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Biomedical subjects

C Detrembleur

Publications and source records attributed to C Detrembleur.

18 recordsLinked to original sources
PubMed2005

Celecoxib improves the efficiency of the locomotor mechanism in patients with knee osteoarthritis. A randomised, placebo, double-blind and cross-over trial.

OBJECTIVE: To compare the effect of celecoxib vs placebo treatment on clinical and gait variables in knee osteoarthritis (OA) patients; focusing on the efficiency of the locomotor mechanism. METHODS STUDY DESIGN: A prospective, randomised, double-blind placebo-controlled trial. PATIENTS: Eight adult patients with painful OA of the knee. OUTCOME MEASURES: Clinical assessment included knee pain assessed by the visual analogue scale, range of knee motion assessed by goniometer, and locomotor function status assessed by a Knee Score Scale. Gait was assessed by means of instrumented analysis including synchronous kinematic, dynamic, electromyographic, and energetic recordings. STATISTICAL ANALYSIS: The effect of treatment on the primary variable, the efficiency of the locomotor mechanism, and on secondary clinical and gait variables was assessed by the Hills and Armitage non-parametric approach. RESULTS: Celecoxib treatment improved the efficiency of the locomotor mechanism significantly. Among the secondary outcome measures assessed, celecoxib treatment improved walking cadence and reduced the knee pain significantly. CONCLUSION: This study shows that celecoxib is effective in improving locomotor function and pain in patients with knee OA.

Aged↗
PubMed2004

Efficiency of work production by spastic muscles.

The present study compared the muscular efficiency in spastic and healthy lower limbs producing the same mechanical work. Sixteen chronic post-stroke hemiparetic and spastic patients and 14 age-matched healthy subjects were submitted to a submaximal stepwise exercise testing on a bicycle ergometer, pedalling with only one lower limb. Net energetic expenditure was computed from oxygen consumption above resting values. Electrical activity of antagonistic muscles in the thigh and in the shank was recorded and co-contraction was defined as the percentage of the pedalling cycle when antagonistic muscles were activated simultaneously. The efficiency was calculated as the ratio between the mechanical work done on the ergometer and the net energetic expenditure. Spasticity was quantitatively evaluated by measuring passive ankle plantar flexor muscle stiffness. The working capacity of the patients' paretic lower limb was very low (<40W). The energy expenditure increased linearly as a function of work intensity, without statistical difference between the patients paretic lower limb (PPL), the patients healthy lower limb (PHL) and the healthy subjects lower limb (HSL). Shank co-contraction was 2.9 times greater in PPL (p<0.05) and 2.3 times greater in PHL (p<0.05) than in HSL. Thigh co-contraction was also 1.8 times greater in PPL than in HSL (p<0.05). The ankle plantar flexor muscle stiffness was statistically greater in PPL than in PHL and HSL (p<0.05). The efficiency was not statistically different between the three groups (p=0.155). In conclusion, the efficiency of work production by paretic and spastic lower limb muscles was normal ( congruent with 20%) despite significant neurological impairments.

Adult↗
PubMed2003

Preparation of reactive surfaces by electrografting.

The electrografting process has been applied to a new monomer in order to induce reactivity to the surface of various conducting substrates which are then appropriate for the anchoring of a large variety of molecules (catalysts, proteins, amino-polymers etc.).

Journal Article↗
PubMed2003

Energy cost, mechanical work, and efficiency of hemiparetic walking.

The energy cost of walking (C) in nine chronic hemiparetic patients was calculated by measuring the total mechanical work (Wtot) done by the muscles and the efficiency of this work production (eta). The energy cost was twice normal in slow walkers and 1.3 times greater in fast walkers. The increase in C was proportional to the increase in Wtot and eta was normal at around 20%, despite an increase in muscle tone and muscle co-contractions. This type of approach gives a greater understanding into how segmental impairments increase Wtot and C and contribute to a patient's disability.

Adult↗
PubMed2002

Botulinum toxin and short-term electrical stimulation in the treatment of equinus in cerebral palsy.

Intramuscular botulinum toxin type A (BT-A) has been shown to reduce spasticity and to improve gait in children with cerebral palsy. To determine whether the efficacy of BT-A may be enhanced by electrical stimulation, as suggested in focal dystonia or in adult spastic patients, 12 children with dynamic foot equinus deformity were randomly assigned to two groups in a blinded, clinically controlled trial. Intramuscular BT-A into calf muscles was followed by adjuvant electrical stimulation in Group A (n = 6) but not in Group B (n = 6). Clinical assessment and instrumented gait analysis were performed before and 1, 3, and 6 months after treatment. The combined treatment of BT-A and electrical stimulation was not superior to BT-A alone. For all patients, improvement of the clinical and gait variables occurred at 1 and 3 months after BT-A injection.

Botulinum Toxins, Type A↗
PubMed2000

Quantitative assessment of intrathecally administered baclofen in spasticity.

OBJECTIVE: To quantitatively assess the antispastic effect of intrathecally administered baclofen on muscle stiffness in spastic patients. DESIGN: Case-control study. SETTING: Clinical laboratory in a university hospital of a city of more than 1,000,000 inhabitants. PARTICIPANTS: Eighteen healthy adult volunteers (9 men, 9 women) were recruited for establishing the normal values. Eleven spastic patients (8 men, 3 women) comprised the study group. MAIN OUTCOME MEASURES: The resistance to passive sinusoidal displacement of 5 degrees imposed to the ankle joint was measured at frequencies from 3 to 12 Hz. Torque and displacement signals were subjected to a Fourier analysis to isolate the elastic and viscous components of the total muscle stiffness. RESULTS: In comparison with the period before intrathecal injection, and with the control group, it was shown that at 4 hours after injection, stretch reflex activity was abolished and elastic and viscous muscle stiffness approached control values. The abnormal residual stiffness concerned only the elastic component due to chronic transformations of the spastic muscle and/or due to changes in joints and periarticular connective tissue. This antispastic effect was completely reversed 36 hours after injection. CONCLUSION: The present study shows that the antispastic effect of intrathecally administered baclofen in spastic patients can be quantitatively assessed by a sensitive method allowing measurement of elastic and viscous components of muscle stiffness.

Adult↗
PubMed2000

Motion of the body centre of gravity as a summary indicator of the mechanics of human pathological gait.

Abnormal movements of the body segments due to lowest level gait disorders such as musculoskeletal disorders, peripheral neuropathies and radiculopathies or middle-level disorders such as hemiplegia, paraplegia and dystonia influence the motion of the centre of gravity (CG) during walking. The translation of the CG can be studied by the work done by muscles (WExt) with respect to the ground. The efficacy of gait's mechanism can be quantified by the energy transferred between gravitational potential and kinetic energies (recovery). WExt and recovery were investigated in lowest and middle-level gait disorders during level walking. No statistical significant difference was observed between patients with lowest-level gait disorders and normal subjects. However, WExt was increased for the patients with middle-level gait disorders and recovery decreased up to 20%. The measurement of changes in mechanical energy of the CG might be a summary indicator for the mechanics of pathological gait.

Adult↗
PubMed2000

Usefulness of gait analysis combined with motor point block in a stroke patient.

This clinical note describes a typical case of dynamic varus deformity of the rear foot in a stroke patient. An overactive Tibialis Posterior muscle seemed mainly responsible for the varus deformity. However, this hypothesis was not confirmed by a motor point block of this muscle. It appeared that the Tibialis Posterior and Extensor Hallucis Longus muscles were both involved in the varus deformity. A double motor point block of both the Tibialis Posterior and Extensor Hallucis Longus muscles was performed. Kinematic and kinetic data showed improvement. This case report illustrates the usefulness of gait analysis combined with motor point block in the diagnosis and management of gait disturbance.

Adolescent↗
PubMed1999

Impact of the surface slipperiness of grasped objects on their subsequent acceleration.

Seven subjects were asked to reach and grasp an object between the thumb and index finger, lift it about 30 cm high and 25 cm forward from one table to another, at their preferred speed. The perpendicular grip force and the tangential load force applied to the contact surface were digitized at 500 Hz and stored on a laboratory computer. The trajectory of the wrist and of the object was recorded using four infrared cameras tracking the movement of reflective markers attached to the distal styloid process of the radius and on the top of the object. The aim of this study was to demonstrate the influence of low friction (i.e. surface slipperiness) on the acceleration of the wrist. Friction was reduced by coating the smooth brass grasping surface with talc. The seven subjects had skin to surface coefficients of friction which ranged from 0.52-1.18 for dry brass and 0.24 0.34 for talc-coated brass. Two weights (418 and 1070 g) were used with each surface. The results indicated that with the slippery surface the necessary higher grip force/load force ratio was produced by an increase in the grip force and by a decrease in the wrist acceleration and a consequent reduction in the load force. This strategy was observed for both weights over a range of grip strengths between 21-98% of the individual's maximum voluntary contraction (MVC). This implies that even with adequate grip force reserves the reduction in acceleration is an acceptable and probable alternative solution to the force control problem. Our results also suggested that the loading rate and the object acceleration were planned and controlled together which emphasizes the role played by a predictive mechanism in organizing the kinematics of movements involving hand-held objects. This study shows that friction of the grasping surface not only affects the prehensile force dynamics, but it also influences the kinematics of the entire upper limb.

Acceleration↗
PubMed1998

The 3-D motion of the centre of gravity of the human body during level walking. I. Normal subjects at low and intermediate walking speeds.

OBJECTIVE: To measure the mechanical energy changes of the centre of gravity (CG) of the body in the forward, lateral and vertical direction during normal level walking at intermediate and low speeds. DESIGN: Eight healthy adults performed successive walks at speeds ranging from 0.25 to 1.75 m s(-1) over a dedicated force platform system. BACKGROUND: In previous studies, it was shown that the motion of the CG during gait can be altered more than the motion of individual segments. However, more detailed normative data are needed for clinical analysis. METHODS: The positive work done during the step to accelerate the body CG in the forward direction, W(f), to lift it, W(v), to accelerate it in the lateral direction, W(I), and the actual work done by the muscles to maintain its motion with respect to the ground ('external' work), W(ext), were measured. This allowed the calculation of the pendulum-like transfer between gravitational potential energy and kinetic energy of the CG, (percentage recovery, R). At the optimal speed of about 1.3 m s(-1), this transfer allows saving of as much as 65% of the muscular work which would have been otherwise needed to keep the body in motion with respect to the ground. The distance covered by the CG at each step either forward (step length, S(I)), or vertically (vertical displacement, S(v)) was also recorded. RESULTS: W(I) was, as a median, only 1.6-5.9% of W(ext). This ratio was higher, the lower the speed. At each step, W(ext) is needed to sustain two distinct increments of the total mechanical energy of the CG, E(tot). The increment a takes place during the double stance phase; the increment b takes place during the single stance phase. Both of these increments increased with speed. Over the speed range analyzed, the power spent to to sustain the a increment was 2.8-3.9 times higher than the power spent to sustain the b increment.

Journal Article↗
PubMed1998

The 3-D motion of the centre of gravity of the human body during level walking. II. Lower limb amputees.

OBJECTIVE: To analyse the motion of the centre of gravity (CG) of the body during gait in unilateral lower limb amputees with good kinematic patterns. DESIGN: Three transtibial (below-knee, BK) and four transfemoral (above-knee, AK) amputees were required to perform successive walks over a 2.4 m long force plate, at freely chosen cadence and speed. BACKGROUND: In previous studies it has been shown that in unilateral lower limb amputee gait, the motion of the CG can be more asymmetric than might be suspected from kinematic analysis. METHODS: The mechanical energy changes of the CG due to its motion in the vertical, forward and lateral direction were measured. Gait speed ranged 0.75-1.32 m s(-1) in the different subjects. This allowed calculation of (a) the positive work done by muscles to maintain the motion of the CG with respect to the ground ('external' work, W(ext)) and (b) the amount of the pendulum-like, energy-saving transfer between gravitational potential energy and kinetic energy of the CG during each step (percent recovery, R). Step length and vertical displacement of the CG were also measured. RESULTS: The recorded variables were kept within the normal limits, calculated in a previous work, when an average was made of the steps performed on the prosthetic (P) and on the normal (N) limb. Asymmetries were found, however, between the P and the N step. In BK amputees, the P step R was 5% greater and W(ext) was 21% lower than in the N step; in AK amputees, in the P step R was 54% greater and W(ext) was 66% lower than in the N step. Asymmetries were also found in the relative magnitude of the external work provided by each lower limb during the single stance as compared with the double stance: a marked deficit of work occurred at the P to N transition.

Journal Article↗
PubMed1998

[Objective measures of muscle stiffness in the ankle. Evaluation of the effect of intrathecal injection of baclofen in spastic patients].

This paper presents the objective and quantitative measurement of muscle stiffness described by Rack and Lehmann. This method allows analysis of the pathophysiological mechanism of spasticity and assessment of anti-spastic treatment. This is illustrated by a case report, showing the objective effect of intrathecally administered baclofen in a spastic patient.

Adult↗
PubMed1997

Does walking speed influence the time pattern of muscle activation in normal children?

Dynamic electromyography (EMG) of the extrinsic muscles of the ankle is used more and more frequently to assist in the planning of tendon transfers in children with equinovarus deformities. Since these children walk at low speeds (1 to 4km/h), and since walking speed modifies the EMG-time pattern, the clinical investigator must be able to differentiate EMG modifications due to pathology versus those due to slow walking speed. The aim of this work was to study the effect of walking speed on the EMG-time pattern of the extrinsic ankle muscles in healthy children between 4 and 11 years of age. This pattern was found to change significantly with speed of progression but is independent of growth over this age range. A nomograph of EMG timing, taking into account walking speed, is proposed for clinical gait analysis.

Analysis of Variance↗
PubMed1997

Assessment of hand function in a patient with chronic sensory demyelinating neuropathy.

A 60-year-old man presented with progressive large fiber sensory loss in the right first three fingers and, to a lesser extent, in both fourth and fifth fingers. Electrophysiologic studies were characteristic of chronic sensory demyelinating polyneuropathy, a variant of chronic inflammatory demyelinating polyneuropathy. Plasma exchange was unsuccessful, but intravenous immunoglobulin (IVIG) led to complete recovery of sensation for 2 months, although neurophysiologic abnormalities persisted. A battery of noninvasive tests to measure hand grip strength, tactile sensation at the fingertips, and motor control of prehension during precision grip revealed marked abnormalities in the right hand before IVIG. One month after IVIG, all test results had normalized, but they returned to pretreatment levels after 3 months. Functional evaluation of the hand may be a sensitive method to objectively quantify loss of and changes in cutaneous mechanoreceptor function of the fingers in large fiber sensory neuropathy.

Demyelinating Diseases↗
PubMed1997

[Contribution of electromyographic analysis of the walking habits of children with spastic foot in cerebral palsy: a preliminary study].

PURPOSE OF THE STUDY: This preliminary study describes the methodology and the results of gait analysis in cases of equinus and equino-varus deformity of the foot in cerebral palsy children. The ultimate goal was to establish an aid to decision in spastic foot surgical management. MATERIAL: A prospective series of 12 walking children (16 feet) with cerebral palsy has been evaluated prior to surgical correction of equinus or equino-varus deformity of the foot. The mean age was 8 years (range 4 to 11 years of age). METHOD: The pattern of muscle activity during gait cycle has been recorded by surface electrodes for the tibialis anterior, the triceps and the peroneae and by implanted electrodes for the tibialis posterior. Foot switches have been used to differentiate swing and stance gait phases. The results were compared with these of a series of normal children previously published. RESULTS: In four cases, the dynamic equinus was due to an extended or continuous contraction of the triceps surae. The varus deformity appeared to originate from two muscles: the tibialis posterior in 9 cases and the tibialis anterior in 1 case. Both muscles were responsible for the deformity in 2 cases. Two muscular activation patterns were observed in the tibialis posterior: inverted (2 feet) or permanent (9 feet). From the main muscle which was responsible for deformity, we have determined the surgical technique which was most appropriate to restore the muscular balance. DISCUSSION: Our observations confirm Perry's hypothesis, namely that selective and phasic control during the walking cycle does not occur for patients suffering from cerebral palsy. Different surgical procedures were chosen according to the literature on this subject. In the treatment of equinus deformity, lengthening of the Achilles tendon is a satisfactory technique for hemiplegic patients. But we prefer gastrocnemius recession described by Vulpius in spastic diplegia in order to avoid over-lengthening or calcanal gait. If it can be shown that posterior tibial muscle overactivity is the cause of equinovarus, we perform a posterior tibial tendon lengthening, as proposed by Ruda and Frost, or a split posterior tibial tendon transfer as developed by Green. If the posterior tibial muscle is active only during the swing phase, we accomplish a split posterior tibial tendon transfer through the interosseus membrane as advocated by Saji. If the anterior tibial muscle is continuously active, a split anterior tibial tendon transfer to the cuboid described by Hoffer is performed. If the activity is continuous in both the tibial posterior and the tibial anterior muscles, we add a posterior tibial myotendinous lengthening to the split anterior tibial tendon transfer. CONCLUSION: Since 1992, we have developed in our institution a gait analysis laboratory in order to bring objective data in the process of decision making for tendon transfer surgery. With 4 years experience, this objective support now seems to us compulsory in decision of type of transfer. The goal of this preliminary study was to explain how we use the data and match these to our experience and literature.

Achilles Tendon↗
PubMed1991

The two power limits conditioning step frequency in human running.

1. At high running speeds, the step frequency becomes lower than the apparent natural frequency of the body's bouncing system. This is due to a relative increase of the vertical component of the muscular push and requires a greater power to maintain the motion of the centre of gravity, Wext. However, the reduction of the step frequency leads to a decrease of the power to accelerate the limbs relatively to the centre of gravity, Wint, and, possibly, of the total power Wtot = Wext + Wint. 2. In this study we measured Wext using a force platform, Wint by motion picture analysis, and calculated Wtot during human running at six given speeds (from 5 to 21 km h-1) maintained with different step frequencies dictated by a metronome. The power was calculated by dividing the positive work done at each step by the duration of the step (step-average power) and by the duration of the positive work phase (push-average power). 3. Also in running, as in walking, a change of the step frequency at a given speed has opposite effects on Wext, which decreases with increasing step frequency, and Wint, which increases with frequency; in addition, a step frequency exists at which Wtot reaches a minimum. However, the frequency for a minimum of Wtot decreases with speed in running, whereas it increases with speed in walking. This is true for both the step-average and the push-average powers. 4. The frequency minimizing the step-average power equals the freely chosen step frequency at about 13 km h-1: it is higher at lower speeds and lower at higher speeds. The frequency minimizing the push-average power approaches the freely chosen step frequency at high speeds (around 22 km h-1 for our subjects). 5. It is concluded that the increase of the vertical push does reduce the step-average power, but that a limit is set by the increase of the push-average power. Between 13 and 22 km h-1 the freely chosen step frequency is intermediate between a frequency minimizing the step-average power, eventually limited by the maximum oxygen intake (aerobic power), and a frequency minimizing the push-average power, set free by the muscle immediately during contraction (anaerobic power). The first need prevails at the lower speed, the second at the higher speed.

Biomechanical Phenomena↗