Directing Attention Externally Improves Continuous Visuomotor Skill Performance in Older Adults Who Have Undergone Cancer Chemotherapy

To the Editor: Using pharmaceuticals to treat malignancies may result in a condition commonly referred to as “chemo-brain” or “chemo-fog.”1 It has been documented that cancer patients with chemo-brain have reduced memory, diminished motor function, and difficulty performing motor skills that demand visual acuity and tracking.1–3 Despite the fact that chemo-brain can have a deleterious effect on quality of life, little is known about the factors that contribute to its symptoms.1,4 Another common symptom of chemo-brain is the inability to effectively focus attention or concentrate.1 Many motor behavior studies have investigated the efficacy of attentional focus, and findings from this research have robustly demonstrated that focusing on the result of a movement (external focus) rather than on the movement of the body (internal focus) results in a more-efficient and -effective movement.5,6 This performance phenomenon has been demonstrated with a wide range of populations performing a variety of motor skills, but no investigations have examined the relationship between focus of attention and motor performance in a geriatric population that has undergone chemotherapy treatment.7 The purpose of the current study was to determine whether verbal instructions designed to manipulate focus of attention influenced the execution of a continuous visuomotor tracking task in older adults who have undergone chemotherapy. Based on previous research, it was hypothesized that directing attention externally would result in better motor performance than instructions designed to direct attention internally as well as neutral (control) instructions inducing no specific focus of attention. Participants (N=5) were older adults (mean age 65.8±5.8) recruited from a post-cancer population suffering from symptoms consistent with chemo-brain. Using a counterbalanced-within-participant design, participants performed three trials of a novel photoelectric rotary pursuit tracking task in each of the three experimental conditions (control, internal, external). Each of the nine total trials lasted 30 seconds. The task required participants to track a rotating light at a speed of 15 revolutions per minute using a handheld stylus. The tip of the handheld stylus contained a light-sensitive photocell, which allowed continual measurement of the dependent variable: the total time the tip of the stylus was in contact with the rotating light. When participants were in the control condition, they were instructed to “track the rotating light to the best of your ability.” The internal condition instructions were, “While you are tracking the rotating light, focus on moving your hand at the same speed as the rotating light.” In the external condition, participants were given the instruction “While you are tracking the rotating light, focus on moving the handle of the stylus at the same speed of the rotating light.” Participants were reminded in all conditions that they were to keep their eyes on the rotating light. In the external and internal conditions, participants were specifically instructed not to focus visually on the stylus handle or their hand. There was approximately 45 seconds between each trial. An institutional review board approved all methods. Data were analyzed using a three (condition) × three (trial) analysis of variance. The analysis revealed a main effect for condition (F2,42=7.31, P=.002); post hoc analysis indicated that the participants performed significantly better in the external condition (20.8±4.8 seconds) than the control (15.1±3.6 seconds) and internal condition (17.4±3.4 seconds) (Figure 1). The internal and control condition were not significantly different. Average total time on target for each of the three experimental conditions (control, internal, external) when performing the visuomotor tracking task. Participants performing a continuous visuomotor task displayed superior performance following instructions designed to direct attention externally rather than following an internal or neutral set of instructions. The findings reported here add to a growing body of literature demonstrating the performance benefits that exist when verbal instructions are delivered in a way that directs attention externally. Specifically, this study demonstrated that a population suffering from chemo-brain improved their visuomotor performance by directing attention to the result of their body's movement. Adopting methods similar to those presented here may result in immediate improvements in motor skill performance and assist in managing the undesirable side effects of pharmaceutical cancer treatments. Future research is needed to better understand the underlying mechanism of chemo-brain, as well as the improvement in motor behavior elicited when attention is focused externally. Future research is also needed to test the generalizability of the present findings to complex functional skills such as balance, locomotion, and tasks requiring object manipulation in this population. We would like to thank Nicole Wikoff, Russell Nolan, Erik Ostrowski, and Justin Ostrowski for their assistance with this study.