Balint syndrome in anti-NMDA receptor encephalitis

We report 2 cases of NMDA receptor (NMDAR) encephalitis with classic signs and symptoms of encephalitis, but in whom Balint syndrome was a predominant manifestation in the evolution of the disease.

Patient 1, a 24-year-old woman, presented initially with catatonia, mutism, unusual anxiety, and generalized epileptic seizures. She received 3 months of intensive care. She had no psychosis, no movement disorders, no sleep disturbance, or dysautonomia. Cerebral MRI was normal. Based on a large workup (table) and positivity of CSF anti-NMDAR antibodies, a diagnosis of NMDAR encephalitis was made, and she was accordingly treated for encephalitis and seizures (table). No teratoma was detected. One year after disease onset, neuropsychological assessment found deficits in executive functions (working memory, planning, and mental flexibility), constructive apraxia, and left spatial neglect; Balint syndrome was not assessed at this time. She was evaluated again 2 years after disease onset because of visual complaints, such as misreaching when grasping objects and difficulty to judge distances. Ophthalmologic examination and visual field were normal. Neurologic examination highlighted difficulties to reach and grasp a pen introduced in the patient's peripheral visual fields related to bilateral optic ataxia¹; lateralized spatial attention disorder attested by a rightward bias in manual line bisection and left omissions related to left hemineglect; and partial descriptions of complex pictures and embedded shapes, inability to detect the contour of dotted lines and to perform visual labyrinth tests, and inability to enumerate dots with a revisiting phenomenon consistent with simultanagnosia.² Eye movements were normal. A full Balint syndrome was therefore diagnosed on the association of optic ataxia, psychic paralysis of gaze (simultanagnosia), and lateralized disorder of attention (left hemineglect).³ At this time, cerebral MRI remained normal, 18 fluorodeoxyglucose PET (¹⁸F-FDG PET/CT) found a mild left fronto-temporo-parietal and insular hypometabolism, and EEG found diffuse posterior slow waves without epileptiform abnormalities. She was treated with 2 new infusions of rituximab. Anticonvulsants were not modified.

Patient 2, a 19-year-old woman, presented with severe limb apraxia and aphasia, behavioral disorders such as emotional lability and psychomotor slowing, associated with signs of Balint syndrome. The patient had no movement disorders, no epileptic seizure, sleep disturbance, or dysautonomia. Based on a large workup (table) and the positivity of CSF anti-NMDAR antibodies, a diagnosis of NMDAR encephalitis was made, and she was accordingly treated (table). No teratoma was found. At this time, cerebral MRI was normal, ¹⁸F-FDG PET/CT showed left temporo-occipito-parietal and bilateral insular hypermetabolism, and EEG found bilateral occipital and parietal slow waves without epileptiform abnormalities. She was re-evaluated 2 months after diagnosis at a rehabilitation center owing to the persistence of visual symptoms after recovery from aphasia and apraxia. Ophthalmologic examination and visual field were normal. Full Balint syndrome was diagnosed on the association of optic ataxia, simultanagnosia, and lateralized disorder of attention (left hemineglect) (table).^2,3 Eye movements were normal. Balint syndrome recovered over the next 4 months.

Appendix 1 Author contributions

• Received July 2, 2018.
• Accepted in final form November 8, 2018.

• Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.