Abstracts

Rationale:
Proper treatment of autoimmune encephalitis hinges upon aggressive immunomodulatory medical therapy. These treatments for autoimmune encephalitis are not often considered for patients who present predominately with psychiatric symptoms or new onset epilepsy. The purpose of this study was to systematically compare the neuropsychological profiles of patients with autoimmune encephalitis to profiles of primary psychiatric patients and non-autoimmune epilepsy patients. In doing so, a potential opportunity arises in which neuropsychological testing may be used as a tool to identify these patients in an expedient manner across common differentials, such that appropriate therapeutics may be applied, and potentially add to the existing proposed criteria and algorithms for diagnosing autoimmune encephalitis.
Method:
Patients with autoimmune encephalitis completed neuropsychological testing during the acute phase of their illness (n=8). Autoantibodies detected included those directed against VGKC-LGI1 subtype, (n=3), GAD-65 (n=2), NMDA receptor (n=1,) TPO (n=1) and AChR (n =1). The data of patients with primary psychiatric illness (specifically schizophrenia) was taken from previously published data.  Epilepsy control patients (refractory epilepsy surgical candidates of non-suspected autoimmune etiology) were included if they had received our target neuropsychological measures and were matched to autoimmune patients on the basis of age, years of education, and epilepsy laterality to the predominantly affected hemisphere.  A series of analysis (Student’s t-test, Welch’s t-test, etc.) compared neuropsychological assessment performance of autoimmune encephalitis to those of primary psychiatric illness and non-autoimmune epilepsy.
Results:
In comparison to patients with primary psychiatric illness, patients with autoimmune encephalitis performed significantly worse on measures of delayed memory (74.9 vs. 49.0,  p< 0.0001) and language (83.5 vs. 68.3, p=0.042). In comparison to patients with non-autoimmune refractory epilepsy, patients with autoimmune encephalitis performed significantly worse on measures of delayed memory (77.5 vs. 49.0, p=0.008) and immediate memory (90.0 vs. 68.0, p=0.012). Additionally, the density of new onset delayed memory impairment – being amnestic in nature is suggested as a relevant marker of autoimmune encephalitis.
Conclusion:
This study demonstrates neuropsychological assessment as a useful clinical tool to aide in the diagnosis of autoimmune encephalitis and potentially differentiate from primary psychiatric illness and non-autoimmune refractory epilepsy and may play a future role in diagnostic algorithms or predictive models.
Funding:
:None