Abducens Nerve Diseases ; etiology ; Brain ; diagnostic imaging ; Cognitive Dysfunction ; etiology ; Epilepsies, Partial ; etiology ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Multiple Sclerosis, Chronic Progressive ; cerebrospinal fluid ; complications ; diagnostic imaging ; Muscle Weakness ; etiology ; Oligoclonal Bands ; cerebrospinal fluid ; Paresis ; etiology ; Paresthesia ; etiology ; Seizures ; etiology