Benefits of repetitive transcranial magnetic stimulation (rTMS) for spastic subjects: clinical, functional, and biomechanical parameters for lower limb and walking in five hemiparetic patients.

Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients.

Changes in contractile and elastic properties of the triceps surae muscle induced by neuromuscular electrical stimulation training.

Purpose: Neuromuscular electrical stimulation (NMES) training is known to induce improvement in force production capacities and fibre-type transition. The aim of this study was to determine whether NMES training also leads to changes in the mechanical properties of the human triceps surae (TS) muscle.

Methods: Fifteen young male subjects performed a training protocol (4 weeks, 18 sessions, 4-5 sessions per week) based on a high-frequency isometric NMES programme of TS muscle.

Neuromechanical assessment of lidocaine test block in spastic lower limbs.

The objective of this study was to quantify in spastic lower limbs the changes in reflex EMGs and in ankle stiffness after a lidocaine block of the soleus nerve to better understand physiological effects of lidocaine. Twenty patients were prospectively included and assessed before and after lidocaine block of the soleus nerve. We studied clinical and neuromechanical parameters of the triceps surae, including quantification of the maximum Hoffmann's reflex (Hmax) and tendinous reflex (T) normalized to the maximum direct motor response (Mmax), and passive ankle stiffness assessed by sinusoidal length perturbations.

Time course of the soleus M response and H reflex after lidocaine tibial nerve block in the rat.

Aims: In spastic subjects, lidocaine is often used to induce a block predictive of the result provided by subsequent surgery. Lidocaine has been demonstrated to inhibit the Hoffmann (H) reflex to a greater extent than the direct motor (M) response induced by electrical stimulation, but the timecourse of these responses has not been investigated.

Methods: An animal (rat) model of the effects of lidocaine on M and H responses was therefore developed to assess this time course.

Influence of muscle activity on musculotendinous stiffness quantification in stunted, prepubertal children.

The quick-release technique to estimate musculotendinous (MT) stiffness has been extensively used over the last years, in both animals and humans, to gain insights in the adaptive process of the series elastic component (SEC). Recently, MT stiffness quantification, i.e.

Long-term neuromechanical results of selective tibial neurotomy in patients with spastic equinus foot.

Background: The neuromechanical consequences of tibial neurotomy have not been extensively studied.

Methods: Fifteen patients were evaluated before and after selective tibial neurotomy (after 2 months and after 15 months) by means of clinical, neurophysiological [tendon (T) reflexes, Hoffmann (H) reflexes and maximum motor response, Mmax] and mechanical parameters (passive stiffness of plantar flexors at the ankle). The neurotomy concerned the soleus (100 % of cases), gastrocnemius (20 % of cases), posterior tibial (60 % of cases) and flexor digitorum longus (47 % of cases) nerves.

Ipsi- and contralateral H-reflexes and V-waves after unilateral chronic Achilles tendon vibration.

Chronic Achilles tendon vibration has previously shown its effectiveness in improving plantar flexor's strength and activation capacities. The present study investigated the related neural mechanisms by analyzing H-reflexes and V-waves of the soleus (SOL) and gastrocnemii (GM gastrocnemius medialis; GL gastrocnemius lateralis) muscles under maximal isometric plantar flexion. Moreover, recordings were conducted bilaterally to address potential crossed effects.

Acute postural modulation of the soleus H-reflex after Achilles tendon vibration.

Alteration of Soleus (SOL) H-reflex has been reported after prolonged vibratory exposure and it was hypothesized that presynaptic inhibition, known to depress the H-reflex during vibration, largely contributed to the H-reflex changes. To confirm this hypothesis, the purpose of the present study was to quantify the SOL H-reflex changes between sitting and standing positions (postural modulation) with or without the after-effects of 1h of Achilles tendon vibration. Indeed, postural modulation of the SOL H-reflex has been reported to inform on the level of presynaptic inhibition exerted on Ia afferents.

Acute effects of Achilles tendon vibration on soleus and tibialis anterior spinal and cortical excitability.

Prolonged vibration is known to alter muscle performance. Attenuation of Ia afferent efficacy is the main mechanism suggested. However, changes in motor cortex excitability could also be hypothesized.

Stunting delays maturation of triceps surae mechanical properties and motor performance in prepubertal children.

Malnutrition can lead to possible irreversible consequences in the development of muscle function and some of them are yet poorly characterized. The present study evaluated the mechanical properties of the triceps surae and motor performance in stunted (S) and eutrophic (E) prepubertal children (9 years ± 6 months). Height-for-age ratio was used as indicator of stunting due to early malnutrition, according to the World Health Organization.

Hoffmann reflex is increased after 14 days of daily repeated Achilles tendon vibration for the soleus but not for the gastrocnemii muscles.

In a previous study, Achilles tendon vibrations were enough to improve the triceps surae (TS) activation capacities and also to slightly increase TS Hoffmann reflex (H-reflex) obtained by summing up soleus (Sol) and gastrocnemii (GM and GL) EMGs. The purpose of the present study was to analyze separately Sol and GM or GL reflexes to account for different effects of the vibrations on the reflex excitability of the slow soleus and of the gastrocnemii muscles. A control group (n = 13) and a vibration group (n = 16) were tested in pre-test and post-test conditions.

Baclofen-loaded solid lipid nanoparticles: preparation, electrophysiological assessment of efficacy, pharmacokinetic and tissue distribution in rats after intraperitoneal administration.

Intrathecal baclofen administration is the reference treatment for spasticity of spinal or cerebral origin, but the risk of infection or catheter dysfunctions are important limits. To explore the possibility of alternative administration routes, we studied a new preparation comprising solid lipid nanoparticles (SLN) incorporating baclofen (baclofen-SLN). We used SLN because they are able to give a sustained release and to target the CNS.

Effects of repeated Achilles tendon vibration on triceps surae stiffness and reflex excitability.

Clinical studies frequently report an increase in stiffness and a loss of range of motion at joints placed in disuse or immobilization. This is notably the case for subjects maintained in bed for a long period, whilst their joints are not affected. Recently we documented on healthy subjects the benefit in terms of force and activation capacities of the triceps surae offered by vibrations applied to the Achilles tendon.

Effects of repeated Achilles tendon vibration on triceps surae force production.

Many studies reported benefits of whole-body vibration (WBV) on muscle force production. Therefore, WBV may be an important technique for muscle re-education. However vibrating platforms are heavy tools that cannot be easily used by all patients.

Follow-up of ankle stiffness and electromechanical delay in immobilized children: three cases studies.

Clinical manual tests refer to increased ankle stiffness in children immobilized due to hip osteochondritis. The aim of the present study was to investigate musculo-articular stiffness via different techniques in immobilized children to confirm or not and quantify these observations. Ankle stiffness was quantified monthly during the long immobilization period in three diseased children and compared to healthy age-matched children.

Neuromuscular efficiency of the rectus abdominis differs with gender and sport practice.

The purpose of this investigation was to distinguish the abilities of the rectus abdominis (RA) muscle according to gender and sport training by means of neuromuscular parameters extracted from electromyography (EMG)-torque relationships. Thirty-eight healthy students, divided into 4 groups (i.e.

Paired changes in electromechanical delay and musculo-tendinous stiffness after endurance or plyometric training.

When measured in vivo electromechanical delay (EMD) depends mainly on the elastic properties of the muscle-tendon unit. Recent studies have shown changes in stiffness of the triceps surae (TS) following a period of training. To confirm the influence of musculo-tendinous stiffness on EMD, this study investigates paired changes in these two parameters after a training period.

Voluntary activation of the triceps surae in prepubertal children.

The activation capacities and neuromuscular efficiency (NME) of the triceps surae (TS) of prepubescent children (7-11 years) and adults were evaluated during submaximal and maximal (MVC) isometric plantarflexion to determine whether they varied with age. TS-EMG were obtained by summing-up the rectified electromyograms of the soleus and gastrocnemii muscles; these data were quantified using a sliding average method and normalized with reference to the TS maximal compound action potential (TS-M-wave). The maximal EMG increased significantly with age in the children, but less than MVC, what led to a significant increase in NME(Max) (MVC/TS-EMG(max) ratio).

Aging affects passive stiffness and spindle function of the rat soleus muscle.

Aging affects many motor functions, notably the spinal stretch reflexes and muscle spindle sensitivity. Spindle activation also depends on the elastic properties of the structures linked to the proprioceptive receptors. We have calculated a spindle efficacy index, SEI, for old rats.

Age-related changes in twitch properties of plantar flexor muscles in prepubertal children.

The twitch of the triceps surae muscle (TS), which characterizes the contractile properties independently of volition, differs in amplitude, but not in time course, when evoked in pre or postpubertal children. The aim of the present study was to compare the TS twitch contractile properties in prepubertal children (7 to 11 y). M-wave and twitch were recorded at rest by supramaximal electrical stimulations of the posterior tibial nerve.

An index of spindle efficacy obtained by measuring electroneurographic activity and passive tension in the rat soleus muscle.

While muscle spindle afferent discharges are known to change with altered muscle use, the way in which the changes in spindle discharge are affected by modifications to the elastic properties of the muscle-tendon unit remains to analyze. This paper describes a methodology to define, in the rat, a spindle efficacy index. This index relates the spindle afferent discharges recorded from electroneurograms (ENG) due to muscle stretch to the passive elastic properties of the muscle-tendon unit quantified during the stretch imposed for the ENGs recordings.

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.