▁form ▁of ▁ne uro st im ulation ▁which ▁uses ▁constant , ▁low ▁current ▁delivered ▁via ▁electro des ▁placed ▁on ▁the ▁scal p . ▁The ▁mechan isms ▁underlying ▁t D CS ▁effects ▁are ▁still ▁in comple t ely ▁understood , ▁but ▁recent ▁adv ances ▁in ▁ne uro techn ology ▁allowing ▁for ▁in ▁v ivo ▁assess ment ▁of ▁brain ▁electric ▁activity ▁during ▁t D CS ▁promise ▁to ▁advance ▁understanding ▁of ▁these ▁mechan isms . ▁Research ▁into ▁using ▁t D CS ▁on ▁health y ▁adult s ▁have ▁demonstrated ▁that ▁t D CS ▁can ▁increase ▁cogn itive ▁performance ▁on ▁a ▁variety ▁of ▁tasks , ▁depending ▁on ▁the ▁area ▁of ▁the ▁brain ▁being ▁stim ulated . ▁t D CS ▁has ▁been ▁used ▁to ▁enh ance ▁language ▁and ▁mathematical ▁ability ▁( though ▁one ▁form ▁of ▁t D CS ▁was ▁also ▁found ▁to ▁in hib it ▁math ▁learning ), ▁attention ▁span , ▁problem ▁solving , ▁memory , ▁and ▁coord ination . ▁ ▁C ran ial ▁surface ▁measurements ▁Elect ro ence phal ography ▁( E EG ) ▁is ▁a ▁method ▁of ▁meas uring ▁brain wave ▁activity ▁non - in vas ively . ▁A ▁number ▁of ▁electro des ▁are ▁placed ▁around ▁the ▁head ▁and ▁scal p ▁and ▁elect rical ▁signals ▁are ▁measured . ▁Typ ically ▁E EG s ▁are ▁used ▁when ▁dealing ▁with ▁sleep , ▁as ▁there ▁are ▁characteristic ▁wave ▁patterns ▁associated ▁with ▁different ▁stages ▁of ▁sleep . ▁C lin ically ▁E EG s ▁are ▁used ▁to ▁study ▁ep ile ps y ▁as ▁well ▁as ▁stroke ▁and ▁tum or ▁presence ▁in ▁the