In the Tuesday Lessons, two hystero-epilepsy patients exhibited clinical resemblance to anti-NMDAR encephalitis. However, due to the lack of evidence of teratomas, we could not reliably retrospectively diagnose these patients with anti-NMDAR encephalitis without cerebrospinal fluid examinations, electroencephalograms, or serological studies, based on the current diagnostic criteria . Moreover, Charcot himself never considered the concept of encephalitis due to ovarian teratoma. He repeatedly opposed the ovarian resections performed as a treatment for hystero-epilepsy conducted in contemporary America . Charcot’s hystero-epilepsy has been suspected of being a syndrome encompassing conversion and dissociative disorders, drug withdrawal syndrome, and anti-NMDAR encephalitis-like manifestations.
Opisthotonus posturing and phase progression were used as a basis for the diagnosis of hystero-epilepsy by Charcot’s department . Charcot’s pupil Richer performed the most important work in the field by recording numerous cases with hystero-epilepsy . In Richer’s textbook of hystero-epilepsy, he observed the duration of each phase as lasting from seconds to minutes, which is similar to the duration of epileptic attacks or migraine aura. In contrast, in Charcot’s Tuesday Lessons, the durations of the phases varied by as much as months, which was completely different from Richer’s records. Even Charcot himself did not declare a common definition for hystero-epilepsy. In the Friday Conference, the formal lectures, Charcot did not mention the phases, stereotypical movements and reactivity to hypnosis and only emphasized that hystero-epilepsy should be distinguished from true epilepsy .
Soon after Charcot’s death, his pupil Joseph Babinski proposed that hysteria was a reproducible psychogenic condition by suggestion . Later neurologists suspected that the disappearance of hystero-epilepsy could be explained by the absence of suggestion after the greatest hypnotist’s death or misdiagnosis [11, 22]. Charcot’s hystero-epilepsy has been largely ignored by later clinicians until today.
During the twentieth century, anti-NMDAR encephalitis had been called acquired reversible autistic syndrome , acute encephalopathy of obscure origin , and paediatric dyskinetic encephalitis lethargica . Paediatricians recognized a patient group with acute psychosis and executive dysfunction with orofacial dyskinesia, opisthotonic posturing and good prognosis as having acute encephalopathy. Later, one author of the reports wrote that the syndrome was identical to anti-NMDAR encephalitis . Florence and Dalmau listed disorders generally considered in the context of anti-NMDAR encephalitis and previous terms used for disorders likely representing anti-NMDAR encephalitis including acute psychosis, schizophrenia, catatonia, infectious or postinfectious autoimmune encephalitis, drug abuse, acute juvenile female nonherpetic encephalitis and demonic possession . Charcot and Richer wrote Les démoniaques dans l’art, which introduced analogies between medieval demonic possession cases and hystero-epilepsy . We suggest that hystero-epilepsy can be added to the list of the variations in the terms representing anti-NMDAR encephalitis through history.
The similarities between opisthotonus movements in anti-NMDAR encephalitis and the arc de cercle in hystero-epilepsy (Fig. 1) have been indicated previously . However, repetitive opisthotonus movements are not uniquely seen in anti-NMDAR encephalitis. Penfield and Jasper reported alternate repetitions of opisthotonos movements and decerebrate rigidity in a patient with tuberculosis invasion of the midbrain . Repetitive opisthotonus movements with psychiatric changes have been reported in hypoglycaemic psychosis , Hashimoto’s encephalitis , frontal lobe epilepsy  and nonepileptic psychogenic seizure . Hystero-epilepsy in the nineteenth century was a clinical phenotype of a heterogenous syndrome and probably included these conditions.
Lethal cases of hystero-epilepsy in the nineteenth century
Although some modern patients, especially paediatric patients, with anti-NMDAR encephalitis have a good prognosis without signs of central hypoventilation, other patients with anti-NMDAR encephalitis have a lethal course with respiratory failure . Some discussion of the condition’s mortality would have been necessarily conducted. In fact, Charcot discussed fatal cases of hystero-epilepsy in an annotation of the Tuesday Lesson on 26 June 1888  and in the Friday Conference . Charcot wrote in his book that “this sad result is nearly always owing to a peculiar kind of attack, the dyspnoeic seizure”, with temperature elevation, and quoted an autopsy case involving a 19-year-old woman reported by Wunderlich. This woman had an acute-onset hysteriform convulsion for several days and was admitted to the hospital, at which point opisthotonus posturing was presented. After eight weeks, the woman exhibited a sudden elevation in temperature and cyanosis and then died. A post-mortem study demonstrated a slight thickening of the pia mater, and her ovaries contained numerous cysts as large as peas. The clinical course of this patient did not conflict with that of anti-NMDAR encephalitis in an era without respiratory assistance or immunomodulating treatments. This case did not present any analogies to nonepileptic psychogenic seizure.