Biomedical subjects

Ghislaine Lensel

Publications and source records attributed to Ghislaine Lensel.

9 recordsLinked to original sources

PubMed2006

Identification and classification of toe-walkers based on ankle kinematics, using a data-mining method.

A database of 1,736 patients and 2,511 gait analyses was reviewed to identify for trials where the first rocker was absent. A fuzzy c-means algorithm was used to identify sagittal ankle kinematic patterns and three groups were identified. The first showed a progressive dorsiflexion during the stance phase, while the second had a short-lived dorsiflexion, followed by a progressive plantarflexion. The third group exhibited a double bump pattern, moving successively from a short-lived dorsiflexion to a short-lived plantarflexion and then returning to a further short-lived dorsiflexion before ending with plantarflexion until toe-off. The three patterns were linked to different neurological conditions. Myopathy, neuropathy and arthogryposis essentially revealed group 1 patterns, whereas idiopathic toe-walkers mainly displayed group 2 patterns. Cerebral palsy patients, however, were relatively homogeneously distributed amongst the three groups. Able-bodied subjects walking on their toes showed a high proportion of unclassifiable ankle patterns, due to a variable gait whilst toe walking. Despite the variety of neurological conditions included in this meta-analysis repeatable biomechanical patterns appeared that could influence therapeutic management.

Adolescent↗

PubMed2006

Breathing strategy in master athletes and untrained elderly subjects according to the incremental protocol.

To analyze the influence of step-duration protocol (1 vs. 3 min) on breathing strategy according to the physical fitness of healthy elderly subjects, this study compared the ventilatory responses and exercise tidal flow-volume loops (ETFVL) at the first and second ventilatory thresholds (VT(1) and VT(2)). Nineteen master athletes (mean age (+/- SD), 63.1 +/- 3.2 y; (.)VO(2)(max), 41.5 mL x (min x kg)(-1)) and 8 untrained elderly subjects (age, 65.5 +/- 2.3 y; (.)VO(2)(max), 25.8 mL x (min x kg)(-1)) performed 2 exhaustive exercise tests on a cycle ergometer. In untrained subjects, at VT(1) and VT(2), no significant difference was measured in ventilatory responses and ETFVL between protocols. Master athletes, at VT(2), presented a significantly higher (.)VCO(2) (P < 0.01), ventilation ((.)VE; P < 0.01), breathing frequency (f(b); P < 0.05), tidal volume relative to inspiratory capatcity (V(t)/IC) (P < 0.01),V(t) relative to forced vital capacity (V(t)/FVC; P < 0.05), and lower inspiratory reserve volume relative to FVC (IRV/FVC; P < 0.01) during the 1 min protocol than during the 3 min protocol. Master athletes, at maximal exercise, expressed significantly higher (.)VCO(2) (P < 0.01) and dyspnea (P < 0.05) with the shorter protocol. We concluded that, in untrained subjects, neither incremental exercise test had an impact on respiratory responses during exercise. Nevertheless, in master athletes, breathing strategy seems to be protocol dependent. The short test induced higher mechanical ventilatory constraints and dyspneic feeling than the long protocol, which could be explained by a higher (.)VE itself linked to a greater (.)VCO(2) and a higher blood lactate concentration.

Aged↗

PubMed2005

Variability of video-based clinical gait analysis in hemiplegia as performed by practitioners in diverse specialties.

OBJECTIVE: Clinical gait analysis is widely used by different therapists working with hemiplegic patients. The purpose of this study was to assess the reliability of video-based clinical gait assessment, as performed by practitioners in diverse specialties. DESIGN: Five neurologists, 5 physiotherapists, and 5 doctors of physical medicine and rehabilitation (physiatrists) were asked to study a videotape of 6 patients with hemiplegia in the act of walking. This activity was chosen due to the wide use of gait information for therapeutic prescription and medical decision-making during medical consultations, at conventions, or in exchanges between therapists. RESULTS: Results highlighted a certain inconsistency in the use of the gait description indicators. The 15 therapists used 396 different locutions to describe the gaits of the 6 patients. These locutions yielded 60 general indicators, or gait disorders, which were grouped in 5 categories. Eleven of them were classified as "controversial" due to the significant inter-subject variability of the evaluations. CONCLUSION: The study identified a large number of indicators that were used relatively inconsistently by the 3 specialties studied. The results of this study would appear to indicate that greater caution is needed when dealing with some of the "controversial" indicators, as well as with the "unusual" gait patterns observed in some patients.

Adult↗

PubMed2004

A real-time plantar pressure feedback device for foot unloading.

OBJECTIVE: To develop and test a plantar pressure control device that provides both visual and auditory feedback and is suitable for correcting plantar pressure distribution patterns in persons susceptible to neuropathic foot ulceration. DESIGN: Pilot test. SETTING: Sports medicine laboratory in a university in France. PARTICIPANT: One healthy man in his mid thirties. INTERVENTIONS: Not applicable. Main outcome measures A device was developed based on real-time feedback, incorporating an acoustic alarm and visual signals, adjusted to a specific pressure load. Plantar pressure measured during walking, at 6 sensor locations over 27 steps under 2 different conditions: (1) natural and (2) unloaded in response to device feedback. RESULTS: The subject was able to modify his gait in response to the auditory and visual signals. He did not compensate for the decrease of peak pressure under the first metarsal by increasing the duration of the load shift under this area. Gait pattern modification centered on a mediolateral load shift. CONCLUSIONS: The auditory signal provided a warning system alerting the user to potentially harmful plantar pressures. The visual signal warned of the degree of pressure. People who have lost nociceptive perception, as in cases of diabetic neuropathy, may be able to change their walking pattern in response to the feedback provided by this device. The visual may have diagnostic value in determining plantar pressures in such patients. This pilot test indicates that further studies are warranted.

Adult↗

PubMed2004

Ventilatory threshold characterizations during incremental rowing and cycling exercises in older subjects.

In order to individualize the intensity of an aerobic training program on different ergometers in healthy elderly subjects using a single test of muscular exercise, we analysed cardiorespiratory responses in 8 men (65.7 +/- 4.5 yrs) and 10 women (63.3 +/- 4.8 yrs). The heart rate corresponding to the ventilatory threshold was defined as individualised exercise intensity. All subjects carried out two incremental exercise tests on the cycle and rowing ergometers. For men, the results on the cycle ergometer and rowing ergometer demonstrated that, at ventilatory threshold, heart rates were not significantly different (114.6 +/- 13.7 and 115.6 +/- 14.2 beats x min (-1), respectively), but ventilation was significantly higher in rowing (p < 0.05). At ventilatory threshold, heart rates for women were not significantly different between the cycle ergometer and rowing ergometer (121.3 +/- 12.4 and 125.1 +/- 15.2 beats x min (-1 ), respectively), but ventilation was significantly higher in rowing (p< 0.01). At maximal exercise, maximal tidal volume for men (p < 0.01) and women (p < 0.05) was significantly higher in rowing. In spite of alterations of breathing patterns on the rowing ergometer, it is possible to design an individualized training program for healthy elderly subjects based on a single muscle evaluation exercise in order to diversify and optimize the cardiorespiratory benefits following an aerobic training program.

Aged↗

PubMed2003

Comparison of clinical gait analysis strategies by French neurologists, physiatrists and physiotherapists.

Clinical and functional gait analysis is used widely by different professionals dealing with patients with hemiplegia. The aim of this study was to examine the gait analysis strategies of neurologists, specialists in physical and rehabilitation medicine (physiatrists) and physiotherapists. Differences in global analysis strategy and choice of indicators between different clinicians have not previously been studied precisely, and we believe that a standardized approach would enhance the training of young practitioners. The knowledge acquisition phase (specialists' expertise identification) was completed by an identified expert with a subject groups of 5 neurologists, 5 specialists in physical and rehabilitation medicine and 5 physiotherapists, who were asked to comment on a videotape of patients with hemiplegia walking, followed by a semi-directed interview. The results show that specialists use a wide variety of gait indicators. The total number of different medical vocabulary and expressions used to describe gait was 396, semantically grouped as 60 general indicators. Specialists highlighted an analysis strategy (order, type and number of indicators) typical to each professional specialty. The neurologists tried to identify the elements allowing localization of lesions and characterized the hemiplegia globally,while the specialists in physical and rehabilitation medicine conducted a bio-mechanical analysis and the physiotherapists were highly descriptive. The differences in strategies adopted by each specialty contribute to an enrichment of gait analysis. This should be taken into account in teaching and determining gait assessment scales.

Adult↗

PubMed2003

Effects of physical training on the physical capacity of frail, demented patients with a history of falling: a randomised controlled trial.

BACKGROUND: to develop a physical training programme to improve balance in dependent, demented, people with a history of falling, and so decrease falls and increase autonomy. METHODS: the study was undertaken on 20 demented elderly people with a history of falling with an average age of 81.4+/-4.7 years and an average mini mental state score of 16.3+/-6.5. They had all passed 'get up and go', 'chair sit and reach', walking speed and static balance tests. They were assigned to a control group or a training group; the latter were trained with two sessions a week for 16 weeks. RESULTS: walking, mobility, flexibility and static balance were significantly improved in the training group (P<0.05), but not in the controls. The trained subjects did not suffer a relapse, while the controls did during the training period. CONCLUSION: the balance of frail, demented, elderly patients with a history of falling can be improved by training.

Accidental Falls↗

PubMed2002

Measurement of plantar pressure distribution in hemiplegic children: changes to adaptative gait patterns in accordance with deficiency.

OBJECTIVE: A comparison of plantar pressure distribution in hemiplegic children with a healthy control group was performed to illustrate the link between the changing dynamics during the stance phase and the degree of deficiency. DESIGN: Twenty three healthy control subjects and two groups of six hemiplegic children with minor and major spasticity were tested. BACKGROUND: In previous studies, it was shown that the musculoskeletal dysfunction due to spasticity disturbed the hemiplegic gait pattern, for example reduced walking speed and step length. However, plantar pressure measurements which would help to understand the pathological gait mechanisms have not been studied. METHODS: The stance phase parameters measured included spatio-temporal data and the relative impulse measurements during consecutive gait cycles. The relative impulses under eight plantar areas were determined with an in-shoe plantar pressure measurement device. RESULTS: Each group had a specific plantar pressure distribution profile that varied with the degree of deficiency. The most significant differences were found beneath the midfoot, the first metatarsal head and the hallux. CONCLUSION: The neuromuscular disorders and foot deformities due to the cerebral lesion modified the contact of the foot with the ground, and led to specific plantar pressure distribution profiles. The equinovarus, with clawed-toe deformity due to greater spasticity, seemed to be an important factor in disturbances of the terminal stance phase. However, the spastic hemiplegic subjects seemed to adopt a gait pattern required for optimal stability. RELEVANCE: From previous work, comparable data were available only for the hemiparetic adult patients. In-shoe pressure data from spastic hemiplegic children can provide detailed information specific to each region of contact for the support of diagnosis, a clinical decision or the prescription of appropriate footwear, braces or othoses. Both peak pressure and local impulse have proven to be valuable for the understanding of foot function, lower extremity dysfunctions and walking strategies.

Adaptation, Physiological↗

PubMed2002

Critical velocity and time spent at a high level of VO2 for short intermittent runs at supramaximal velocities.

This study was designed to determine the intermittent critical velocity, the time spent at maximal oxygen uptake (VO2max) and the time spent above 90% of VO2max for short intermittent runs of 15 s at supramaximal velocities, alternating with 15 s of passive recovery. Nine male subjects performed 5 field-tests to exhaustion (tlim): 4 intermittent runs at 110%, 120%, 130% and 140% of maximal aerobic speed (MAS) and 1 continuous run at 100% of MAS. Results have shown the mean intermittent critical velocity (4.82 +/- 0.41 m.s-1) was not significantly different from MAS (4.63 +/- 0.37 m.s-1). Intermittent runs at 110% and 120% of MAS and the continuous run at 100% of MAS lead all subjects to reach VO2max. However, intermittent runs at 120% of MAS (202 +/- 66 s) allowed subjects to spend a significantly longer time at VO2max (p < .05) than intermittent runs at 110% (116 +/- 42 s), 130% (50 +/- 47 s), 140% (48 +/- 59 s) of MAS and continuous run at 100% of MAS (120 +/- 42 s). The time spent between 90 and 100% of VO2max was significantly longer (p < .05) for intermittent runs at 110% (383 +/- 180 s) and for 120% (323 +/- 272 s) of MAS than for intermittent runs at 130% (135 +/- 133 s), 140% of MAS (77 +/- 96 s) and for continuous run at 100% of MAS (217 +/- 114 s). Consequently, this kind of intermittent exercise with intensities from intermittent critical velocity to 120% of MAS could be introduced in a training program when the purpose is to increase VO2max.

Adult↗