Assessment of the feasibility of a rehabilitation intervention program for breast cancer survivors with cognitive complaints

Abstract

To assess the feasibility of a cognitive rehabilitation program in breast cancer survivors (BCS) with persistent post-treatment cognitive complaints. BCS with cognitive complaints, 18-months to 5-years post-treatment, were recruited for a once-weekly, five-week, group cognitive training intervention. Outcome measures included self-reported mood and cognitive function, and neurocognitive tests administered at pre-intervention, immediate-, two-month and four-month post-intervention. A sub-study in eight participants evaluated resting state quantitative electroencephalography (qEEG) changes from pre- to immediate post-intervention in relationship to post-intervention changes in cognitive complaints. Twenty-seven BCS completed the protocol and tolerated the intervention well. We observed significant reductions in total and memory-specific cognitive complaints from pre-intervention to immediate post-intervention (p = 0.031 and p = 0.009, respectively) and at four-months post-intervention (p < 0.0001 and p < 0.001, respectively). Significant improvement in neurocognitive tests were found for Symbol Digit, Stroop, and Trails A tests (df = 26, all p’s <0.05). Effect sizes for changes from pre-intervention to immediate and to four-month post intervention ranged from 0.429 to 0.607, and from 0.439 to 0.741, respectively. Increase in qEEG absolute alpha power over the course of the intervention was associated with reduced complaints at immediate post-intervention (r = −0.78, p = 0.021), two-months (r range = −0.76 to −0.82, p-value range 0.004 to 0.03), and four-months (r = −0.71, p = 0.048). A five-week group cognitive training intervention is feasible and well tolerated. Cognitive complaints and neurocognitive test performances showed positive changes. qEEG may serve as a potential biomarker for improvement in self-reported complaints. A randomized clinical trial is underway to test the efficacy of the intervention.

Appendix: Details of cognitive training protocol

The cognitive rehabilitation intervention is a 5-week, 2-hour-per-session intervention.

Attention

Because attention dysfunction is a major complaint associated with “chemo brain” and often has downstream effects on other cognitive functions, the first two weeks emphasized attention enhancing strategies. Attention exercises targeted vigilance, concentration, selective attention, alternating/switching attention and working memory (White and Shah 2006; Wilson 2003). Week 1 focused on vigilance and expanding concentration. These exercises involved visual searches for numbers in an array, and listening for target letters in an array. To improve concentration, participants first found their ‘baseline’ attention span by performing an attention exercise and using a stopwatch to note how much time passed before they felt their attention wane (e.g. 60 s). Participants would then work on the exercise again, but stop before their baseline (e.g. stop after 45 s), and repeat this process, gradually extending the time they worked without feeling distracted, until they surpassed their baseline (e.g. from 45 to 50 s, then 60, then 75 s etc.). For reducing distractibility, participants were instructed to first perform exercises in a quiet room, and then with mastery, perform exercises under increasingly distracting conditions (e.g. with the radio or TV on, in a public place). Week 2 focused on more complex attentional functions, including divided attention, selective attention, and alternating attention. For example, participants performed exercises that required them to perform mental operations that alternated between focusing on numbers and letters; to sequence numbers and letters in forward and reverse order; and, to ignore irrelevant stimuli. Figure 2A provides an example of an alternating attention exercise (Rogers and Monsell 1995). Participants were told that improving attention would take time and were encourage to practice the exercises over the 5-week course.

Fig. 1

Changes in alpha power pre- vs. post-intervention for low and high improvers as determined by median split on changes in PAOFI total score. Warm colors represent higher activity. Visual inspection suggests that high improvers (right) generated more alpha globally, and generated the more usual pattern of posterior dominant alpha activity

Executive function

These exercises involved plan development and execution, organizing, goal management, using checklists, word generation grids and multi-tasking. Examples of class exercises for executive function included using a check list and organizational strategies for following a recipe (e.g. check for ingredients, lay out wet and dry ingredients and utensils, preheat oven, etc.), and for organizing a pot-luck (e.g. budgeting, planning meals around food preferences of guests, assigning food to bring). Executive exercises also focused on working memory and dual-task performance. Figure 2B is an example of a dual-task ‘proof reading’ exercise (Levine et al. 2000).

Memory

Participants learned mnemonic strategies involving association, imagery, story creation, and semantic organization (McCarty 1980; Verhaeghen et al. 1992; Yesavage 1985). Exercises included using these mnemonic strategies for remembering daily life information such as street names, names of books and authors, faces and names, and for shopping. Effective use of practical memory strategies (e.g. post-it notes, calendars) was also discussed. They also were told to use these memory strategies in daily life, as in when grocery shopping.

Fig. 2

A Example of a high difficulty Divided Attention exercise (Adapted from Rogers and Monsell 1995). B Example of a low difficulty level “Proof Reading” exercise (adapted from Levine et al. 2000)

Education

Participants received education about memory, attention and executive functions, and empirical studies of the effects of chemotherapy on cognition. This was done in session 1 and at the beginning of each week that related to the specific topic to be discussed. Education provided a foundation for understanding their own strengths and weaknesses and for understanding how and why their exercises were targeting the relevant cognitive functions. To cope with anxiety that may be related to engaging in homework exercises, participants received training in deep breathing, muscle relaxation, countering negative thoughts, self-pacing, taking breaks, and spacing practice (Stigsdotter 2000)

Goal setting

Participants formulated their own concrete, measurable short- and long-term goals. Short-term goal (e.g. “organizing my closet for 15 min”) attainment was reviewed weekly, and new goals were set as prior goals were met. Participants finalized a long-term goal (e.g. “plan a birthday party”) by the last session and attainment of that goal was assessed by the study coordinator at the follow-up visits. We explained to participants that an important part of accomplishing a goal was to schedule it with themselves, as if it were an appointment. Hence, if a participant needed to buy and send a greeting card, they would estimate how much time this would take (e.g. 30 min), use a calendar to determine when they could fit this in (e.g. 20 min go to the store on Saturday at 10 am; 10 min to write a message in the card Sunday at 10 am). We educated participants that long-term goals were actually a series of short-term goals that could be met in stages to accomplish the larger goal. For instance, planning a child’s birthday party would involve setting the date for the party, estimating how many to invite, and setting up smaller goals to write invitations, call venues to reserve an activity or cake etc.