Is Allodynia a Determinant Factor in the Effectiveness of Transcranial Direct Current Stimulation in the Prophylaxis of Migraine?

Update of Neuromodulation in Chronic Migraine

“…Two open-label small studies also reported reductions in headache frequency 30 days after anodal stimulation [26,28]. However, Cerrahoglu Sirin et al found no difference in monthly headache days 1 month after anodal or sham stimulation [29]. A larger study by Grazzi et al also reported no difference among anodal tDCS, cathodal tDCS, and sham at 6 and 12 months on CM patients getting acute withdrawal treatment from medication overuse [27].…”

“…In the past 5 years, there were four CM-focused tDCS randomized sham-controlled trials (two probably singleblind) and two open-label studies but of significantly dissimilar study design [24][25][26][27][28][29]. Andrade et al showed anodal but not sham stimulation of left primary motor (M1) or dorsolateral prefrontal cortex (DLPFC) reduced HIT-6 score and pain intensity [25].…”

Long-term prophylactic efficacy of transcranial direct current stimulation in chronic migraine. A randomised, patient-assessor blinded, sham-controlled trial

“…In the literature, we found 14 sham-controlled tDCS studies performed in migraine patients. Six studies were based on cathodal tDCS of the occipital cortex [70][71][72][73][74][75] and 5 studies were based on anodal tDCS of the left motor cortex or the motor cortex contralateral to the most frequent migraine side [8,37,39,76,77]. Other studies included the cathodal tDCS of the right sensorimotor cortex [40,78], the cathodal tDCS of a scalp region identified by thermographic examination [38], or the stimulation of the dorsolateral prefrontal cortex [37,74].…”

“…Finally, typical CM was only addressed in 5 studies. In two of these studies, patients with CM were mixed with patients with episodic migraine without any distinction in the results provided [39,40]. Therefore, only 3 studies were specifically conducted in patients with typical CM.…”

“…Notably, only a few controlled studies have investigated the use of tDCS in patients with CM [8,37,38], while patients with CM and episodic migraine were mixed in other studies [39,40]. Also, the primary objective of our randomized sham-controlled study was to assess the longterm prophylactic effect of a-tDCS delivered to the left motor cortex on the frequency of migraine attacks in a homogeneous population of patients with long-lasting resistant CM.…”