title: Pretreatment Differences in Intraindividual Variability in Reaction Time between Women Diagnosed with Breast Cancer and Healthy Controls.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: 1Department of Psychology,York University,Toronto,Ontario,Canada.
authors.forename: Christie
authors.identifier: http://orcid.org/0000-0002-0507-4717
authors.initials: C
authors.lastname: Yao
authors.affiliation: 1Department of Psychology,York University,Toronto,Ontario,Canada.
authors.forename: Jill B
authors.initials: JB
authors.lastname: Rich
authors.affiliation: 2Department of Medical Oncology,Princess Margaret Cancer Centre,Toronto,Ontario,Canada.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Tannock
authors.affiliation: 3Department of Medical Oncology,Institute of Oncology Ljubljana and University of Ljubljana,Ljubljana,Slovenia.
authors.forename: Bostjan
authors.initials: B
authors.lastname: Seruga
authors.affiliation: 4Department of Supportive Care,Cancer Rehabilitation and Survivorship Program,Princess Margaret Cancer Centre,Toronto, Ontario,Canada.
authors.forename: Kattleya
authors.initials: K
authors.lastname: Tirona
authors.affiliation: 4Department of Supportive Care,Cancer Rehabilitation and Survivorship Program,Princess Margaret Cancer Centre,Toronto, Ontario,Canada.
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D000368:Aged; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D001943:Breast Neoplasms / Q000150:complications* / Q000188:drug therapy / Q000601:surgery; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology*; D005221:Fatigue / Q000209:etiology*; D005260:Female; D006801:Humans; D007206:Individuality; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology*; D057566:Self Report
keywords: Attention; Breast neoplasms; Cognition; Executive function; Frontal lobes; Neoadjuvant therapy