Botulinum toxin type A and short-term electrical stimulation in the treatment of upper limb flexor spasticity after stroke: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To investigate whether the combined approach of botulinum toxin type A (BtxA) and electrical stimulation was more effective than the toxin alone in the treatment of chronic upper limb spasticity after stroke. DESIGN: Randomized, placebo-controlled study with four treatment groups: 1000 units BtxA (Dysport) + electrical stimulation (A), 1000 units BtxA (B), placebo + electrical stimulation (C) and placebo (D). SETTING: A neurological rehabilitation clinic. SUBJECTS: Twenty-four stroke patients with chronic upper limb spasticity after stroke, six patients in each treatment group. INTERVENTIONS: Intramuscular injection of either toxin or placebo into six upper imb flexor muscles. In group A and C additional electrical stimulation of the injected muscles with surface electrodes, three times half an hour each day for three days. MAIN OUTCOME MEASURES: Muscle tone rated with the modified Ashworth score, limb position at rest and difficulties encountered during three upper limb motor tasks assessed before and 2, 6 and 12 weeks after injection. RESULTS: Most improvements were observed in patients of group A. Cleaning the palm (p = 0.004) differed across groups. Pairwise comparison for this target variable showed that group A differed from group B and D (p <0.01), but not from C. Indicative across-group differences were obtained for elbow spasticity reduction (p = 0.011), and improvement of putting the arm through a sleeve (p = 0.020). CONCLUSIONS: The placebo-controlled trial favours the concept that electrical stimulation enhances the effectiveness of BtxA in the treatment of chronic upper limb flexor spasticity after stroke.

Immediate effects of therapeutic facilitation on the gait of hemiparetic patients as compared with walking with and without a cane.

OBJECTIVES: Although the neurodevelopmental technique (Bobath) is the most widely used approach in the gait rehabilitation of hemiparetic subjects in Europe, there is little neurophysiological evidence for its presumed effects on gait symmetry and facilitation of paretic muscles during the therapeutic intervention. The study, therefore, investigated the immediate effects of gait entrainment by a physical therapist on the gait of hemiparetic subjects. METHODS: Cycle parameters, gait symmetry, hip joint movement and the electromyographic activity of several lower limb muscles were assessed in 22 patients during a classic intervention by five Bobath therapists and while walking with and without a cane. RESULTS: Multivariate statistics revealed that, while being assisted by the therapist, patients walked faster (P = 0.022), with a longer relative stance period of the affected leg (P = 0.005), a higher symmetry (P = 0.002), larger hip extension (P = 0.001) and more activation (P = 0.026) of the Mm. triceps surae, vastus lateralis, biceps femoris and gluteus medius as compared to walking with and without a cane. Extensor spasticity of the plantar-flexor tended to increase (n.s.). In five subjects, no after-effect could be documented 1 h after a gait training of 30 min. CONCLUSIONS: The study confirmed a more balanced walking pattern in conjunction with facilitation of various weight bearing muscles during the therapeutic intervention. A prolonged single stance period of the affected leg, an unobstructed hip movement, enhanced weight acceptance and a faster gait seemed to be responsible for the observed immediate effects of the therapeutic intervention.

Gait function in spastic hemiparetic patients walking barefoot, with firm shoes, and with ankle-foot orthosis.

The purpose of the study was to investigate the effect of firm shoes and a particular type of a frequently prescribed ankle-foot orthosis in Germany, the Valens calliper, on functional gait parameters in hemiparetic patients with marked extensor spasticity and corresponding heel-strike problems. Cycle times, vertical ground reaction forces, trajectories of the centre of pressure (gait line) under the soles and the mode of initial contact were assessed in 19 hemiparetic patients walking barefoot, with firm shoes and the orthosis. With the shoes, significant improvements (p < 0.006) were observed for: walking velocity, stride length, initial double stance duration and gait line of the non-affected foot. The pattern of the vertical force diagram improved qualitatively in six patients. With the orthosis the following variables showed an even more marked improvement (p < 0.006): walking velocity, cadence, stride length, and gait line of both the affected and non-affected foot. Fourteen patients became rear-foot strikers and the vertical force pattern further improved in six patients. It is concluded that the ankle-foot orthosis (more than the shoes) provide a useful support in the early rehabilitation of hemiparetic patients with marked spasticity.

Ankle muscle activity before and after botulinum toxin therapy for lower limb extensor spasticity in chronic hemiparetic patients.

BACKGROUND AND PURPOSE: Recent studies have been made of the novel treatment of lower limb spasticity after stroke with botulinum toxin A, and the results were based mostly on the clinical assessment made before and after treatment. This study investigated the effects of toxin on ankle muscle activity during gait in patients with severe extensor spasticity. The questions posed were whether the toxin particularly diminishes the so-called premature muscle activity as a major cause of equinovarus deformity and whether different types of altered motor control allow a prediction of the outcome of the treatment. METHODS: In 12 chronic hemiparetic outpatients with pronounced lower limb spasticity, we injected 400 U botulinum toxin A into the soleus and tibialis posterior muscles and both heads of the gastrocnemius muscles. Ankle spasticity and complex gait analysis including kinematic electromyography (EMG) of the soleus and tibialis muscles were assessed before treatment and 4 weeks after the injection. RESULTS: Nine patients profited with a reduction of spasticity, improved gait ability, and a more normal temporal pattern of muscle activity with a prominent reduction of the premature activity of the plantar flexors. Eight patients exhibited a qualitative pattern (type I) corresponding to an increased stretch-reflex excitability. Three patients did not profit; their muscle tone, gait ability, and muscle activation remained stable or even deteriorated. CONCLUSIONS: This study further supports the beneficial effects of botulinum toxin in the treatment of lower limb extensor spasticity. A correlation was observed between the clinical reduction of muscle tone, functional gait parameters, and a more normal EMG pattern with a predominant reduction of the premature activity of the plantar flexors. The qualitative type of EMG pattern corresponding to an increased stretch-reflex excitability (type I) was a positive predictor for the outcome.

Short-term electrical stimulation enhances the effectiveness of Botulinum toxin in the treatment of lower limb spasticity in hemiparetic patients.

The study tested the spasmolytic effect of Botulinum toxin A in two groups of hemiparetic patients with lower limb spasticity: in the first group (n = 5) 2000 U Dysport were injected into the soleus, tibialis posterior and both heads of gastrocnemius muscles alone; the second (n = 5) received additional repetitive alternating electrical stimulation of M. tibialis anterior and plantar flexors for 30 min six times per day during the 3 days following the injection. Muscle tone, rated by the Ashworth spasticity score, and gait analysis including recording of vertical ground reaction forces, were assessed before and 4 weeks after injection. The combined treatment proved to be more effective with respect to the clinically assessed reduction of muscle tone, gait velocity, stride length, stance- and swing-symmetry (P < 0.05). The result is discussed with reference to animal experiments demonstrating enhanced toxin uptake and accelerated onset of its paralytic effect by electrical stimulation.

Treadmill training with partial body weight support compared with physiotherapy in nonambulatory hemiparetic patients.

BACKGROUND AND PURPOSE: Treadmill training with partial body weight support is a new and promising therapy in gait rehabilitation of stroke patients. The study intended to investigate its efficiency compared with gait training within regular physiotherapy in nonambulatory patients with chronic hemiparesis. METHODS: An A-B-A single-case study design compared treadmill training plus partial body weight support (A) with physiotherapy based on the Bobath concept (B) in seven nonambulatory hemiparetic patients. The minimum poststroke interval was 3 months, and each treatment phase lasted 3 weeks. Variables were gait ability assessed by the Functional Ambulation Category, other motor functions tested by the Rivermead Motor Assessment, muscle strength assessed by the Motricity Index, muscle tone rated by the Modified Ashworth Spasticity Scale, and gait cycle parameters. RESULTS: Treadmill training was more effective with regard to restoration of gait ability (P < .05) and walking velocity (P < .05). Other motor functions improved steadily during the study. Muscle strength did not change, and muscle tone varied in an unsystematic way. The ratio of cadence to stride length did not alter significantly. CONCLUSIONS: Treadmill training offers the advantages of task-oriented training with numerous repetitions of a supervised gait pattern. It proved powerful in gait restoration of nonambulatory patients with chronic hemiparesis. Treadmill training could therefore become an adjunctive tool to regain walking ability in a shorter period of time.

Eye movements and fixation characteristics in perception of stationary scenes: normal subjects as compared to patients with visual neglect or hemianopia.

Saccade amplitudes, fixation times, and the spatial distribution of fixation points were comparatively studied in patients with visual hemineglect and/or homonymous hemianopia, as well as in normals (each group, n = 8). Two types of picture slides were presented (with and without search task) while eye movements were recorded with the infrared reflection technique. Self-developed software served to detect fixations, and to document their spatio-temporal parameters. Spectra of saccade amplitudes and fixation times were characteristic of each slide, while exhibiting notable similarities across subject groups. It is concluded that foveal information processing may not be much different in patients and in normals. Average saccade amplitudes and total scanpath lengths across all pictures were significantly smaller in the patients than in normals with both types of slides. In the neglect patients, saccades starting and terminating in the unaffected visual hemifield were larger, on an average, than those entirely located in the affected hemifield. The same was true for many of the hemianopic patients. Nevertheless, during free exploration, mean amplitudes of saccades restricted to the unaffected hemifield of the patients were apparently still smaller than those of normal controls within the corresponding hemifield. Average dwell time of fixations, total fixation time, as well as the total number of fixations did not vary significantly between groups. However, in the patient groups, average fixation times were shorter after large as compared to small saccades. This finding is discussed in the context of saccadic programming on the background of the sequential attention model of eye movement control. In subsamples of five hemianopic and six neglect patients, asymmetry in the distribution of fixation points was compared before and after a 4-week period of comprehensive rehabilitation that Included computerized scanning and attentional training. Only patients with pure hemianopia (who were less severely impaired from the beginning) improved according to this criterion, while neglect patients remained unchanged or deteriorated slightly. Total scanpath lengths, however, were not significantly different before and after therapy in any of the two groups of patients, indicating a persisting disturbance in scanning performance also in the hemianopic group.

Gait outcome in ambulatory hemiparetic patients after a 4-week comprehensive rehabilitation program and prognostic factors.

BACKGROUND AND PURPOSE: Although gait training is prominent in the rehabilitation of hemiparetic stroke patients, little is known about its outcome and prognostic factors in mildly affected patients. We therefore intended to assess gait in ambulatory stroke patients before and after a 4-week inpatient rehabilitation program based on the neurodevelopmental technique. METHODS: We measured vertical ground reaction forces by force plates in 148 stroke patients. Variables were stance durations, peak vertical ground reaction forces at heel strike (Fz1) and toe-off (Fz2), loading and deloading rates, time to Fz1, and time to Fz2. The absolute changes for both legs and symmetry outcome were calculated. In addition, we assessed maximal walking speed, walking endurance, stair climbing ability, and the Motricity Index. RESULTS: Stance duration, weight acceptance, push-off of both legs, and the stance duration symmetry improved independent of changes of gait velocity. The symmetry of the ground reaction forces did not improve. Results were even worse for Fz1 and the loading rate at the end of treatment. Sex, age, side of hemiparesis, motor strength, stroke interval, and sensory impairment had no influence on the outcome of symmetry. Functional performance did not improve considerably. CONCLUSIONS: The absolute changes of the ground reaction forces indicated better weight acceptance and push-off of both legs and thus confirmed the efficacy of the neurodevelopmental technique. The symmetry outcome and the functional performance at the end of treatment, however, challenge the efficacy of intensive rehabilitation therapy for 4 weeks in its attempts to restore physiological gait in these mildly affected patients.

[A clinically applicable system for analysis of standing up using measurements of floor reaction forces]. / Klinisch einsetzbares System zur Analyse des Aufstehens mittels Messung der Bodenreaktionskräfte.

A system for clinical analysis of sit-to-stand transfer using two force plates is presented. Distinct time-events and phases are estimated. Illustrative parameters are also determined, such as the distribution of the vertical ground reaction forces, displacement of the center of gravity in the sagittal and frontal planes, and a comparison of the displacement of the center of gravity and the center of pressure. These parameters indicate a symmetrical raising while keeping the middle of the body. Future applications include the validation of therapy, biofeedback and the control of closed-loop FES.

Responses of human muscle spindle afferents during isotonic position holding and active movements.

Discharge characteristics of muscle spindle primary afferents from human finger flexors were investigated during load-bearing isotonic position holding, and intentional shortening or lengthening contractions. During position holding, units mostly showed a negative relationship between muscle length and impulse rate, particularly when the load was small. When the load was increased, Ia-discharge rates increased more in the elongated than in the shortened muscle, and the inverse position response became less pronounced. During active lengthening contractions, a stretch response pattern was sometimes absent or could be abolished by increasing the load.

Stereoencephalotomy and control of skeletal muscle tone.

Stereotactic interventions at the thalamic or subtalamic level for treatment of pathological hyperkinesias provide a good model for investigation of the systems controlling tonic innervation in the alert subject. It is suggested that the poststereotactic muscular hypotonia observed contralaterally to the lesion is due to changes in the tonic innervation pattern caused by interruption of a proprioceptive feedback loop.

Response of human muscle spindle afferents to abrupt load perturbations.

Response patterns of single muscle spindle primary afferents to abrupt load perturbations inflicted upon the contracting finger flexors were investigated in awake human subjects using the technique of microneurography. Units showed a transient high-frequency discharge in the rising phase of the stretch. No repeated burst activity attributable to irregularities of the stretch velocity or to mechanical oscillations of the muscle could be detected.

Measurements of muscle stiffness, the electromyogram and activity in single muscle spindles of human flexor muscles following conditioning by passive stretch or contraction.

In experiments on adult human subjects we examined the effect on passive mechanical properties of a muscle by conditioning it with either an isometric contraction or passive muscle extension. The test measurement was the amount of muscle displacement (stiffness) and the accompanying EMG in response to a brief torque pulse. Two muscles were tested, flexor digitorum profundus (FDP) and brachialis. In FDP the discharge of single muscle spindles was recorded as well. After muscle extension and return to the initial length, passive stiffness was less than after an isometric contraction. The changes in stiffness were accompanied by changes in pattern of EMG and in the responses of muscle spindles. It is suggested that in resting muscle there are stable cross bridges between actin and myosin filaments of muscle fibres which largely determine the passive stiffness. Muscle extension leads to detachment of these cross bridges which then re-form at the longer length. Return of the muscle to its starting length leads to development of slack in muscle fibres because, stiffened by the presence of the stable cross bridges, they are unable to shorten. Slack in muscle fibres lowers their measured stiffness. Muscle contraction, on the other hand, will result in any preexisting slack being taken up by the actively shortening muscle fibres, thereby raising muscle stiffness. Stiffness in intrafusal fibres is likely to follow a similar pattern to that in extrafusal fibres, leading to changes in stretch responsiveness of muscle spindles and consequently in the reflex EMG. It is concluded that the changes in stiffness and accompanying reflexes observed in this study are likely to be seen, at least under some conditions, in normal movements.

Responses of human cutaneous afferents to CO2 laser stimuli causing pain.

Microelectroneurographic studies in man allow the comparison of stimulus induced activity in the single peripheral nerve unit with the subject's ratings of sensation. Relationships between stimulus intensity, single unit discharges, and pain ratings were investigated using a CO2 laser stimulator which delivers radiant heat pulses of 50 ms duration. Recordings were performed percutaneously from the radial nerve at the wrist. Receptor types were identified by their response to different stimulus modalities and by their reaction delay to electrical test stimuli within the receptive field. Receptive fields of identified units were stimulated with randomised series of different radiant heat intensities between half and double the individual pain threshold (5 to 20 W; stimulation area 64 mm2). The largest receptor class observed to be activated by CO2 laser stimuli were polymodal C-nociceptors. None of them was spontaneously active. High discharge rates up to 75/s were not necessarily associated with pain but, if pain was felt, the impulse trains usually lasted for more than 60 ms. Inter-spike intervals were distributed over a wide range between 8 and 145 ms with a peak at about 25 ms. This peak was only slightly shifted by increasing the stimulus intensity. Higher correlations were found between the number of spikes and stimulus intensity. Measures of Signal Detection Theory indicated that the single unit discharges discriminated stimulus intensities better than the subjects' ratings. These findings underline the importance of temporal summation in the processing of C-fibre input with a considerable loss of information in the nociceptive system.

Properties of a microcoaxial electrode designed for unit recording from human peripheral nerves.

A new microcoaxial electrode is presented, which has been used successfully for recording single- and multiunit activity from myelinated and unmyelinated human nerve fibres. The main advantages (as compared with conventional needle electrodes) are electrical stability, mechanical durability, capability of being re-used and an insulation not easily scraped off, resulting in a low leakage capacitance. The AC polarization impedance and the potential transducing properties of the microelectrode have also been studied.