Model-independent assessment of accumulation kinetics based on moments of drug disposition curves

Summary The bounds of the accumulation profile can be predicted on the basis of the mean disposition residence time (MDRT) of a drug. The time to reach 90% of the plateau level (t _0.9) is less than 3.7 MDRT. This prediction can be improved if, in addition, the variance of disposition residence time (VDRT, CV _D ² =VDRT/MDRT²), or the terminal exponential coefficient (), is known. For CV _D ² 1 or MDRT1, the time to reach steady state (t_0.9) approaches 2.3 MDRT (limiting case of monoexponential drug disposition curve). Conditions are stated under which can be regarded as the principal determinant of the accumulation rate.     

Self-narrative reconstruction after dilemma-focused therapy for depression: A comparison of good and poor outcome cases

Objective: The aim of this study is to improve the understanding of self-changes after an intervention for depression focused on implicative dilemmas, a type of cognitive conflict related to identity. As recent research has highlighted the relevance of identity-related dilemmas in clients with depression, we sought to assess the way in which clients resolve such inner conflicts after a tailored dilemma-focused intervention and how this is reflected in the clients’ self-narratives. Method: We used three instruments to observe differences between good (n?=?5) and poor (n?=?5) outcome cases: (i) the Repertory Grid Technique to track the resolution of dilemmas, (ii) the Change Interview to compile clients’ accounts of changes at posttreatment, and (iii) the Innovative Moments Coding System to examine the emergence of clients’ novelties at the Change Interview. Results: Groups did not differ in terms of the number and relevance of client-identified significantly helpful events. However, between-group differences were found for the resolution of dilemmas and for the proportion of high-level innovative moment (IM) types. Furthermore, a greater self-narrative reconstruction was associated with higher levels of symptom improvement. Conclusions: Good outcome cases seem to be associated with the resolution of conflicts and high-level IMs.     

Testing a parametric function against a non‐parametric alternative in IV and GMM settings

Summary This paper develops a specification test for functional form for models identified by a conditional moment restriction, including IV and GMM settings. The framework is one where the moment restriction is specified as a function of data, a finite‐dimensional parameter vector and a non‐parametric function (an infinite‐dimensional parameter vector). The null hypothesis is that the moment restriction does not depend on the non‐parametric function. The test is relatively easy to implement and its asymptotic distribution is known. The test performs well in simulation experiments.     

Effects of artificially induced bilateral internal rotation gait on gait kinematics and kinetics

BackgroundBilateral internal rotation gait is a common gait abnormality in children with bilateral cerebral palsy, but still not fully understood.Research questionThe aim of this clinical study was to analyze the effects of artificially induced bilateral internal rotation gait on kinematics and kinetics. Our hypothesis was, that the internal rotation gait defined as increased dynamic internal hip rotation itself causes significant alterations in gait kinematics and kinetics.Methods30 typically developing children with a mean age of 12 (SD 3) years (range 8 – 16) performed three-dimensional gait analysis in two different conditions: with unaffected gait and with artificially induced bilateral internal rotation gait with two rotation bandages worn in order to internally rotate the hips. Kinematic and kinetic changes between these two conditions were calculated and compared using a mixed linear model with “gait condition” as fixed effect and both “limb” and “patient” as random effects.ResultsThe rotation bandages induced a significant increase in internal hip rotation and foot progression angle towards internal without affecting pelvic rotation. The peak hip internal rotator moment during loading response and the peak hip external rotator moment during the first half of stance phase increased significantly and the peak hip internal rotator moment during the second half of stance phase decreased significantly. Anterior pelvic tilt, hip flexion, knee flexion and ankle dorsiflexion increased significantly. The first peak of the frontal hip moment decreased, and the second increased significantly. The second peak of the frontal knee moment decreased significantly, while the first didn’t change significantly.SignificanceThe data suggest, that the bilaterally increased dynamic internal hip rotation itself has a relevant impact on frontal hip moments. The increased anterior pelvic tilt, hip and knee flexion may be either induced by the pull of the rotation bandage or a secondary gait deviation.     

The role of mutual in-feeding in maintaining problematic self-narratives: Exploring one path to therapeutic failure

Abstract

According to the author's narrative model of change, clients may maintain a problematic self-stability across therapy, leading to therapeutic failure, by a mutual in-feeding process, which involves a cyclical movement between two opposing parts of the self. During innovative moments (IMs) in the therapy dialogue, clients’ dominant self-narrative is interrupted by exceptions to that self-narrative, but subsequently the dominant self-narrative returns. The authors identified return-to-the-problem markers (RPMs), which are empirical indicators of the mutual in-feeding process, in passages containing IMs in 10 cases of narrative therapy (five good-outcome cases and five poor-outcome cases) with females who were victims of intimate violence. The poor-outcome group had a significantly higher percentage of IMs with RPMs than the good-outcome group. The results suggest that therapeutic failures may reflect a systematic return to a dominant self-narrative after the emergence of novelties (IMs).     

Narrative change in emotion-focused therapy: How is change constructed through the lens of the innovative moments coding system?

Abstract

The aim of this study was to advance understanding of how clients construct their own process of change in effective therapy sessions. Toward this end, the authors applied a narrative methodological tool for the study of the change process in emotion-focused therapy (EFT), replicating a previous study done with narrative therapy (NT). The Innovative Moments Coding System (IMCS) was applied to three good-outcome and three poor-outcome cases in EFT for depression to track the innovative moments (IMs), or exceptions to the problematic self-narrative, in the therapeutic conversation. IMCS allows tracking of five types of IMs events: action, reflection, protest, reconceptualization, and performing change. The analysis revealed significant differences between the good-outcome and poor-outcome groups regarding reconceptualization and performing change IMs, replicating the findings from a previous study. Reconceptualization and performing change IMs seem to be vital in the change process.     

Modulation of head movement control in humans during treadmill walking

The purpose of this study was to investigate the coordination of the head relative to the trunk within a gait cycle during gaze fixation. Nine normal subjects walked on a motorized treadmill driven at 1.79 m/s (20 s trials) while fixing their gaze on a centrally located earth-fixed target positioned at a distance of 2 m from their eyes. The net and relative angular motions of the head about the three axes of rotations, as well as the corresponding values for the moments acting on it relative to the trunk during the gait cycle were quantified and used as measures of coordination. The average net moment, as well as the average moments about the different axes were significantly different (P<0.01) between the high impact and low/no impact phases of the gait cycle. However, the average net angular displacement as well as the average angular displacement about the axial rotation axis of the head relative to the trunk was maintained uniform (P>0.01) throughout the gait cycle. The average angular displacement about the lateral bending axis was significantly increased (P<0.01) during the high impact phase while that about the flexion–extension axis was significantly decreased (P<0.01) throughout the gait cycle. Thus, the coordination of the motion of the head relative to the trunk during walking is dynamically modulated depending on the behavioral events occurring in the gait cycle. This modulation may serve to aid stabilization of the head by counteracting the force variations acting on the upper body that may aid in the visual fixation of targets during walking.     

Movement‐based feedback may reduce spinal moments in male workers during lift and lowering tasks

Background and Purpose . To assess if lifting performance can be modified and spine stresses reduced in workers who perform repetitive material‐handling jobs in a warehouse environment via a novel real‐time, movement‐based feedback training protocol. Method . A pre‐test/post‐test group study design was used with a control group. Data were collected in a warehouse setting and analysed in a university setting. A convenience sample of 22 male warehouse employees was divided equally, based on height and weight, and assigned to either an experimental group or a control group. The experimental group received real‐time, performance‐based auditory feedback from their calculated moments during lifting or lowering using an electromagnetic tracking system. The electromagnetic tracking system was used to measure the side‐bending, flexion and rotation moments during six lifts under four different conditions. A series of repeated‐measures analyses of variance (ANOVA) (one between (Group); one within (Time)) was performed on the average maximum moments from six lifting or lowering cycles for all three directions: side‐bending, flexion and rotation. Results . There were significant group X time interactions for the side‐bending moment (p < 0.05) and the flexion moment (p < 0.05) but not the rotation moment (p > 0.05). Lower moments were found in the experimental group, which received the training and feedback, compared to the control group. Conclusions . Real‐time, auditory feedback combined with coaching during lifting or lowering tasks may be effective in the short term (six weeks) in reducing the average maximum side‐bending and flexion moments in warehouse workers. Further research is needed to determine the long‐term effects of this training protocol on low back injury rates. Copyright © 2006 John Wiley & Sons, Ltd.     

A system to measure the forces and moments at the knee and hip during level walking

The forces and moments in the sagittal plane at the knee and hip were calculated using gait data collected during level walking. Accelerations were measured by accelerometers attached to the legs, and the force reactions at the foot were measured by a force plate. The recorded accelerations and the foot forces were used to determine the joint reactions through a Newtonian formulation modeling the leg as articulated, rigid links. Twelve normal subjects were included in this study along with nine lower limb amputees. Obvious differences were observed when comparing amputee data to normal data both at the knee and hip. Gait data obtained by this system can be readily used to form criteria for objective gait analysis and improved prosthesis design.