Abnormal evoked potentials in autoimmune glial fibrillary acidic protein astrocytopathy

Autoimmune GFAP astrocytopathy is a new clinical entity and only a limited number of cases have been reported. Here we report the results of multimodal central conduction studies performed in a case of this disorder. A 72-year-old woman developed gradual cognitive decline and gait disturbance. A neurological examination revealed moderate amnesia, papilloedema, and pyramidal tract impairment of the bilateral lower limbs. The diagnosis of autoimmune GFAP astrocytopathy was made based on the typical MRI findings of periventricular radial linear gadolinium enhancement in the brain and longitudinally extensive lesions in the spinal cord, and anti-GFAP antibody detected in the cerebrospinal fluid. Somatosensory evoked potentials and transcranial magnetic stimulation studies revealed prolongation of conduction times. Visual evoked potentials showed an unusual W-shaped pattern. To our knowledge, this is the first neurophysiological demonstration of prolonged central conduction times in the autoimmune GFAP astrocytopathy. Further investigations are needed to establish the clinical value the neurophysiological examinations in this disorder.