The effect of combined use of botulinum toxin type A and functional electric stimulation in the treatment of spastic drop foot after stroke: a preliminary investigation.

OBJECTIVE: To investigate the effect of combined botulinum toxin type A (BTX) and functional electric stimulation (FES) treatment on spastic drop foot in stroke. DESIGN: Nonblinded randomized controlled trial. SETTING: Hospitals. PARTICIPANTS: Consecutive sample of 21 ambulant adults within 1 year after stroke with a spastic drop foot, of whom 18 completed the study. INTERVENTIONS: The treatment group received BTX injections (Dysport) on 1 occasion into the medial and lateral heads of the gastrocnemius (200U each) and tibialis posterior (400U each) muscles and FES, used on a daily basis for 16 weeks to assist walking. Both groups continued with physiotherapy at the same rate. MAIN OUTCOME MEASURES: Walking speed, Physiological Cost Index, Modified Ashworth Scale, Rivermead Motor Assessment, and Medical Outcomes Study 36-Item Short-Form Health Survey. RESULTS: Walking speed increased over 12 weeks in both control (P=.020) and treatment groups (nonstimulated, P=.004; stimulated, P=.042). The baseline corrected (analysis of covariance) increase in mean walking speed at 12 weeks, relative to controls, was.04m/s (95% confidence interval [CI],.003-.090) without stimulation, and.09m/s (95% CI,.031-.150) with stimulation. CONCLUSIONS: Combined treatment effectively improved walking and function. A larger study is needed to quantify the treatment effect and to investigate its impact on quality of life.

New results in feedback control of unsupported standing in paraplegia.

The aim of this study was to implement a new approach to feedback control of unsupported standing and to evaluate it in tests with an intact and a paraplegic subject. In our setup, all joints above the ankles are braced and stabilizing torque at the ankle is generated by electrical stimulation of the plantarflexor muscles. A previous study showed that short periods of unsupported standing with a paraplegic subject could be achieved. In order to improve consistency and reliability and to prolong the duration of standing, we have implemented several modifications to the control strategy. These include a simplified control structure and a different controller design method. While the reliability of standing is mainly limited by the muscle characteristics such as reduced strength and progressive fatigue, the results presented here show that the new strategy allows much longer periods (up to several minutes) of unsupported standing in paraplegia.

Is the spinal cord the generator of 16-Hz orthostatic tremor?

Primary orthostatic tremor is characterized by 16-Hz motor activity that is coherent between muscles. It has been suggested that this tremor originates in the brain. This view is questioned by findings from a patient with complete paraplegia who experiences intermittent leg spasms at rest. The EMG activity within the spasms showed a 16-Hz component that was coherent between muscles unilaterally and bilaterally. This raises the possibility that the spinal cord could be the source of orthostatic tremor.

Spinally generated electromyographic oscillations and spasms in a low-thoracic complete paraplegic.

We have measured some oscillatory properties of severe lower limb spasms experienced by a low-thoracic complete paraplegic during assisted standing. Electromyograms (EMG) were recorded from the leg muscles while the patient stood passively in a standing frame. The patient also stood using functional electrical stimulation (FES) while ground and handle reaction force vectors were measured together with EMG activity. During passive standing, spasms appeared simultaneously in all leg muscle groups on one side. The interval between spasms varied between 3 and 30 seconds. Within the spasms, there was a tendency of repetitive grouped discharge of motor units as well as a strong 10-Hz component in the EMG that was coherent across ipsilateral muscle groups. Thus, the spasms were inherently oscillatory. During FES-assisted standing, clinically similar spasms were observed. However, the interspasm interval became relatively fixed at around 16 seconds, which may indicate entraining of the spasm cycle by FES. There are similarities between this patient's spasms and the pathological motor activities seen in other movement disorders that may also be of spinal origin.

Control of leg-powered paraplegic cycling using stimulation of the lumbo-sacral anterior spinal nerve roots.

We investigated leg-powered cycling in a recumbent tricycle for a paraplegic using functional electrical stimulation (FES) with the lumbo-sacral anterior root stimulator implant (LARSI). A female complete T9 paraplegic had a stimulator for the anterior L2 to S2 spinal roots (bilaterally) implanted in 1994. She was provided with equipment for daily FES cycling exercise at home. The cycling controller applies a pattern of stimulation in each of 16 crank angle phases. A 7-bit shaft encoder measures the crank angle with adequate precision. Each pattern was originally chosen to give the greatest propulsive force in that position when there was no motion. However, dynamically, some reduction in co-contraction is needed; also the patterns are applied with a preset advance time. Maximal power is obtained with an advance of 250 ms, which compensates for muscle response delay and accommodates changes in cadence (from about 25 to 85 rpm). With this system, she has cycled 1.2 km at a time on gently undulating road. We found that spinal root stimulation gives sufficient control over the muscles in the legs to produce a fluid cycling gait. We propose that root stimulation for leg cycling exercise may be a practicable and valuable function for paraplegics following spinal cord injury.

A pilot study to investigate the combined use of botulinum neurotoxin type a and functional electrical stimulation, with physiotherapy, in the treatment of spastic dropped foot in subacute stroke.

The objective was to inform sample size calculations for a full randomized controlled trial (RCT). The design included an RCT pilot trial with a 16 week study period, including a 4 week baseline phase. The subjects were adults within 1 year of first stroke, ambulant with a spastic dropped foot. Twenty-one participants were recruited from the stroke services of 4 centers. For intervention all participants received physiotherapy; the treatment group also received botulinum neurotoxin Type A (BoNTA) intramuscular injections to triceps surae (800 U Dysport) and functional electrical stimulation (FES) of the common peroneal nerve to assist walking. The main outcome measure was walking speed. The result was a significant upward trend in median walking speed for both the control (p = 0.02) and treatment groups (nonstimulated p = 0.004, stimulated p = 0.042). Trend lines were different in location (p = 0.04 and p = 0.009, respectively). In conclusion, there is evidence of an additional, beneficial effect of BoNTA and FES. Sufficient information has been gained on the variability of the primary outcome measure to inform sample size calculations for a full RCT to quantify the treatment effect with precision.