The test-retest reliability of non-navigated transcranial magnetic stimulation (TMS) measures of corticospinal pathway excitability early after stroke

Kathryn C Collins; Allan B Clark; Valerie M Pomeroy; Niamh C Kennedy

doi:10.1080/09638288.2024.2337107

The test-retest reliability of non-navigated transcranial magnetic stimulation (TMS) measures of corticospinal pathway excitability early after stroke

Disabil Rehabil. 2024 Apr 18:1-8. doi: 10.1080/09638288.2024.2337107. Online ahead of print.

Authors

Kathryn C Collins¹, Allan B Clark², Valerie M Pomeroy^{3

4}, Niamh C Kennedy⁵

Affiliations

¹ Faculty of Health and Social Sciences, Bournemouth University, Bournemouth, UK.
² Norwich Medical School, University of East Anglia, Norwich, UK.
³ Acquired Brain Injury Rehabilitation Alliance, School of Health Sciences, University of East Anglia, Norwich, UK.
⁴ National Institute of Health Research Brain Injury MedTech Cooperative, Cambridge, UK.
⁵ School of Psychology, Ulster University, Coleraine, UK.

PMID: 38634228
DOI: 10.1080/09638288.2024.2337107

Abstract

Purpose: Motor evoked potential (MEP) characteristics are potential biomarkers of whether rehabilitation interventions drive motor recovery after stroke. The test-retest reliability of Transcranial Magnetic Stimulation (TMS) measurements in sub-acute stroke remains unclear. This study aims to determine the test-retest reliability of upper limb MEP measures elicited by non-neuronavigated transcranial magnetic stimulation in sub-acute-stroke.

Methods: In two identical data collection sessions, 1-3 days apart, TMS measures assessed: motor threshold (MT), amplitude, latency (MEP-L), silent period (SP), recruitment curve slope in the biceps brachii (BB), extensor carpi radialis (ECR), and abductor pollicis brevis (APB) muscles of paretic and non-paretic upper limbs. Test-retest reliability was calculated using the intra-class correlation coefficient (ICC) and 95% confidence intervals (CI). Acceptable reliability was set at a lower 95% CI of 0.70 or above. The limits of agreement (LOA) and smallest detectable change (SDC) were calculated.

Results: 30 participants with sub-acute stroke were included (av 36 days post stroke) reliability was variable between poor to good for the different MEP characteristics. The SDC values differed across muscles and MEP characteristics in both paretic and less paretic limbs.

Conclusions: The present findings indicate there is limited evidence for acceptable test-retest reliability of non-navigated TMS outcomes when using the appropriate 95% CI for ICC, SDC and LOA values.

Clinical trial registration: Current Controlled Trials: ISCRT 19090862, http://www.controlled-trials.com.

Keywords: Test-retest reliability; smallest detectable change; stroke; transcranial magnetic stimulation (TMS); upper limb.

Plain language summary

This study identified that Non-navigated Transcranial Magnetic Stimulation (TMS) demonstrates low reliability of TMS measures in upper limb with variation between muscles and measures in sub-acute strokeWhen using non-navigated TMS to explore corticospinal pathway excitability the individual target muscle and TMS measure should be taken into considerationNon-navigated TMS may be more useful in exploring group differences rather than individual differences in corticospinal pathway excitabilityNon-navigated TMS could provide a means of measuring recovery in clinical practice and could inform the development of more effective interventions but this needs further development before it can be used as a clinical recovery biomarker.