The effect of botulinum toxin-A on neural and non-neural components of wrist hyper-resistance in adults with stroke or cerebral palsy.

BACKGROUND: Botulinum toxin-A (BoNT) is widely used to manage focal upper limb spasticity and is effective in reducing resistance to passive movement, as measured with the modified Ashworth scale. Discrimination and quantification of the underlying neural and non-neural components of hyper-resistance may further improve understanding of the effect of BoNT. OBJECTIVE: To explore the effects of BoNT on neural (NC), non-neural elastic (EC), and viscous (VC) components of resistance to passive wrist extension in adults with stroke or cerebral palsy and the association between the effects on wrist hyper-resistance components and clinical spasticity, pain and motor function scales. DESIGN: Pre-experimental study with pre- and post-intervention measurements at 6 and 12 weeks. SETTING: An outpatient clinic of a hospital. PARTICIPANTS: Adults with chronic stroke or cerebral palsy indicated for BoNT treatment for hyper-resistance in the wrist (N = 18). INTERVENTIONS: BoNT injections in the wrist and/or finger flexor muscles. MAIN OUTCOME MEASURES: Wrist hyper-resistance components, using the NeuroFlexor, and clinical scales (modified Ashworth scale, Tardieu scale, passive wrist extension, pain, Fugl-Meyer motor assessment of the upper extremity, and action research arm test). RESULTS: NC was significantly reduced 6 and 12 weeks post-intervention (median -11.96 Newton, P < .001 and median -9.34 Newton, P = .001, respectively); non-neural EC and VC showed no change. NC reduction 6 weeks post-intervention correlated significantly with BoNT dose (Pearson correlation coefficient rp = -0.56). No significant correlations were found between change scores in wrist hyper-resistance components and clinical scales. CONCLUSIONS: BoNT affected the neural component of resistance to passive wrist extension, while leaving the non-neural elastic and viscous components unaffected. This instrumented approach to quantify the effects of BoNT in the wrist and finger flexor muscles on the components of wrist hyper-resistance may have an added value for BoNT treatment evaluation in clinical practice.

Adherence to wearing prescription custom-made footwear in patients with diabetes at high risk for plantar foot ulceration.

OBJECTIVE: Prescription custom-made footwear can only be effective in preventing diabetic foot ulcers if worn by the patient. Particularly, the high prevalence of recurrent foot ulcers focuses the attention on adherence, for which objective data are nonexisting. We objectively assessed adherence in patients with high risk of ulcer recurrence and evaluated what determines adherence. RESEARCH DESIGN AND METHODS: In 107 patients with diabetes, neuropathy, a recently healed plantar foot ulcer, and custom-made footwear, footwear use was measured during 7 consecutive days using a shoe-worn, temperature-based monitor. Daily step count was measured simultaneously using an ankle-worn activity monitor. Patients logged time away from home. Adherence was calculated as the percentage of steps that prescription footwear was worn. Determinants of adherence were evaluated in multivariate linear regression analysis. RESULTS: Mean ± SD adherence was 71 ± 25%. Adherence at home was 61 ± 32%, over 3,959 ± 2,594 steps, and away from home 87 ± 26%, over 2,604 ± 2,507 steps. In 35 patients with low adherence (<60%), adherence at home was 28 ± 24%. Lower BMI, more severe foot deformity, and more appealing footwear were significantly associated with higher adherence. CONCLUSIONS: The results show that adherence to wearing custom-made footwear is insufficient, particularly at home where patients exhibit their largest walking activity. This low adherence is a major threat for reulceration. These objective findings provide directions for improvement in adherence, which could include prescribing specific off-loading footwear for indoors, and they set a reference for future comparative research on footwear adherence in diabetes.

Assessing gait adaptability in people with a unilateral amputation on an instrumented treadmill with a projected visual context.

BACKGROUND: Gait adaptability, including the ability to avoid obstacles and to take visually guided steps, is essential for safe movement through a cluttered world. This aspect of walking ability is important for regaining independent mobility but is difficult to assess in clinical practice. OBJECTIVE: The objective of this study was to investigate the validity of an instrumented treadmill with obstacles and stepping targets projected on the belt's surface for assessing prosthetic gait adaptability. DESIGN: This was an observational study. METHODS: A control group of people who were able bodied (n=12) and groups of people with transtibial (n=12) and transfemoral (n=12) amputations participated. Participants walked at a self-selected speed on an instrumented treadmill with projected visual obstacles and stepping targets. Gait adaptability was evaluated in terms of anticipatory and reactive obstacle avoidance performance (for obstacles presented 4 steps and 1 step ahead, respectively) and accuracy of stepping on regular and irregular patterns of stepping targets. In addition, several clinical tests were administered, including timed walking tests and reports of incidence of falls and fear of falling. RESULTS: Obstacle avoidance performance and stepping accuracy were significantly lower in the groups with amputations than in the control group. Anticipatory obstacle avoidance performance was moderately correlated with timed walking test scores. Reactive obstacle avoidance performance and stepping accuracy performance were not related to timed walking tests. Gait adaptability scores did not differ in groups stratified by incidence of falls or fear of falling. LIMITATIONS: Because gait adaptability was affected by walking speed, differences in self-selected walking speed may have diminished differences in gait adaptability between groups. CONCLUSIONS: Gait adaptability can be validly assessed by use of an instrumented treadmill with a projected visual context. When walking speed is taken into account, this assessment provides unique, quantitative information about walking ability in people with a lower-limb amputation.

Variability and stability analysis of walking of transfemoral amputees.

Variability and stability of walking of eight transfemoral amputees and eight healthy controls was studied under four conditions: walking inside on a smooth terrain, walking while performing a dual-task and walking outside on (ir)regular surfaces. Trunk accelerations were recorded with a tri-axial accelerometer. Walking speed, mean and coefficient of variation of stride times (ST) and the root mean squares (RMS) of trunk accelerations was calculated. Gait variability and stability were quantified using measures derived from the theory of stochastic dynamics. Regularity was indexed using the sample entropy (SEn) and the scaling exponent α derived form Detrended Fluctuations Analysis. Local stability (LSE) quantified gait stability. Walking speed was lower, but ST variability was not different for amputees than controls. RMS of medio-lateral accelerations was higher for amputees; SEn was higher, implying less predictable accelerations, and LSE higher, indicating decreased stability. The largest condition effect was present for walking outside: trunk RMS increased and LSE decreased. Differences in walking between amputees and healthy controls and their responses to perturbations revealed themselves in the magnitude, variability and stability measures of trunk accelerations. These results imply that quantifying the dynamical structure of trunk accelerations can differentiate between groups with different walking abilities and between conditions of increasing difficulty and may therefore provide a useful diagnostic tool.

The energy cost for the step-to-step transition in amputee walking.

The purpose of this study was to investigate whether the increased energy cost of amputee gait could be accounted for by an increase in the mechanical work dissipated during the step-to-step transition in walking. Eleven transtibial amputees (AMP) and 11 age-matched controls (CO) walked at both comfortable (CWS) and fixed (FWS, 1.3m/s) walking speed, while external mechanical work of each separate leg and metabolic energy consumption were measured. At FWS the metabolic energy consumption (E(met)) was significantly higher in AMP compared to CO (3.34 Jkg(-1)s(-1) vs. 2.73 Jkg(-1)s(-1)). At CWS, no difference in energy consumption was found (3.56 Jkg(-1)s(-1) vs. 3.58 Jkg(-1)s(-1)) but CWS was significantly lower in AMP compared to CO (1.35 ms(-1) vs. 1.52 ms(-1)). In conjunction with the higher E(met) at FWS, the negative work generated by the intact leading leg for the step-to-step transition in double support was significantly higher for AMP than CO at FWS. A moderate though significant correlation was found between negative mechanical power generated during the step-to-step transition and metabolic power (CWS: r=-0.56, p=0.007; FWS: r=-0.50, p=0.019). Despite the difference in negative work during the step-to-step transition, the total absolute mechanical work over a stride did not differ between groups. This could possibly be attributed to exchange of internal positive and negative work during single support, which remains unnoticed in the external work calculations. It was concluded that the increased mechanical work for the step-to-step transition from prosthetic to intact limb contributes to the increased metabolic energy cost of amputee walking.