Psychometric deficits in autoimmune encephalitis: A retrospective study from the Australian Autoimmune Encephalitis Consortium

Abstract

Background and purpose Despite the rapid increase in research examining outcomes in autoimmune encephalitis (AE) patients, there are few cohort studies examining cognitive outcomes in this population. The current study aimed to characterise psychometric outcomes in this population, and explore variables that may predict psychometric outcomes. Methods This retrospective observational study collected psychometric data from 59 patients across six secondary and tertiary referral centres in metropolitan hospitals in Victoria, Australia between January 2008 and July 2019. Frequency and pattern analysis were employed to define and characterize psychometric outcomes. Univariable logistic regression was performed to examine predictors of intact and pathological psychometric outcomes. Results Deficits in psychometric markers of executive dysfunction were the most common finding in this cohort, followed by deficits on tasks sensitive to memory. A total of 54.2% of patients were classified as having psychometric impairments across at least two cognitive domains. Twenty‐nine patterns were observed, suggesting outcomes in AE are complex. None of the demographic data, clinical features or auxiliary examination variables were predictors of psychometric outcome. Conclusions Cognitive outcomes in AE are complex. Further detailed and standardized cognitive testing, in combination with magnetic resonance imaging volumetrics and serum/cerebrospinal fluid biomarkers, is required to provide rigorous assessments of disease outcomes.

Characterizing cognitive function in patients with autoimmune encephalitis: an Australian prospective study

“…While the male cohort was likelier to be older, the finding is unusual, as the normative data are stratified by age. Of note, this reflects similar results from the consortium’s previous retrospective study, which indicate that while not significant, being a male was a predictor of intact cognition after AE, with one of the larger effect sizes of all the variables explored [ 31 ]. This finding has yet to arise in other studies, with previous systematic reviews concluding that sex is unlikely to have significant prognostic value [ 32 ].…”

“…Of note was the isolated visual memory impairment observed. This unusual finding of an isolated domain, heavily loaded to visuospatial/ visuoconstructional abilities, mirrors a similar result in a retrospective analysis that retrospectively examined patients with a diagnosis of possible AE [ 31 ]. However, the visual reproduction test can potentially be a sensitive measure of memory, as verbal memory strategies, such as labelling components, are commonly employed during visual memory tasks [ 33 ].…”

Outcome and Sequelae of Autoimmune Encephalitis

“…Several studies involving mixed populations of antibody-associated autoimmune encephalitis have produced outcomes based on mRS alone ( Supplementary Table 1 in the online-only Data Supplement). Five studies performed more-detailed assessments of neurocognitive outcomes and sequelae in patients with autoimmune encephalitis due to mixed etiologies, 65 66 67 68 but only one of those studies had a prospective design. Griffith et al 69 evaluated 50 patients at a mean of 3.2 years after diagnosis.…”

“…They found that 41% had impairment in at least one domain (1.5 SDs below the normative mean), with impairments being most common in visual memory (19%), processing speed (18%), auditory (16%), and delayed memory (16%). That group also investigated a large retrospective series of 59 patients, 65 and found that 75% of patients had impairment in at least 1 domain at a mean of 14.7 months after symptom onset, with executive function (42%), memory (41%), and attention (31%) being most commonly affected. Hébert et al 66 retrospectively investigated 21 patients with autoimmune encephalitis and applied MoCA during follow-up, which revealed persistent cognitive impairment in 52% at the last follow-up at a median of 20 months.…”

Language impairments in seropositive and seronegative autoimmune encephalitis

“…However, what tests were included in the language measures is unclear. Similarly, another retrospective study of seropositive and seronegative patients identified language impairments in 27.1% of AE patients [ 6 ]. In a retrospective case series involving anti-LGI1 ab-mediated AE patients, 20% of the patients exhibited reduced test performance in tests assessing language including reduced semantic fluency and reduced ability in visual confrontation naming, suggesting variable language outcomes [ 7 ].…”