Neurostimulation in People with Oropharyngeal Dysphagia: A Systematic Review and Meta-Analysis of Randomised Controlled Trials—Part II: Brain Neurostimulation

Abstract

Objective. To assess the effects of brain neurostimulation (i.e., repetitive transcranial magnetic stimulation [rTMS] and transcranial direct current stimulation [tDCS]) in people with oropharyngeal dysphagia (OD). Methods. Systematic literature searches were conducted in four electronic databases (CINAHL, Embase, PsycINFO, and PubMed) to retrieve randomised controlled trials (RCTs) only. Using the Revised Cochrane risk-of-bias tool for randomised trials (RoB 2), the methodological quality of included studies was evaluated, after which meta-analysis was conducted using a random-effects model. Results. In total, 24 studies reporting on brain neurostimulation were included: 11 studies on rTMS, 9 studies on tDCS, and 4 studies on combined neurostimulation interventions. Overall, within-group meta-analysis and between-group analysis for rTMS identified significant large and small effects in favour of stimulation, respectively. For tDCS, overall within-group analysis and between-group analysis identified significant large and moderate effects in favour of stimulation, respectively. Conclusion. Both rTMS and tDCS show promising effects in people with oropharyngeal dysphagia. However, comparisons between studies were challenging due to high heterogeneity in stimulation protocols and experimental parameters, potential moderators, and inconsistent methodological reporting. Generalisations of meta-analyses need to be interpreted with care. Future research should include large RCTs using standard protocols and reporting guidelines as achieved by international consensus.

Assessment and treatment of neurogenic dysphagia in stroke and Parkinson's disease

“…Although there is no clear evidence of superiority of one NIBS technique over the other, the effects of rTMS seem to be greater than those of tDCS [101,100 ▪▪ ]. Anyway, among the strengths of tDCS, there are greater accessibility to treatment and possibility of home therapy, thanks to portable devices.…”

Advances in the Treatment of Dysphagia in Neurological Disorders: A Review of Current Evidence and Future Considerations

“… 92 , 93 In dysphagic patients, particularly stroke patients, a large number of RCTs on the effects of these NIBS techniques on swallowing have been published in the last decade. 78 , 94 Overall, although there is substantial variability in stimulation parameters and no consensus has been reached as regards the optimal stimulation protocol, NIBS techniques have shown preliminary treatment benefits for patients with post-stroke dysphagia. Importantly, Cheng et al analysed the effects of neuromodulation treatments based on the timing of follow-ups.…”

Evaluating the Therapeutic Application of Neuromodulation in the Human Swallowing System

“…Over the last two decades, a number of randomized controlled trials (RCTs) have been conducted to explore the therapeutic value of rTMS for the treatment of dysphagia (Table 1). Recent systematic reviews and meta-analyses suggested that rTMS may have potential benefits for neurogenic dysphagia [35,36]. However, the stimulation protocol, in particular the stimulation hemisphere and frequency, remains the centre of debate for rTMS treatments.…”