Effectiveness of antidepressant repetitive transcranial magnetic stimulation in a patient with refractory psychogenic dysphagia: A case report and review of literature

Abstract

BACKGROUND

Dysphagia is a common condition in older as well as young patients, and a variety of treatments have been reported depending on the cause. However, clinicians are challenged when the cause is unclear. This is the case with psychogenic dysphagia, which has typically been treated with supportive psychotherapy, medication, swallowing exercise, and dysphagia rehabilitation therapy. Here, we aimed to relieve the symptoms of a patient with refractory psychogenic dysphagia, who was unresponsive to conventional swallowing therapy, with repetitive transcranial magnetic stimulation (rTMS).

CASE SUMMARY

A relatively calm-looking 35-year-old female patient presented with a 2-year history of dysphagia. She showed little improvement with conventional swallowing treatments over the past 2 years. She was relatively compliant with in-hospital dysphagia therapy, but uncooperative with home exercise and medication. In particular, since she was resistant to drug treatment, we had to take a different approach than the treatment she had been receiving for the past 2 years. After much deliberation, we decided to initiate antidepressant rTMS treatment with her consent (IRB No. 2023-05-021). Antidepressant rTMS treatment was performed twice weekly for a total of 20 sessions over 10 wk. The results showed improvement in subjective symptoms and video fluoroscopic swallowing study findings. To the best of our knowledge, this is the first report of symptomatic improvement using antidepressant rTMS protocol for refractory psychogenic dysphagia.

CONCLUSION

This case demonstrates that rTMS with antidepressant protocol can be used to improve swallowing in patients with refractory psychogenic dysphagia.

Key Words: Deglutition disorder, Depression, Health, Rehabilitation, Transcranial magnetic stimulation, Case report

Core Tip: This case report describes the use of repetitive transcranial magnetic stimulation (rTMS) to improve swallowing in a patient with refractory psychogenic dysphagia. The patient had not responded to conventional swallowing therapy for the past two years. Interviews with her reveal that she appears calm but is very depressed. Therefore, rTMS with antidepressant protocol was deemed appropriate and applied for 10 wk. After the treatment, the patient’s swallowing symptoms improved, and the effect was maintained for 1 mo. This case shows that antidepressant rTMS treatment can be a good alternative for patients with psychogenic dysphagia who do not respond to conventional swallowing therapy.

INTRODUCTION

Dysphagia impairs not only activities of daily life but also quality of life (QoL)[1]. Even if the cause is known, treating dysphagia requires a substantial amount of time and effort[2-4]. Worse yet, if the cause is unclear, clinicians face challenges in treating the condition. One example of this is psychogenic dysphagia. Psychogenic dysphagia is defined as dysphagia caused in the absence of organic or neurological abnormality, and a gold standard for diagnosis is still lacking[5,6]. For this reason, diagnosis of psychogenic dysphagia is difficult, which delays treatment and increases the likelihood of the condition becoming chronic, prolonging the patient’s suffering. Even if the diagnosis of psychogenic dysphagia is made later on, the condition cannot be completely cured. The traditional treatments for psychogenic dysphagia include supportive psychological therapy, exercise therapy, and pharmacological treatment. Supportive psychological therapy and exercise therapy cannot be effective without the patient’s and family’s cooperation and effort. While pharmacological treatment is effective to some degree, the complete remission rate remains low at 50%, and the effectiveness of the treatment declines with poor medication adherence[7].

Repetitive transcranial magnetic stimulation (rTMS) has long been used as a treatment option for dysphagia. However, in most cases, it was combined with the traditional dysphagia treatment modalities and was rarely used independently. In addition, the general rTMS protocol for treating dysphagia specifies the supplementary motor area (SMA) as the target site[8-10]. To the best of our knowledge, our case is the first case to demonstrate improvement of symptoms of refractory psychogenic dysphagia through rTMS alone using the dorsolateral prefrontal cortex (DLPFC) as the target in a patient who has not responded to the traditional dysphagia treatment for an extended period.

CASE PRESENTATION

Chief complaints

A 35-year-old woman presented to the outpatient clinic for dysphagia that has not responded to various treatment modalities in the past 2 years.

History of present illness

The patient first presented to the hospital with dysphagia that slowly developed around December 2020. The patient had no underlying diseases or any special events that might have triggered dysphagia symptoms. The patient had severe difficulty swallowing food after chewing, with the problem more evident with solid foods. The physician who examined the patient at the time ordered blood test, brain magnetic resonance imaging (MRI), and nerve-motor function test, but the findings were unremarkable. Subsequently, the patient underwent conventional dysphagia treatment for approximately 2 years with neither marked improvements nor exacerbation, and the patient eventually presented to our outpatient clinic. The patient seemed relatively calm considering the tremendous stress she has had for not being able to eat normally for a prolonged period. The patient had been taking nutrients by swallowing the liquid form after chewing and spitting out the remaining solids and by drinking liquid food during gastrointestinal tube feeding. At the time of initial presentation 2 years before treatment initiation, the patient had a normal weight and body mass index (BMI) (48.0 kg, BMI 20.0 kg/m²) but was underweight at the time of presentation to our clinic (42.7 kg, BMI 17.8 kg/m²).

History of past illness

There was no illness in previous medical history.

Personal and family history

No abnormalities.

Physical examination

The patient first underwent otolaryngological testing and gastroscopy, and the findings were within normal limits. The basic neurological test findings, including cognition, limb strength, balance, and cranial nerve examination, were also within normal limits. However, the patient exhibited laryngeal elevation and some hesitancy in swallowing.

Laboratory examinations

In the videofluoroscopic swallowing study (VFSS), severe oral phase delay was observed in all types of food boluses. Particularly, solid food boluses were unable to progress to the pharyngeal phase. Fortunately, the patient was able to swallow liquid boluses without aspiration, although in small amounts. No neuromuscular or structural causes that could result in transfer dysphagia were identified. Blood tests were performed to investigate for any possible abnormal findings, anemia, hypoproteinemia, or trace element deficiencies, but all results were within normal limits.

The patient had no restrictions of activities of daily living (ADLs) due to physical problems, as evidenced by a modified Rankin scale score of 0 and modified Barthel Index of 100. However, she scored lower than the normal ranges in assessments that consider psychological aspects in ADLs[11-14], such as Montgomery and Asberg Depression Rating Scale, Hamilton Depression Inventory, Beck Depression Inventory, EuroQol five-dimension questionnaires, and Patient Health Questionnaire. Additionally, the patient reported discomfort and difficulty with most forms of diet in a survey inquiring about subjective discomfort with dysphagia using a four-point scale (0, no difficulty; 1, mild difficulty; 2, moderate difficulty; 3, severe difficulty)[15].

Imaging examinations

Brain MRI and c-spine anterior-posterior/lateral X-ray findings were unremarkable.

FINAL DIAGNOSIS

Based on the patient’s medical history, neurological exam findings, physical examination, VFSS results, and depression and QoL assessments, psychogenic dysphagia was diagnosed in collaboration with psychiatrists.

TREATMENT

Over the past 2 years, the patient had undergone swallowing rehabilitation to treat dysphagia, including Shaker’s exercise and vital-stim therapy. Although selective serotonin reuptake inhibitor (SSRI) therapy was also attempted, symptoms did not improve owing to poor medication adherence. Additionally, conventional exercises and occupational rehabilitation therapy for dysphagia did not show significant improvement. Therefore, we decided to use a different treatment approach. After careful consideration and obtaining the patient’s consent, we decided to proceed with rTMS using the Food and Drug Administration-approved protocol for refractory depression (10 Hz frequency, 120% of the derived motor threshold, 3000 pulses per session over the left DLPFC)[16,17]. However, the patient could not make frequent hospital visits, so the treatment schedule had to be slightly modified. The modified treatment schedule was two sessions per week for a total of 20 antidepressant rTMS sessions over a 10-wk period. The treatment flowchart of this case is shown in Figure 1.

Figure 1 Treatment flowchart. ENT: Ear-nose-and-throat department; N/A: No abnormality; RM: Rehabilitation medicine department; DTx: Dysphagia therapy; SSRI: Selective serotonin reuptake inhibitor; rTMS: Repetitive transcranial magnetic stimulation; F/U: Follow-up; VFSS: Videofluoroscopic swallowing study.

OUTCOME AND FOLLOW-UP

Depression and QoL-related assessments performed upon the conclusion of the 10-wk (20-session) rTMS treatment regimen showed improvements compared to those before rTMS treatment (Table 1). Furthermore, VFSS and subjective discomfort from dysphagia survey scores obtained 1 mo after the conclusion of rTMS treatment also were improved (Figure 2). During follow-up, the improvements in dysphagia symptoms were still retained 1 mo after the conclusion of rTMS treatment, and the patient’s body weight increased to 43.9 kg (BMI, 18.3 kg/m²). We plan to continue to monitor whether the effects of rTMS are retained.

Figure 2 Changes of subjective dysphagia scale (4-point scale) after antidepressant repetitive transcranial magnetic stimulation therapy. The 4-point scale consists of patient subjective reports of dysphagia ranging from 0 (no difficulty) to 3 (severe difficulty). rTMS: Repetitive transcranial magnetic stimulation; NRD: Normal regular diet; SBD: Soft blended diet; SFD: Soft fluid diet; F/U: Follow-up.

Table 1 Survey results related to depression and quality of life after antidepressant repetitive transcranial magnetic stimulation therapy.

Survey item	Before rTMS	After rTMS	Improvement (%)
Depression
MADRS	30	18	40
HDI	16	9	44
BDI	40	25	38
QoL
EQ-5D	8	6	25
PHQ-9	7	5	29

QoL: Quality of life; rTMS: Repetitive transcranial magnetic stimulation; MADRS: Montgomery and Aasberg Depression Rating Scale; HDI: Hamilton Depression Inventory; BDI: Beck Depression Inventory; EQ-5D: EuroQoL five dimensions; PHQ-9: Patient Health Questionnaire.

DISCUSSION

Psychogenic dysphagia is also referred to as phagophobia, globus hystericus, hysterical dysphagia, and pseudodysphagia, and some view it as a symptom of conversion disorder[18-23]. Although the condition is referred by various names and the cause is often unclear, one common feature is swallowing difficulty in the oral phase[19-22], which is not explained neurologically by physical, laboratory, or imaging tests[23,24]. Symptoms can occur unintentionally and, in rare cases, can persist for a prolonged period[25].

A 35-year-old female had developed symptoms without any special cause 2 years ago and presented for rehabilitation medicine after an otolaryngologist and gastroenterologist could not find any specific abnormalities. Subsequently, the patient underwent conventional swallowing rehabilitation with SSRI therapy, but showed no improvement. In particular, the patient was unable to adhere to the prescribed SSRI pills because of difficulty in swallowing and eventually refused drug therapy. In addition to the pills, she complained of more severe dysphagia while consuming solid foods such as meat and rice, and her body weight decreased by 5.3 kg in 2 years. Compared with the severity of her symptoms, the patient presented with calm facial expressions. However, inconsistent with her appearance, she was found to be severely depressed, with substantial QoL impairment in the self-report depression and QoL questionnaires. These results indicated psychogenic dysphagia. Thus, we initiated rTMS with an antidepressant protocol to improve symptoms in this patient with depression who refused pharmacological treatment.

rTMS is widely used to treat migraines, depression, and motor dysfunctions[16,17,26,27]. Moreover, several reports have suggested that rTMS is effective for dysphagia, and most of these studies targeted the middle SMA, an area involved in motor function[8-10]. However, we determined that the Food and Drug Administration-approved rTMS protocol for major depressive disorder (MDD) would be more effective for psychogenic dysphagia without organic causes, as seen in our patient[16,17]. As no previous studies have reported the use of rTMS with the left DLPFC as the target, we explained this to the patient and obtained informed consent. However, the patient could not make frequent hospital visits owing to the distance of her residence from the hospital, and we revised the treatment regimen to two sessions per week for 10 wk; fortunately, the patient’s symptoms improved substantially. The subjective dysphagia scale (4-point scale) score obtained immediately after the conclusion of the 20-session rTMS improved for all diets. Furthermore, VFSS performed 1 mo after the conclusion of the rTMS regimen confirmed a smooth oral phase transition. Thus, we determined that the effects of the antidepressant rTMS regimen on psychogenic dysphagia were retained for at least 1 mo, which is consistent with the results of previous studies on the retention of the effects of rTMS treatment for MDD[28-31]. Another notable outcome was that the patient showed improvement in all aspects of the self-reported depression and QoL measurements, with a more remarkable improvement in depression. Despite the unclear mechanism underlying psychogenic dysphagia[5,6], these results suggest a link between psychogenic dysphagia and MDD. During follow-up, the improvements in dysphagia symptoms were retained 1 mo after the conclusion of rTMS treatment; further monitoring is required to ascertain whether the effects of rTMS are retained.

CONCLUSION

The antidepressant rTMS protocol may be an effective alternative treatment for patients with psychogenic dysphagia who do not respond to conventional treatments.