Objective: To assess the feasibility of a structured telephone interview examining the long-term cognitive and functional status in anti-leucine-rich, glioma-inactivated 1 (LGI1) encephalitis.
Methods: Telephone interviews were conducted with 37 patients after a median follow-up of 87 months from disease onset and 23 healthy controls matched for age and sex. Cognitive status was assessed with the telephone Mini-Mental State Examination (t-MMSE) and 3 tests exploring verbal memory, fluency, and executive function. Functional status was evaluated with the Functional Activities Questionnaire and the modified Rankin Scale (mRS). Patients were classified as normal, with mild cognitive impairment (MCI), or with dementia based on cognitive and functional status. Assessment of the cognitive reserve was performed with a structured questionnaire. Logistic regression analysis was applied to identify predictors of cognitive impairment.
Results: Telephone interviews were successful in 36/37 (97%) patients. Cognitive impairment was detected in 27 (75%) including 17 with MCI and 10 with dementia. Eight (29%) patients would have been misclassified using only the t-MMSE. Twenty-six (72%) patients were functionally independent according to the mRS, but only 9 (35%) were cognitively normal. Independent predictors for long-term cognitive impairment were a low cognitive reserve (OR = 1.36, 95% CI: 1.05-1.76; p = 0.02) and bilateral hippocampal hyperintensity at initial MRI (OR = 27.03, 95% CI: 1.87-390; p = 0.02).
Conclusions: Telemedicine is a feasible tool to assess the cognitive and functional outcome in patients with anti-LGI1 encephalitis. Cognitive impairment is often missed if only functional scales are used. Premorbid cognitive reserve and MRI with bilateral hippocampal hyperintensity were predictors for long-term cognitive impairment.
Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.