▁to ▁the ▁cancer ▁cells ▁suppress es ▁their ▁growth ▁and ▁impro ves ▁the ▁pro gn osis ▁from ▁the ▁cancer . ▁ ▁Di agn osis ▁ ▁The ▁diagn osis ▁is ▁usually ▁made ▁with ▁n erve ▁condu ction ▁study ▁( N CS ) ▁and ▁elect rom y ography ▁( EM G ), ▁which ▁is ▁one ▁of ▁the ▁standard ▁tests ▁in ▁the ▁investigation ▁of ▁otherwise ▁un exp la ined ▁mus cle ▁weak ness . ▁EM G ▁involves ▁the ▁insert ion ▁of ▁small ▁need les ▁into ▁the ▁mus cles . ▁ ▁N CS ▁involves ▁admin ister ing ▁small ▁elect rical ▁imp uls es ▁to ▁the ▁n erves , ▁on ▁the ▁surface ▁of ▁the ▁skin , ▁and ▁meas uring ▁the ▁elect rical ▁response ▁of ▁the ▁mus cle ▁in ▁question . ▁N CS ▁investigation ▁in ▁LE MS ▁primarily ▁involves ▁evaluation ▁of ▁comp ound ▁motor ▁action ▁potential s ▁( C MAP s ) ▁of ▁effect ed ▁mus cles ▁and ▁sometimes ▁EM G ▁single - fi ber ▁exam ination ▁can ▁be ▁used . ▁ ▁C MAP s ▁show ▁small ▁amplit udes ▁but ▁normal ▁laten cy ▁and ▁condu ction ▁veloc ities . ▁If ▁repeated ▁imp uls es ▁are ▁admin ister ed ▁( 2 ▁per ▁second ▁or ▁ 2   Hz ), ▁it ▁is ▁normal ▁for ▁C MAP ▁amplit udes ▁to ▁become ▁smaller ▁as ▁the ▁ac et yl ch oline ▁in ▁the ▁motor ▁end ▁plate ▁is ▁de ple ted . ▁In ▁LE MS , ▁this ▁decrease ▁is ▁larger ▁than ▁observed ▁normally . ▁Event ually , ▁stored ▁ac et yl ch oline ▁is ▁made ▁available