Intermittent Theta-Burst Stimulation Over the Suprahyoid Muscles Motor Cortex Facilitates Increased Degree Centrality in Healthy Subjects

A systematic review of the neurobiological effects of theta-burst stimulation (TBS) as measured using functional magnetic resonance imaging (fMRI)

Theta burst stimulation (TBS) is associated with the modulation of a range of clinical, cognitive, and behavioural outcomes, but specific neurobiological effects remain somewhat unclear. This systematic literature review investigated resting-state and task-based functional magnetic resonance imaging (fMRI) outcomes post-TBS in healthy human adults. Fifty studies that applied either continuous-or intermittent-(c/i) TBS, and adopted a pretest-posttest or sham-controlled design, were included. For resting-state outcomes following stimulation applied to motor, temporal, parietal, occipital, or cerebellar regions, functional connectivity generally decreased in response to cTBS and increased in response to iTBS, though there were some exceptions to this pattern of response. These findings are mostly consistent with the assumed long-term depression (LTD)/long-term potentiation (LTP)-like plasticity effects of cTBS and iTBS, respectively. Task-related outcomes following TBS were more variable. TBS applied to the prefrontal cortex, irrespective of task or state, also produced more variable responses, with no consistent patterns emerging. Individual participant and methodological factors are likely to contribute to the variability in responses to TBS. Future studies assessing the effects of TBS via fMRI must account for factors known to affect the TBS outcomes, both at the level of individual participants and of research methodology.

Bilateral Cerebellar Intermittent Theta Burst Stimulation Combined With Swallowing Speech Therapy for Dysphagia After Stroke: A Randomized, Double-Blind, Sham-Controlled, Clinical Trial

BACKGROUND

Previous studies have found that high-frequency repetitive transcranial magnetic stimulation (rTMS) of the cerebellar hemisphere could improve swallowing function, but whether intermittent theta burst stimulation (iTBS), which has similar excitatory effect and higher efficiency, can also improve swallowing function for dysphagia after stroke remains unclear.

OBJECTIVE

This trial aimed to explore the efficacy and safety of bilateral cerebellar transcranial magnetic stimulation with iTBS for dysphagia after stroke.

METHODS

Seventy patients with dysphagia after stroke were divided into 2 treatment groups: true bilateral cerebellar iTBS and sham bilateral cerebellar iTBS. The true iTBS group underwent ten 100% resting motor threshold (RMT) iTBS sessions for 2 weeks. In the sham iTBS group, the parameters were the same except that the figure-eight coil was perpendicular to the skull. Both groups received traditional swallowing rehabilitation treatment 5 times a week for 2 weeks. Swallowing function was assessed with the Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS), Penetration/Aspiration Scale (PAS), Standardized Swallowing Assessment (SSA), and Functional Oral Intake Scale (FOIS) at baseline, 2 weeks after the intervention, and at 4 weeks of follow-up.

RESULTS

There were significant time and group interaction effects in both multi-factorial adjusted and unadjusted FEDSS, PAS, SSA, and FOIS score (P < .001). In the pairwise comparison of the swallowing parameters among the 2 groups, the FEDSS, PAS, SSA, and FOIS scores at 2 weeks and 4 weeks showed a significantly higher improvement in the iTBS simulation group than sham group (P < .05). In both the true iTBS and sham iTBS stimulation groups, all FEDSS, PAS, SSA, and FOIS scores were significantly improved over time (P < .001).

CONCLUSIONS

The present study suggested that as a more efficient TMS stimulation mode, iTBS could efficiently improve swallowing function by stimulating the bilateral cerebellar hemisphere. In addition, 100% resting motor threshold bilateral cerebellar iTBS is a relatively safe treatment.

CLINICAL TRIAL REGISTRATION

Effect analysis of repeated transcranial magnetic stimulation of cerebellar on dysphagia after stroke. www.chictr.org.cn. Identifier: ChiCTR2100042092.

Theta burst stimulation versus high-frequency repetitive transcranial magnetic stimulation for poststroke dysphagia: A randomized, double-blind, controlled trial

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) of high-frequency (10 Hz) on suprahyoid motor cortex has been an evidence-based treatment for poststroke dysphagia. Intermittent theta burst stimulation (iTBS) can be performed in 3 minutes compared with 20 ± 5 minutes for 10 Hz rTMS. This study aimed to ensure the clinical efficacy, safety, and tolerability of iTBS compared with 10 Hz rTMS for patients with poststroke dysphagia.

METHOD

In this randomized, double-blind, single-center, controlled trial, 47 participants were randomly assigned to iTBS (n = 24) and rTMS (n = 23) group. Each participant received iTBS or rTMS daily at suprahyoid motor cortex of affected hemisphere for 10 consecutive days. The outcomes were assessed at baseline, immediately, and 2 weeks after intervention, including water-swallowing test, standardized swallowing assessment, Mann assessment of swallowing ability, Murray Secretion Scale, Yale Pharyngeal Residue Severity Rating Scale, Penetration-Aspiration Scale, and motor evoked potential (MEP) of bilateral suprahyoid muscle.

RESULTS

There were no significant differences between groups. There was a significant improvement on all rating scales and MEP after rTMS and iTBS. No significant differences on water-swallowing test, Mann assessment of swallowing ability, standardized swallowing assessment, Murray Secretion Scale scores, and MEP were observed between groups. In particular, there was significant differences on Penetration-Aspiration Scale scores (viscous liquid: mean difference = 1.016; 95% CI: 0.32-1.71; effect size: 0.360; P = .005) and the residue rate of pyriform fossa (viscous liquid: mean difference = 0.732; 95% CI: 0.18-1.28; effect size: 0.248; P = .010) in between-group. Comparing the differences over the changes of all rating scales, only the residue rate of epiglottis valley between groups was found to be significantly different (dilute liquid: mean difference = -0.567; 95% CI: -0.98 to -0.15; P = .009). There was no severe adverse effect and high dropout rates in both groups.

CONCLUSION

The clinical efficacy, safety, and tolerability of iTBS showed non-inferior to 10 Hz rTMS for patients with poststroke dysphagia. The present study can be used to improve the clinicians' knowledge and clinical decision skills on iTBS and rTMS for poststroke dysphagia.