Toulouse Neuroimaging Center (ToNIC), INSERM-University of Toulouse Paul Sabatier, Toulouse, France; Pediatric Neurology Department, Children's Hospital, Toulouse University Hospital, Toulouse, France.
Toulouse Neuroimaging Center (ToNIC), INSERM-University of Toulouse Paul Sabatier, Toulouse, France; Pediatric Neurology Department, Children's Hospital, Toulouse University Hospital, Toulouse, France.
Clin Oncol (R Coll Radiol). 2024 Sep;36(9):e312-e321. doi: 10.1016/j.clon.2024.06.054. Epub 2024 Jun 27.
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.
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.
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.
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.
小儿后颅窝肿瘤（PFT）幸存者会出现长期认知后遗症，包括记忆障碍，其中放疗是主要危险因素之一。本研究旨在：（1）探索放疗与未放疗 PFT 幸存者在情景、语义、工作和程序性记忆系统方面的损伤特征；（2）测试自传体问卷和评估情景记忆的两阶段生态测试（Epireal）是否比常用测试更能检测出放疗引起的海马损伤。
共纳入前瞻性 IMPALA 研究中的 60 名参与者（22 名放疗后 PFT 幸存者、17 名未放疗 PFT 幸存者和 21 名对照组）。所有参与者均在相隔 3 周的 2 天内接受了广泛的测试，以评估不同的记忆系统。我们进行了组间比较，并分析了损伤特征，使用 -1.65 SD 作为截断值。对于放疗患者，计算了关键记忆结构（海马体、小脑和纹状体）的平均辐射剂量与相应记忆评分之间的相关性。
PBT 幸存者在传统的情景、语义和工作记忆测试中表现明显差于对照组（p < 0.001）：64%的放疗患者和 35%的未放疗患者至少有两个记忆系统存在缺陷，情景记忆损伤更具放疗组特异性。Epireal 的效果比其他情景记忆测试更大，使我们能够进一步检测到 18%的放疗患者存在缺陷。这些缺陷与左侧海马体的平均辐射剂量相关。
记忆损伤是 PFT 幸存者常见的长期认知后遗症，尤其是放疗后。比传统测试更能检测出放疗引起的内侧颞叶损伤的新的情景记忆生态测试，可能会产生内侧颞叶照射毒性的特异性标志物。
