Macnaha qaamuuska ereyga "demyelinate" waa in la dhaawaco ama la saaro galka myelin-ka ee ku wareegsan fiilooyinka dareemayaasha. Myelin waa walax dufan leh oo dahaaran oo ilaalisa fiilooyinka dareemayaasha, taas oo u oggolaanaysa inay si dhakhso ah oo hufan u gudbiyaan calaamadaha korantada. Marka xuubka myelinku uu dhaawacmo ama la burburiyo, calaamadaha neerfaha ayaa khalkhal gelin kara, taasoo keenta calaamado kala duwan oo neerfaha ah oo ku xiran meesha iyo inta uu le'eg yahay demyelination. Demyelination waa astaamo lagu garto dhowr cudur oo neerfaha, oo ay ku jiraan sclerosis badan iyo xanuunnada hidda-socodka qaarkood.