Re-establishing postural stability as it relates to crossing the midline of the body in individuals with spastic diplegic cerebral palsy

The purpose of this study was to determine whether there were deficits in posture and postural recovery following bilateral perturbation in individuals with diplegic spastic cerebral palsy (CP) as compared to age matched controls. In addition midline crossing inhibition (MCI) was investigated in the lower extremity by reaction and movement time measures. The relationship between recovery of balance and cross lateral integration, a motor milestone, was also addressed.; Ten adults with spastic diplegic CP and ten neurologically normal participants completed this study. In a standing position, utilizing the protocol developed by Eason and Surburg (1993) midline crossing behavior was assessed. Using the lower extremity, participants performed a choice reaction time (CRT) and movement time (MT) task. Static balance assessment consisted of stance on a force platform measuring sway path excursion, mean frequency and elliptical sway area. During the postural perturbation protocol, a bilateral stimulus was delivered simultaneously to the tibial nerves resulting in an involuntary contraction and posterior displacement of the individual's center of gravity. Phase duration was calculated as well as elliptical sway area prior to the perturbation. This variable was calculated in order to compare these measurements with static balance results. Balance protocols were conducted with and without vision. Intraclass correlation coefficients were calculated in order to measure the reliability of all scores. Multivariate analysis and univariate analyses were conducted to determine whether dependent variables were significantly different between the two groups. Pearson Product Moment correlation coefficients were computed to examine the relationship between reaction time and postural perturbation.; Analysis of data revealed that adults with CP were significantly slower in both CRT and MT tasks as compared to age matched controls. Both groups were significantly slower in the contralateral direction of this task. Values for static balance were significantly different for adults with CP although values for mean frequency were greater for age matched controls. Differences were found during the postural perturbation protocol; adults with CP took longer to recover to a stable stance than the controls. No relationship was evident between CRT and MT measures and postural perturbation recovery time.