Variation inflation factor-based regression modeling of anthropometric measures and temporal-spatial performance: Modeling approach and implications for clinical utility.

BACKGROUND: Understanding the relationship of underlying anthropometry to temporal-spatial performance is critical to appropriate assessment of patients with ambulatory dysfunction. The current body of literature has established the importance of limb length in this relationship. This study sought to re-examine these relationships in light of recent trends in body habitus and obesity, using Variation Inflation Factor analysis to optimize the model. METHODS: Elementary school children (n=452; ages 5-13) were tested during walking at a self-selected speed across an instrumented walkway. Temporal-spatial and anthropometric measures were compiled for all children. The relationship between temporal-spatial and anthropometric measures was assessed using regression modeling with Variation Inflation Factor optimization. FINDINGS: Body weight was identified as a significant predictor of cycle duration, stride length, stance duration, and step width during initial modeling. However, it did not meet the constraints imposed during Variation Inflation Factor optimization and was removed from the final models. The final optimized models identified significant relationships between both temporal-spatial parameters of interest and other temporal-spatial measures, with the best fit identified for walking speed (R2=0.6148). INTERPRETATION: The use of the Variation Inflation Factor constraint during the regression modeling process ensured final models composed of truly independent predictor variables. The resulting models are highly robust and highlight the complex relationships between body structure, functional conditions, and walking performance. These models have value for routine clinical assessment of ambulatory dysfunction, and may provide a foundation for classifying temporal-spatial performance in the context of multiple contributing parameters.

Participation and community-based walking activity after neuroprosthesis use in children with hemiplegic cerebral palsy: A pilot study1.

PURPOSE: To explore the effects of neuroprosthesis use on participation, level of community-based walking activity, safety and satisfaction in children with hemiplegic CP. METHODS: Eleven children (mean 9 years 11 months) with hemiplegic CP Gross Motor Function Classification System (GMFCS) Level I and II participated in a 16-week intervention using the Ness L300 neuroprosthesis. Outcome measures included satisfaction and performance with self-selected participation goals (Canadian Occupational Performance Measure (COPM)), level of community-based walking activity (Step Watch Activity Monitor (SAM)), trip and fall frequency (caregiver report) and a satisfaction questionnaire. RESULTS: Significant (p< 0.001) improvements in performance and satisfaction with self-selected participation goals (COPM) were demonstrated. No significant changes were noted in SAM values. A significant (p= 0.01) decrease in trips was demonstrated from baseline to post. Satisfaction with the device was high. CONCLUSION: Results indicate that daily neuroprosthesis use may improve performance and satisfaction with participation goals and reduce trips. No changes in community-based walking activity were noted. Further study is needed to examine response based on GMFCS levels, across geographical regions and between FES neuroprosthesis and a control group.

An exploratory study of gait and functional outcomes after neuroprosthesis use in children with hemiplegic cerebral palsy.

PURPOSE: To evaluate the immediate orthotic, total and therapeutic effects of functional electrical stimulation (FES) neuroprosthesis use on clinic based measures of gait and function in children with hemiplegic cerebral palsy. METHODS: Eleven children (mean 9 years 11 months) participated in an FES neuroprosthesis (Ness L300) intervention (4 week accommodation period followed by 12 weeks of daily use) and were assessed at baseline and post in stimulation off and stimulation on conditions. Measures included clinic based outcomes of gait and function. RESULTS: No significant immediate orthotic effects were observed. Significant (p < 0.01) total effects were noted for dorsiflexion at initial contact, Six-Minute Walk Test (6MWT), and walking speed. A significant therapeutic effect was found for steps off path on the Standardized Walking Obstacle Course (SWOC). CONCLUSIONS: Results support previous findings of neuroprosthesis total effects on gait and provide some evidence for effects on function. Therapeutic effects remain unclear. Implications for Rehabilitation In this study, children with hemiplegic CP did not demonstrate immediate improvements in gait or function at their first clinic visit using the FES neuroprosthesis device suggesting one visit using the device is not sufficient to determine potential benefits. Over time with daily use of the FES neuroprosthesis, ankle dorsiflexion in swing and at initial contact, walking speed and endurance increased with the device worn. Overtime, no carryover effects in ankle dorsiflexion in swing and at initial contact were noted at the end of the intervention period with the device off. Clinicians should consider purchasing units to loan or rent to individuals to trial a device at home before determining long-term potential for benefit.