Effects of Long-term Tai Chi, Meditation, and Aerobic Fitness Training on

Executive Attention Skills

Teresa HawkesWoollacott Laboratory

Human Physiology Institute of Neuroscience

Background

• More efficient executive attention function has been correlated with:– Meditation training (Chan & Woollacott, 2007; Slagter et al, 2007;

Tang et al, 2008).– Aerobic fitness training (Hatta, et al, 2005).

• Mechanisms underlying attentional improvement are hypothesized to differ in the two skills:– Meditation: long term practice results in plasticity in

microcircuits subserving the executive attention network (Lazar, et al, 2005).

– Aerobic finess: improved blood-flow to brain.• Executive attention is required for motor learning

(Halsband & Lange, 2006).

Sitting MeditationAttention Function Benefits

• Numerous studies of meditation reveal consistent evidence of state and trait training effects including – Enhanced executive function (Chan & Woollacott, 2007), – Orienting (Jha et al, 2007), – Management of attentional resources in the

attentional blink paradigm (Slagter, et al, 2007).

Aerobic FitnessExecutive Function Benefits

• Speed of information processing indexed by P300 during visual or auditory oddball tasks (Kamijo et al, 2004):– latency and reaction time decreases– accuracy increases

• Enhancement of reaction time and accuracy on Erikson flanker tasks in older adults who take up aerobic exercise (Hatta et al, 2005)

Tai Chi

• Is a form of moving meditation (Luskin, 2004).• Requires motor learning, and thus executive attention

(Halsband & Lange, 2006)• Same range of metabolic equivalents (METs) as Aerobic

Walking: 4-6 METs (Li, et al, 2001).• Has been shown to be superior to aerobic walking for

cardiovascular function (Audette, et al, 2006).• Improves neuromuscular and biomechanical responses to

perturbations in elders (Gatts & Woollacott, 2006, 2007).• Improves tactile acuity (Kerr, et al, 2008).• Improves immune function in elders (Irwin, et al, 2003).

Executive Attention

• Components (Miyake, et al, 2000; Hausdorff, et al, 2006)

– Inhibition (Tower of Hanoi, Stroop, Go No-go, Random Number Generation)

– Updating (Random Number Generation, Operation Span)

– Shifting (Stroop, Wisconsin Card Sort)• Go No-go: Inhibition

– This component is required for Sitting Meditation• Visuo-spatial Task Switch

– Inhibition, Updating, & Shifting

Question: Do different kinds of executive training produce different training outcomes?

Summary & Knowledge Gap• Tai Chi, a form of moving meditation, combines

both moderate aerobic exercise and executive attention training.

• Therefore it could be hypothesized that Tai Chi training will produce greater improvements in executive function than meditation or aerobic fitness training.

• In an uncontrolled study, Matthews & Williams, 2008 found positive correlation between Tai Chi training and improvements in executive attention function.

Hypothesis

• Executive attention performance, as measured on a visuo-spatial task switch test (VSTS), will be most efficient in Tai Chi experts, followed by exercising meditators, with aerobic walkers and meditators being equal, and all four groups showing significantly more efficient performance than sedentary control participants

• Efficient executive performance = % switch costs.

Methods

• Subjects: We are testing persons trained in Tai Chi, meditation, meditation + exercise, and aerobic fitness and comparing them to non-practicing controls.

• Inclusion criteria: Experts must have 5 yrs+ training, 3x or more/wk, 50 min/session experience.

• No history of physiological or cognitive abnormalities.

• Subjects in the current data set are aged 28-69. • We are working to education-match subjects.

Tests

• Visuo-spatial Task Switch (VSTS) with dense array EEG (Multi-point Executive attention function)

• Sustained Attention Go No-go (Sitting Meditation Proficiency – 1 point attention focus)

• Leg Kick Motor Control Assessment (Tai Chi proficiency – motor attention function, neuromuscular function, skeleto-muscular integrity)

• Rockport 1-mile Walk (Cardiovascular fitness)

Visuo-Spatial Task Switch (Mayr Laboratory, University of Oregon)

Subject Instructions

Meditation Proficiency

Sustained Attention Go No-go(Smallwood, et al, 2008)

• Part 1– 1 or 2 targets per block, 24 blocks (test duration: 20-30 minutes).

• Part 21 = On Task: Made a mistake. Did not make a mistake2 = Off Task: Tuned out. Maybe made an error. Zoned out – have no idea.

Dependent variables: RT for non-targets (assessing ongoing attention), efficacy of response inhibition, and % accuracy assessing own performance.

Tai Chi Proficiency – Leg Kick

A ten camera system with 31 reflective markers (Motion Analysis Corporation, Santa Rosa, CA) capture subject whole body motion at 60 Hz. DVs: Hip & Torso angles; Coordination of body segments.

Rockport 1-mile walk

Subjects are fitted with an Athletic Connection Polar E600 heart rate monitor (Polar Electro-USA). A chest strap with heart sensor sends information on heart rate and walk time to a wrist recorder. (http://www.exrx.net/Calculators/Rockport.html: estimated VO2max, METs, population average, performance rating.)

Preliminary results

Group n’s– Tai Chi (n=9)– Sitting Meditation (n=2)– Meditation + Exercise (n=3)– Aerobic Fitness (n=3)– Sedentary (n=3)

Meditation Proficiency Test

Single Point Executive Attention Function

Tai Chi Proficiency

Leg Kick

M+E, 30 y, 63 yo F

Med, 35 y, 69 yo MTai Chi 10y, 51 yo F

Aerobics 35 y, 66 yo M Sedentary, 52 yo F

Sedentary, 28 yo F

Hip Flexion Angle

Aerobic Capacity

Measurements: 1) 256-channel dense array EEG, 2) button press reaction time, 3) accuracy, and 4) RT for: Rule 1: 144 trials. Rule 2: 144 trials. Rule 3: Switch trials - 288. No-switch trials - 288.

Inhibition, Shifting, and Updating (Miyake et al, 2000).

Task Switch Costs

(Mayr Laboratory, Univ.Oregon)

Limitations of the Pilot Study

• Limited number of participants (final number will be 30 or more per group)

• Age-matched• Education-matched• Computer experience-matched

• Experts are outperforming all non-expert subjects in each training modality.

• Very low switch costs (<8%) are clustered in the Tai Chi group.

Trends

Acknowledgments

• Committee– Marjorie Woollacott – Adviser– Terry Takahashi – Li-Shan Chou– Paul van Donkelaar

• Research Assistant– Wayne Manselle

• Undergraduate Research Assistant– Jackson Blackburn

• Special Thanks– All the individuals who volunteered their time as subjects and support staff.

• Funding– Mind & Life Institute, Francisco J. Varela Award, 2008.– Institute of Neuroscience, University of Oregon, Systems Training Grant, 2008-9.