Department of Psychology, York University, Toronto, Ontario, Canada.
Department of Supportive Care, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
Psychooncology. 2017 Dec;26(12):2261-2268. doi: 10.1002/pon.4351. Epub 2017 Feb 1.
Women treated with chemotherapy for breast cancer experience subtle cognitive deficits. Research has focused on mean performance level, yet recent work suggests that within-person variability in reaction time performance may underlie cognitive symptoms. We examined intraindividual variability (IIV) in women diagnosed with breast cancer and treated with neoadjuvant chemotherapy.
Patients (n = 28) were assessed at baseline before chemotherapy (T1), approximately 1 month after chemotherapy but prior to surgery (T2), and after surgery about 9 months post chemotherapy (T3). Healthy women of similar age and education (n = 20) were assessed at comparable time intervals. Using a standardized regression-based approach, we examined changes in mean performance level and IIV (eg, intraindividual standard deviation) on a Stroop task and self-report measures of cognitive function from T1 to T2 and T1 to T3.
At T1, women with breast cancer were more variable than controls as task complexity increased. Change scores from T1 to T2 were similar between groups on all Stroop performance measures. From T1 to T3, controls improved more than women with breast cancer. IIV was more sensitive than mean reaction time in capturing group differences. Additional analyses showed increased cognitive symptoms reported by women with breast cancer from T1 to T3. Specifically, change in language symptoms was positively correlated with change in variability.
Women with breast cancer declined in attention and inhibitory control relative to pretreatment performance. Future studies should include measures of variability, because they are an important sensitive indicator of change in cognitive function.
接受化疗的乳腺癌女性会出现轻微的认知缺陷。研究集中在平均表现水平上，但最近的研究表明，反应时间表现的个体内变异性可能是认知症状的基础。我们检查了接受新辅助化疗的乳腺癌诊断女性的个体内变异性（IIV）。
患者（n=28）在化疗前（T1）、化疗后约 1 个月但在手术前（T2）以及化疗后约 9 个月（T3）进行评估。年龄和教育程度相似的健康女性（n=20）在类似的时间间隔进行评估。使用基于标准化回归的方法，我们研究了 Stroop 任务和认知功能自我报告测量的平均表现水平和 IIV（例如个体内标准差）从 T1 到 T2 和 T1 到 T3 的变化。
在 T1 时，随着任务复杂性的增加，乳腺癌女性比对照组的变异性更大。在所有 Stroop 表现测量中，从 T1 到 T2 的变化分数在两组之间相似。从 T1 到 T3，对照组的改善程度大于乳腺癌女性。与平均反应时间相比，IIV 更能敏感地捕捉组间差异。进一步的分析表明，乳腺癌女性从 T1 到 T3 报告的认知症状增加。具体来说，语言症状的变化与变异性的变化呈正相关。
与治疗前表现相比，乳腺癌女性在注意力和抑制控制方面下降。未来的研究应包括变异性测量，因为它们是认知功能变化的重要敏感指标。
