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Spinal dynamics during gait have been of interest in research for many decades. Based on respective previous investigations, the pelvis is generally expected to be maximally forward rotated on the side of the reference leg at the beginning of each gait cycle and to reach its maximum counterrotation approximately at the end of the reference leg's stance phase. The pelvic-upper-thoracic-spine coordination converges towards an anti-phase movement pattern in high velocities during ambulation. The vertebral bodies around the seventh thoracic vertebra are considered to be an area of transition during human ambulation where no or at least little rotary motion can be observed. The respective cranial and caudal vertebrae meanwhile are expected to rotate conversely around this spinal point of intersection. However, these previous assumptions are based on scarce existing research, whereby only isolated vertebrae have been analyzed contemporaneously. Due to huge methodological differences in data capturing approaches, the results are additionally hardly comparable to each other and involved measurement procedures are often not implementable in clinical routines. Furthermore, none of the above-mentioned methods provided reference data for spinal motion during gait based on an appropriate number of healthy participants. Hence, the aim of this study was to present such reference data for spinal rotary motion of every vertebral body from C7 down to L4 and the pelvis derived from surface topographic back shape analyses in a cohort of 201 healthy participants walking on a treadmill at a given walking speed of 5 km/h. Additionally, the spine's functional movement behavior during gait should be described in the transverse plane based on data derived from this noninvasive, clinically suitable measurement approach and, in conclusion, the results shall be compared against those of previous research findings derived from other measurement techniques. Contrary to the previous functional understanding, the area of the mid-thoracic spine was found to demonstrate the largest amplitude of rotary motion of all investigated vertebrae and revealed an approximately counterrotated movement behavior compared to the rotary motion of the pelvis. In both directions, spinal rotation during gait seemed to be initiated by the pelvis. The overlying vertebrae followed in succession in the sense of an ongoing movement. Therefore, the point of intersection was not statically located in a specific anatomical section of the spine. Instead, it was found to be dynamic, ascending from one vertebra to the next from caudal to cranial in dependence of the pelvis's rotation initiation.

Truck platoon driving technology uses vehicle-to-vehicle communication to allow one truck to follow another in an automated fashion. The first vehicle is operated manually, the second vehicle is dr...

Objective The aim of the study was to investigate (1) how different gap sizes are perceived by professional truck drivers under real traffic conditions and (2) whether semi-automated platoon driving leads to changes in driving behavior of subsequent manual driving. Background Platoon driving is a current branch in the development of automated driving in which two or more vehicles build a convoy. The lead vehicle is controlled manually while following vehicles are electronically coupled to it and drive semi-automated with small gaps in order to achieve a better traffic flow and potential fuel savings. Method In a real road experiment, 10 trained professional truck drivers completed a total of 33 test drives with a two-truck platoon on the German highway A9 with a gap size of either 15 or 21 m, in the leading and the following vehicle. Results (1) The drivers experienced both gap sizes as comfortable and preferred the smaller gap size of 15 m. (2) Both gap sizes led to significantly higher standard deviation of lane position in post- compared to pre-platoon driving. No significant difference in distance keepings in post- compared to pre-platoon driving occurred. Qualitative data give hints on difficulties, when switching back to regular truck driving. Conclusion The results implicate that small gap sizes are perceived as comfortable by drivers and that platoon driving has an influence on subsequent manual driving. Application Countermeasures to behavioral adaptations should be considered in order to ensure a safe conduction of platoon driving.

Previous studies on factors influencing decision making focused on the effects of additional cognitive load, stress, psychological disorders, and the process of aging. The potential effects of simu...

Bus driving maneuvers are likely to trigger perturbation forces that may cause postural instability in standing passengers and cause tumble. These noncollision incidents are considered a major cause of injuries and may induce passenger discomfort in public transport. Therefore, we analyzed the effects of acceleration and deceleration forces on older passengers in an upright standing position in everyday bus transport situations. We recorded ground reaction and handgrip forces, electromyographic data of the leg muscles, and the acceleration pattern of 8 elderly participants (68.1±5.2 years). The participants were exposed to acceleration and deceleration maneuvers while standing upright in three different positions: in the direction of travel (IT), against the direction of travel (AT), and sideways to the direction of travel (ST). The acceleration pattern of the bus was similar to everyday driving situations (starting and stopping in traffic). Ground reaction forces were higher in free-standing positions, as expected, with peak forces of 135% (ST) to 165% (AT) of individual body weight, than in standing position by grasping a strap, with peak forces of 120% (all conditions). However, when participants grasped the strap, peak forces comprised 65% (ST) to 90% (AT) of individual maximal pulling power. A passenger may experience these forces numerous times during a typical bus transport. Electromyographic analysis revealed a correlation between jerk events and muscle activation and coactivation of antagonistic muscles. This study presents, for the first time, relevant information with regard to the biomechanical demands of older passengers standing upright in bus transportation. On this basis, conceptual solutions may be introduced to improve passenger safety and comfort. Further research studies exploring the relationship between acceleration forces and travel safety of the elderly should be conducted.

Truck platoon driving is a current branch of automated driving, which has the potential to radically change the work routine of professional drivers. In a platoon system, one truck (semi-)automatically follows a lead truck with a reduced distance, which produces significant savings in fuel and enables better traffic flow. In a current application of truck platoon driving, the following vehicle operates at level-2 automation. Thus, the driver of the following truck merely has to supervise the semi-automated system, which takes over steering and speed control when engaged. Level-2 truck platoon driving had not been tested with professional drivers in real traffic before. We hypothesized that user acceptance would improve after the experience of platoon driving. Quantitative questionnaires and qualitative interviews were conducted with 10 drivers before and after an extensive Autobahn experience. The results show a clear increase of acceptance after the experience. Platoon driving was evaluated to be more useful, easier to use, and safer after the experience. Besides perceived driving safety, the prestige of truck platooning, the perceived usefulness of the system, and general technology affinity co-determined user acceptance.

Bewegungs- und Trainingsprogramme weisen ein bedeutendes Potenzial bei der Behandlung von Morbus Parkinson auf. Vor allem durch gezielt variable Trainingsinhalte konnen hier krankheitsbedingte Storungen im Bereich der Gang- und Gleichgewichtsmotorik reduziert werden. Zudem gibt es Hinweise, dass ein solches Bewegungstraining uber die Freisetzung neurotropher Faktoren neuroprotektive Funktionen hat. Die Ubersicht erlautert die aktuelle Studienlage zur Bewegungsvariabilitat und gibt einen Ausblick auf infrage kommende Trainingsansatze.

Public transportation by bus is an essential part of mobility. Braking and starting, e.g., approaching a bus stop, are documented as the main reason for non-collision incidents. These situations are evoked by the acceleration forces leading to perturbations of the passenger’s base of support. In laboratory studies perturbations are applied to getting insight into the postural control system and neuromuscular responses. However, bus perturbations diverge from laboratory ones with respect to duration, maximum and shape, and it was shown recently that these characteristics influence the postural response. Thus, results from posturographic studies cannot be generalised and transferred to bus perturbations. In this study, acceleration (ACC) and deceleration (DEC) signals of real traffic situations were examined. A mathematical approach is proposed in order to identify characteristics of these signals and to quantify their similarity and complexity. Typical characteristics (duration, maximum, and shape) of real-world driving manoeuvres concerning start and stop situations could be identified. A mean duration of 13.6 s for ACC and 9.8 s for DEC signals was found which is clearly longer than laboratory perturbations. ACC and DEC signals are more complex than the used signals for platform displacements in the laboratory. The proposed method enables the reconstruction of bus ACC and DEC signals. The data can be used as input for studies on postural control with high ecological validity.

The quantification of postural sway is considered to be an essential part of posturography and is important for research and clinical utility. A widely used method to calculate the scatter of center of pressure data is an ellipse that encloses about 100(1-α)% of the observations. However, underlying definitions and terminologies have been misused in many cases. Hence, outcomes of different studies are proved to be incommensurable. In order to attain inter-study comparability, standardization of calculation methods has to be advanced. This work features a comprehensive and consistent overview of the methods for elliptic area approximation contrasting general principles of confidence and prediction regions. As a result, we recommend the usage of the prediction ellipse, as far as we demonstrate that confidence ellipses emerge to be inappropriate for posturographic scatter evaluation. Furthermore, we point at problems that come along with different sample sizes.

Mobility is essentially based on successful balance control. The evaluation of functional strategies for postural stability is requisite for effective balance rehabilitation and fall prevention in elderly subjects. Our objective was to clarify control mechanisms of different standing positions reflecting challenges of typical everyday life situations. For this purpose, elderly subjects stood on different surfaces resulting in a change of the biomechanical constraints. Sway parameters out of time and frequency domain were calculated from center-of-pressure (COP) excursions. Besides the classic quantification of the amount of sway variability, we investigated the temporal organization of postural sway by means of nonlinear time series analysis. Limb load symmetry was quantified via foot pressure insoles. We found task dependent motor outputs: (1) asymmetrical loading in all conditions; (2) altered amount and structure of COP movements with dissimilar changes in medio-lateral and anterior-posterior direction; (3) changes of the motor output affect several time scales especially when standing on a balance board or with one foot on a step. Our results indicate that elderly subjects preferred forcefully one limb which supports a step-initiation strategy. Modifications of the postural sway structure refer to the interaction of multiple control mechanisms to cope with the altered demands. The identification of postural strategies employed in daily activities augments the ecological validity of postural control studies.

The analysis of postural control has a long history. Traditionally, the amount of body sway is solely used as an index of postural stability. Although this leads to some extent to an effective evaluation of balance performance, the control mechanisms involved have not yet been fully understood. The concept of nonlinear dynamics suggests that variability in the motor output is not randomness but structure, providing the stimulus to reveal the functionality of postural sway. The present work evaluates sway dynamics by means of COP excursions in a quiet standing task versus a dual-task condition in three different test times (30, 60, 300 s). Besides the application of traditional methods–which estimate the overall size of sway–the temporal pattern of body sway was quantified via wavelet transform, multiscale entropy and fractal analysis. We found higher sensitivity of the structural parameters to modulations of postural control strategies and partly an improved evaluation of sway dynamics in longer recordings. It could be shown that postural control modifications take place on different timescales corresponding to the interplay of the sensory systems. A continued application of nonlinear analysis can help to better understand postural control mechanisms.

There exists a great variety of posturographic parameters which complicates the evaluation of center of pressure (COP) data. Hence, recommendations were given to use a set of complementary parameters to explain most of the variance. However, it is unknown whether a dual task paradigm leads to different parametrization sets. On account of this problem an exploratory factor analysis approach was conducted in a dual task experiment. 16 healthy subjects stood on a force plate performing a posture-cognition dual task (DT, focus of attention on a secondary task) with respect to different sampling durations. The subjects were not aware of being measured in contrast to a baseline task condition (BT, internal focus of attention) in the previously published part I. In compareson to BT a different factor loading pattern appears. In addition, factor loadings are strongly affected by different sampling durations. DT reveals a change of factor loading structure with longer sampling durations compared to BT. Specific recommendations concerning a framework of posturographic parametrization are given.

There is increasing evidence that physical exercise leads to numerous positive effects in PwMS. However, long-term effects of exercise may only be achievable if training is implemented in daily routine. Enabling patients to exercise regularly, we developed a patient education program focused on evidence-based information of training. PwMS were educated in neurophysiological effects of physical exercise, exercise-induced benefits for PwMS, and risk factors (e.g., weather). Fifteen PwMS were analyzed before (T0) and after (T1) a 12-week patient education. Afterwards, participants performed their exercises autonomously for 32 weeks and were tested in sustainability tests (T2). Guided interviews were carried out, additionally. Significant improvements fromT0toT1were found in 6MWT, gait velocity, TUG, fatigue, and quality of life. Significant results of TUG and gait velocity fromT1toT2demonstrated that participants kept few effects after the 32-week training phase. Qualitative analyses showed improved self-confidence and identified training strategies and barriers. This pilot study provides evidence that PwMS are able to acquire good knowledge about physical exercise and apply this knowledge successfully in training management. One might conclude that this exercise-based patient education seems to be a feasible option to maintain or improve patients’ integral constitution concerning physical and mental health.

Variability indicates motor control disturbances and is suitable to identify gait pathologies. It can be quantified by linear parameters (amplitude estimators) and more sophisticated nonlinear methods (structural information). Detrended Fluctuation Analysis (DFA) is one method to measure structural information, e.g., from stride time series. Recently, an improved method, Adaptive Fractal Analysis (AFA), has been proposed. This method has not been applied to gait data before. Fractal scaling methods (FS) require long stride-to-stride data to obtain valid results. However, in clinical studies, it is not usual to measure a large number of strides (e.g., [Formula: see text][Formula: see text] strides). Amongst others, clinical gait analysis is limited due to short walkways, thus, FS seem to be inapplicable. The purpose of the present study was to evaluate FS under clinical conditions. Stride time data of five self-paced walking trials ([Formula: see text] strides each) of subjects with PD and a healthy control group (CG) was measured. To generate longer time series, stride time sequences were stitched together. The coefficient of variation (CV), fractal scaling exponents [Formula: see text] (DFA) and [Formula: see text] (AFA) were calculated. Two surrogate tests were performed: A) the whole time series was randomly shuffled; B) the single trials were randomly shuffled separately and afterwards stitched together. CV did not discriminate between PD and CG. However, significant differences between PD and CG were found concerning [Formula: see text] and [Formula: see text]. Surrogate version B yielded a higher mean squared error and empirical quantiles than version A. Hence, we conclude that the stitching procedure creates an artificial structure resulting in an overestimation of true [Formula: see text]. The method of stitching together sections of gait seems to be appropriate in order to distinguish between PD and CG with FS. It provides an approach to integrate FS as standard in clinical gait analysis and to overcome limitations such as short walkways.

It is well known that dual-tasking is adversely affected by physiological degenerative processes. Furthermore, the completion of a secondary task while walking is frequently discussed as a key contributor for falls in the elderly. Age-related differences in both activated neural structures and human behavior are indicated in numerous previous studies. Besides a general overview of dual-tasking and aging, this article reviews studies aiming at improving gait or postural control in older adults using dual- or multi-task interventions. Approximately, 130 parameters out of 17 illustrated studies presented significant changes after dual-task-specific interventions regarding gait, postural control/balance, and falls. On the one hand, the article at hand shows highly consistent results in all of the dual-task intervention studies analyzed, indicating significant improvements related to postural control, gait, falls, or the performance of a secondary task. On the other hand, the results represent a heterogeneous structure and a gap between theoretical aspects and practical use. To optimize the use of dual-task, a systematization of underlying tasks is inevitable and should be focused on in further research.

After reading the above mentioned article of [1], we identified a mistake considering the results of the paragraph “3.6. Nonlinear Parameters AP” and the related Table 5 (both on p. 512). Unfortunately, published Table 5 is a duplicate of Table 4, and therefore it is not possible for the reader to comprehend any underlying interrelations. To correct this mistake, we would like to offer the corrected table (Table 5) as follows.