The safety of ipsilateral high-frequency repetitive transcranial magnetic stimulation in brain tumour patients

Background Motor deficits following resection of intrinsic brain tumours impair quality-of-life and survival. Repetitive transcranial magnetic stimulation (rTMS) has shown promise for motor rehabilitation. Only contralesional low-frequency stimulation (CL-LFS) has been tested in this setting. Ipsilesional high-frequency stimulation (IL-HFS), effective in stroke recovery, has not been explored in patients with brain tumours due to several safety concerns, namely: seizure risk, wound healing, and implant heating. Methods Four patients received IL-HFS and six received standard CL-LFS following resection of motor-eloquent tumours. Patients were eligible for IL-HFS if ipsilateral motor evoked potentials were preserved. Pre- and post-rTMS myotomal strength (MRC) and functional status (AMPAC 6-Click Daily Activity and Mobility) were compared using the Wilcoxon signed-rank test. Adverse events were recorded. Results All patients demonstrated significant improvements in MRC grade ( p < 0.05). Strength gains were greater in lower-limb myotomes. AMPAC scores improved in both groups. No seizures or heating effects occurred. One IL-HFS patient required wound revision of a third-time operated wound. The same patient had a 30-s syncopal episode during their final rTMS session with no features of seizures. Another patient reported transient (24-h) paraesthesia in the unaffected foot. Finally, another patient with two programmable ventriculoperitoneal shunts in situ did not demonstrate any shunt setting changes. Conclusion IL-HFS rTMS appears to be safe in the early post-operative period following tumour resection. These preliminary findings support further prospective trials evaluating IL-HFS —alone or combined with CL-LFS— to optimise motor recovery in patients with brain tumours.