Assessment of Neural and Motor Performance

The neural basis underlying motor performance in children using a prosthesis has been severely understudied resulting in minimal empirical evidence. With the use of low-cost 3D printed prosthetics, the purpose of this study is to examine the assessment of primary motor cortex activation and the representation of gray and white matter in a child with congenital limb loss. This will be accomplished by cross-examining results from fNIR and Anatomical Magnetic Resonance Imaging (MRI). The proposed research uses anatomical MRI to test if children with unilateral congenital partial hand reductions demonstrate less gray and white matter in the motor representation zones. Moreover, the proposed research will focus on an assessment of motor performance using continuous and discrete tasks with a robotic manipulandum. Assessment of motor performance and neural networking are critical to increasing our limited knowledge of how the child increases the number of motor repertoires.

The investigators anticipate enrolling a total of 40children between 3 and 18 years of age. Specifically, two groups of children will be recruited; children with unilateral congenital upper-limb reductions (n=20) and age and sex-matched control group of typically developing children (n=20). Considering the effect size from preliminary data and to account for a 10% drop-out rate, a total sample of 40 subjects will provide 80% power to detect a true standardized effect size. All subjects including controls will attend four data collection sessions that will include: one fitting session, second to obtain a baseline, the third visit will be one month after baseline, and the final visit will be four months after baseline. Participants will attend an initial measurement session to take a 3D scan of the affected and nonaffected upper limbs as well as several anthropometric measurements. During this session, three pictures of the upper limbs will be taken which will also be used to verify the fit the prostheses in a process previously validated by our research team. The subjects will then perform an anatomical MRI scan. The MRI scan is not a clinical scan intended for diagnostic or therapeutic purposes. The research participants will then be asked to come for two testing visits. During the first testing visit (visit 1), participants will be fitted with the prosthesis and required adjustments to improve comfort and avoid pressure point will be performed. After fitting the prosthesis, participants will be given 15 minutes to explore the prosthesis and adjust the tensioner dial to regulate the opening of the fingers to perform the Box and Block Test. After the training and accommodation period, participants will be asked to perform 3 trials of flexion and extension of each wrist with and without the prosthesis and 3 different trials of the Box and Blocks Test for each hand while monitoring neural activity of the primary motor cortex using a fNIRS device. After a brief period of rest and encouragement, the subject will be asked to perform eight trials of discrete (four trials) and continuous (four trials) tasks using a robotic manipulandum (InMotion Arm Robot, Interactive Motion Technologies, Inc., Cambridge, MA, USA). These tasks have been previously used for the assessment of changes in upper-limb performance and the effect of different treatments in the recovering of motor function of children with acquired or congenital hemiparesis, ataxia, and hemiparesis. This data collection performed at baseline will be performed again one and four months after baseline. Eight weeks after the baseline measurements, participants will be asked to visit our laboratory for a second time and perform the same assessments. Between the testing visits, participants will be encouraged to use the prosthesis for a minimum of 2 hours a day.