Exploring Theta Burst Stimulation as an intervention to improve motor recovery in chronic stroke

Abstract

Objective: To explore the effects of a single session of repetitive Transcranial Magnetic Stimulation, given as Theta Burst Stimulation, on behavioural and physiological measures of hand function in chronic stroke patients.

Methods: Six chronic stroke patients with incomplete recovery of the hand were tested under three conditions: excitatory TBS over the stroke hemisphere (iTBS(SH)), inhibitory TBS (cTBS(IH)) over the intact hemisphere and sham stimulation. Behavioural outcomes included simple and choice reaction time paradigms. Physiological effects were assessed using single pulse TMS on both sides. Changes were sought for up to 40min after TBS.

Results: Immediately after iTBS(SH) simple reaction times in the paretic hands were decreased and, compared to sham stimulation, remained significantly shorter throughout the testing period. The amplitude of the MEPs at rest and during background contraction and the area under the Input-Output curves were also increased on the stroke side after iTBS(SH). cTBS(IH) suppressed the MEPs evoked in the healthy hands but did not change motor behaviour or the electrophysiology of the paretic hands. No side effects were encountered.

Conclusions: TBS seems safe in chronic stroke patients. iTBS over the stroke hemisphere transiently improved motor behaviour and corticospinal output in the paretic hands.

Significance: Excitatory TBS may represent a useful rTMS protocol to apply to the stroke hemisphere in future longer term therapy trials.