Characterising executive functioning in the chronic phase of autoimmune encephalitis: A study by the Australian autoimmune encephalitis consortium.

BACKGROUND AND

OBJECTIVES

This study investigated executive functioning in patients with autoimmune encephalitis (AE) in the chronic phase of the illness. Relationships between Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) scores and clinical outcomes-including AE subtype, time since disease onset, and scores on the modified Rankin Scale (mRS) and Clinical Assessment Scale in Autoimmune Encephalitis (CASE)-were also examined.

METHODS

Sixty-six AE patients (50% female, Mage=55.71, SDage=17.26) from the Australian Autoimmune Encephalitis Consortium Project completed BRIEF-A questionnaires, time-matched to their CASE and/or mRS scores within six months.

RESULTS

On average, assessments occurred 12 months post-onset. Median CASE and mRS scores were 2, with 66.67% of patients having mRS ≤2. Self- and informant-reported BRIEF-A scores were significantly elevated across domains, indicating substantial executive dysfunction, particularly in Emotional Control and Working Memory, where patients reported worse outcomes than informants. Patients with seronegative AE reported the most severe dysfunction, especially in emotional and behavioural regulation. Psychiatric comorbidities and seizures were associated with poorer executive functioning, while disease duration showed no significant impact. Dichotomising mRS at ≤1 vs. >1 better captured executive dysfunction, with patients in the >1 group showing significantly greater executive dysfunction than those classified as mRS >2. mRS scores significantly predicted executive dysfunction (28-43% variance); the inclusion of the CASE score did not improve these models.

DISCUSSION: AE patients in the chronic stage of the illness exhibit significant executive dysfunction. Combining self- and informant reports offers a comprehensive approach to assess executive dysfunction and guide personalised treatment strategies.