Scoping review maps combined TES and TMS neurophysiology work

A scoping review published online in Clinical Neurophysiology on 14 October 2026 takes stock of one of the field's more methodologically demanding pairings: transcranial electrical stimulation delivered concurrently with transcranial magnetic stimulation. The authors — Jemima Shickle, Alexander Axford, Sue Fen Tan, Domenica Veniero, Lucy Webster, Richard Morriss and Paul M Briley — set out to map what the combined-stimulation literature has actually established, in both neurophysiological and clinical studies, rather than to argue for a single mechanism.

The pairing itself is not new. Researchers have used transcranial electrical stimulation, most often transcranial direct current stimulation, to prime cortex before or during TMS pulses, reading the effect out through motor-evoked potentials measured with EMG. The logic is straightforward: TMS supplies the probe, the electrical current supplies the modulation, and the EMG response reports the net change in cortical excitability. What has been missing, and what a scoping review is built to supply, is an organised picture of how many studies, with which parameters, in which populations.

What does a scoping review actually do?

A scoping review does not pool effect sizes. It charts territory. It asks which questions have been asked, with what methods, in which cohorts, and where the gaps sit. For a technique that has spread across both healthy-volunteer neurophysiology and clinical investigation, that cartography matters. Readers in monitoring units and stimulation labs will recognise the problem: results scattered across journals, montage and current-density details reported unevenly, and clinical claims resting on thin samples.

The review's authors span the relevant disciplines. Veniero and Briley bring the neurophysiology of stimulation; Morriss and Webster bring the clinical psychiatry side; Shickle, Axford and Tan bridge the two. That composition suggests the review treats the clinical literature as more than an appendix to the mechanistic work.

What does this change for practice?

The honest answer, before the full text circulates: it consolidates. For labs already pairing TES with TMS, a scoping map offers a reference against which to check parameter choices and outcome measures — whether motor-evoked potential amplitude, latency, or intracortical inhibition and facilitation curves. For clinicians weighing whether combined stimulation carries evidence sufficient for therapeutic use, the review should make the state of that evidence explicit. Distinguishing what the technique has demonstrated in controlled neurophysiology from what it has shown in patient cohorts is precisely the separation a scoping review exists to draw.

One caution belongs here. This is a review of published human studies, not a trial and not a device evaluation. Nothing in it confers regulatory status on any apparatus. TMS platforms and transcranial electrical stimulators carry their own clearances; combining them in a protocol is an investigator's decision, governed by the protocol's own approvals.

Why the pairing interests the field

Concurrent stimulation gives researchers a causal lever that passive recording cannot. Where scalp EEG or EMG readouts describe state, the TES-TMS combination lets an experimenter shift the state and measure the shift in the same session. The cost is methodological: current spread, reference electrode placement, blinding of TMS operators, and interaction between the electrical field and the TMS pulse all complicate interpretation. A review that catalogues how individual studies handled these problems gives future protocols a firmer floor.

The clinical stakes sit mostly in psychiatry and rehabilitation, where both stimulation families already have independent literatures and where the Nottingham-based author group has prior work. Whether combination outperforms either technique alone is the question the field wants answered; whether the existing evidence can yet support that comparison is the question this review was positioned to assess.

The verdict

Scoping reviews rarely close debates. They define them. If the map shows dense motor-cortex physiology and sparse patient data, as the territory often does, that asymmetry becomes the review's practical finding — and the agenda for the next round of studies.