Persistent poor outcomes for individuals with ADHD make it imperative to explore intervention approaches beyond medication, particularly interventions that could provide sustained improvements in control of hyperactive, impulsive and distractible behavior. Two lines of evidence converge to support a movement-based mindfulness training intervention as a potential stand-alone or adjunct treatment for the treatment of ADHD symptoms. First, decades of research, including from our lab, has established that many children with ADHD show impairments in motor control that parallel their impairments in behavioral and cognitive control. Second, there is mounting evidence that movement-based mindfulness interventions are effective for enhancing behavioral control in adults, although there has been limited examination in children. These lines of evidence suggest an outstanding opportunity for development of novel treatment approaches for ADHD through engagement of the motor system.
In this application we propose to examine the efficacy of a specific movement-based mindfulness intervention for children with ADHD - Tai Chi. This approach was chosen for a number of reasons: 1) extensive documentation in the research literature, 2) engagement afforded by a martial approach to mindful movement, and 3) scalability given the existing availability of Tai Chi instruction in the United States and the ease of performing gentle Tai Chi movements even in the presence of physical limitation. Consistent with the "Fast-Fail" approach in the first two years (R21 phase) we will investigate the impact of Tai Chi on the motor system targets our lab has established as highly correlated with measures of classic ADHD symptoms. Specifically, we will measure SICI (short-interval intra-cortical inhibition via TMS) and overt movement behavior resulting from failures of motor control (mirror overflow and motor impersistence). Milestones will comprise successful motor system target engagement in the context of Tai Chi training. The findings will lay a foundation for the clinical exploration of Tai Chi and other movement-based mindfulness training approaches in ADHD and other conditions where the motor system is implicated. Our brain-based approach further provides a clear path for reliable assessment as well as integration with the cognitive neuroscience literature on inhibition and other aspects of cognitive control.
The motor system provides a locus for the integration of multiple neural systems, with clear abnormalities in inhibitory function in ADHD. An intervention targeting the motor system stands to make productive contact with these motor system targets. Indeed, there is broad evidence for the efficacy of Tai Chi (and other mindfulness-based movement training) in addressing a wide range of issues, including high level cognitive functions such as attentional control.2 The majority of these effects have been established in adults, but given the greater brain plasticity documented in children,1 we have reason to expect strong effects in children. Indeed, successes have been reported in child populations as early as preschool.32 Moreover, there is a recognized need for physiologic biomarkers in mindfulness and movement training studies.15 Our robust ability to track changes in specific motor markers at behavioral and physiologic (from TMS) levels, provides an ideal target measure to establish specificity in a Tai Chi training intervention.
Overview of intervention
Tai Chi is a form of exercise with a variety of components and a strong cultural tradition. In consultation with experienced teachers of Tai Chi, we have received consistent feedback that "martial applications," and specifically push hands, will likely be a valuable component of training for children with high distractibility. Central to the martial practice of Tai Chi is a collaborative game called "Push Hands," in which partners attempt to push one another off balance without the use of strong effort. Push hands, and other Tai Chi inspired "games" will be used to motivate engagement in slower, more focused movement training: Tai Chi warm-up, postural and breathing exercises, and a section of a Tai Chi form. We expect these components to collectively drive learning and development of behavioral control in the motor domain, with high potential for impact on other features of ADHD.
The Tai Chi instructor, a graduate student from the Johns Hopkins Tai Chi club, has extensive experience with youth instruction, as well as a keen understanding of the relationships between Tai Chi and "hard" martial arts from over 20 years of practice in martial arts, including 12 years of Tai Chi. An assistant instructor will additionally be engaged to assist with maintaining class focus. All instructors will be certified for ethical treatment of human subjects, as well as standards for youth physical education. Sessions will be held in an athletic facility on the Kennedy Krieger Institute (KKI) Greenspring campus. The athletic facility was designed and equipped for children with a range of abilities as part of the LEAP Program (Life-skills and Education for Students with Autism and other Pervasive Behavioral Challenges). It is advantageously located on a campus that is very convenient for most Baltimore area families. The facility moreover has a high-impact floating rubber floor. This environmentally friendly and slip-resistant flooring provides cushioning, which reduces fatigue and potential for injury to the participants during physical activities.
Recruitment and testing
Recruitment, preintervention data collection (see below for details), and logistical preparation will commence as early as is practicable once the funding period is established. At least three sessions will be completed, scheduled so as to ensure sessions both during the school year and during summer break. Six-eight students will be enrolled in each session, with a target of five-seven children successfully completing each session and participating in preintervention (three week period prior to the start of classes) , midpoint intervention (during weeks four-six of classes), and postintervention (the three weeks after classes complete) physiologic and behavioral assessments. Outcomes will be computed as the difference between preintervention and postintervention scores, while midpoint intervention scores will be used to give a sense of the timecourse of change for each measure.
It is expected that one student on average will be unable to successfully complete a given class series. Enrollment procedures will be adapted if necessary. As per our "intent to treat" approach (see below), children will be included in primary analyses irrespective of adherence to protocol (i.e., attendance). However, children may be requested to leave the class if their absence becomes disruptive. In total, we anticipate a minimum of 18 participants completing the training out of a total of 21 children enrolled.
