Biomedical subjects

Martin Descarreaux

Publications and source records attributed to Martin Descarreaux.

11 recordsLinked to original sources

PubMed2007

Postural development in school children: a cross-sectional study.

BACKGROUND: Little information on quantitative sagittal plane postural alignment and evolution in children exists. The objectives of this study are to document the evolution of upright, static, sagittal posture in children and to identify possible critical phases of postural evolution (maturation). METHODS: A total of 1084 children (aged 4-12 years) received a sagittal postural evaluation with the Biotonix postural analysis system. Data were retrieved from the Biotonix internet database. Children were stratified and analyzed by years of age with n = 36 in the youngest age group (4 years) and n = 184 in the oldest age group (12 years). Children were analyzed in the neutral upright posture. Variables measured were sagittal translation distances in millimeters of: the knee relative to the tarsal joint, pelvis relative to the tarsal joint, shoulder relative to the tarsal joint, and head relative to the tarsal joint. A two-way factorial ANOVA was used to test for age and gender effects on posture, while polynomial trend analyses were used to test for increased postural displacements with years of age. RESULTS: Two-way ANOVA yielded a significant main effect of age for all 4 sagittal postural variables and gender for all variables except head translation. No age x gender interaction was found. Polynomial trend analyses showed a significant linear association between child age and all four postural variables: anterior head translation (p < 0.001), anterior shoulder translation (p < 0.001), anterior pelvic translation (p < 0.001), anterior knee translation (p < 0.001). Between the ages of 11 and 12 years, for anterior knee translation, T-test post hoc analysis revealed only one significant rough break in the continuity of the age related trend. CONCLUSION: A significant linear trend for increasing sagittal plane postural translations of the head, thorax, pelvis, and knee was found as children age from 4 years to 12 years. These postural translations provide preliminary normative data for the alignment of a child's sagittal plane posture.

Journal Article↗

PubMed2006

Learning spinal manipulation: the importance of augmented feedback relating to various kinetic parameters.

BACKGROUND CONTEXT: Spinal manipulation is a widely accepted therapeutic approach in the treatment of back pain. In standard training programs, feedback on student performances is provided by an instructor based on teaching and clinical experience. Systematic study of the type of augmented feedback provided and skill learning is lacking in the literature. PURPOSE: The goal of this investigation is to compare the performance of two groups of chiropractic students, one receiving traditional training from experienced instructors, and the other, augmented feedback on specific biomechanical aspects of spinal manipulation therapy using an instrumented manikin. STUDY DESIGN: Randomized controlled study. PATIENT SAMPLE: Thirty-one fourth-year students from the Department of Chiropractic of Université du Québec à Trois-Rivières participated in this study. OUTCOME MEASURES: Kinetic parameters (force-time curves) of spinal manipulation were evaluated. METHODS: Spinal manipulation parameters were measured before and after a 5-week training period in which one group received standard chiropractic training while a second group received augmented feedback about specific biomechanical parameters of spinal manipulation. For both groups, practice scheduling and time duration were similar and consisted of a weekly practice session of 90 minutes for five consecutive weeks. Both groups had to practice thoracic spine manipulation throughout the training period. RESULTS: Both groups showed a decrease in peak force applied, with a diminution in the number of trials where a downward incisural point was present in preload force. Participants in the feedback training group significantly reduced their peak force variability and significantly increased their preload force. No significant difference was observed for time to peak force. CONCLUSIONS: The results of this study highlight the merits of practicing with an instrumented manikin or other instrumented training aids. Such a device can provide specific feedback on specific parameters of the task during learning; it can also serve as a tool to assess the progress of students and eliminate the risks relating to repetitive spinal manipulative therapy practice on student colleagues.

Adult↗

PubMed2005

Isometric force production parameters during normal and experimental low back pain conditions.

BACKGROUND: The control of force and its between-trial variability are often taken as critical determinants of motor performance. Subjects performed isometric trunk flexion and extension forces without and with experiment pain to examine if pain yields changes in the control of trunk forces. The objective of this study is to determine if experimental low back pain modifies trunk isometric force production. METHODS: Ten control subjects participated in this study. They were required to exert 50 and 75% of their isometric maximal trunk flexion and extension torque. In a learning phase preceding the non painful and painful trials, visual and verbal feedbacks were provided. Then, subjects were asked to perform 10 trials without any feedback. Time to peak torque, time to peak torque variability, peak torque variability as well as constant and absolute error in peak torque were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak torque achieved. RESULTS: Absolute and constant errors were higher in the presence of a painful electrical stimulation. Furthermore, peak torque variability for the higher level of force was increased with in the presence of experimental pain. The linear regressions between peak dF/dt, time to peak dF/dt and peak torque were similar for both conditions. Experimental low back pain yielded increased absolute and constant errors as well as a greater peak torque variability for the higher levels of force. The control strategy, however, remained the same between the non painful and painful condition. Cutaneous pain affects some isometric force production parameters but modifications of motor control strategies are not implemented spontaneously. CONCLUSIONS: It is hypothesized that adaptation of motor strategies to low back pain is implemented gradually over time. This would enable LBP patients to perform their daily tasks with presumably less pain and more accuracy.

Adult↗

PubMed2004

Repositioning accuracy and movement parameters in low back pain subjects and healthy control subjects.

STUDY DESIGN: A control group study with repeated measures. OBJECTIVE: To compare trunk repositioning parameters in chronic low back pain (LBP) and healthy subjects. SUMMARY AND BACKGROUND DATA: Recent evidence suggests that chronic LBP patients exhibit deficits in trunk proprioception and motor control. Trunk repositioning and the various spatio-temporal parameters related to it can be used to evaluate sensori-motor control and movement strategies. METHODS: Fifteen control subjects and 16 chronic LBP subjects participated in this study. Subjects were required to reproduce different trunk position in flexion (15 degrees, 30 degrees and 60 degrees) and extension (15 degrees). In the learning phase preceding each condition, visual feedback was provided. Following these learning trials, subjects were asked to perform ten consecutive trials without any feedback. Movement time, movement time variability and peak velocity were obtained and a temporal symmetry ratio was calculated. Peak angular position variability and absolute error in peak angular position were also calculated to evaluate spatial accuracy. RESULTS: Two subgroups of LBP patients were identified. One subgroup of LBP subjects demonstrated longer movement time and smaller peak velocities and symmetry ratios than normal subjects. No group difference was observed for peak angular position variability and absolute error in peak angular position. CONCLUSION: Chronic LBP patients, when given a sufficient learning period, were able to reproduce trunk position with a spatial accuracy similar to control subjects. Some LBP subjects, however, showed modifications of movement time, peak velocity and acceleration parameters. We propose that the presence of persistent chronic pain could induce an alteration or an adaptation in the motor responses of chronic LBP subjects.

Adult↗

PubMed2004

Force production parameters in patients with low back pain and healthy control study participants.

STUDY DESIGN: A control group study with repeated measures. OBJECTIVE: To compare isometric force production parameters in low back pain and healthy study participants. SUMMARY AND BACKGROUND DATA: Recent evidence suggests that chronic patients with low back pain exhibit deficits in trunk proprioception and motor control. The control of force and its between-trial variability are often taken as critical determinants of performance. We compared various force time characteristics in patients with low back pain and healthy study participants. METHODS: Fifteen control study participants and 16 patients with low back pain participated in this study. Study participants were required to exert 50% and 75% of the maximal trunk flexion and extension. In a learning phase, visual and verbal feedback was provided. Following these learning trials, study participants were asked to perform 10 trials without any feedback. Time to peak force, time to peak force variability, peak force variability, and absolute error in peak force were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak force achieved. RESULTS: Two subgroups of patients with low back pain were identified. Controls and patients with low back pain with more pain showed faster time to peak force than patients with low back pain with less pain (331 ms and 341 ms vs. 574 ms, respectively). Linear regressions showed that, for control study participants and low back pain study participants with more pain, peak dF/dt explained 94.0% and 97.0% of the variance observed in peak force while 84.4% was explained for low back pain study participants with less pain. Peak force variability and absolute error in peak force were similar for all groups. CONCLUSIONS: Patients with low back pain were able to produce isometric forces with an accuracy similar to control study participants. The longer time to peak force and the smaller percentage of variance observed for the linear regressions suggest that some patients with low back pain adopted a control mode that was less "open-loop." It is possible that this mode of producing forces results from an adaptation to chronic pain or tissue degeneration.

Adult↗

PubMed2004

Efficacy of preventive spinal manipulation for chronic low-back pain and related disabilities: a preliminary study.

OBJECTIVE: To document the potential role of maintenance chiropractic spinal manipulation to reduce overall pain and disability levels associated with chronic low-back conditions after an initial phase of intensive chiropractic treatments. METHODS: Thirty patients with chronic nonspecific low-back pain were separated into 2 groups. The first group received 12 treatments in an intensive 1-month period but received no treatment in a subsequent 9-month period. For this group, a 4-week period preceding the initial phase of treatment was used as a control period to examine the sole effect of time on pain and disability levels. The second group received 12 treatments in an intensive 1-month period and also received maintenance spinal manipulation every 3 weeks for a 9-month follow-up period. Pain and disability levels were evaluated with a visual analog scale and a modified Oswestry questionnaire, respectively. RESULTS: The 1-month control period did not modify the pain and disability levels. For both groups, the pain and disability levels decreased after the intensive phase of treatments. Both groups maintained their pain scores at levels similar to the postintensive treatments throughout the follow-up period. For the disability scores, however, only the group that was given spinal manipulations during the follow-up period maintained their postintensive treatment scores. The disability scores of the other group went back to their pretreatment levels. CONCLUSIONS: Intensive spinal manipulation is effective for the treatment of chronic low back pain. This experiment suggests that maintenance spinal manipulations after intensive manipulative care may be beneficial to patients to maintain subjective postintensive treatment disability levels. Future studies, however, are needed to confirm the finding in a larger group of patients with chronic low-back pain.

Adult↗

PubMed2003

Self-initiating a seated perturbation modifies the neck postural responses in humans.

When seated subjects are submitted to a linear acceleration, reports indicate that the kinematic and electromyographic (EMG) responses of the head-neck system can be modulated with the magnitude of the linear acceleration. There is no evidence, however, that head kinematics or neck EMG activity can be modulated when specific knowledge and active control about the onset of platform acceleration are available. Sixteen seated subjects were given forward linear accelerations in two different conditions nested within subjects: reactive and predictive. In the reactive condition, the acceleration was initiated following a variable delay unknown to the subjects whereas in the predictive condition, subjects manually self-initiated the perturbation. All neck muscle activities were decreased 50-100 ms after platform movement onset in the predictive condition relative to the reactive condition, whereas head and neck peak angular positions and velocities were not different between the two conditions. These results suggest that feedforward control could use the self-generated timing information of platform movement onset to scale the appropriate neck motor output.

Acceleration↗

PubMed2003

Attenuation of human neck muscle activity following repeated imposed trunk-forward linear acceleration.

It has been suggested that, after a passive linear acceleration of a seated subject which resembles a small, rear-end car impact, sensory information from proprioceptive, vestibular, and visual systems elicit stabilizing neck muscular responses. These neck muscular responses are presumably reflex based and are modified with the magnitude of the perturbation. A key issue that remains is to determine whether the neck and head postural responses can be modulated by a previous experience of the acceleration and not only by the magnitude of the acceleration. This question is of interest because, contrary to cadaver studies, one could expect that humans apprehending a rapid trunk acceleration would adopt a bracing behavior to minimize head movements. The aim of the present experiment was to verify whether neck-muscle activities can be modulated when prior knowledge about whole-body acceleration onset, direction, and magnitude are unknown compared with when only acceleration onset is unknown. Nine seated subjects were submitted to 11 imposed, forward linear accelerations (1.1 g). For the first trial, subjects were completely unaware of the platform acceleration characteristics (onset, direction, amplitude, and acceleration magnitude). For the subsequent ten trials, subjects knew they would be submitted to a forward linear acceleration, but the onset of the acceleration was unknown. Head kinematics and EMG responses of the neck muscles to the first perturbation were similar for all subjects (6.2 degrees head extension, EMG activity starting from 55 to 72 ms after platform onset). Following the first trial, however, all subjects showed a decreased neck EMG activity. Moreover, subjects responded in one of two ways across trials: one group of subjects ( n=5) maintained a constant head angular position and velocity, whereas the other group ( n=4) showed an increased head angular position (up to 12.6 degrees ) and velocity. This suggests that the first perturbation trial revealed a completely reactive response. After this initial trial, the responses observed may present a mixture of feedforward and feedback control. It is likely that whiplash injuries occur under conditions resembling those observed for the first trial only. If this is the case, the behavior for the following trials cannot be representative of injury mechanisms occurring in whiplash-like motion. Altogether, our results strongly suggest that, following repeated trunk linear accelerations of a constant magnitude, the nervous system prefers to minimize muscle stress instead of adopting a bracing strategy.

Acceleration↗

PubMed2003

A non-invasive technique for measurement of cervical vertebral angle: report of a preliminary study.

Non-invasive methods have traditionally been used to assess spine positioning and range of motion. Recently, the use of prediction models derived from external stick markers and videographic analysis has been shown to be effective at predicting lumbosacral and segmental lumbar vertebral angles. The objective of this study was to develop a similar non-invasive method to predict cervical vertebral inclination in forward head flexion. Fourteen subjects with no history of trauma or inflammatory or arthritic disorders (mean age: 25+/-1 years) participated in this study on a voluntary basis. Radiographic and videographic measurements of four external markers (C0, C2, C6, C7) were taken for each subject at three different static head positions (neutral, and 30 degrees and 60 degrees of flexion). The data obtained from nine subjects with normal cervical configuration (lordosis) were used to develop statistical models predicting the radiographic segmental angles (dependent variables) from external markers (independent variables). A multiple regression model was developed for each vertebra (C1 to C6). These regression models predict the inclination of each cervical vertebra at three different neck angles with positional data derived from the four external skin markers. Adjusted R2 values of 0.97, 0.93, 0.93, 0.96, 0.95 and 0.89 were obtained for C1, C2, C3, C4, C5 and C6, respectively. The prediction models developed in this study can explain a large part of the variance for the relative contribution of each vertebral segment to global neck flexion and provide a greater accuracy then using external stick markers only. These models were not able to adequately predict the vertebral angular positioning of subjects presenting a cervical alordosis or kyphosis.

Adult↗

PubMed2002

Evaluation of a specific home exercise program for low back pain.

BACKGROUND: The prescription of exercise as a conservative treatment for lumbar pain is frequent and seems effective for the chronic cases of nonspecific low back pain. However, there is no evidence favoring one type of exercise over another. Often, exercise programs are prescribed without adequate evaluation of the individual characteristics like posture, muscular force, and extensibility. Patients with totally different causes of low back pain will often be given the same type of exercises. OBJECTIVE: Our objective was to compare the effectiveness of 2 home exercise programs in decreasing disability and pain related to subacute and chronic nonspecific low back pain. To do so we compared a specific (individualized) exercise program with a program of commonly prescribed exercises for low back pain. METHOD: In a control group study, 20 patients with chronic or subacute nonspecific low back pain participated after giving their informed consent. All subjects were evaluated (physical evaluation of lumbar and pelvic muscles [1] force and [2] extensibility, [3] trunk range of motion) and then divided in 2 groups: 10 patients received specific exercises (experimental group) based on their evaluation, and 10 patients received a commonly prescribed exercise program for low back pain (control group). Six weeks later a second physical evaluation was conducted. Pain (visual analog pain scale) and disability (modified Oswestry) questionnaires were also completed by each subject at both evaluations. DESIGN: This was a randomized experimental study. RESULTS: Both groups had similar age, weight, and sex characteristics. The experimental group showed significant improvements for some components targeted by the program. The control group significantly had improvement of some physical characteristics not related to their initial deficits. Even if both groups showed some improvements in muscular force and extensibility, only the members of the group who received specific exercises significantly reduced their level of pain and disability. Both groups showed a similar rate of participation in the program. CONCLUSION: The results of this study suggest that applying a specific physical evaluation and exercise prescription is an appropriate treatment for people having subacute or chronic nonspecific pain. Thus clinicians should prescribe exercise programs based on individual muscular deficits rather than most commonly prescribed exercise programs.

Activities of Daily Living↗

PubMedDate not supplied

Diagnosis and management of posttraumatic piriformis syndrome: a case study.

OBJECTIVE: The aim of this study is to describe the clinical management of a young male patient with sciatica symptoms that developed after an avulsion of the ischial tuberosity. This is a rare injury, but complications may occur. CLINICAL FEATURE: A 19-year-old patient developed sciatica 6 months after a football injury. The patient described his symptoms as a shooting pain from the buttock to the lateral part of the foot, along the back of his thigh and calf, sometimes accompanied by paresthesia. Physical examination showed restricted hip range of motion and a positive Bonnet's test. X-ray analysis revealed a bony overgrowth of the right ischial tuberosity. INTERVENTION AND OUTCOME: A treatment plan was designed to decrease the pain level, increase sacroiliac and lumbar joint mobility, and augment muscular extensibility. The patient received 20 treatments over a period of approximately 3 months. Complete recovery was observed 5 months later. CONCLUSION: Although many differential diagnoses were contemplated, it is most likely that changes in muscular tension and gait pattern, resulting from the ischial tuberosity avulsion, contributed to overuse of the piriformis muscle leading to a piriformis syndrome.

Adult↗