Proprioception in Cerebral Palsy

1. Proprioception in Cerebral Palsy 1 Aaron, M.B., 2 Kaufman J., 2Warchausky, S., 1Langan, J.M., 2 Goble, D.J., 2Hurvitz, E.A. 1 Motor Control Laboratory, School of Kinesiology, University of Michigan 2 Department of Physical Medicine and Rehabilitation, University of Michigan Results Introduction RELATIONSHIP WITH COGNITIVE TESTS • Cerebral Palsy (CP) results from brain injury during the first years of life and is often associated with cognitive and motor impairment. • Evidence suggests that proprioception (i.e. the ability to know body position in space independent of vision) is also affected in CP. However, proprioceptive tests often involve cognitive factors such as memory for a target joint angle, which may be influenced by target duration (the length of time the stimulus is presented to the subject). • The present study, therefore, sought to determine the influence of target duration and various cognitive factors on a memory-based joint position matching test of proprioceptive ability. PROPRIOCEPTIVE MEMORY IS MORE VARIABLE WITH SHORTER TARGET DURATION Processing Speed • While there is a positive but weak correlation between visual processing time and variable error in the 2s hold time duration, there is a positive but moderate correlation in the 15 s target duration. Visuospatial Ability Methods • Participants: • Five individuals with CP (age range 23-50yrs) • Active elbow range of motion was approximately normal and low measured spasticity (Ashworth<2) • Overall, CP participants did not consistently overshoot or undershoot during the different hold time durations. • CP participants had less variable matches with a longer hold time duration. 15s DURATION IMPROVEMENT IS PORPORTIONAL TO 2s DURATION PERFORMANCE • There is no correlation between the CP participants’ ability to judge line orientations and their variable error in either of the target durations. • Proprioceptive Test: • Target elbow angles (20 & 40 deg) were presented to the blindfolded participant by passively extending his/her elbow. The target position was held for either 2s or 15s before returning to the start position at which time the participant was asked to actively reproduce the target position with the same arm. Conclusions • The results from this study demonstrate that with increased target presentation time individuals with Cerebral Palsy (CP) become more consistent in their proprioceptive matching. • This data also shows that individuals who were most variable in the 2s target duration improved the greatest with the longer duration time. • Finally, there is no strong correlation with any of the cognitive tests. However, the processing speed of a CP participant is positively but moderately correlated to proprioceptive matching consistency. • Cognitive Tests: • In addition to comparing the different target durations (i.e. 2s vs. 15s) correlations between proprioceptive performance and various cognitive tests were conducted. Cognitive tests included: Corsi Blocks – Spatial Working Memory Inspection Time – Processing Speed Line Orientation – Visuospatial Ability Acknowledgements • CP participants who showed the greatest variable error in the 2s target duration also showed the greatest improvement with a 15s hold time duration. We would like to acknowledge Dr. Susan Brown for use of the Motor Control Lab in the School of Kinesiology.