Presentation on theme: "Effects of Attentional Focus on Oral-Motor Control and Learning Skott E. Freedman 1, Edwin Maas 1, Michael P. Caligiuri 2, Gabriele Wulf 3, & Donald A."— Presentation transcript:
Effects of Attentional Focus on Oral-Motor Control and Learning Skott E. Freedman 1, Edwin Maas 1, Michael P. Caligiuri 2, Gabriele Wulf 3, & Donald A. Robin 1 1 Joint Doctoral Program in Language and Communicative Disorders, San Diego State University and University of California, San Diego 2 University of California, San Diego 3 University of Nevada, Las Vegas Introduction This study examined the effects of an external versus internal focus of attention on motor learning. It has been found that the focus of attention during a motor task is a critical variable in understanding performance enhancement 1. An internal focus (on bodily movements, e.g., an arm swing in golf) is less effective than an external focus of attention (on the object/outcome, e.g., a golf club) in a variety of limb tasks 2,3. Study of attentional focus during oral-facial motor learning is a logical step to understanding its role during speech treatment of individuals with motor speech disorders, including apraxia of speech. The learning of motor skills is enhanced when utilizing an external relative to an internal focus of attention 3-5. This benefit of an external focus has been explained by the “constrained action hypothesis.” 1 According to this view, individuals utilizing an internal focus constrain or “freeze” their motor system by consciously attempting to control it. In contrast, an external focus promotes the use of more automatic control processes. Based on the “constrained action hypothesis”, we predicted: Smaller absolute error for the external focus group during practice, retention, and transfer Less variability for the external focus group as indicated by variable error Methods Participants: Forty-six undergraduate students with no known health conditions were selected from the population and randomly assigned to either an internal or external focus of attention group. Task: Participants practiced an isometric task consisting of rapid pressure bursts (with the hand and tongue) to a target level of 20% their maximal strength. Each participant practiced manual and oral-motor performance in a single session. Participants applied only enough pressure in a rapid exertion to see their pressure burst appear in a 20% target window slot. Visual feedback was present for each trial. A digitally recorded metronome generated a chime every five seconds to signal participants to exert one pressure burst. The internal group was instructed to focus on the pressure exerted with their hand/tongue, whereas the external group was instructed to focus on the pressure exerted on the bulb. Reminders of participants’ assigned focus of attention were provided once a minute by the examiner. Instructions were the same for each group: Internal: “Focus on how your hand/tongue muscles tighten up. Remember to push with your hand/tongue.” External: “Focus on how soft the bulb feels. Remember to push against the rubber bulb.” There were 40 practice trials each for hand and tongue per participant. Retention and transfer trials (without focus instructions) were administered five days after practice. Retention trials reproduced the original 20% target level, while transfer trials introduced a novel 30% target level to examine the generalizability of attentional focus effects. Statistical analyses involved a mixed model ANOVA with Group (External, Internal) as the between- subjects factor and Structure (Hand, Tongue) and Block (Quartile) as the within-subjects factors. Block refers to practice trials divided into four 10 trial blocks. A separate ANOVA was run on retention and transfer trials comparing the last block of practice. Data that were greater than 3.5 standard deviations from the mean were excluded from analyses, which were performed on ln transformed data. Results Discussion The external focus group demonstrated smaller absolute and variable error during practice trials than the internal focus group, supporting the “constrained action hypothesis.” Retention and transfer trials did not show differences related to focus. A marked decrease in performance was observed for both groups relative to practice, more so for the external focus group. (Note: The external focus group performed significantly better during practice trials). However, practice was limited to 40 trials per structure per participant and retention tests were administered at a substantially longer interval (5 days vs. 24 hours) than previous studies. The present study extends previous findings of an advantageous external focus of attention to the oral- facial system, suggesting a possible role of attentional focus as a critical variable in speech treatments. If a similar external focus advantage is found during a speech task, it may change speech treatment for persons with speech and/or voice disorders since such therapy traditionally uses an internal attentional focus (e.g., phonetic placement therapy). Future studies are exploring the effects of attentional focus on electromyographic activity and on speech production skills (e.g., singing, public debating, speech disorders). References 1. Wulf, G., & Prinz, W. (2001). Directing attention to movement effects enhances learning: A review. Psychonomic Bulletin & Review, 8, Wulf, G., Höß, M., & Prinz, W. (1998). Instructions for motor learning: Differential effects of internal versus external focus of attention. Journal of Motor Behavior, 30, Wulf, G., McNevin, N., & Shea, C.H. (2001). The automacity of complex motor skill learning as a function of attentional focus. The Quarterly Journal of Experimental Psychology, 54A (4), Wulf, G., Lauterbach, B., & Toole, T. (1999). Learning advantages of an external focus of attention in golf. Research Quarterly for Exercise and Sport, 70, Vance, J., Wulf, G., McNevin, N., Töllner, T., & Mercer, J. (2004). EMG activity as a function of the performer's focus of attention. Journal of Motor Behavior, 36 (4), Absolute Error (2 X 2 X 4: Focus X Structure X Block)* During practice, significant effects were found for focus, structure, block, and structure X block. During retention, a significant effect was found for phase (last block of practice and first block of retention/transfer). During transfer, significant effects were found for structure, phase, and focus X phase. Variable Error (2 X 2 X 4: Focus X Structure X Block)* During practice, significant effects were found for focus, structure, and block. During retention and transfer, significant effects were found for structure and phase. *Only significant effects are reported. A special thank you to all of the study’s participants, to Alisa Schleper who assisted in data collection, and to the Clinical Aphasiology Conference and NIDCD for a student fellowship awarded to the first author.