CENTRE FOR HUMAN MOVEMENT ANALYSIS

Research to Practice: The Centre for Human Movement Analysis

By Naznin Virji-Babul, Research Director

Down Syndrome Research Foundation and Centre for Human Movement Analysis

Queen Alexandra Centre for Children's Health, Victoria, B.C., Canada

In recent years, clinicians have come under increasing pressure to demonstrate the effectiveness of treatment outcomes, to streamline intervention programs and to show treatment carry-over into functional activities. However, in a clinical setting there is very little, if any, time or resources allocated for research endeavors. In academic settings, researchers are becoming more aware of the need for multidisciplinary research to answer both basic and applied research questions. The Centre for Human Movement Analysis (CHUMA) was therefore created to bring together clinicians, researchers, and community partners interested in participating in research on human movement in general, and on movement disorders in children and adolescents in particular. CHUMA is a partnership between the Queen Alexandra Centre for Children's Health (QACCH), the University of Victoria (UVIC), and the Down Syndrome Research Foundation (DSRF). The Centre was awarded a three-year development grant from the Queen Alexandra Foundation and was established in September 2001.

From the left: Gray Eakins (CHUMA Administrator), Eynn Purves (Clinical Coordinator), Llewellyn Fonseca (Co-op student, UVIC), Ajay Kumar (Graduate Student, UVIC), Naznin Virji-Babul (Principal Investigator).

The focus of the Centre is on multidisciplinary research related to movement, clinical assessment of movement disorders, evaluation of current clinical interventions, and development of new interventions and technology. The lab is equipped with a six-camera Vicon motion analysis system, an AMTI portable force platform, and an eight- channel Delsys EMG system. The uniqueness of the center stems from the active collaboration between clinicians and researchers that is driven by clinical needs and questions, yet is in the forefront of new inquiry with respect to clinical issues and interventions.

Faculty and students from the Departments of Mathematics and Statistics, Physical Education, Psychology, and Mechanical and Electrical Engineering from the University of Victoria have collaborated with physical and occupational therapists in the Child and Family Rehabilitation program (QACCH) to develop research questions and design clinically relevant projects. The recent acquisition of a Omega 151-Channel Magnetoencephalography System (MEG) by the Down Syndrome Research Foundation will provide new and exciting opportunities for collaboration to understand the neural basis of motor control and motor learning.

A brief description of some of the current work currently underway at CHUMA follows:

Evaluating the effectiveness of constraint induced movement therapy (CIMT) in young children with hemiplegia.

(Joan Glover, Catherine Mateer, Barbara Smith)

Upper limb dysfunction is of particular concern in children with hemiplegia due to the implications in both sensory-motor and cognitive domains. These children demonstrate early poverty of movement on the affected side, and often avoid use of the affected arm. The unaffected side is used predominantly during play and manipulative activities, leading to decreased muscle strength, increased spasticity and asymmetrical posturing in the affected arm. Neglect of the affected side also becomes more pronounced with increasing use of the unimpaired arm and hand causing further impairments in sensory function. In addition, many children with hemiplegia exhibit delays in cognitive and language development as a consequence of either the brain injury itself or of limited experiences/ opportunities in their activities and social interactions.

Currently, physical and occupational therapy of the upper limb in children with hemiplegia is directed at increasing mobility, strength, and frequency of use of the affected arm, as well as reducing spasticity. Substantial effort is also focused on assisting the child in compensating through use of the unaffected limb.

Recently, there has been renewed interest clinically in investigating constraint induced movement therapy (CIMT). CIMT involves constraining the use of the less affected arm for 90% of waking hours for two weeks, while intensively training the use of the more affected arm through massed practice and task repetition (Taub et al, 1999). CIMT has been shown to be highly effective in improving the use of an impaired upper limb in adults with hemiplegia, following stroke (Blanton & Wolf, 1999; Taub, Uswatte, & Pidiki, 1999; Taub & Wolf, 1997), and there have been a few reports of effectiveness of CIMT in children with cerebral palsy (Charles, Lavinder, & Gordon, 2000; Crocker, McKay-Lyons, & McDonnell, 1997).

We have just completed a two-week intervention using CIMT with six children with hemiplegia, aged six to 13. Data on specific standardized clinical outcomes (such as upper limb function, upper limb muscle strength and mobility, self-care and specific parameters of the quality of movement) as well as full-body motion data from the Vicon system to compute changes in gait and upper limb joint angles pre- and post- intervention were collected. We are currently analyzing the data.

Evaluation of the Wilbarger protocol in decreasing sensory defensiveness in children

(Susan Gmitroski, Kimberly Kerns, Susan Siklos)

The purpose of this project is to assess the effectiveness of a treatment intervention used by occupational therapists called the “Wilbarger protocol”, used with children that display sensory defensive behaviours (such as avoidance or hypersensitivity to certain types of touch, sounds, light, smells, tastes or movements. The Wilbarger protocol includes parent education, introduction of a “sensory diet” to maintain a child's optimal level of performance, and a direct intervention of deep pressure and joint compression. The results of this research will help occupational therapists determine best practice for the treatment of sensory defensiveness. Pilot work for this study will begin in the next couple of months.

Stepping over obstacles: anticipatory modifications in children with and without Down Syndrome

(Naznin Virji-Babul, Michelle Brown)

Children with Down Syndrome (DS) often exhibit both motor and perceptual difficulties that impact on motor development. While specific sensory, motor, cognitive and perceptual impairments have been widely reported, the effects of how these localized deficits impact on perceptual-motor processing and function, remains unclear. One experimental approach that has been used to study the relationship between visual perception and motor output is through anticipatory gait modifications during obstacle crossing. Walking in the natural environment often involves anticipatory adaptations to either avoid or negotiate obstacles. The interaction between the visual perception of the obstacle and the execution of strategies to avoid the obstacle has recently received much attention in adults. However, few studies have examined the developmental basis of anticipatory behaviour during walking in individuals with intellectual disability.

In this study we investigated the strategies used by children with and without DS to negotiate obstacles. In order to evaluate the effect of the visual perception of the obstacle on the resulting movement strategies, we chose one obstacle height of a very minimal distance off the floor to create a “subtle” obstacle and compared the responses to an obstacle of a much increased height. Our results seem to indicate that visual information about the obstacle is not used consistently to modulate movements early in the gait cycle. Further study is currently underway to examine the trajectories of the hip and knee joints to determine whether any changes are observed in the execution of the movement during obstacle crossing.

Assessing the effectiveness of bilateral KAFOs in improving ambulation: a single case study

(James Filby, Pat Whitby-Bailey, Lynn Purves, Llewellyn Fonseca)

At the Queen Alexandra Centre's Prosthetic, Seating and Orthotic Service, an adult client with a history of progressive limb weakness, decreasing ability to ambulate, and fatigue was fitted with bilateral KAFOs. A stance control style joint was incorporated into one of the KAFOs, to control knee collapse. Full body motion data from the Vicon system was used to obtain both qualitative and quantitative measures of gait to determine the effectiveness of the KAFOs for this client. Data capture is complete and analysis is underway. Preliminary analysis shows an increase in walking speed and a more symmetric stride length with the KAFOs. In addition, there is a significant decrease in side to side trunk movement suggesting a more energy efficient pattern of walking. Figures 2A and B show the trajectory of the shoulder segment without (top) and with the KAFOs (bottom). Note the decrease in variability with the orthoses. These measures will be combined with the patient's subjective reports to determine the overall effectiveness of the KAFOs.

Fig 2A

Fig 2B

Towards gesture based affective computing

(Asha Kapur, Ajay Kapur, Naznin Virji-Babul, George Tzanetakis, Peter F. Driessen)

Humans have the ability to extract emotional content from non-verbal human interaction, facial expressions and body gestures. Training a machine to recognize human emotion is far more challenging and is an active field of research generally referred to as affective computing. Our team has designed a system that uses the Vicon motion capture system to obtain data of the gestural movement of the entire body to determine emotion. Gestural data from five subjects were collected depicting four emotions: sadness, joy, anger, and fear (see Figure 3). Feature extraction algorithms using a custom built MATLAB software is currently being used in conjunction with a variety of machine learning techniques to experiment with machine's perception of human emotion.

Children's ability to perceive human motion and distinguish ‘typical' from ‘atypical' human motion

(Naznin Virji-Babul, Maggie Shiffrar, Kimberly Kerns, Asha Kapur, Eric Zhou)

As inherently social creatures, humans must accurately perceive and interpret the actions of other people. Previous research has demonstrated that the visual perception of human movement differs from the visual perception of object movement. What might account for this difference? One possibility is that visual analyses are particularly sensitive to human movement because humans have a lifetime of experience watching other people move. Another possibility relates to the fact that human movement is the only category of visual motion and people can both produce and perceive. As a result, the visual processes underlying the perception of human movement benefit from motor system input in a manner that fundamentally differs from all other visual motion processes. Thus, in adult observers, human motion perception may depend upon both visual and motor experience. Using Johansson's (1973; 1975) classic technique, point light displays of typical and atypical movements were created using the Vicon system (see Figure 3). In order to understand how perceptual capacity develops in children, we are currently examining how children with and without developmental disabilities perceive human action.

Fig 3