Have MULTIPLE questions about MULTIPLE sclerosis?   Having trouble seeing neuromyelitis optica?   In a fog about MOG?   Here’s the cheat sheet you NEED to distinguish the demyelinating diseases!   Demyelinating diseases predominantly involve the optic nerves, brain, & spine.    The three main chronic demyelinating diseases are Multiple sclerosis (most common), neuromyelitis optica (NMO), & myelin oligodendrocyte glycoprotein (MOG) antibody associated disease or MOGAD   Each has its own features in the optic nerve, brain, & spine.  Here’s how to remember them!   MS Optic nerve: MS only has 2 letters, so MS involvement of the optic nerve tends to be short segment Brain: Letter M makes the shape of the perivascular distribution of lesions along the ventricles (Dawson’s fingers) Letter S makes the shape of the subcortical U fiber involvement Spine: MS is only 2 letters, so lesions are usually less than 2 vertebral bodies in length   NMO Optic nerve: NMO is a longer abbreviation, three letters, so longer involvement NMO can stand for Near My Occiput. Occiput is posterior, so more posterior nerve involvement Brain: NMO can stand for Near My Ocean. What is your brain’s ocean? The ventricles. NMO lesions are all periventricular Spine: NMO is 3 letters, so lesions usually more than 3 vertebral bodies in length   MOGAD Optic Nerve: Remember MO’ GAD-olinium.  So things that cause more regions of enhancement.  MOGAD lesions are commonly bilateral & long segment & enhancement can extend perineural Brain: Remember LO’ GAD.  MOGAD typically involves the lower areas of the brain Spine: Remember MO’ PLAID. MOGAD can give a plaid-like H shape in the cord from predominantly gray matter involvement   Hopefully, this cheat sheet will help you remember how to distinguish the demyelinating diseases! It ain’t lyin’ about diseases of myelin!