[Repair of a facial nerve substance loss by interposition of a collagen neurotube]. / Réparation d'une perte de substance du nerf facial par neurotube en collagène.

We are exposing the case of a 22 year-old patient presenting a wound of the right cheek, with a palsy of the right corner of the mouth. He has been sent to us 6 days after the trauma for secondary exploration. A section of the buccal branch of the right facial nerve with a 1cm gap has been brought out. We have bypassed the loss of substance with a collagen absorbable biological conduit. The 6-months clinical and electromyographic follow-up has shown a clear improvement of the function of the orbicularis oris, as well as its reinnervation by the buccal branch of the right facial nerve.

The effects of experimentally-induced fatigue on gait parameters during obstacle crossing: A systematic review.

Striking an obstacle while walking can be dangerous, reflecting the higher risks of losing one's balance, tripping and falling. Particular situations during which internal resources are limited, such as in a fatigued state, may impair performance when crossing obstacles, enhancing the risks of falls or accidents. Our goal was thus to review the effects of experimentally-induced fatigue (EIF) on gait parameters during obstacle crossing by healthy individuals. We systematically searched PubMed and Web of Science databases using 'fatigue', 'obstacle crossing' and their equivalent terms to extract data from studies investigating this domain. Nine studies were found. First, EIF-related effects on kinetics, EMG and obstacle contacts have been poorly studied. Second, consistent and inconsistent results were found in the kinematic outcomes after EIF. Consistent results included reductions in stride duration and increased step width. Inconsistent results included gait velocity (no-effect vs increased), leading and trailing-foot vertical clearance (reduced vs increased) and horizontal distance from foot to the obstacle before obstacle avoidance (no-effect vs increased). These findings should be interpreted cautiously, however, due to the heterogeneity of the obstacle crossing and EIF protocols.

Spatio-temporal gait parameters obtained from foot-worn inertial sensors are reliable in healthy adults in single- and dual-task conditions.

Inertial measurement units (IMUs) are increasingly popular and may be usable in clinical routine to assess gait. However, assessing their intra-session reliability is crucial and has not been tested with foot-worn sensors in healthy participants. The aim of this study was to assess the intra-session reliability of foot-worn IMUs for measuring gait parameters in healthy adults. Twenty healthy participants were enrolled in the study and performed the 10-m walk test in single- and dual-task ('carrying a full cup of water') conditions, three trials per condition. IMUs were used to assess spatiotemporal gait parameters, gait symmetry parameters (symmetry index (SI) and symmetry ratio (SR)), and dual task effects parameters. The relative and the absolute reliability were calculated for each gait parameter. Results showed that spatiotemporal gait parameters measured with foot-worn inertial sensors were reliable; symmetry gait parameters relative reliability was low, and SR showed better absolute reliability than SI; dual task effects were poorly reliable, and taking the mean of the second and the third trials was the most reliable. Foot-worn IMUs are reliable to assess spatiotemporal and symmetry ratio gait parameters but symmetry index and DTE gait parameters reliabilities were low and need to be interpreted with cautious by clinicians and researchers.

Superimposed electrical stimulation decreases maximal grip force.

AIM: The purpose of this study was to assess maximal grip force in two conditions of voluntary muscular contraction (MVC) and electrical stimulation superimposed on voluntary muscular contraction (SES) to better understand mechanisms and effectiveness of electrical stimulation of the hand. There is conflicting evidence regarding the effectiveness of electrical stimulation superimposed on voluntary muscular contraction on improving maximal force. Increased knowledge of the physiologic and mechanical effects of electrical stimulation applied during voluntary muscular contraction can lead to refinement of its clinical application. METHODS: Twenty subjects (36+/-13 years; 17 males and 3 females) participated in this study. All subjects were undergoing physical therapy within a hand rehabilitation center. They were instructed to randomly perform three grip determinations in both voluntary muscular contraction and superimposed electrical stimulation conditions to elicit maximal grip force of the unaffected hand. Force was assessed using a handheld dynamometer. Subjective force and contraction were assessed just after sessions as well as pain and discomfort using a visual analogue scale. RESULTS: The mean force values were 22+/-7 kg and 30+/-1 kg for the superimposed electrical stimulation and voluntary muscular contraction conditions, respectively. Analyses of the force measures showed that force was weaker in the superimposed electrical stimulation condition (P<0.001). Patients rated their pain and discomfort at 0+/-0 mm and 4+/-2.9 mm, respectively. CONCLUSION: Maximal grip force is reduced when electrical stimulation is superimposed to voluntary muscular contraction. This result could be explained by unbalanced muscular synergies at the hand due to SES, confirming these synergies as essential to produce maximal grip force.

Do gait and muscle activation patterns change at middle-age during split-belt adaptation?

Advancing age affects gait adaptability, but it is unclear if such adaptations to split-belt perturbations are already affected at middle-age. Changes in neuromuscular control, that already start at middle-age, may underlie the age-related changes in gait adaptation. Thus, we examined the effects of age on adaptations in gait and muscle activation patterns during split-belt walking in healthy young and middle-aged adults. Young (23.3 ± 3.13 years) and middle-aged adults (55.3 ± 2.91 years) walked on an instrumented split-belt treadmill. Both age groups adapted similarly by reducing asymmetry in step length and double support time. Surface EMG was recorded from eight leg muscles bilaterally. Principal Component Analysis (PCA) was applied to the EMG data of all subjects, for the fast and slow leg separately, to identify muscle activation patterns. The principal components consisted of i.e. temporal projections that were analyzed with Statistical Parametric Mapping (SPM). The functional muscle groups, identified by PCA, increased activation during early adaptation and post-adaptation, and decreased activation over time similarly in both age groups. Extra activation peaks of the plantar- and dorsiflexors suggest a role in gait modulation during split-belt walking. Both young and middle-aged adults re-established gait symmetry and showed adaptation effects in the muscle activation patterns. Since the adaptation of muscle activation patterns parallels adaptation of gait symmetry, changes in muscle activation likely underlie the changes in step parameters during split-belt adaptation. In conclusion, split-belt adaptation, in terms of gait and muscle activation patterns, is still preserved at middle-age, suggesting that age-related differences occur later in the lifespan.

Validity of wearable actimeter computation of total energy expenditure during walking in post-stroke individuals.

BACKGROUND: Recent studies reported that wearable sensor devices show low validity for assessing the amount of energy expenditure in individuals after stroke. OBJECTIVE: We aimed to evaluate the validity of energy expenditure calculation based on the product of energy cost and walked distance estimated by wearable devices in individuals after hemispheric stroke. METHODS: We recruited individuals with hemispheric stroke sequelae who were able to walk without human assistance. The participants wore a tri-axial accelerometer (Actigraph GT3x) and a pedometer (ONStep 400) on the unaffected hip in addition to a respiratory gas exchange analyzer (METAMAX 3B) during 6min of walking at their self-selected walking speed and mode. The energy expenditure was calculated from the product of energy cost measured by the METAMAX 3B and the distance estimated by wearable devices. It was compared to the energy expenditure measured by the METAMAX 3B and the energy expenditure values recorded by the devices according to the manufacturer's algorithms. The validity was investigated by Bland-Altman analysis (mean bias [MB], root mean square error [RMSE], limits of agreement [95%LoA]), and Pearson correlation analysis (r). RESULTS: We included 26 participants (mean [SD] age 64.6 [14.8] years). With the pedometer, the energy expenditure calculated from the product of energy cost and walked distance showed high accuracy and agreement with METAMAX 3B values (MB=-1.6kcal; RMSE=4.1kcal; 95%LoA=-9.9; 6.6kcal; r=0.87, P<0.01) but low accuracy and agreement with Actigraph GT3x values (MB=15.7kcal; RMSE=8.7kcal; 95%LoA=-1.3; 32.6kcal; r=0.44, P=0.02) because of poorer estimation of walked distance. With the pedometer, this new method of calculation strongly increased the validity parameter values for estimating energy expenditure as compared with the manufacturer's algorithm. CONCLUSIONS: This new method based on the energy cost and distance estimated by wearable devices provided better energy expenditure estimates for the pedometer than did the manufacturer's algorithm. The validity of this method depended on the accuracy of the sensor to measure the distance walked by an individual after stroke.

Can a plantar pressure-based tongue-placed electrotactile biofeedback improve postural control under altered vestibular and neck proprioceptive conditions?

We investigated the effects of a plantar pressure-based tongue-placed electrotactile biofeedback on postural control during quiet standing under normal and altered vestibular and neck proprioceptive conditions. To achieve this goal, 14 young healthy adults were asked to stand upright as immobile as possible with their eyes closed in two Neutral and Extended head postures and two conditions of No-biofeedback and Biofeedback. The underlying principle of the biofeedback consisted of providing supplementary information related to foot sole pressure distribution through a wireless embedded tongue-placed tactile output device. Center of foot pressure (CoP) displacements were recorded using a plantar pressure data acquisition system. Results showed that (1) the Extended head posture yielded increased CoP displacements relative to the Neutral head posture in the No-biofeedback condition, with a greater effect along the anteroposterior than mediolateral axis, whereas (2) no significant difference between the two Neutral and Extended head postures was observed in the Biofeedback condition. The present findings suggested that the availability of the plantar pressure-based tongue-placed electrotactile biofeedback allowed the subjects to suppress the destabilizing effect induced by the disruption of vestibular and neck proprioceptive inputs associated with the head extended posture. These results are discussed according to the sensory re-weighting hypothesis, whereby the CNS would dynamically and selectively adjust the relative contributions of sensory inputs (i.e. the sensory weights) to maintain upright stance depending on the sensory contexts and the neuromuscular constraints acting on the subject.

Reduction of Prolonged Excessive Pressure in Seated Persons With Paraplegia Using Wireless Lingual Tactile Feedback: A Randomized Controlled Trial.

Pressure ulcers (PU) are known to be a high-cost disease with a risk of severe morbidity. This paper evaluates a new clinical strategy based on an innovative medical device [Tongue Display Unit (TDU)] that implements perceptive supplementation in order to reduce prolonged excessive pressure, recognized as one of the main causes of PU. A randomized, controlled, and parallel-group trial was carried out with 12 subjects with spinal cord injuries (SCI). Subjects were assigned to the control (without TDU, [Formula: see text]) or intervention (with TDU, [Formula: see text]) group. Each subject took part in two sessions, during which the subject, seated on a pressure map sensor, watched a movie for one hour. The TDU was activated during the second session of the intervention group. Intention-to-treat analysis showed that the improvement in adequate weight shifting between the two sessions was higher in the intervention group (0.84 [0.24; 0.89]) than in the control group (0.01 [-0.01; 0.09]; [Formula: see text]) and that the ratio of prolonged excessive pressure between the two sessions was lower in the intervention group (0.74 [0.37; 1.92]) than in the control group (1.72 [1.32; 2.56]; [Formula: see text]). The pressure map sensor was evaluated as being convenient for use in daily life; however, this was not the case for the TDU. This paper shows that persons with SCI could benefit from a system based on perceptive supplementation that alerts and guides the user on how to adapt their posture in order to reduce prolonged excessive pressure, one of the main causes of PU.

Biomechanical assessment of the sitting posture maintenance in patients with stroke.

BACKGROUND AND PURPOSE: Regaining control of sitting posture is one of the first goals in the rehabilitation of patients with stroke. So, it requires a precise quantification of this postural behaviour. The purpose of the present investigation was thus to assess postural control during sitting in people with hemiparesis through a biomechanical analysis. METHODS: Centre-of-pressure displacements were recorded by means of a force platform on which 10 patients with stroke and 10 age-matched healthy subjects were sitting. Centre-of-pressure trajectories were processed through space-time and frequency analyses. RESULTS: These centre-of-pressure displacements of the patients with stroke were characterised by an increased control for maintaining sit position and by reduced postural performance, as enlightened by the larger surfaces covered by the centre-of-pressure displacements (P<.05) and increased velocities (P<.001), respectively. As shown from the frequency analysis, the impairment have affected predominantly the displacements occurring along the antero-posterior axis (P<.05). INTERPRETATIONS: The analysis of centre-of-pressure displacements during sitting posture indicates an increased postural disturbance in patients with stroke. A platform device, because of the non-invasive, easy and fast measures carried out, should thus be viewed as an attractive tool for assessing the postural dysfunctioning encountered in sat patients with stroke. This tool could also be used for evaluating, the rehabilitation process following stroke.

[Cervicocephalic relocation test: a study of performance stability]. / Test de repositionnement céphalique: étude de la stabilité de performance.

OBJECTIVE: The purpose of the present experiment was to determine the reliability of the cervicocephalic relocation test (CRT). METHODOLOGY: Thirteen young healthy adults were recruited to undergo a CRT test-retest. The test-retest reliability was determined by repeatedly measuring CR to a neutral position after active movement, with trials approximately 1 hour apart. Each CRT involved 20 CRs to a natural head position, 10 repositioning after right head rotation, and 10 repositioning after left head rotation (with the order of rotation sides randomized). The performance score for each subject for each CRT was the mean of the errors made during the 20 relocations (in degrees). STUDY RESULTS: The mean rate of error of the first and second trials was 3.2+/-1.1 degrees and 2.9+/-0.9 degrees, respectively. The intra class correlation coefficient was 0.81, and the standard error of measurement 0.90 degrees. CONCLUSION: CRT testing supports evidence of reliable cervicocephalic performance stability in healthy young adults. CRT shows promise as a relevant tool of assessment in head and neck proprioception.

[Prediction of falls with performance on Timed "Up-and-Go" and one-leg-balance tests and additional cognitive tasks]. / Modification des performances au Timed "Up and Go" test et à l'appui monopodal par l'addition d'une charge cognitive: valeur discriminative des résultats.

OBJECTIVE: This study aimed to determine whether ordinary clinical performance on the timed "up-and-go" and one-leg-balance tests varied with additional cognitive tasks and the predictive value of this combination for future falls. METHODOLOGY: The sample comprised 95 women with osteoporosis who lived independently in the community and were older than 70 years (mean 73.4+/-1.7 years) who were randomized to perform the timed "up-and-go" (TUG) and one-leg-balance (OLB) tests. The tests were performed with or without an additional cognitive task (math task involving subtraction by 2 s or 5 s or addition by 3 s). RESULTS: For both TUG and OLB, performance decreased in the dual-task condition (P<0.05) but did not differ in older women with and without a history of falling, whatever the test, and with or without an additional cognitive load. CONCLUSION: Performance on the TUG and OLB tests was less efficient when patients simultaneously performed a cognitive task. Performance on these tests, without or with cognitive tasks, did not predict falls in a sample of women who lived independently.

iProprio: a smartphone-based system to measure and improve proprioceptive function.

It is well known that proprioception is necessary to maintain balance control. Although proprioceptive exercices have shown to have beneficial effects on balance, the joint position sense is not easy to measure and patient cannot practise self-measurement. This article proposes a new system specifically desinged to allow measure and improve proprioceptive function. This so-called `iProprio' system uses inertial sensors included in a smartphone, wireless communication and voice command to allow joint position sense measurment in autonomous way and provide a configurable vibrotactile biofeedback for end-users at home. A proof-of-concept study was performed to assess the effectiveness of iProprio on sixteen young healthy subjects. Results showed that they were able to take advantage of vibrotactile biofeedback to increase knee joint repositioning accuracy and consistency. Results suggest that iProprio can be used for rehabilitation proprioceptive home exercices.

Clinical workflow for personalized foot pressure ulcer prevention.

Foot pressure ulcers are a common complication of diabetes because of patient's lack of sensitivity due to neuropathy. Deep pressure ulcers appear internally when pressures applied on the foot create high internal strains nearby bony structures. Monitoring tissue strains in persons with diabetes is therefore important for an efficient prevention. We propose to use personalized biomechanical foot models to assess strains within the foot and to determine the risk of ulcer formation. Our workflow generates a foot model adapted to a patient's morphology by deforming an atlas model to conform it to the contours of segmented medical images of the patient's foot. Our biomechanical model is composed of rigid bodies for the bones, joined by ligaments and muscles, and a finite element mesh representing the soft tissues. Using our registration algorithm to conform three datasets, three new patient models were created. After applying a pressure load below these foot models, the Von Mises equivalent strains and "cluster volumes" (i.e. volumes of contiguous elements with strains above a given threshold) were measured within eight functionally meaningful foot regions. The results show the variability of both location and strain values among the three considered patients. This study also confirms that the anatomy of the foot has an influence on the risk of pressure ulcer.

Results with the Roseland(®) HAC trapeziometacarpal prosthesis after more than 10 years.

The Roseland(®) hydroxyapatite-coated prosthesis is a total trapeziometacarpal joint prosthesis used for the surgical treatment of thumb basal joint arthritis. The aim of this retrospective study was to evaluate its long-term outcomes. Fifty-one patients (64 thumbs) underwent trapeziometacarpal joint replacement with this prosthesis. The mean follow-up was 12.5 years. Survival rate of the prosthesis was 91%. There was either no pain or only occasional pain in 91% of cases. The mean QuickDASH score was 27.6. Abnormal radiographic findings were present in 70% of cases. Since they were often asymptomatic, no further treatment was carried out. Complications were common (25%) and occurred early on but could often be treated without surgery. The long-term results with the Roseland(®) HAC prosthesis are satisfactory in terms of pain relief and function. However, the high complication rate is a major concern.

Influence of the calcaneus shape on the risk of posterior heel ulcer using 3D patient-specific biomechanical modeling.

Most posterior heel ulcers are the consequence of inactivity and prolonged time lying down on the back. They appear when pressures applied on the heel create high internal strains and the soft tissues are compressed by the calcaneus. It is therefore important to monitor those strains to prevent heel pressure ulcers. Using a biomechanical lower leg model, we propose to estimate the influence of the patient-specific calcaneus shape on the strains within the foot and to determine if the risk of pressure ulceration is related to the variability of this shape. The biomechanical model is discretized using a 3D Finite Element mesh representing the soft tissues, separated into four domains implementing Neo Hookean materials with different elasticities: skin, fat, Achilles' tendon, and muscles. Bones are modelled as rigid bodies attached to the tissues. Simulations show that the shape of the calcaneus has an influence on the formation of pressure ulcers with a mean variation of the maximum strain over 6.0 percentage points over 18 distinct morphologies. Furthermore, the models confirm the influence of the cushion on which the leg is resting: a softer cushion leading to lower strains, it has less chances of creating a pressure ulcer. The methodology used for patient-specific strain estimation could be used for the prevention of heel ulcer when coupled with a pressure sensor.

The effect of expertise in gymnastics on proprioceptive sensory integration in human subjects.

The ability of experts in motor skills requiring a fine postural control to keep a stable upright posture while facing the task of reinserting proprioceptive information was investigated. Seven expert gymnasts and seven experts in other non-gymnastics sports were asked to stand as immobile as possible in two conditions of vision and no-vision. Within a trial, ankle proprioceptive input was modified by means of tendon vibration of both antagonistic ankle muscles. Center of foot pressure (COP) displacements were recorded using a force platform. Contrasting with the non-gymnasts, the gymnasts were able to rapidly take advantage of the reinsertion of proprioceptive information to decrease their COP displacements. These results suggest that the efficiency of the integration process leading to the reweighting of sensory information can be significantly improved through a specific training.

Effects of a reaction time task on postural control in humans.

The purpose of the present experiments was to investigate the effects of a reaction time (RT) task on postural control, during and following the execution. Three different RT tasks consisting in verbal responses to visual and auditory stimuli were supposed to require different demands on cognitive resources. There was also a control condition in which no concurrent task was required. Postural control was assessed using a force platform. Results showed that (1) center of foot pressure (COP) displacements significantly decreased while concurrently performing the RT tasks, (2) this effect lasted for at least 10 s following the secondary task performance and (3) COP displacements decreased similarly, whatever the attentional requirements of the secondary task.

Can vision compensate for a lower limbs muscular fatigue for controlling posture in humans?

The purpose of the present experiment was to investigate the effect of vision on postural control following a lower limbs muscular fatigue. Ten adult males were asked to maintain a single leg upright posture as immobile as possible in two conditions of no-fatigue and fatigue of the calf muscles. This muscles fatigue was achieved by standing on the toes until exhaustion. Within a trial, vision was suppressed or reinserted by eyes closure or opening. Center of foot pressure displacements were recorded using a force platform. Results showed that the availability of vision allowed the subjects to immediately cope with the destabilizing effect induced by muscular fatigue.

The effect of expertise in gymnastics on postural control.

The goal of this paper was (1) to investigate if gymnasts have a more stable standing posture than experts in other sports, and (2) to determine how much gymnasts are affected by the removal of vision in different postural tasks. Six expert gymnasts and six experts in other non-gymnastic sports were asked to maintain balance in three standing postures of increasing difficulty: bipedal, unipedal, and unipedal + unstable support (i.e. 7 cm thick foam surface). Each posture was tested successively with and without vision. Based on the displacement of the center of pressure (range and mean average speed), the results showed that when visual cues were available, postural sway increased with the difficulty of the task, but both groups had comparable performance in all the tasks. When vision was removed, although both groups demonstrated larger postural sway in the unipedal tasks, this effect was less accentuated for the gymnasts. We concluded that gymnasts are able to use the remaining sensory modalities to compensate for the lack of vision in unstable postures.