Exploring complex movement disorders through shared assessment– new challenges through shared assessment

by Diane Damiano, PhD PT

The Shared Movement Assessment Center (SMAC) in the Department of Neurology at Washington University specializes in the analysis of individuals with complex movement disorders for both clinical and research purposes. As an integral part of the Cerebral Palsy Center at St Louis Children’s Hospital, the primary goal of our research efforts is to improve the lives of persons with cerebral palsy by enhancing their motor capabilities.

Dr. Brunstrom reviewing a clinical study with Julie Weber, the research physical therapist. Looking on is our administrator, Freda Branch.

While the mission of the center as stated is hardly unique, the fact that it is housed within the Department of Neurology is somewhat atypical as most similar clinical and/or research facilities have tended for the most part to be housed within orthopaedic departments. Applications for motion analysis technologies within the medical field alone have been expanding rapidly in recent years not only across clinical disciplines, but across different diagnoses and with respect to other types of movement difficulties beyond level gait at a self-selected speed. Our facility is consistent with the above trends and in addition, we also exemplify the growing interest in relating biomechanical changes to the underlying neurophysiology of central nervous system disorders.

A view of the SMAC laboratory (showing four of the eight M2 cameras), where a diverse population of children and adults is investigated in clinical and research studies.

The SMAC houses a Vicon 612 motion analysis system with eight M2 cameras and Workstation, Polygon and BodyBuilder software, all provided by a grant from the National Center for Research Resources which requires that the system be requested and utilized by a team of at least three NIH-funded investigators. These individuals include Janice Brunstrom MD, a pediatric neurologist who is the Medical Director of the facility, Diane Damiano PhD, a physical therapist and researcher who primarily evaluates and studies individuals with cerebral palsy in collaboration with Dr. Brunstrom and others, Joel Perlmutter MD, a neurologist and senior scientist renowned for his work in adult movement disorders particularly Parkinson Disease, and John McDonald MD PhD, a well-recognized spinal cord researcher/ physician, who now heads the International Center for Spinal Cord Injury at Kennedy-Krieger Institute in Baltimore. In addition to the Vicon Motion capture system, the SMAC also has two Kistler force plates, a Noraxon 16 channel EMG system with MyoResearch software, a Biodex System 3, and a touch screen computer for patient questionnaires, among other quantitative assessment instruments and tools.

Picture of Lab Staff including (left to right) Julie Weber, Julie Anderson and Cole, Jason Wingert and Diane Damiano. Far wall is a mural of Forest Park in St Louis by two young local artists.

This movement assessment center was the vision of Diane Damiano, who was previously the Research Director of the Motion Analysis and Motor Performance Laboratory in the Department of Orthopaedics at the University of Virginia before coming to Washington University in St Louis in 2000. Her research focus has been almost exclusively on characterizing motor impairments in children with cerebral palsy and on evaluating the effects of existing or novel interventions on gait and gross motor function. Several years ago, she and her colleagues challenged the conventional wisdom that strengthening was contraindicated for those with spasticity, and they have since shown that direct muscle strengthening has a clinically important effect on motor performance in these individuals with no evidence of worsening spasticity. In fact, intense physical activity may actually decrease spasticity, an intriguing hypothesis that was proposed and recently tested by Dr. McDonald in collaboration with Dr. Sadowsky and Dr. Damiano in a project funded by the Christopher Reeve Paralysis Foundation. Using resistance torque and EMG measurements, these investigators demonstrated that, in addition to many other positive effects on health and function, subjects with spinal cord injuries who regularly used an FES-cycle had significantly lower spasticity and less of a need for spasticity reducing medication compared to age and injury matched non-exercising controls.

Figure 2. Sagittal view of upper extremity ‘reach to target’ task in person with cerebral palsy. The red dots indicate the pointing finger and wrist markers, and the blue dot indicates the target.

The clinical population we serve at the Shared Movement Assessment Center is very diverse and includes not only children with cerebral palsy, but has also included children and adults with other relatively common, rare, or as yet undiagnosed neurological deficits. Our interest also extends beyond (above) the lower extremity and we regularly employ the full body gait model in combination with EMG to evaluate dystonic posturing in the trunk and upper extremities. However, as initially intended, we are predominantly a research facility even though our clinical and research interests are inextricably linked.

One of the first novel intervention studies we conducted in our now two-year old center was an investigation lead by Dr. Janice Brunstrom on the use of levodopa for children with hypertonic cerebral palsy (CP). This project, funded by a Young Investigator Award from the Child Neurology Society, tested the hypothesis that many of the movement abnormalities in CP which are classically attributed to spasticity may actually be due to dystonia and would therefore respond positively to a medication that only addresses the latter symptom. Dr. Brunstrom believes that dystonia is far more common in CP than the 20% previously reported. We have conducted an open label trial of a short term course of levodopa on nine children with a diagnosis of spastic cerebral palsy who also demonstrated abnormal postures or movement patterns at rest, or when attempting to perform various motor tasks that resemble those seen in persons with primary dystonia. Our two main outcome measures were upper extremity kinematics and lower extremity balance measures. Since no single ‘standard’ upper extremity 3D kinematic model yet exists, we sought permission to use the one developed by Drs. George Rab and Anita Bagley from the Sacramento Shriners Hospital and adapted to Vicon motion capture systems by Ms. Robin Devoriak from the Portland Shriners Hospital . We chose two upper extrem­ity ‘reaching to target’ tasks, one which emphasized accuracy and one which emphasized speed of movement, and a rapid repetitive elbow flexion-extension task utilized previously by Dr. Amy Bastian, now of Kennedy-Krieger, as described in a published case study on the use of levodopa in an individual with CP with Dr. Brunstrom and colleagues, and which were adapted from Optitrak to our Vicon system. Figure 2 shows a stick figure for the dominant upper extremity ‘reach to target’ task in the sagittal plane with the target position shown in blue. The main output parameters we evaluated were peak wrist velocity (see Figure 3), 3D wrist path and endpoint error as the person attempted to hold the finger position on the target. Consistent and statistically significant improvements were noted in these parameters as a result of the medication at both freely chosen and fast reaching speeds; however, these were not associated with functional gains on the Melbourne Assessment of Unilateral Upper Limb Function. We also evaluated tandem gait performance before and after medication on those subjects who were independently ambulatory. Based on the results from our pilot study, a larger, longer duration controlled trial is being planned.

We are also nearing completion of a pilot study funded by the United Cerebral Palsy Research and Education Foundation testing the hypothesis suggested by Allison Arnold, Scott Delp and their colleagues at Stanford University that lower extremity extensor strength training alone will improve the 3D kinematics of crouch gait. Specifically, they proposed that as a result of intense strengthening, mid stance knee and hip position will be in greater extension with a concurrent reduction of stance phase hip internal rotation and adduction, and ankle dorsiflexion, if excessive. Future goals are to extend this investigation and perform dynamic simulations in collaboration with Arnold and Delp to model and predict which patients are more likely to respond positively to strength training and which may be more successfully treated through surgical or other interventions.

Two new investigations funded primarily though the NIH (NINDS and NCMRR) are just now underway in our center and involve close collabor­ation with neurologists and neuro­scientists, specifically Dr. Brunstrom, Dr. McDonald, and Dr. Harold Burton who is an expert on somatosensory function and functional brain imaging. The first project involves the characterization of sensorimotor function in cerebral palsy and its relationship to sensory processing in the brain. Jason Wingert, a doctoral candidate in the Movement Science Program at Washington University who has been in the center since its opening, has received fellowship awards from the NIH and the Foundation of Physical Therapy to help support this project in addition to support from UCP. The sensory testing includes precise quantification of tactile discrimination and proprioception in both the upper and lower extremities which will be correlated to temporal-spatial and kinematic gait performance during free and fast speed walking with and without vision of one’s lower extremities using ‘dribble’ glasses which allow one to look forward but not down (See Figure 4 overleaf for: a) photo of the dribble glasses and b) the proprioception testing device). Using the full body COM model and dual force plates, we will also evaluate standing balance with and without vision – in essence, a quantitative Romberg Test. We hypothesize that sensory performance and processing will be deficient in CP compared to normal and that sensory function will be related to motor performance. The second investigation is focused on quantifying the effects of a novel intervention in CP, motor-assisted cycling, on lower extremity coordination during reciprocal lower extremity activities such as active cycling and overground walking, modeled after the investigations by Drs. McDonald and Sadowsky on the use of FES-cycles in patients with spinal cord injuries. As a secondary goal, Dr. Burton will lead the fMRI investigation of potential changes in cortical activation in response to a standardized lower extremity sensory stimulus before and after the intense training. We are testing the hypotheses of whether imposed fast reciprocal movements alone, in the absence of electrical stimulation, can alter spinal circuitry and drive changes in the spatial extent and magnitude of activation in the motor cortex.

Figure 3. Data from a single subject with cerebral palsy showing faster reaction time, greater peak velocity and less endpoint fluctuation after the course of medication

Other important members of our team include Julie Anderson (Witka) who is now our part-time engineer in addition to being a full-time new mom to Cole (See lab photos); Julie Weber is a research physical therapist who plays an integral role in the assessment of both clinical and research subjects and Freda Branch who heads the administrative aspects of the cerebral palsy center in general as well as for our facility. Our program is obviously very dependent on strong collaboration among our center’s team and ‘outside’ clinical and basic scientists at Washington University and at other hospitals and universities across the country. In addition to projects we have initiated in our center, other investigators are encouraged to perform studies here with our assistance, for example, another doctoral student in the Movement Science Program mentored by Dr. Joel Perlmutter, recently completed a project evaluating arm swing in relation to lower extremity step length and cadence across gait velocities in patients with mild Parkinson Disease compared to age-matched healthy controls. Examples of nearly completed or newly initiated projects that involve multi­center collaborations include the Functional Assessment Research Group (FARG) investigations led by Drs. Chet Tylkowski and Donna Oeffinger at Lexington Shriners Hospital, and a newly funded randomized placebo controlled trial on hamstring botulinum toxin injections led by Dr. Phil Gates of the Shreveport Shriners Hospital with Dr. Brad Racette, a neurologist here at Wash U, as the site PI. We are committed to the idea that advances in our understanding of movement abnormalities and the effects that treatments have on these abnormalities involve precise quantification, creative exploration and extensive collaboration. We feel that the motion capture community, in particular, has served as an excellent model of the pursuit of excellence in measurement and evaluation and of the willingness to share information and expertise to move our respective fields forward.

Figure 4a The ‘dribble glasses used to test how much the loss of vision disrupts the gait kinematics and temporal spatial features. These data will be correlated with those obtained on our quantitative device (below) made in house that measures lower extremity proprioception.
Figure 4b

We appreciate this opportunity to introduce our center to the Vicon community and would like to thank Gerald Bishop and the STANDARD staff for this interest and assistance. If anyone would like to share information or to learn more about our center’s clinical and research efforts, please do not hesitate to contact us at (314) 286-1581 or at damianod@neuro.wustl.edu