Quantitative electroencephalography biomarkers of cognitive complaints after adjuvant therapy in breast cancer survivors: a pilot study.

Abstract

Psycho-Oncology Psycho-Oncology 23: 713–715 (2014) Published online 6 February 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/pon.3487 Clinical Correspondence Quantitative electroencephalography biomarkers of cognitive complaints after adjuvant therapy in breast cancer survivors: a pilot study Aimee M. Hunter 1,2 , Lorna Kwan 3 , Linda M. Ercoli 1 , Barbara Kahn Mills 3 , Ian A. Cook 1,2 , Patricia A. Ganz 3,4,5 and Andrew F. Leuchter 1,2 Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Laboratory of Brain, Behavior, and Pharmacology, UCLA, Los Angeles, CA, USA Division of Cancer Prevention and Control Research, Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA Department of Health Policy and Management, Fielding School of Public Health, UCLA, Los Angeles, CA, USA Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA *Correspondence to: Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, 760 Westwood Plaza, Rm 57-455, Los Angeles, CA 90024-1759, USA. E-mail: amhunter@ucla.edu Received: 19 December 2013 Accepted: 30 December 2013 Dear Editor, for BCS with cognitive complaints [6] and the UCLA mind body study (MBS)—a prospective study of early stage, posttreatment breast cancer patients [1]. All patients had been treated for stage 0, I, II, or IIIA breast cancer and were on no active cancer therapy other than possible endocrine therapy. For CRS, patients had to have increased cognitive complaints to enter the rehabilitation intervention trial, and for MBS, there were no selection criteria other than the exclusion of health conditions that would interfere with the assessment of study outcomes. Across protocols, exclusions were evi- dence of current or past central nervous system or medical disorder/disease that might be expected to impact cognitive functioning (e.g., multiple sclerosis, thyroid dysfunction); history of head trauma with loss of consciousness greater than 30 min; epilepsy, dementia, or severe learning disability; current mood, anxiety, or psychotic disorder, or current substance abuse or dependence; and history of whole-brain irradiation or brain surgery. These same criteria were applied during recruitment to the secondary, qEEG study. Participants were treated in accordance with the Declaration of Helsinki. Experimental procedures were approved by the UCLA Institutional Review Board, and all participants provided written informed consent. Cognitive complaints are pervasive among breast cancer survivors (BCS), yet their biology is not well understood. Complaints are only partly reflected in neuropsychological test performance [1]. Moreover, their etiology is likely mul- tifactorial; such complaints have been linked not only to ad- juvant therapies (‘chemobrain’ phenomenon) but also to the development of cancer itself [2]. In fact, biologic processes including DNA damage, oxidative stress, inflammation, and shortened telomeres have been shown to underlie both can- cer progression and the impact of cancer treatments; further, these same processes are related to aging and cognitive de- cline [3]. Models of aging therefore have been proposed as a framework for studying cognitive dysfunction in BCS [4]. Resting-state quantitative electroencephalography (qEEG) offers an indicator of brain function that has been related to aging and cognitive function [5]. Changes in the resting- state EEG have been linked to cognitive decline in normal aging and to cognitive deficits in mild cognitive impairment (MCI) and Alzheimer’s disease. An overarching pattern is one of the shifts in EEG power from higher (beta and alpha) to lower (theta and delta) frequencies with decreased cognitive status. Physiologic tests such as qEEG constitute a reproducible objective measure that could complement performance measures. In this vein, we explored resting- state qEEG measures as correlates of cognitive complaints in a cross-section of well-characterized BCS. Methods Participants and recruitment Participants were recruited from the University of California, Los Angeles (UCLA) cognitive rehabilitation study (CRS) Copyright © 2014 John Wiley & Sons, Ltd. Clinical assessments Participants completed the Patient’s Assessment of Own Functioning Inventory (PAOFI) at the time of the EEG assessment. This 33-item self-report questionnaire has been used previously in studies of cognitive complaints in BCS [7]. The PAOFI assesses the frequency with which an individual experiences difficulties in four functional domains: memory (MEM), higher-level cognition (HLC), language and communication (LC), and motor sensory