Impairment of cognitive functions in patients with the most frequent autoimmune disorders of the central nervous system

Clinical significance of cognitive impairment in patients with autoimmune nervous system disorders has been increasing recently, because of standardized diagnostic procedures and recommended treatment. The paper reviews the spectrum of cognitive domains disturbed in multiple sclerosis, acute disseminated encephalomyelitis, neuromyelitis optica and limbic encephalitis. In multiple sclerosis patients' cognitive impairment includes attention, concentration and memory deficits, which correlate with the size of cerebral ventricles. The effects of endogenous neurotrophic factors on cognition observed in the course of multiple sclerosis suggest novel therapeutic approaches. Currently available diseasemodifying drugs enable not only the improvement of motor, but also cognitive functions. Cognitive impairment observed in neuromyelitis optica patients uncovers novel pathophysiological aspects of the disease, which has been recognized, so far, as being limited to the spinal cord, and not affecting the brain functions. Limbic encephalitis manifests typically as subacute, progressing dementia associated with epileptic seizures and psychiatric disorders. The diagnosis of limbic encephalitis is based on neuroimaging and evaluation of serum autoantibodies. Onconeuronal antibodies directed against intracellular antigens suggest paraneoplastic limbic encephalitis, whereas antibodies against surface neuronal antigens are detected predominantly in patients with non-paraneoplastic disorders. Precise identification of autoantibodies enables not only the differential diagnostics of limbic encephalitis, but also underlies therapeutic decisions.