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Center for Motor Behavior & Pediatric Disabilities

Research Participants Needed for the Following Study:  

Modulation of Leg Coordination Patterns in Infants with and without Down Syndrome

Rosa Angulo-Barroso, Ph.D. (Principal Investigator)   

Timothy R.B. Johnson, M.D. (Co-investigator)   


       Infants learn complex and adaptive forms of motor behavior as the information generated by their own bodies (action) is dynamically coupled with the information available in the context (perception). Infants must, therefore, attend to relevant information for effective behavior to be selected. 

       With their classic conjugate reinforcement procedure, Rovee-Collier and her colleagues (Rovee-Collier & Gekoski, 1979) have repeatedly shown that infants increase their leg movement frequency to control a mobile when it is attached to their ankles. However, this traditional experimental design allows multiple motor solutions to the task (Collier, 1993) and therefore, it provides limited information about the infants’ capacity to explore and select specific motor solutions. Although infants with Down syndrome acquire new behaviors much slowly, they are complex and adaptive organisms as well. Furthermore, the same learning principles that take into account individual characteristics and task demands are applicable to them. How infants discover task-specific patterns of coordination is the general question addressed in this study. Specifically, I am interested in the process by which infants solve motor problems in real time, that is, over the span of minutes rather than weeks or months. 

The purpose of this study is two-fold: 

(1) to examine the motor activity profiles of infants with and with Down syndrome, and

(2) to examine the exploratory strategies infants use to control their legs when placed in a special reinforcement procedure. 

       To obtain the reinforcement - the movement of an overhead mobile - infants must discover which pattern of leg movement is the one that triggers the mobile. Infants will need to selectively attend to relevant sensory information and explore their capacities, that is, engage in a perception-action process. To solve the problem at hand, that of moving a mobile with a new or non-preferred leg movement pattern, the stability of previously preferred movement patterns will be temporarily lost and new forms of movement will become the preferred ones. This study will provide useful information about the process by which infants learn and remember how to solve motor problems. In addition, the experimental procedure utilized in this study has some clinical intervention potential. If indeed infants can select a specific pattern of movement to obtain the reinforcement, then we can design intervention programs using this experimental procedure so functional movements are reinforced and therefore practiced. In addition, learning about the physical activity profiles of infants with Down syndrome may provide useful information for early intervention in a population that has a high incidence of adolescent and adulthood obesity.

 2.Research Hypothesis

This study is composed of 5 experiments:


a.  To compare and contrast the motor-perceptual learning capabilities of infants with and without Down syndrome

Hypothesis 1a: Infants with DS will learn the contingent relationship between leg movement and motion of the mobile 2 months later than normally developing infants.

b.  To compare and contrast the overall level of spontaneous movements in infants with and without Down syndrome.


       The participants will be normally developing infants and infants with Down syndrome from 3 to 7 months of age. Infants enrolled in this study will come to the Motor development laboratory for 1 to 5 45-minute sessions. Their participation will be voluntary and contingent upon their parents’ consent. An effort will be made to have equal distribution of gender, and inclusion of minorities in the study.

      There is minimal risk involved in this study. Parents will remain close to their infants at all times. The infant will be secure and save in the crib, or in the infant seat. The electrical devices we utilized are grounded and isolated. We have previously used these devices in other experiments without any problems.

            There is no guarantee that infants, parents or caregivers will directly benefit from participating in this study. However, parents may learn more about the perceptual-motor capacities of their infants, and new ways to stimulate their physical activity.

4. Data Collection

We will place infants in a supine or seated position with a view of an overhead mobile or a TV screen. We will place small goniometers (Penny-Giles XM110 & XM75) and EMG electrodes (Therapeutics Unlimited) on the surface of the infant’s limbs. We will record the output signal from the goniometers (i.e. angular displacement) and electrodes (i.e muscle activity) as the infant moves. The goniometers, which will be interfaced with a computer and customized software, will allow us to evaluate, in real-time, the characteristics of the joint movement and therefore, to determine when the reinforcement (movement of the mobile or picture in the screen) should be given. When the electrodes and the goniometers are in place, we will videotape and collect data for no more than 20 minutes. At the end of the session, we will weight and measure the infant. In addition, we will place an actigraph (small watch-type device that counts frequency of movements) on the infant’s ankle to be worn for 48hr. 

       There is an immense void in our knowledge about physical activity during infancy as well as learning processes at this early age.  If we understand how infants learn and remember tasks like this one, we will ultimately be able to improve the perceptual and motor development of disabled infants. Also, better knowledge of the physical activity patterns of infants with Down syndrome may help to better design interventions to ameliorate the incidence of obesity in this population.

If you are interested in volunteering for this study, please send an email to Rosa Angulo-Barroso at: or to Dale Ulrich at or call them at 734-936-2607.

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Center for Motor Behavior & Pediatric Disabilities
401 Washtenaw Ave
Ann Arbor, MI 48109-2214
(734)936-2607, Fax (734)936-1925

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Created September 1, 1999