目的:儿童后颅窝肿瘤(PFT)幸存者经历长期认知后遗症,包括记忆障碍,其中辐照是主要的危险因素之一。本研究的目的是(1)探索情节损害的概况,语义,辐照和未辐照PFT幸存者的工作和程序记忆系统,(2)测试自传问卷和评估情景记忆的两阶段生态测试(Epireal)是否比常用测试对辐射引起的海马损伤更敏感。
方法:共有60名参与者(22名接受照射的PFT幸存者,17名未经辐照的PFT幸存者,和21个对照)被纳入前瞻性IMPALA研究。他们都接受了一系列广泛的测试,在相隔3周的两个为期2天的会议中评估不同的记忆系统。我们进行了组间比较,并分析了损伤情况,使用-1.65SDs作为截止值。对于受照射的患者,计算了与记忆相关的关键大脑结构的平均辐射剂量之间的相关性(海马,小脑,和纹状体)和相应的记忆得分。
结果:PBT幸存者在常规发作性测试中的表现明显差于对照组(p<0.001),语义记忆和工作记忆:64%的受照射患者和35%的未受照射患者在至少两个记忆系统中存在缺陷,情景记忆障碍对接受照射的人群更有特异性。Epireal的效果比其他情景记忆测试更大,使我们能够在另外18%的受照射患者中检测到缺陷。这些缺陷与左侧海马的平均辐射剂量相关。
结论:记忆障碍是PFT幸存者常见的长期认知后遗症,尤其是放疗后.新的情景记忆生态测试比常规测试对辐射引起的缺陷更敏感,可以产生颞叶内侧辐射毒性的特定标记。
OBJECTIVE: Pediatric posterior fossa tumor (PFT) survivors experience long-term cognitive sequelae, including memory disorders, for which irradiation is one of the main risk factors. The aims of the present study were to (1) explore the profile of impairment in episodic, semantic, working and procedural memory systems in irradiated versus nonirradiated PFT survivors, and (2) test whether an autobiographical questionnaire and a two-phase ecological test (Epireal) assessing episodic memory are more sensitive to radiation-induced hippocampal damage than commonly used tests.
METHODS: A total of 60 participants (22 irradiated PFT survivors, 17 nonirradiated PFT survivors, and 21 controls) were included in the prospective IMPALA study. They all underwent a broad battery of tests assessing the different memory systems in two 2-day sessions 3 weeks apart. We performed between-groups comparisons and analyzed impairment profiles, using -1.65 SDs as a cut-off. For irradiated patients, correlations were calculated between mean radiation doses to key brain structures involved in memory (hippocampus, cerebellum, and striatum) and corresponding memory scores.
RESULTS: PBT survivors performed significantly more poorly than controls (p < 0.001) on conventional tests of episodic, semantic and working memory: 64% of irradiated patients and 35% of nonirradiated patients had a deficit in at least two memory systems, with episodic memory impairment being more specific to the irradiated group. Epireal had a larger effect size than the other episodic memory tests, allowing us to detect deficits in a further 18% of irradiated patients. These deficits were correlated with the mean radiation dose to the left hippocampus.
CONCLUSIONS: Memory impairment is a frequent long-term cognitive sequela in PFT survivors, especially after radiation therapy. New ecological tests of episodic memory that are more sensitive to radiation-induced deficits than conventional tests could yield specific markers of the toxicity of medial temporal lobe irradiation.