TOPLINE

Patients with tick-borne encephalitis (TBE) reported significantly more everyday memory lapses and symptom burden at 12 months compared with matched control individuals, a study showed. 

METHODOLOGY

• A prospective, controlled, multicenter cohort study in Norway and included 109 hospitalized patients with TBE aged 16 years or older and 80 matched control individuals recruited from patients' social networks. 
• The participants completed validated patient-reported outcome measures at 3 and 12 months, including the Behavior Rating Inventory of Executive Function–Adult Version (BRIEF-A), Everyday Memory Questionnaire–Revised (EMQ-R), and Rivermead Post-Concussion Symptoms Questionnaire (RPQ). 
• Disease severity was classified as mild (23.9%), moderate (64.2%), or severe (11.9%) based on meningeal symptoms and EEG (mild, 23.9%), altered consciousness and/or focal neurological signs (moderate, 64.2%), and multifocal neurological symptoms and/or pronounced encephalitis signs with more substantial altered consciousness (severe, 11.9%). 
• Primary outcomes were changes in BRIEF-A, EMQ-R, and RPQ scores from 3 to 12 months within the patient group and comparing these scores at 12 months between the patient group and the control group. Secondary outcomes were BRIEF-A subscale T-scores comparing patients and control individuals, and the proportion of individuals with clinically relevant impairment.
• The analysis was adjusted for age, sex, comorbidity, and symptoms of anxiety and depression assessed using the Norwegian version of the Hospital Anxiety and Depression Scale.

TAKEAWAY

• Between 3 and 12 months, patient-reported cognitive and functional symptoms remained stable with no significant changes in BRIEF-A Global Executive Composite, EMQ-R, or RPQ scores.
• At 12 months, the patient group reported significantly higher everyday memory difficulties (EMQ-R mean, 13.8 vs 7.7; P <.001) and symptom burden (RPQ mean, 16.8 vs 6.0; P <.001) than control individuals.
• Among BRIEF-A subscales, only Working Memory was significantly worse in patients than control individuals (mean, 56.2 vs 50.3; P = .002). Patients were more than six times as likely to report clinically elevated everyday memory difficulties (30.1% vs 6.3%; odds ratio [OR] 6.46; P <.001) and working memory impairment (28.0% vs 6.3%; OR, 5.83; P = .001), and more than eight times as likely to report clinically elevated symptom burden (45.5% vs 9.0%; OR, 8.19; P <.001) than control individuals. 
• Comorbidities, a greater acute disease burden, anxiety, depression, and female sex were each linked to poorer 12-month outcomes.

IN PRACTICE

"Clinicians should not assume full recovery after 'uncomplicated' TBE. In a routine clinical setting, cognitive follow-up could feasibly include a short, structured interview focusing on attention, memory and executive functioning, in combination with brief standardized tests and validated questionnaires for everyday executive problems," the authors wrote.

SOURCE

The study was led by Hilde Skudal, Telemark Hospital Trust, Skien, Norway. It was published online on August 27 in the Journal of Neurology.

LIMITATIONS

The study was limited by reliance on patient-reported outcomes, unmeasured confounding, and a small sample size for subgroup analyses. 

DISCLOSURES

The study was funded by Telemark Hospital. Three authors reported having financial ties with various organizations. Details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.