Efficacy of Repetitive Transcranial Magnetic Stimulation for Acute Central Post-stroke Pain: A Case Study

Abstract

Although rare, central post-stroke pain remains one of the most refractory forms of neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) has been reported to be effective in chronic cases. However, there are no data on the effects in the acute and subacute phases after stroke. In this study, we present a case of a patient with thalamic stroke with acute onset of pain and paresthesia who was responsive to rTMS. After a right thalamic stroke, a 32-year-old woman presented with drug-resistant pain and paresthesia on the left side of the body. There were no motor or sensory deficits, except for blunted thermal sensation and allodynia on light touch. Ten daily sessions were performed, where 10 Hz rTMS was applied to the hand area of the right primary motor cortex, 40 days after stroke. Before rTMS treatment (T0), immediately after treatment conclusion (T1), and 1 month after treatment (T2), three pain questionnaires were administered, and cortical responses to single and paired-pulse TMS were assessed. Eight healthy participants served as controls. At T0, when the patient was experiencing the worst pain, the excitability of the ipsilesional motor cortex was reduced. At T1 and T2, the pain scores and paresthesia' spread decreased. The clinical improvement was paralleled by the recovery in motor cortex excitability of the affected hemisphere, in terms of both intra- and inter-hemispheric connections. In this subacute central post-stroke pain case, rTMS treatment was associated with decreased pain and motor cortex excitability changes.

Current evidence, clinical applications, and future directions of transcranial magnetic stimulation as a treatment for ischemic stroke

“…In addition, most studies suggest that the possible cause of CPSP is central de-inhibition or central imbalance due to ischemia ( Ri, 2022 ), then restoration of abnormal cortical excitability by TMS may be one of the potential mechanisms for the relief of recalcitrant CPSP. As found in the study, 10 Hz HF-rTMS had significant analgesic effects in CPSP patients in all periods, and M1 HF-rTMS had better analgesic effects than M1 LF-rTMS ( Leung et al, 2020 ; Malfitano et al, 2021 ). This suggests that in patients with CPSP, increasing cortical excitability in the lesioned hemisphere is far more effective than inhibiting cortical excitability in the unlesioned hemisphere, after all, the imbalance in the regulation of downstream somatosensory pathways due to reduced cortical excitability in the lesioned hemisphere is the most direct cause of CPSP.…”

“…Currently, CPSP is mainly treated with pharmacological agents, such as anticonvulsants, which have good effects on improving the symptoms of CPSP ( Bo et al, 2022 ), but when it comes to intractable CPSP, the drugs may only play the role of placebo and do not provide a good solution to the patient’s CPSP troubles. A recent study found that rTMS in the cerebral motor cortex had a significant effect on relieving recalcitrant CPSP ( Malfitano et al, 2021 ), but the duration varied, which may be related to the site of ischemia, the period of disease progression, the site of stimulation, and individual patient differences. Therefore, there is a need to explore the therapeutic parameters related to the improvement of CPSP by TMS.…”

The mechanism and effect of repetitive transcranial magnetic stimulation for post-stroke pain

“…In a case study, 10 Hz rTMS was applied to the M1 site of a subacute CPSP patient for 2,000 pulses each time, with an intensity of 90% of RMT, for a total of 10 sessions, and the pain levels were measured before, after stimulation, and 1 month after stimulation. The results showed that the level of post-stimulation was significantly lower than the baseline level, suggesting that rTMS had the same analgesic effect on acute CPSP (Malfitano et al, 2021).…”

Repetitive transcranial magnetic stimulation in central post-stroke pain: current status and future perspective

“…Short-term analgesia was produced by targeted stimulation of S2 and M1, but the results were no different than those in the placebo group, demonstrating a potent placebo effect [ 100 ]. Table 4 contains additional in-depth research concerning the influence of rTMS on CPSP [ 101 – 103 ].…”