Lidocaine hyperselective motor blocks of the triceps surae nerves: role of the soleus versus gastrocnemius on triceps spasticity and predictive value of the soleus motor block on the result of selective tibial neurotomy

OBJECTIVES: This prospective study was designed to evaluate the clinical and gait parameter changes induced by two types of hyperselective motor blocks of the triceps surae nerves (superior soleus and gastrocnemius nerves) and their ability to predict the results of selective tibial neurotomy. DESIGN: Seven adult patients (four males and three females, mean age of 41 yrs old) with spastic foot were included in this study. Clinical (equinus foot score, ankle range of motion, spasticity, pain, and comfort wearing shoes), and gait analysis (kinematic and electromyographic parameters) assessment were performed before and after each motor block (superior soleus nerve and gastrocnemius nerve) and 1 mo after selective tibial neurotomy. RESULTS: The superior soleus nerve block was effective on clinical parameters (triceps surae stretch reflex scores decreased from 2.57 to 0.9, and mean walking time decreased from 44 to 32.1 secs) and on kinematics parameters (the total duration of the gait cycle was decreased because of a reduction of the R3 and swing phases). The same results are observed after soleus neurotomy. CONCLUSION: This work confirms the practical value of selective superior soleus nerve motor block and that this block provides a useful prediction of the effect of selective soleus neurotomy. It constitutes an additional argument in favor of the predominant role of the soleus in spastic foot.     

Relieving effect of TENS on painful muscle contraction produced by an impairment of reciprocal innervation: an electrophysiological analysis

A young female outpatient experienced painful tonic contractions in the right triceps surae muscles as a result of a partial damage of the right peroneal nerve. Electrophysiological recordings of the soleus muscle showed a tonic EMG activity and an hyperexcitability of the monosynaptic H reflex (Hmax/Mmax ratio: 90%). Application of transcutaneous electrical nerve stimulation (TENS, 1-2 min) on the peroneal nerve trunk at the head of the fibula resulted both in a pain relief and in the disappearance of the tonic activity in the muscles supplied by the antagonist nerve. Simultaneously, the Hmax/Mmax ratio decreased to normal values (49%). This was followed by an after-effect lasting more than 30 min. The potential role of an impairment of reciprocal inhibition in the originating mechanism of these troubles is discussed.     

Comparison of electric stimulation methods for reduction of triceps surae spasticity in spinal cord injury

OBJECTIVES: To compare the effect of 3 methods of electric stimulation to reduce spasticity of the triceps surae in patients with complete spinal cord injury (SCI) and to investigate the carryover effect. DESIGN: Placebo-controlled study with repeated measurements after the interventions. SETTING: Research department affiliated with a rehabilitation hospital in the Netherlands. PARTICIPANTS: Ten patients with a complete SCI were recruited from the outpatient population of the rehabilitation hospital. All subjects had American Spinal Injury Association grade A impairment scores, except for one, who had grade C. The patients had no voluntary triceps surae contractibility. INTERVENTIONS: Forty-five minutes of cyclic electric stimulation of the agonist, antagonist, or dermatome of the triceps surae or a placebo approach. MAIN OUTCOME MEASURES: Outcome measures were the Modified Ashworth Scale (MAS), clonus score, and the H-reflex and M wave (H/M) ratio. The electromyographic response to a stretch of the soleus over the whole range of motion was also determined. The magnitude and ankle angle at which the electromyographic response started were calculated. RESULTS: Stimulation of the agonist provided a significant reduction in the MAS compared with the placebo approach (P<.001). There was no significant change in the H/M ratio or the electromyographic response amplitude after any of the stimulation methods, whereas stimulation of the antagonist muscle resulted in a significant reduction in the ankle angle at which the electromyographic response started, compared with the placebo approach (P<.037). CONCLUSIONS: Triceps surae stimulation reduces the MAS for that specific muscle, whereas the angle at which the reflex starts changes after antagonist stimulation.     

The effect of cooling on muscle co-ordination in spasticity: assessment with the repetitive movement test

Purpose: Cooling muscles might produce a temporary reduction of spasticity. This study investigated muscle coordination in spasticity under the influence of cooling. Methods: A repetitive movement (RM-) test of the ankle was used, while measuring the angle and surface-electromyography (EMG) of the m. tibialis anterior and m. triceps surae. Ensemble averaging provided quantified measures of muscle activation. Sixteen patients with spasticity in their lower extremity due to stroke or spinal cord injury participated in the study. Physical examination and the RM-test was done before and after cooling the m. triceps surae for 20 minutes by coldpacks. Results: The results show that Achilles hyperreflexia and clonus were abolished in all, and all but one patient, respectively. The EMG of the m. triceps surae, acting as a prime mover, was increased (p 0.028). However, this improved muscle coordination resulted in just a slightly increased active range of motion (less than 2 degrees at p 0.049). Conclusion: Apparently, the increase in excitability of the alpha motoneuron pool in voluntary movements of patients with spasticity is not followed by an improvement in the ability to move.     

The effect of cooling on muscle co-ordination in spasticity: assessment with the repetitive movement test

Purpose: Cooling muscles might produce a temporary reduction of spasticity. This study investigated muscle coordination in spasticity under the influence of cooling. Methods: A repetitive movement (RM-) test of the ankle was used, while measuring the angle and surface-electromyography (EMG) of the m. tibialis anterior and m. triceps surae. Ensemble averaging provided quantified measures of muscle activation. Sixteen patients with spasticity in their lower extremity due to stroke or spinal cord injury participated in the study. Physical examination and the RM-test was done before and after cooling the m. triceps surae for 20 minutes by coldpacks. Results: The results show that Achilles hyperreflexia and clonus were abolished in all, and all but one patient, respectively. The EMG of the m. triceps surae, acting as a prime mover, was increased (p 0.028). However, this improved muscle coordination resulted in just a slightly increased active range of motion (less than 2 degrees at p 0.049). Conclusion: Apparently, the increase in excitability of the alpha motoneuron pool in voluntary movements of patients with spasticity is not followed by an improvement in the ability to move.     

Effects of prolonged muscle stretch on reflex and voluntary muscle activations in children with spastic cerebral palsy

We studied the short term effects of a single session of prolonged muscle stretch (PMS) on reflex and voluntary muscle activations in 22 children with spastic cerebral palsy (CP) assigned to an experimental (n = 12) and a control group (n = 10). Children of the experimental group underwent PMS of the triceps surae (TS) by standing with the feet dorsiflexed on a tilt-table for 30 min, whereas children of the control group were kept at rest. The effects were determined by measuring the associated changes in torque and in electromyographic (EMG) activity of the TS and tibialis anterior (TA) muscles during both passive ankle movements and maximal static voluntary contractions. The results indicate that PMS led to reduced spasticity in ankle muscles as demonstrated by the significant reductions (p less than 0.05) of the neuromuscular responses (torque and EMG) to passive movement. These inhibitory effects lasted up to 35 min after cessation of PMS. In addition, the capacity to voluntarily activate the plantar flexors was significantly (p less than 0.05) increased post-PMS, but the capacity to activate the dorsiflexors was apparently not affected. These findings suggest that repeated sessions of PMS may have beneficial effects in the management of spasticity in children with CP.     

Quantified electromyography of lower-limb muscles during level walking

The electromyography (EMG) of eleven different lower limb muscles of ten healthy subjects was quantified during normal level walking. The surface EMGs obtained were normalized, in percentage, to the activity obtained during an isometric maximum voluntary test contraction of each subject. The mean peak activities of the gluteus maximus, gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and medial hamstring muscles occurred at heel-strike and were between 5 and 15% of max isometric EMG. The magnitudes of tibialis anterior and triceps surae muscular activity were higher than those of the other muscles investigated. Mean peak activity in tibialis anterior was 27%, in gastrocnemius medialis 42%, in gastrocnemius lateralis 19% and in soleus 40%. The important role of the triceps surae during walking was reflected in comparatively high muscular activity at push-off.     

Quantitative assessment of the velocity-dependent increase in resistance to passive stretch in spastic plantarflexors

BACKGROUND: Although numerous studies revealed that isokinetic dynamometers were valuable tools for assessing spastic hypertonia, no standard methodology using such devices is currently widespread in clinical setting. The aim of this study was to standardize a protocol to assess spastic hypertonia in the triceps surae. METHODS: The passive resistance during dorsiflexions imposed from 10 to 300 degrees /s with an isokinetic dynamometer was measured at the neutral position in 15 patients with spastic hypertonia and 12 healthy subjects. The normalized passive resistance was obtained by expressing raw passive resistance as a percent of the values measured at the lowest velocity (10 degrees /s). EMG signals from plantar and dorsiflexors were also recorded. FINDINGS: While no significant difference between spastic patients and control subjects was observed in raw passive resistance values, the difference was significant for each tested velocity when considering the normalized values. Furthermore, the Ashworth score was significantly correlated with the normalized passive resistance for each velocity whereas no correlation was observed with the raw passive resistance. For the patients, except at the highest velocity, the normalized passive resistance was not affected by the fact that reflex responses in the triceps surae were elicited or not. INTERPRETATION: The normalized passive resistance, expressed with respect to the initial one, i.e., measured at very low velocity, seems a very effective parameter to quantify the velocity-dependent increase in resistance to passive stretch in spastic plantarflexors. However, while the simplicity of the isokinetic tests and the reduced time of data treatment seems to support the clinical use of this methodology, further investigations are required to definitely standardize the protocol.     

Effects of a single session of prolonged plantarflexor stretch on muscle activations during gait in spastic cerebral palsy

Activations of the triceps surae (TS) and tibialis anterior (TA) muscles during gait were studied in children with spastic cerebral palsy (CP) immediately before and after 30 min of standing on a tilt-table with the ankle dorsiflexed to stretch the TS in the experimental group (n = 8) or after a rest period in the control group (n = 11). The EMG activity from the TS and TA was recorded concomitantly with electronic footswitch signals by a computer. Video records were made of the sagittal gait movements. Effects of PMS were determined by comparing change scores for selected spatiotemporal and muscle activation parameters between the groups. The change scores defined for the muscle activations were: a post-test/pre-test ratio of the EMG activity in specific segments of the gait cycle and a locomotor spasticity index. PMS did not significantly (p greater than 0.05) affect any of the spatiotemporal parameters nor did it alter any of the TS and most of the TA activation parameters or the SI indexes for the TS and TA. Only the TA post/pre activation ratio for the 0-16% segment of the gait cycle was smaller (p less than 0.01), indicating a decrease in TA activation post-PMS.     

Ankle muscle activity during gait in children with cerebral palsy and equinovarus deformity

Temporal electromyographic (EMG) characteristics of lower limb muscles during gait of spastic hemiplegic and diplegic children with cerebral palsy are described. All subjects were referred for presurgical evaluation of equinovarus deformity. The data indicated both similar and discriminating phasic EMG characteristics between groups of patients. All children displayed premature triceps surae activity beginning in swing phase of gait and continuing through stance. Tibialis posterior, normally active during stance, was also active during swing phase of gait. However, some patients displayed cocontraction of triceps surae and tibialis anterior during stance, together with hamstring muscle activity within normal limits. The remainder of the patients displayed a prolonged duration of hamstring activity. How this gait analysis contributed to presurgical decisions for equinovarus gait is discussed and compared with data from postsurgical gait analysis.     

Intersession Reliability of Hoffmann Reflex Gain and Presynaptic Inhibition in the Human Soleus Muscle

Hayes BT, Hicks-Little CA, Harter RA, Widrick JJ, Hoffman MA. Intersession reliability of Hoffmann reflex gain and presynaptic inhibition in the human soleus muscle.

Objective

To determine the day-to-day reliability of Hoffmann reflex (H-reflex) gain and presynaptic inhibition of spinal reflexes in the human soleus muscle.

Design

Controlled trial.

Setting

Research laboratory.

Participants

Volunteers (N=30; mean ± SD age, 23.4±3.9y; height, 175.64±10.87cm; mass, 84.50±24.18kg) with no history of lower extremity pathology and/or injury participated.

Interventions

Subjects lay prone with the head, shoulders, arms, and hips supported in a static position by a massage body pillow and the ankle positioned at 90°. Recording electrodes were placed over the soleus and tibialis anterior muscle bellies, and the stimulating electrodes were positioned over the tibial nerve in the popliteal space and the common peroneal nerve near the fibular head.

Main Outcome Measures

The H-reflex and motor wave recruitment curves were then measured and recorded. Presynaptic inhibition was also assessed in the soleus muscle, and a conditioning stimulation of the common peroneal nerve (1 × motor threshold = motor threshold) was used prior to soleus H-reflex measurement. Two testing sessions took place between 2 and 7 days, and each session occurred at the same time of day.

Results

Assessments of H-reflex gain and presynaptic inhibition yielded test-retest reliability of R equal to . 95 and .91, respectively.

Conclusions

Measures of presynaptic inhibition and H-reflex gain (H slope/M slope) in the human soleus muscle are consistent and reliable day to day.     

Stretch reflex adaptation in elbow flexors during repeated passive movements in unilateral brain-injured patients

OBJECTIVE: To evaluate the effects of repeated, externally imposed, flexion-extension movements of the elbow on the resulting stretch reflex response in hemiparetic spastic brain-injured patients. These effects were compared within a recording session and across sessions for the same subject to determine the impact of movement history on the quantification of spastic hypertonia using the stretch reflex response. DESIGN: Twenty to 30 sequential, constant velocity flexion-extension movements were applied to the impaired elbow of our cohort, with a 10-second hold interposed between flexion and extension. Movements were applied regularly at 1-minute intervals. Changes in stretch reflex responses were monitored during the applied movements. PARTICIPANTS: We examined a convenience sample of seven hemiparetic brain-injured subjects between the ages of 26 and 60 yrs, with moderate-to-severe spastic hypertonia of elbow muscles (Ashworth score 2-4/4). Subjects participated in 2 to 9 sessions. MEASURES: Elbow torque, position, velocity, and electromyograms of the biceps, brachioradialis, and triceps muscles were recorded for each flexion and extension movement. Stretch reflex torque was calculated by subtracting passive torque from total elbow torque, recorded over large amplitude movements. A linear regression analysis quantified both the initial torque response of the stretch reflex and the ensuing adaptation of the stretch reflex during sequential movements. Intersession variability was characterized both for spastic hypertonia measures and for stretch reflex adaptation. RESULTS: Repeated, externally imposed, sequential flexion-extension movements of the elbow decreased the elbow flexor stretch reflex in six of seven subjects. The mean reduction in reflex torque after 30 movements was 50% of the initial torque values (p = .001, t test vs. 0% change). Intersession stretch reflex responses for each subject were found to vary greatly (SDs of reflex torque ranged from 0.1 to 4.0 Nm), and there were also significant variations in the degree of adaptation between subjects. CONCLUSIONS: Stretch reflex adaptation must be taken into consideration when spastic hypertonia is quantified using repeated joint motion, as is often the case. The magnitude of intersession variation in spastic hypertonia measures suggests that ideally, such measurements should be made across multiple sessions before conclusions are made regarding the efficacy of spastic hypertonia interventions. This study provides quantitative evidence that repeated joint movements may have a significant short-term beneficial effect on spastic hypertonia.     

Effects of heavy-resistance triceps surae muscle training on strength and muscularity of men and women

The purpose of this study was to determine selected functional and structural effects of heavy-resistance training on the triceps surae muscles of men and women. We pretested 28 men and 28 women for triceps surae muscle isotonic strength and muscularity after five practice sessions that familiarized them with the study equipment. Triceps surae muscle isotonic strength was determined using a 1-repetition maximum seated heel raise. Muscularity involved the measurement of relaxed lower leg circumference and net circumference and ultrasonically determined triceps surae muscle thickness. Twenty-eight subjects (14 men, 14 women) were selected randomly after pretesting to participate in 24 sessions of standardized weight training primarily involving the triceps surae muscles, and the remaining subjects (14 men, 14 women) served as nontraining controls. After eight weeks of training, triceps surae muscle isotonic strength had increased significantly (p less than .001) for both men and women in the Treatment Group when compared with the Control Group. No other dependent variables changed significantly. We concluded that eight weeks of heavy-resistance training involving the triceps surae muscles elicits similar significant increases in isotonic muscle strength in both men and women without concurrent increases in muscularity.     

Changes in Motor Unit Firing Rate in Synergist Muscles Cannot Explain the Maintenance of Force During Constant Force Painful Contractions

The firing rate of low threshold motor units is decreased in constant force contractions during experimental pain. However, as firing rate is a determinant of force, it is unclear how force is maintained. Increased synergist muscle activity may compensate. This was investigated by evaluation of motor unit firing rate in synergist ankle plantar flexor muscles (triceps surae). Single motor unit action potentials were recorded in medial gastrocnemius and soleus muscles with fine wire electrodes in 10 subjects. Gross muscle activity was estimated from surface electromyographic (EMG) recordings. Bolus injections of 5% hypertonic saline were injected into lateral gastrocnemius to induce pain (low intensity, 0.5 mL; high intensity, 1.5 mL). Subjects gently plantar-flexed the ankle to recruit 1 to 4 motor units and performed 3 20-second contractions to this target before, during, and after pain. Firing rate decreased ∼12% in synergist heads of triceps surae during pain and recovered after pain. Despite reduced firing rate, root-mean-square surface EMG amplitude did not change. The effect of nociceptor stimulation is not restricted to painful muscles but reduces motor unit firing in synergist muscles. Changes in synergist muscles cannot explain the maintenance of muscle force. Maintenance of surface EMG amplitude suggests recruitment of additional motor units.PerspectiveThis study showed that activity of synergist muscles can be affected by muscle pain. However, the changes in activity of synergist muscles may not compensate for changes in the painful muscle. This finding provides evidence of more widespread effects of pain on muscle control.     

Soleus muscle electromyographic activity and ankle dorsiflexion range of motion during four stretching procedures

Volitional muscle contractions are used frequently in some combination with muscle stretching to promote muscle relaxation and to increase range of motion. In this study, muscle lengthening procedures were evaluated in the ankle plantar flexors. Four soleus muscle stretching procedures--static stretch (SS), hold relax (HR) (isometric plantar flexor contraction before stretch), agonist contract (AC) (dorsiflexor contraction assisting stretch), and hold relax-agonist contraction (HR-AC)--were performed in the sagittal plane by 12 physically active adults. The dorsiflexion angle, soleus muscle electromyogram, and soleus muscle motoneuron excitability as determined by the Hoffmann-reflex (H-reflex) amplitude were measured throughout the duration of each stretch. The range of dorsiflexion achieved at the end of the stretch did not differ significantly between stretching procedures, although in 8 of the 12 subjects and in the subject group as a whole, the AC and HR-AC procedures were associated with higher levels of soleus muscle EMG than the levels in the SS and HR procedures (p less than .01). The H-reflex amplitudes during the AC and HR-AC procedures were smaller than the amplitudes during the SS and HR procedures (p less than .001), suggesting the possibility of reciprocal inhibition during the agonist contraction. Increased tonic EMG levels produced by input from other neural pathways affecting alpha motoneurons in the AC and HR-AC procedures may have masked this inhibitory reflex. In healthy adults, a complicated procedure, involving muscle contractions for decreasing active resistance to stretch, may be unnecessary because active resistance to stretch is minimal and muscle relaxation during stretch appears to have little or no direct effect on the ROM achieved.     

超声剪切波弹性成像在脑卒中患者小腿康复评定中的应用

目的 探讨超声剪切波弹性成像对脑卒中下肢运动障碍患者小腿三头肌和跟腱进行康复评定的价值。方法 2018年至2019年,脑卒中后单侧下肢运动障碍住院患者32例,于康复治疗前后,对患者双侧小腿三头肌和跟腱行超声二维测量和剪切波弹性成像检查,记录剪切波速度(SWV)以及跟腱(比目鱼肌肌腱)长度和厚度。结果 治疗前,患侧跟腱和小腿三头肌SWV较健侧增高(t > 2.426, P < 0.05);患侧跟腱长度较健侧显著增加( t = 11.801, P < 0.001);治疗后,患侧小腿三头肌SWV减低( t > 2.447, P < 0.05);患侧跟腱长度显著缩短( t = 8.577, P < 0.001)。 结论 康复治疗可降低脑卒中下肢运动障碍患者小腿三头肌肌张力。超声剪切波弹性成像可用于评价跟腱和小腿三头肌弹性特征,指导脑卒中康复。     

胫神经局部振动对脑卒中患者小腿三头肌痉挛的影响及神经生理机制研究

目的:观察胫神经局部振动治疗对脑卒中患者小腿三头肌痉挛及神经电生理功能的影响。方法:选取脑卒中后偏瘫下肢功能障碍患者60例,按随机数字表法将其分为治疗组和对照组,每组30例。2组均给予常规康复训练,治疗组在此基础上增加局部振动治疗。治疗前、后,采用改良Ashworth量表(MAS)、Clonus阵挛分级法分别评价2组患...     

Hyperactive tendon reflexes in spastic multiple sclerosis: measures and mechanisms of action

OBJECTIVE: To develop new measures of tendon reflexes and evaluate hyperactive reflexes in patients with spastic multiple sclerosis (MS). DESIGN: With the subject relaxed, a hand-held instrumented hammer was used to tap the patellar tendon and record the tapping force, while knee extension torque and quadriceps EMG were recorded isometrically as measures of the reflex response. SETTING: Research laboratory in a rehabilitation hospital. SUBJECTS: Ten spastic MS and 14 healthy subjects. MAIN OUTCOME MEASURES: Tendon tapping force (designated as system input), reflex torque (as output), their dynamic relationship (characterized as system parameters tendon reflex gain, contraction rate, and reflex loop delay), Ashworth scale, and tendon reflex scale. RESULTS: The system parameters provide more repeatable measures than do input or output parameters alone because they quantify the input and output simultaneously and dynamically. Compared with control subjects, MS patients had a significantly lower threshold in tapping force (p = .026), yet their evoked reflex torque was significantly higher (p = .033). Despite significant quadriceps weakness (p < .0001), MS patients had a significantly higher reflex gain (p = .0002) and contraction rate (p = .0002), and shorter reflex loop delay (p = .0046), indicating hyperexcitability of motoneurons and peripheral receptors, and indicating that relatively more of the muscle was activated reflexively, with greater recruitment of larger fast-twitch fibers. Both the reflex gain and rate measures correlated more closely with the Ashworth scale and tendon reflex scale than did the output measures, indicating their potential clinical value. CONCLUSIONS: With appropriate simplification, the method may be used in clinical practice to quantify more precisely the tendon jerk than is currently feasible with standard clinical tests.     

Development of a new method for objective assessment of spasticity using full range passive movements

OBJECTIVE: To develop a method for assessment of spasticity, in which the whole range of motion (ROM) at a wide variation of speeds is applied. DESIGN: Cross-sectional design to study construct validity. SETTING: Research department affiliated with a rehabilitation hospital in The Netherlands. PARTICIPANTS: Nine patients with complete spinal cord injury recruited from the rehabilitation hospital. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Thirty to 45 stretches over the whole ROM were applied to the triceps surae muscle at varying velocities measuring from 30 degrees to 150 degrees/s. Electromyographic responses were measured in order to assess reflex excitability. The torque over the ankle joint was measured during the whole stretch. The angle and velocity at which the reflex was initiated was also determined. RESULTS: The electromyographic responses increased significantly at increasing stretch velocities (P<.001). The applied maximum angles are reproducible (intraclass correlation coefficient, .81) and provide representative torque responses. CONCLUSIONS: The assessment method of spasticity using full range passive movements provides objective outcomes. The angular velocity is responsible for an exponential increase in amplitude of the electromyographic response.