Post-Stroke Dysphagia: Is Transcranial Magnetic Stimulation an Effective Therapy?

Both repeated transcranial magnetic stimulation (rTMS) and transcutaneous neuromuscular electrical stimulation (TNES) reduced symptoms of dysphagia following acute ischemic stroke. However, rTMS was the most effective treatment. These are the findings of a study published in the Journal of Stroke and Cerebrovascular Diseases.

Among patients with stroke, 37%-78% will experience poststroke dysphagia. This can lead to aspiration and increase the risk for stroke-associated pneumonia (SAP). In an effort to reduce the SAP risk, acute stroke treatments are centered on evaluating dysphagia. Prior studies suggest rTMS and TNES could help treat swallowing difficulties, yet, there have been no direct comparisons between these 2 techniques.

The objective of the current study was to evaluate the effectiveness of rTMS compared with TNES in the treatment of poststroke dysphagia.

Researchers conducted a randomized, parallel, comparative, controlled trial from August 2019 to August 2020, screening 143 patients treated for acute ischemic stroke at the Department of Neurology at Al-Zahraa University Hospital at Al-Azhar University in Egypt.

The researchers randomly assigned the 45 patients who met their study’s inclusion criteria into 3 groups of 15 patients each — the rTMS group, the TNES group, and the control group.

All 45 patients had dysphagia as diagnosed per the swallowing disturbance questionnaire (SDQ) and validated with a bedside evaluation followed by a fiberoptic endoscopic evaluation of swallowing (FEES). The researchers obtained scores on the Yale pharyngeal residue severity rating scale (YPRSRS) and penetration aspiration scale (PAS) based on the results of the FEES.

Patients in the rTMS group received daily treatment for 10 minutes over 5 consecutive days to the unaffected side of the cortical motor area for the pharyngeal musculature, consisting of 10 trains of 5-Hertz stimulations for a duration of 10 seconds with repetitions each minute. Patients in the TNES group received daily treatment for 30 minutes over 5 consecutive days to the submental muscles, consisting of a fixed pulse rate of 80 Hertz and pulse duration of 700 µsec.

Following 5 days of intervention, both the rTMS and TNES groups demonstrated reduced SDQ scores compared with the control group (P <.001). Additionally, rTMS improved dysphagia symptoms more effectively than TNES (P <.05) and maintained these improvements as evidenced by better SDQ scores after 1 month following the treatment (P =.004).

After 1 month, both rTMS and TNES decreased PAS scores compared with the control group (P =.027); however, patients in the rTMS group demonstrated significantly lower PAS scores compared with the TNES group (P <.05).

While both TNES and rTMS interventions effectively reduced the YPRSRS scores compared with the control group (P =.009), patients in the rTMS group exhibited lower scores of grades 1 (80%) and 2 (20%) after intervention, whereas patients in the TNES group scored higher grades 1 (46.7%), 2 (26.7%), 2 (13.3%), and 4 (13.3%) after treatment.

Study limitations included a small sample size and the single-center setting which impacted generalizability as well as the short follow-up duration.

“The study findings showed that high-frequency rTMS and TNES effectively improved the clinical condition of acute poststroke dysphagic patients in terms of swallowing disturbance assessed by SDQ, pharyngeal residue assessed by YPRSRS, and the severity of penetration and aspiration event evaluated by PAS, compared to the controls,” the researchers stated. “The outcomes of high-frequency rTMS were more favorable than those of TNES in terms of SDQ and PAS.”

Reference

Hammad AB, Elhamrawy EA, Abdel-Tawab H, et al. Transcranial magnetic stimulation versus transcutaneous neuromuscular electrical stimulation in post stroke dysphagia: A clinical randomized controlled trial. J Stroke Cerebrovasc Dis. Published online June 9, 2022. doi:10.1016/j.jstrokecerebrovasdis.2022.106554