Long-term neurological and neurocognitive impairments after tick-borne encephalitis in Lithuania - a prospective study

The aim of this study was to characterise long-term neurological and neurocognitive sequelae after tick-borne encephalitis (TBE) in adults. 98 prospective consecutive TBE patients, classified by disease severity, were included. Immediate outcomes were evaluated with Glasgow Outcome Scale (GOS) and Rankin Scale (RS). After 6 and 18 months, long-term disability was evaluated using Modified Rankin Scale (MRS) and neurocognitive assessment was performed with Matrics Consensus Cognitive Battery (MCCB), measuring processing speed, attention/vigilance, working memory, verbal learning, visual learning, reasoning/problem solving and social cognition. The MCCB results were compared to healthy age, gender and education-matched controls. Mild, moderate, and severe TBE was diagnosed in 53.1%, 38.8%, and 8.2% of cases, respectively. At discharge, 25.5% of the patients had major or moderate impairments (GOS) and various levels of disability in 34.7% (RS). Up to 18 months from the onset of TBE, over 20% remained with slight to moderate disability (MRS). GOS, RS and MRS scores correlated with disease severity. At 6 months after the onset, TBE patients scored significantly lower than controls in processing speed, verbal, and visual learning. Two latter domains were significantly more impaired in patients with mild TBE. Patients aged 18-39 performed significantly worse in attention/vigilance and working memory, whereas aged 60+ in verbal learning. A year later, significant improvement was observed in six of seven cognitive domains. Long-term neurological sequelae persist in a substantial proportion of TBE patients with significant impairment in several cognitive domains, especially in younger patients and even after mild TBE.

本研究旨在明确成人蜱传脑炎（tick-borne encephalitis, TBE）后长期神经及神经认知后遗症的特征。研究纳入98例连续入组的前瞻性TBE患者，按疾病严重程度进行分类。即刻结局采用格拉斯哥预后量表（Glasgow Outcome Scale, GOS）与兰金量表（Rankin Scale, RS）进行评估。在发病后6个月及18个月时，采用改良兰金量表（Modified Rankin Scale, MRS）评估长期残疾情况，并通过MATRICS共识认知成套测验（Matrics Consensus Cognitive Battery, MCCB）开展神经认知评估，该测验可测量处理速度、注意力/警觉性、工作记忆、言语学习、视觉学习、推理/问题解决及社会认知7个认知维度。研究将MCCB测验结果与年龄、性别、教育程度相匹配的健康对照者进行比较。本研究中轻度、中度及重度TBE患者占比分别为53.1%、38.8%及8.2%。出院时，25.5%的患者存在重度或中度神经功能损伤（GOS评分），34.7%的患者存在不同程度的残疾（RS评分）。截至发病后18个月，仍有超过20%的患者存在轻度至中度残疾（MRS评分）。GOS、RS及MRS评分均与疾病严重程度显著相关。发病后6个月时，TBE患者在处理速度、言语学习及视觉学习维度的得分显著低于健康对照者。其中后两个认知维度在轻度TBE患者中受损更为显著。18~39岁的患者在注意力/警觉性及工作记忆维度表现显著更差，而60岁及以上患者则在言语学习维度得分显著偏低。发病后1年时，7个认知维度中有6个均出现显著改善。相当比例的TBE患者仍存在长期神经后遗症，多项认知维度存在显著受损，这一情况在年轻患者及轻度TBE患者中尤为突出。