Yao Christie, Rich Jill B, Tannock Ian F, Seruga Bostjan, Tirona Kattleya, Bernstein Lori J
1Department of Psychology,York University,Toronto,Ontario,Canada.
2Department of Medical Oncology,Princess Margaret Cancer Centre,Toronto,Ontario,Canada.
J Int Neuropsychol Soc. 2016 May;22(5):530-9. doi: 10.1017/S1355617716000126. Epub 2016 Mar 10.
Chemotherapy has adverse effects on cognitive performance in women treated for breast cancer, but less is known about the period before chemotherapy. Studies have focused on mean level of performance, yet there is increasing recognition that variability in performance within an individual is also an important behavioral indicator of cognitive functioning and underlying neural integrity.
We examined intraindividual variability (IIV) before chemotherapy and surgery in women diagnosed with breast cancer (n=31), and a healthy control group matched on age and education (n=25). IIV was calculated across trials of a computerized Stroop task, including an examination of the slowest and fastest trials of reaction time (RT) responses.
The groups were equivalent on overall accuracy and speed, and participants in both groups were less accurate and slower on incongruent trials compared with congruent trials. However, women with breast cancer became more variable with increased task difficulty relative to healthy controls. Among the slowest RT responses, women with breast cancer were significantly more variable than healthy controls on incongruent trials. This suggests that a specific variability-producing process (e.g., attentional lapses) occurs in task conditions that require executive control (e.g., incongruent trials).
Results are consistent with other evidence of executive dysfunction among women treated for breast cancer. These findings highlight the importance of pretreatment assessment and show that variability in performance provides information about cognition that measures of central tendency do not.
化疗对接受乳腺癌治疗的女性的认知表现有不良影响，但对于化疗前的时期了解较少。研究主要集中在平均表现水平上，然而，人们越来越认识到个体内部表现的变异性也是认知功能和潜在神经完整性的重要行为指标。
我们检查了被诊断为乳腺癌的女性（n = 31）以及年龄和教育程度相匹配的健康对照组（n = 25）在化疗和手术前的个体内部变异性（IIV）。通过计算机化斯特鲁普任务的试验计算IIV，包括对反应时间（RT）反应最慢和最快的试验进行检查。
两组在总体准确性和速度上相当，并且与一致试验相比，两组参与者在不一致试验中的准确性较低且速度较慢。然而，与健康对照组相比，乳腺癌女性随着任务难度增加变异性更大。在最慢的RT反应中，乳腺癌女性在不一致试验中的变异性明显高于健康对照组。这表明在需要执行控制的任务条件下（例如，不一致试验）会发生特定的变异性产生过程（例如，注意力不集中）。
结果与乳腺癌女性执行功能障碍的其他证据一致。这些发现强调了预处理评估的重要性，并表明表现的变异性提供了关于认知的信息，而集中趋势测量则无法提供这些信息。
