Trend: Rethinking (and treating) chronic pain as a brain disease

Can stim­u­lat­ing the brain treat chron­ic pain? (Sci­ence Daily):

“We’ve pub­lished numer­ous brain stim­u­la­tion papers over sev­er­al years, and we always learn some­thing impor­tant,” said senior author Flavio Frohlich, PhD, direc­tor of the Car­oli­na Cen­ter for Neu­rostim­u­la­tion and asso­ciate pro­fes­sor of psy­chi­a­try. “But this is the first time we’ve stud­ied chron­ic pain, and this is the only time all three ele­ments of a study lined up per­fect­ly. We suc­cess­ful­ly tar­get­ed a spe­cif­ic brain region, we enhanced or restored that region’s activ­i­ty, and we cor­re­lat­ed that enhance­ment with a sig­nif­i­cant decrease in symp­toms” …

Chron­ic pain is the lead­ing cause of dis­abil­i­ty in the world, but there is not con­sen­sus among sci­en­tists that brain activ­i­ty plays a causal role in the con­di­tion. Frohlich says the pain research field has focused large­ly on periph­er­al caus­es of chron­ic pain. For exam­ple, if you have chron­ic low­er back pain, then the cause and solu­tion lie in the low­er back and relat­ed parts of the ner­vous sys­tem in the spine. But some researchers and clin­i­cians believe chron­ic pain runs deep­er, that the con­di­tion can reor­ga­nize how cells in the ner­vous sys­tem com­mu­ni­cate with each oth­er, includ­ing net­works of neu­rons in the brain. Over time, the the­o­ry goes, these net­works get stuck in a kind of neur­al rut, essen­tial­ly becom­ing a cause of chron­ic pain.”

The Study:

Iden­ti­fy­ing and Engag­ing Neu­ronal Oscil­la­tions by Tran­scra­nial Alter­nat­ing Cur­rent Stim­u­la­tion in Patients With Chron­ic Low Back Pain: A Ran­dom­ized, Crossover, Dou­ble-Blind, Sham-Con­trolled Pilot Study

Abstract: Chron­ic pain is asso­ci­at­ed with mal­adap­tive reor­ga­ni­za­tion of the cen­tral ner­vous sys­tem. Recent stud­ies have sug­gest­ed that dis­or­ga­ni­za­tion of large-scale elec­tri­cal brain activ­i­ty pat­terns, such as neu­ronal net­work oscil­la­tions in the thal­a­m­o­cor­ti­cal sys­tem, plays a key role in the patho­phys­i­ol­o­gy of chron­ic pain. Yet, lit­tle is known about whether and how such net­work patholo­gies can be tar­get­ed with non­in­va­sive brain stim­u­la­tion as a non­phar­ma­co­log­i­cal treat­ment option. We hypoth­e­sized that alpha oscil­la­tions, a promi­nent thal­a­m­o­cor­ti­cal activ­i­ty pat­tern in the human brain, are impaired in chron­ic pain and can be mod­u­lat­ed with tran­scra­nial alter­nat­ing cur­rent stim­u­la­tion (tACS). We per­formed a ran­dom­ized, crossover, dou­ble-blind, sham-con­trolled study in patients with chron­ic low back pain (CLBP) to inves­ti­gate how alpha oscil­la­tions relate to pain symp­toms for tar­get iden­ti­fi­ca­tion and whether tACS can engage this tar­get and there­by induce pain relief. We used high-den­si­ty elec­troen­cephalog­ra­phy to mea­sure alpha oscil­la­tions and found that the oscil­la­tion strength in the somatosen­so­ry region at base­line before stim­u­la­tion was neg­a­tive­ly cor­re­lat­ed with pain symp­toms. Stim­u­la­tion with alpha-tACS com­pared to sham (place­bo) stim­u­la­tion sig­nif­i­cant­ly enhanced alpha oscil­la­tions in the somatosen­so­ry region. The stim­u­la­tion-induced increase of alpha oscil­la­tions in the somatosen­so­ry region was cor­re­lat­ed with pain relief. Giv­en these find­ings of suc­cess­ful tar­get iden­ti­fi­ca­tion and engage­ment, we pro­pose that mod­u­lat­ing alpha oscil­la­tions with tACS may rep­re­sent a tar­get-spe­cif­ic, non­phar­ma­co­log­i­cal treat­ment approach for CLBP. 

The Study in Context:

Focused ultra­sound as emerg­ing method of non-inva­sive neu­rotech­nol­o­gy
Good sur­vey of brain stim­u­la­tion meth­ods, val­ue and limitations