Clinical study of repetitive transcranial magnetic stimulation of the motor cortex for thalamic pain

Thalamic pain is a severe pain that is often unresponsive to medical therapy. Repetitive transcranial magnetic stimulation (rTMS) entirely non-invasively modulates neuronal plasticity to produce therapeutic benefit. Since the rTMS stimulation parameters varied, it is difficult to determine which specific parameters are best for clinical use. The aim of this study was to evaluate the analgesic lasting effect of 10-Hz rTMS over the motor cortex (M1) for 10 consecutive days to treat thalamic pain. Patients were treated with daily 10-Hz rTMS sessions for 1000 pulses applied over the M1 for 10 consecutive days. Pain severity and mood were assessed at baseline, immediately after, 2 weeks, 4 weeks, 6 weeks, 8 weeks after rTMS. Pain severity was measured by the visual analogue scale (VAS) and the percentage of pain relief on VAS score was calculated between baseline and final examination. Mood was monitored using the Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale (HAMD). Seven patients with thalamic pain were enrolled. VAS score was significantly decreased after rTMS. Mean VAS scores were 7 at baseline and decreased to 5.6 at 2 weeks after rTMS and then decreased to 3.9 at 8 weeks after rTMS. The analgesic effect of rTMS can last up to 8 weeks. The percentage of pain relief ranges from 25.0% to 66.7% at the 8th week. Four patients (3 moderate pain and 1 severe pain) achieved satisfactory relief (pain relief >= 40-69%). Although this was an open-label study without a control group, our findings show that 10 Hz rTMS over the M1 for 10 consecutive days can produce satisfactory or partial antalgic effect on patients with thalamic pain.