Low-frequency rTMS of the unaffected hemisphere in stroke patients: A systematic review

Abstract

The aim of this review was to summarize the evidence for the effectiveness of low-frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the unaffected hemisphere in promoting functional recovery after stroke. We performed a systematic search of the studies using LF-rTMS over the contralesional hemisphere in stroke patients and reviewed the 67 identified articles. The studies have been gathered together according to the time interval that had elapsed between the stroke onset and the beginning of the rTMS treatment. Inhibitory rTMS of the contralesional hemisphere can induce beneficial effects on stroke patients with motor impairment, spasticity, aphasia, hemispatial neglect and dysphagia, but the therapeutic clinical significance is unclear. We observed considerable heterogeneity across studies in the stimulation protocols. The use of different patient populations, regardless of lesion site and stroke aetiology, different stimulation parameters and outcome measures means that the studies are not readily comparable, and estimating real effectiveness or reproducibility is very difficult. It seems that careful experimental design is needed and it should consider patient selection aspects, rTMS parameters and clinical assessment tools. Consecutive sessions of rTMS, as well as the combination with conventional rehabilitation therapy, may increase the magnitude and duration of the beneficial effects. In an increasing number of studies, the patients have been enrolled early after stroke. The prolonged follow-up in these patients suggests that the effects of contralesional LF-rTMS can be long-lasting. However, physiological evidence indicating increased synaptic plasticity, and thus, a more favourable outcome, in the early enrolled patients, is still lacking. Carefully designed clinical trials designed are required to address this question. LF rTMS over unaffected hemisphere may have therapeutic utility, but the evidence is still preliminary and the findings need to be confirmed in further randomized controlled trials.

Transcranial magnetic stimulation in stroke rehabilitation

“…In a systematic review, Sebastianelli et al found that low-frequency rTMS over unaffected hemisphere may have therapeutic utility after stroke (29). Recently McIntyre et al evaluated the effectiveness of rTMS in improving spasticity after stroke (30). Using Modified Ashworth Scale as main outcome 10 studies met the inclusion criteria: two randomized control trials and eight uncontrolled pre-post studies.…”

“…In the uncontrolled pre-post studies they found significant improvements in Modified Ashworth Scale for elbow, wrist, and finger flexors. However the two available RCTs failed to find a significant rTMS treatment effect on Modified Ashworth Scale for the wrist (30). Zhang et al evaluated the short-and long-term effects of rTMS on upper limb recovery after stroke and they show that 5-session rTMS and intermittent theta burst stimulation in the acute phase of stroke significantly improved short-term and long-term manual dexterity (31).…”

Facilitation of Auditory Comprehension After Theta Burst Stimulation of Wernicke's Area in Stroke Patients: A Pilot Study

“…Several studies indicated that inhibitory rTMS over the contralesional inferior frontal gyrus improves recovery from poststroke non-fluent aphasia by reducing right hemisphere hyperactivity and transcallosal inhibition on left Broca's area [for a review: (12,13)]. With small left hemisphere lesions, perilesional regions are recruited to subserve the recovery of language function.…”

Effects of Hand Training During the Aftereffect Period of Low-Frequency rTMS in Subacute Stroke Patients

“…Recent reports suggest that post-stroke low-frequency rTMS over the motor cortex of the unaffected hemisphere helps patients recover their affected hand motor functions [ 9 - 11 ]. In a recently published guideline, stimulating the unaffected motor cortex with low-frequency rTMS in the acute to chronic phase of stroke was methodologically sufficient to reach a Level B or ‘probable efficacy’ recommendation [ 12 ].…”