Armstrong C L, Corn B W, Ruffer J E, Pruitt A A, Mollman J E, Phillips P C
Department of Neurology, University of Pennsylvania Medical School and Children's Hospital of Philadelphia, 19104-4399, USA.
Neuropsychiatry Neuropsychol Behav Neurol. 2000 Apr;13(2):101-11.
The neurocognitive sequelae of therapeutic cranial irradiation are not well characterized in adults with primary brain tumors. To address this problem, we prospectively examined neuropsychological findings during two phases of radiation effects.
Investigations of radiation effects have revealed variable outcomes that range from no radiation-associated morbidity to severe cognitive impairment, but have relied on case reports or retrospective studies of late-delayed changes in white matter or in cognition. No reliable radiographic or neurocognitive tools exist to describe the multiple phases of radiation effects.
Twenty adult patients (median age, 39 years) from a university hospital were treated with radiotherapy (RT) for low-grade primary brain tumors. Prospective longitudinal neuropsychological studies were compared at baseline (after surgery and before irradiation) and at 3, 6, and 12 months after RT to examine early-delayed effects, including verbal memory changes in 20 patients and visual memory changes in 11 patients. We also examined cognitive changes during the late-delayed phase for up to 3 years after RT and determined whether early-delayed memory deficit predicted late-delayed memory deficit in a small subset of patients. A comprehensive neuropsychological battery was used, including verbal and visual memory tests designed to compare learning, storage, and retrieval.
Patients demonstrated normal verbal memory at baseline, decrement, and then rebound in verbal retrieval. Deficit at baseline and recovery up to 1 year after RT defined visual memory. Together, these observations constitute a double dissociation of memory functions. No changes over time were observed in other neurocognitive tests or in fatigue or mood measures. Time-dependent patterns of each long-term memory test were examined in relation to lesion site in individual patients.
The double dissociation of memory functions after RT may provide markers for the damaging and facilitative early-delayed effects of RT. Late-delayed effects were not predicted based on early-delayed changes in a small sample.
原发性脑肿瘤成年患者接受治疗性颅脑照射后的神经认知后遗症尚未得到充分描述。为解决这一问题，我们前瞻性地研究了放射效应两个阶段的神经心理学结果。
对放射效应的研究显示出不同的结果，从无放射相关发病率到严重认知障碍，但这些研究依赖于病例报告或对白质或认知的晚期延迟变化的回顾性研究。目前尚无可靠的影像学或神经认知工具来描述放射效应的多个阶段。
来自一家大学医院的20名成年患者（中位年龄39岁）因低级原发性脑肿瘤接受了放射治疗（RT）。在基线（手术后和放疗前）以及放疗后3、6和12个月进行前瞻性纵向神经心理学研究，以检查早期延迟效应，包括20名患者的言语记忆变化和11名患者的视觉记忆变化。我们还研究了放疗后长达3年的晚期延迟阶段的认知变化，并确定早期延迟记忆缺陷是否能预测一小部分患者的晚期延迟记忆缺陷。使用了一套综合的神经心理学测试，包括旨在比较学习、存储和检索的言语和视觉记忆测试。
患者在基线时言语记忆正常，随后言语检索能力下降，然后反弹。基线时的缺陷以及放疗后长达1年的恢复情况定义了视觉记忆。这些观察结果共同构成了记忆功能的双重分离。在其他神经认知测试或疲劳或情绪测量方面未观察到随时间的变化。针对个体患者，研究了每项长期记忆测试的时间依赖性模式与病变部位的关系。
放疗后记忆功能的双重分离可能为放疗的早期延迟损伤和促进作用提供标志物。基于小样本的早期延迟变化无法预测晚期延迟效应。
