an average of 52.2 + 21.8 days to achieve full oral diet. Huckabee and Cannito[23] reported 10 patients with chronic brainstem dysphagia, dependent on feeding tube with n = 8; patients recovered in 5.8 months with full oral intake, and two achieved the ability for partial oral intake.

Swallowing safety of low-viscosity liquids (IDDSI ≤2) was analyzed and confirmed with VFSS study. In our study, one patient was clinically able to have fluids without any signs of aspiration, but on VFSS, the patient showed mild/silent aspiration and was reviewed again after a month of swallow therapy and pharyngeal strengthening [Figure 3c].

As the strength of pharyngeal muscles improved, there was sequential improvement in the esophageal passage of bolus with minimal or nil pharyngeal residue and no aspiration, which was acknowledged in VFSS. After the improvement, the removal process of feeding tube was initiated [Figure 3d-e].

The concept of neural plasticity in swallowing disorders is also proposed, which draws on the possibility of reversible changes seen in our study despite the chronicity and severity of dysphagia.[24] The 7-year-old case of stroke presenting with complete dependence on tube feeding was able to recover in approximately 5 months following rehabilitation. This is a classic example supporting neural plasticity. There are reports on surgical intervention (cricopharyngeal myotomy, Botox, balloon catheter dilatation) for the treatment of dysphagia due to LMS. Either these invasive modalities were ineffective in changing the tube feeding to oral feeding or their efficacy could not be sustained for long and repeated intervention is required. Aspiration pneumonia and gastro esophageal reflux are reported as adverse effects particularly after myotomy.[2]

In the context of outpatient care for post-stroke patients, particularly those living with or recovering from lateral medullary syndrome, this case series highlights the critical role of interdisciplinary coordination and caregiver education in facilitating effective functional recovery. The findings advocate for the integration of structured dysphagia rehabilitation protocols into community-based healthcare frameworks to enhance clinical outcomes and minimize the chronic burden of morbidity associated with severe dysphagia.

Limitations of this study

We could get a very low number of cases, and one of the main reasons was that the patient needs to be compliant with the swallowing rehabilitation for a long and unspecified duration.

There are, to the best of our knowledge, no studies being done on swallowing outcomes in patients with severe and chronic dysphagia due to LMS.

Conclusion

Chronic and severe dysphagia in LMS has a potential of complete recovery. In our study, patients were weaned off from the tube to complete oral feeding in approximately 5 months despite the severity and chronicity of the dysphagia post stroke. Therefore, active intervention with consistent therapy targeting facilitation and strengthening of pharyngeal muscles and UES relaxation, which are most affected in LMS, can be a better approach for recovery.

Author contributions

HG: Conceived, designed, Drafted the manuscript and provided the figures and tables. DKM: Designed, Drafted the manuscript, provided the figures and tables. RA and VR: Designed, critically reviewed the manuscript.

Conflicts of interest

No potential conflict of interest relevant to this article was reported.

Data availability statement

All data supporting the findings of this study are available within the paper (Figures and Tables).

Funding Statement

Nil.