Current perspectives on the benefits, risks, and limitations of noninvasive brain stimulation (NIBS) for post-stroke dysphagia

ABSTRACT

Introduction

Studies have shown that noninvasive brain stimulation (NIBS), including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), can promote neuroplasticity, which is considered important for functional recovery of swallowing after stroke. Despite extensive studies on NIBS, there remains a gap between research and clinical practice.

Areas covered

In this article, we update the current knowledge on the benefits and challenges of rTMS and tDCS for post-stroke dysphagia. We identify some key limitations of these techniques that hinder the translation from clinical trials to routine practice. Finally, we discuss the future of NIBS as a treatment for post-stroke dysphagia in real-world settings.

Expert opinion

Current evidence suggests that rTMS and tDCS show promise as a treatment for post-stroke dysphagia. However, these techniques are limited by the response variability, uncertainty on the safety in patients with comorbidities and difficulties in clinical study designs. Such limitations call for further work to enhance their utility through individualized approaches. Despite this, the last decade has seen a growing acceptance toward these techniques among clinical personnel. As such, we advocate caution but support optimism that NIBS will gradually be recognized as a mainstream treatment approach for post-stroke dysphagia in the future.

KEYWORDS:

• Brain stimulation
• dysphagia
• neuroplasticity
• stroke
• swallowing
• treatment

Article highlights

• Current evidence supports the use of non-invasive brain stimulation (NIBS), including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), to improve swallowing after stroke.

• There is no consensus on the optimal NIBS protocol for post-stroke dysphagia.

• The clinical adoption of rTMS and tDCS is prevented by several limitations, including response variability, safety in patients with comorbidities, and difficulties in clinical study designs.

• Future NIBS treatments should be individualized based on patient’s needs and pathological characteristics to enhance treatment outcomes.

• Pre-clinical data have shown plausible promise in several new NIBS protocols, including cerebellar NIBS, transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). Further work is needed to fully elucidate the effects of these protocols.

Declaration of interest

S Hamdy is a board director and chief scientific officer of Phagenesis Ltd., a company that is involved in dysphagia treatment. S Hamdy was also awarded a Medical Research Council (MRC; United Kingdom) research grant (Award reference number: MR/P006183/1, Title of award: ‘An exploration of the application of non-invasive cerebellar stimulation in the neurorehabilitation of dysphagia after stroke’). The author(s) have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.