Children with Cerebral Palsy have Altered Cortical Oscillations when Planning and Executing their Motor Actions.

Research Report
Population: Pediatric

Max J Kurz, PhD, Associate Professor, Physical Therapy Department, Munroe-Meyer Institute for Genetics and Rehabilitation

Amy Proskovec, MS, Graduate Research Assistant, Center for Magnetoencephalography, University of Nebraska Medical Center

Jamie Gehringer, BS, Graduate Research Assistant, Department of Physical Therapy, Munroe-Meyer Institute, University of Nebraska Medical Center

Elizabeth Heinrichs-Graham, PhD, Assistant Professor, Center for Magnetoencephalography, University of Nebraska Medical Center

Tony Wilson, PhD, Associate Professor, Center for Magnetoencephalography, University of Nebraska Medical Center

Keywords: Plasticity, Cerebral palsy, Motor Planning, Brain Imaging

PURPOSE:  Recent therapeutic trends have shifted towards a task-orientated approach, which focuses on the neurological impairments first, with a secondary emphasis on the musculoskeletal impairments resulting from the neurological insult. Despite this change in focus, we still have limited insight on how the brain insults seen in children with cerebral palsy (CP) impact their ability to plan, execute and correct movements. Our prior magnetoencephalography (MEG) brain imaging investigations have revealed that the sensorimotor cortices exhibit robust changes in beta oscillatory activity (14-30 Hz) during the motor planning stage, with subsequent changes in the gamma-frequency range (>50 Hz) when the plan is executed. The aim of this investigation was to evaluate if the beta and gamma sensorimotor cortical oscillations are different in children with CP relative to those seen in typically-developing (TD) during a knee motor task.

SUBJECTS: Children with a diagnosis of either spastic diplegic or hemiplegic CP (N=16; Age = 15 +/- 3 yrs.) and GMFCS levels between I-III. A cohort of age-matched TD children (N=20; Age = 14 +/- 3 yrs.) served as a control group.

MATERIALS/METHODS:  High-density MEG was used to quantify beta and gamma cortical oscillations as the children performed an isometric, knee-extension target force matching task. Advanced beamforming methods were used to image the source of these neural oscillations, and the output from the force transducer was used to quantify the child’s motor performance.

RESULTS: Compared with the TD children, the children with CP had uncharacteristic beta oscillations during the motor planning stage within in the supplementary motor area, left premotor cortices, precentral gyrus and left prefrontal cortex (P < 0.001; cluster-corrected). The children with CP also had weaker gamma oscillations during the motor execution stage within the premotor cortices (P < 0.001; cluster-corrected). Behaviorally, the children with CP took longer to initiate the isometric force (CP Children = 0.67 +/- 0.06 sec; TD Children = 0.45 +/- 0.03 sec; P=0.0003), had larger overshoot errors (CP Children = 87+/- 19%; TD Children = 35 +/- 6%; P=0.004), and took longer to reach the target after they initiated their motor actions (CP Children = 2.8 +/- 0.2 sec; TD Children = 2.3 +/- 0.1 sec; P=0.004).

CONCLUSIONS: The sensorimotor cortical oscillations that serve motor planning and movement execution are abnormal in children with CP, and likely play a central role in the impaired motor actions seen in these children.

CLINICAL RELEVANCE: The new neural indices established in this proposal may provide critical insight on why some children with CP show vast improvements after physical therapy, while other children are classified as non-responders. Potentially, the sensorimotor cortices of non-responders may be unable to compute an adequate motor plan. Physical therapy treatment strategies that focus on teaching these children how to plan their motor actions may result in clinically relevant improvements.

Kurz, Max J, PhD; Proskovec, Amy , MS; Gehringer, Jamie E, BS; Heinrichs-Graham, Elizabeth , PhD; Wilson, Tony W, PhD. Children with Cerebral Palsy have Altered Cortical Oscillations when Planning and Executing their Motor Actions.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online.