1,720,996 research outputs found
Posture and movement laboratory: from posturography evaluation to rehabilitation treatment
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The generation of centripetal force when walking in a circle: insight from the distribution of ground reaction forces recorded by plantar insoles.
No full textBACKGROUND: Turning involves complex reorientation of the body and is accompanied by asymmetric motion of the lower limbs. We investigated the distribution of the forces under the two feet, and its relation to the trajectory features and body medio-lateral displacement during curved walking. METHODS: Twenty-six healthy young participants walked under three different randomized conditions: in a straight line (LIN), in a circular clockwise path and in a circular counter-clockwise path. Both feet were instrumented with Pedar-X insoles. An accelerometer was fixed to the trunk to measure the medio-lateral inclination of the body. We analyzed walking speed, stance duration as a percent of gait cycle (%GC), the vertical component of the ground reaction force (vGRF) of both feet during the entire stance, and trunk inclination. RESULTS: Gait speed was faster during LIN than curved walking, but not affected by the direction of the curved trajectory. Trunk inclination was negligible during LIN, while the trunk was inclined toward the center of the path during curved trajectories. Stance duration of LIN foot and foot inside the curved trajectory (Foot-In) was longer than for foot outside the trajectory (Foot-Out). vGRF at heel strike was larger in LIN than in curved walking. At mid-stance, vGRF for both Foot-In and Foot-Out was higher than for LIN foot. At toe off, vGRF for both Foot-In and Foot-Out was lower than for LIN foot; in addition, Foot-In had lower vGRF than Foot-Out. During curved walking, a greater loading of the lateral heel occurred for Foot-Out than Foot-In and LIN foot. On the contrary, a smaller lateral loading of the heel was found for Foot-In than LIN foot. At the metatarsal heads, an opposite behaviour was seen, since lateral loading decreased for Foot-Out and increased for Foot-In. CONCLUSIONS: The lower gait speed during curved walking is shaped by the control of trunk inclination and the production of asymmetric loading of heel and metatarsal heads, hence by the different contribution of the feet in producing the body inclination towards the centre of the trajectory
Test-retest reliability of an insole plantar pressure system to assess gait along linear and curved trajectories.
No full textBACKGROUND: Previous studies have assessed reliability of insole technology for evaluating foot pressure distribution during linear walking. Since in natural motion straight walking is intermingled with turns, we determined the test-retest reliability of insole assessment for curved as well as linear trajectories, and estimated the minimum number of steps required to obtain excellent reliability for each output variable. METHODS: Sixteen young healthy participants were recruited. Each performed, two days apart, two sessions of three walking conditions: linear (LIN) and curved, clockwise (CW) and counter-clockwise (CCW). The Pedar-X system was used to collect pressure distribution. Foot print was analyzed both as a whole and as subdivided into eight regions: medial and lateral heel, medial and lateral arch, I metatarsal head, II-V metatarsal heads, hallux, lateral toes. Reliability was assessed by using intraclass correlation coefficient (ICC) for clinically relevant variables from analysis of 50 steps per trajectory: Peak Force (PF); Peak Pressure (PP); Contact Area (CA); Stance Duration (S). RESULTS: When considering whole-foot, all variables showed an ICC >0.80, therefore highly reliable. This was true for both LIN and curved trajectories. There was no difference in ICC of the four variables between left and right foot. When collapsing foot and trajectories, S had a lower ICC than PP and CA, and PP lower than CA. Mean percent error between the values of first and second session was 0.90, indicating excellent reliability. In curved trajectories, S showed smaller ICCs. Since the least ICC value for S was 0.60 in LIN trajectory, we estimated that to achieve an ICC ≥0.90 more than 200 steps should be collected. CONCLUSIONS: High reliability of insole dynamic variables (PF, PP, CA) is obtained with 50 steps using the Pedar-X system. On the contrary, high reliability of temporal variable (S) requires a larger step number. The negligible differences in ICC between LIN and curved trajectory allow use of this device for gait assessment along mixed trajectories in both clinical and research setting
Using psychometric techniques to improve the Balance Evaluation Systems Test: the mini-BESTest
No full textOBJECTIVE:
To improve, with the aid of psychometric analysis, the Balance Evaluation Systems Test (BESTest), a tool designed to analyse several postural control systems that may contribute to poor functional balance in adults.
METHODS:
Performance of the BESTest was examined in a convenience sample of 115 consecutive adult patients with diverse neurological diagnoses and disease severity, referred to rehabilitation for balance disorders. Factor (both explorative and confirmatory) and Rasch analysis were used to process the data in order to produce a new, reduced and coherent balance measurement tool.
RESULTS:
Factor analysis selected 24 out of the 36 original BESTest items likely to represent the unidimensional construct of "dynamic balance". Rasch analysis was then used to: (i) improve the rating categories, and (ii) delete 10 items (misfitting or showing local dependency). The model consisting of the remaining 14 tasks was verified with confirmatory factor analysis to meet the stringent requirements of modern measurement.
CONCLUSION:
The new 14-item scale (dubbed mini-BESTest) focuses on dynamic balance, can be conducted in 10-15 min, and contains items belonging evenly to 4 of the 6 sections from the original BESTest. Further studies are needed to confirm the usefulness of the mini-BESTest in clinical settings
Instrument assisted soft tissue mobilization and eccentric training treatment for Chronic Hip Adductor Tendinitis (CHAT): a single clinical trial
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Enhancing the usefulness of the Mini-BESTest for measuring dynamic balance: a Rasch validation study
No full textBACKGROUND:
Recently, a new balance scale, the Mini-BESTest, was introduced. This scale can be administered in about 15 min, and focuses on "dynamic balance". In spite of the recently increased use of this scale, further psychometric studies seem called for to enhance confidence in its use in different fields of clinical practice and research.
AIM:
To re-examine through Rasch analysis the metric properties of the Mini-BESTest and provide a nomogram that allow to quickly transform raw scores of the scale into linear estimates of dynamic balance.
DESIGN:
Observational cross-sectional study.
SETTING:
Rehabilitation hospital.
POPULATION:
A total of 234 patients were consecutively admitted with a variety of neurological diseases causing balance impairment.
METHODS:
Internal construct validity was assessed by determining how well data fit the Rasch model. Reliability was estimated for both persons and items. Scale unidimensionality and local independence of items were analysed performing a principal component analysis (PCA) on the standardized residuals. Also, a differential item functioning (DIF) analysis was run to assess the stability of item calibration across subsamples of patients.
RESULTS:
All 14 items of Mini-BESTest fitted the "dynamic balance" construct, i.e., the mean of the squared residuals for both the infit and outfit was between 0.8 and 1.2. The person abilities-item difficulty matching was very good. The reliability indices of the Mini-BESTest were as follows: person separation index=3.24 and person reliability=0.91; item separation index=12.00 and item reliability=0.99. The PCA of standardized residuals showed that the variance attributable to the Rasch factor was good (68%) and the eigenvalue of the unexplained variance in the first contrast was just 1.9, thus confirming the unidimensionality of the scale. No DIF was found across gender and age groups.
CONCLUSION:
The reliability indexes confirmed their high values, giving a high degree of confidence in the consistency of both person-ability and item-difficulty estimates. Results allowed to transform the ordinal summed raw scores of the Mini-BESTest into interval-level measurements using a nomogram. Since no significant local dependence between items was found, this means that each Mini-BESTest item is appropriate for measuring the variable of interest (dynamic balance) and not redundant. DIF analysis showed the stability of item hierarchy and difficulty among subsamples of patients of different gender and age.
CLINICAL REHABILITATION IMPACT:
This study further increases confidence in use of the Mini-BESTest for clinical assessment of dynamic balance in patients undergoing rehabilitation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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