H-coil repetitive transcranial magnetic stimulation for pain relief in patients with diabetic neuropathy

Background:

Painful neuropathy is associated with plasticity changes inthe nervous system. Standard repetitive transcranial magnetic stimulation(rTMS) is a non-invasive technique used to study changes in corticalexcitability and to inhibit pain perception. Deep rTMS is a newerdevelopment that allows direct activation of deeper neuronal populations,by a unique coil design termed the H-coil.

Objective:

This study was designed to assesswhether deep rTMS applied over the motor cortical lower-limb representation relieves pain in patients with diabetic neuropathy.

Methods:

Patients were randomly assigned to receive daily real or shamH-coil rTMS for 5 consecutive days. After a 5-week washout period, theycrossed over to the alternative treatment for additional 5 days (accordingto a crossover study design). Outcome measures were changes in the visualanalogue scale (VAS) for pain and in area and threshold of RIII nociceptiveflexion reflex (RIII reflex).

Results:

Of the 25 patients randomized, 23 completed the study. After real rTMS, the VAS scores decreased significantly (p=0.01), and so did RIII reflex area (p<0.01), while no significant effects in these variables were induced by thesham rTMS treatment. The rTMS-induced changes in the outcome measures disappeared about 3 weeks after stimulation. Allpatients tolerated stimulation well.

Conclusions:

Deep H-coil rTMS provides pain relief in patients with diabetic neuropathy. This innovative technique can induce a therapeutic effect on brain areas that otherwise remain difficult to target. rTMS may produce its analgesic effects, inducing motor cortex plasticity and activating descending inhibitory pain control systems.

Related Resources: