Subjective neuropsychological deficits in autoimmune encephalitis: Patient-informant discrepancies and cognitive test outcomes.

BACKGROUND AND

OBJECTIVES

This study aimed to characterise the profile of neuropsychological symptoms reported by patients with autoimmune encephalitis (AE) and their caregivers, and to compare self- versus informant-reported perspectives on neuropsychological impairment.

METHODS

Seventy-seven patients with AE (49.35 % female, mean age = 54.04 years, SD = 18.03) and their caregivers were recruited through the Australian Autoimmune Encephalitis Consortium. Patients completed the Neuropsychological Impairment Scale (NIS), and caregivers provided parallel informant ratings. Patients also underwent psychometric testing. Clinical outcome measures, including the modified Rankin Scale (mRS) and Clinical Assessment Scale for Autoimmune Encephalitis (CASE), were obtained within six months of NIS completion.

RESULTS

Assessments occurred on average 12 months post symptom onset (SD = 5.77). Median CASE and mRS scores were 2, with 82 % of patients classified as having good functional outcomes (mRS ≤ 2). Despite this, patients endorsed significant, widespread neuropsychological impairments, particularly in Cognitive Efficiency and Learning-Verbal domains, where 100 % reported elevated symptoms. Discrepancies between self- and informant reports emerged: patients rated memory as more impaired, while informants reported greater difficulties on Critical Items, reflecting worse outcomes associated with neurological symptoms. Seronegative AE patients showed significantly greater symptom burden than seropositive subtypes. Poorer functional outcome (mRS > 2) was associated with higher symptom severity across domains. Both self- and informant ratings moderately correlated with objective cognitive test performance.

DISCUSSION: Both patients and caregivers reported considerable neuropsychological impairments following AE, emphasising the ongoing burden of disease. Importantly, discrepancies between patient and informant perspectives illustrate the limitations of conventional clinical outcome measures, which may underestimate functional impact.