Age-related changes in time perception:The impact of naturalistic environments and retrospective judgements on timing performance

Reduced timing abilities have been reported in older adults and are associated with pathological cognitive decline. However, time perception experiments often lack ecological validity. Especially the reduced complexity of experimental stimuli and the participants’ awareness of the time-related nature of the task can influence lab-assessed timing performance and thereby conceal age-related differences. An approximation of more naturalistic paradigms can provide important information about age-related changes in timing abilities. To determine the impact of higher ecological validity on timing experiments, we implemented a paradigm that allowed us to test (1) the effect of embedding the to-be-timed stimuli within a naturalistic visual scene and (2) the effect of retrospective time judgements, which are more common in real life than prospective judgements. The results show that compared with out-of-context stimuli, younger adults benefit from a naturalistic embedding of stimuli (reflected in higher precision and less errors), whereas the performance of older adults is reduced when confronted with naturalistic stimuli. Differences between retrospective and prospective time judgements were not modulated by age. We conclude that, potentially driven by difficulties in suppressing temporally irrelevant environmental information, the contextual embedding of naturalistic stimuli can affect the degree to which age influences the performance in time perception tasks

Temporal context effects are associated with cognitive status in advanced age

The perception of temporal intervals changes during the life-span, and especially older adults demonstrate specific impairments of timing abilities. Recently, we demonstrated that timing performance and cognitive status are correlated in older adults, suggesting that timing tasks can serve as a behavioral marker for the development of dementia. Easy-to-administer and retest-capable timing tasks therefore have potential as diagnostic tools for tracking cognitive decline. However, before being tested in a clinical cohort study, a further validation and specification of the original findings is warranted. Here we introduce several modifications of the original task and investigated the effects of temporal context on time perception in older adults (> 65 years) with low versus high scores in the Montreal Cognitive Assessment survey (MoCA) and a test of memory functioning. In line with our previous work, we found that temporal context effects were more pronounced with increasing memory deficits, but also that these effects are stronger for realistic compared to abstract visual stimuli. Furthermore, we show that two distinct temporal contexts influence timing behavior in separate experimental blocks, as well as in a mixed block in which both contexts are presented together. These results replicate and extend our previous findings. They demonstrate the stability of the effect for different stimulus material and show that timing tasks can reveal valuable information about the cognitive status of older adults. In the future, these findings could serve as a basis for the development of a diagnostic tool for pathological cognitive decline at an early, pre-clinical stage

Moderation of alcohol consumption as a recommendation in European hypertension management guidelines: a survey on awareness, screening and implementation among European physicians

Objectives: Moderation of alcohol consumption is included as a class I, level of evidence A recommendation in the current European guidelines for the management of hypertension. We investigated its awareness and self-reported implementation among European physicians across different specialties and workplaces. Design and setting: A cross-sectional survey study conducted in two annual German meetings (German Society of Cardiology and the German Society of Internal Medicine) and two annual European meetings (European Society of Hypertension and European Society Cardiology) in 2015. Participants: 1064 physicians attending the European meetings were interviewed including 52.1% cardiologists, 29.2% internists and 8.8% general practitioners. Main outcome measures: Physician screening of alcohol consumption, awareness and self-implementation of the recommendation of the current European guidelines about moderation of alcohol consumption for the management of hypertension. Results: Overall, 81.9% of physicians reported to generally quantify alcohol consumption in patients with hypertension. However, only 28.6% and 14.5% of participants reported screening alcohol consumption in their patients with newly detected or treatment-resistant hypertension. Physicians recommended a maximum alcohol intake of 13.1 +/- 11.7 g/day for women (95% CI 12.3 to 13.8) and 19.9 +/- 15.6 g/day for men (95% CI 18.8 to 20.9). In case of moderate to high alcohol consumption, 10.3% would manage only hypertension without addressing alcohol consumption, while 3.7% of the physicians would do so in case of alcohol dependence (p<0.001). Conclusions: The average amount of alcohol intake per day recommended by European physicians in this survey was in agreement with the guidelines. The low number of physicians that screen for alcohol consumption in patients with newly detected and with treatment-resistant hypertension indicates an important deficit in the management of hypertension

comparison of methadone and levomethadone in long-term treatment

Background This study aimed to investigate the development of opioid tolerance in patients receiving long-term methadone maintenance treatment (MMT). Methods A region-wide cross-sectional study was performed focusing on dosage and duration of treatment. Differences between racemic methadone and levomethadone were examined. All 20 psychiatric hospitals and all 110 outpatient clinics in Berlin licensed to offer MMT were approached in order to reach patients under MMT fulfilling the DSM IV criteria of opiate dependence. In the study, 720 patients treated with racemic methadone or levomethadone gave information on the dosage of treatment. Out of these, 679 patients indicated the duration of MMT. Results Treatment with racemic methadone was reported for 370 patients (54.5 %), with levomethadone for 309 patients (45.5 %). Mean duration of MMT was 7.5 years. We found a significant correlation between dosage and duration of treatment, both in a conjoint analysis for the two substances racemic methadone and levomethadone and for each substance separately. These effects remained significant when only patients receiving MMT for 1 year or longer were considered, indicating proceeding tolerance development in long-term treatment. When correlations were compared between racemic methadone and levomethadone, no significant difference was found. Conclusions Our data show a tolerance development under long-term treatment with both racemic methadone and levomethadone. Tolerance development did not differ significantly between the two substances

Is Therapeutic Drug Monitoring Relevant for Antidepressant Drug Therapy? Implications From a Systematic Review and Meta-Analysis With Focus on Moderating Factors

Inter-individual differences in antidepressant drug concentrations attained in blood may limit the efficacy of pharmacological treatment of depressive disorders. Therapeutic drug monitoring (TDM) enables to determine drug concentrations in blood and adjust antidepressant dosage accordingly. However, research on the underlying assumption of TDM, association between concentration and clinical effect, has yielded ambiguous results for antidepressants. It has been proposed that this ambiguity may be caused by methodological shortcomings in studies investigating the concentration-effect relationship. Guidelines recommend the use of TDM in antidepressant treatment as expert opinion. This reflects the lack of research, particularly systematic reviews and meta-analyses of randomized controlled trials, on the relationship between concentration and effect as well as on the benefits of the use of TDM in clinical practice. In this study, a systematic review and meta-analysis of randomized controlled trials has been performed to investigate the relationship between antidepressant concentration, efficacy, and side effects. It is the first meta-analytical approach to this subject and additionally considers methodological properties of primary studies as moderators of effect in quantitative analysis. Our results identified methodological shortcomings, namely the use of a flexible dose design and the exclusion of concentrations in lower- or subtherapeutic ranges, which significantly moderate the relationship between antidepressant concentration and efficacy. Such shortcomings obscure the evidence base of using TDM in clinical practice to guide antidepressant drug therapy. Further research should consider these findings to determine the relationship between concentration and efficacy and safety of antidepressant treatments, especially for newer antidepressants.Peer Reviewe

Methode zur Untersuchung des dynamischen Verhaltens von Netzhautgefässen

This paper offers various approches to destine the changing of the diameter of human relatinal vessel. The focus is rather on the approches than on the physiological discussion of the results. The source signal has particular properties thus a costly signal preprocessing is necessary. This approches will be explained and discussed. The final transformation in the freqency domain is based on a common DFT algorithm. The calculated results will be compared

A novel push-pull central-lever mechanism reduces peak forces and energy-cost compared to hand-rim wheelchair propulsion during a controlled lab-based experiment

BACKGROUND: Hand-rim wheelchair propulsion is straining and mechanically inefficient, often leading to upper limb complaints. Previous push–pull lever propulsion mechanisms have shown to perform better or equal in efficiency and physiological strain. Propulsion biomechanics have not been evaluated thus far. A novel push–pull central-lever propulsion mechanism is compared to conventional hand-rim wheelchair propulsion, using both physiological and biomechanical outcomes under low-intensity steady-state conditions on a motor driven treadmill. METHODS: In this 5 day (distributed over a maximum of 21 days) between-group experiment, 30 able-bodied novices performed 60 min (5 × 3 × 4 min) of practice in either the push–pull central lever wheelchair (n = 15) or the hand-rim wheelchair (n = 15). At the first and final sessions cardiopulmonary strain, propulsion kinematics and force production were determined in both instrumented propulsion mechanisms. Repeated measures ANOVA evaluated between (propulsion mechanism type), within (over practice) and interaction effects. RESULTS: Over practice, both groups significantly improved on all outcome measures. After practice the peak forces during the push and pull phase of lever propulsion were considerably lower compared to those in the handrim push phase (42 ± 10 & 46 ± 10 vs 63 ± 21N). Concomitantly, energy expenditure was found to be lower as well (263 ± 45 vs 298 ± 59W), on the other hand gross mechanical efficiency (6.4 ± 1.5 vs 5.9 ± 1.3%), heart-rate (97 ± 10 vs 98 ± 10 bpm) and perceived exertion (9 ± 2 vs 10 ± 1) were not significantly different between modes. CONCLUSION: The current study shows the potential benefits of the newly designed push–pull central-lever propulsion mechanism over regular hand rim wheelchair propulsion. The much lower forces and energy expenditure might help to reduce the strain on the upper extremities and thus prevent the development of overuse injury. This proof of concept in a controlled laboratory experiment warrants continued experimental research in wheelchair-users during daily life

Spatial Updating Depends on Gravity

As we move through an environment the positions of surrounding objects relative to our body constantly change. Maintaining orientation requires spatial updating, the continuous monitoring of self-motion cues to update external locations. This ability critically depends on the integration of visual, proprioceptive, kinesthetic, and vestibular information. During weightlessness gravity no longer acts as an essential reference, creating a discrepancy between vestibular, visual and sensorimotor signals. Here, we explore the effects of repeated bouts of microgravity and hypergravity on spatial updating performance during parabolic flight. Ten healthy participants (four women, six men) took part in a parabolic flight campaign that comprised a total of 31 parabolas. Each parabola created about 20-25 s of 0 g, preceded and followed by about 20 s of hypergravity (1.8 g). Participants performed a visual-spatial updating task in seated position during 15 parabolas. The task included two updating conditions simulating virtual forward movements of different lengths (short and long), and a static condition with no movement that served as a control condition. Two trials were performed during each phase of the parabola, i.e., at 1 g before the start of the parabola, at 1.8 g during the acceleration phase of the parabola, and during 0 g. Our data demonstrate that 0 g and 1.8 g impaired pointing performance for long updating trials as indicated by increased variability of pointing errors compared to 1 g. In contrast, we found no support for any changes for short updating and static conditions, suggesting that a certain degree of task complexity is required to affect pointing errors. These findings are important for operational requirements during spaceflight because spatial updating is pivotal for navigation when vision is poor or unreliable and objects go out of sight, for example during extravehicular activities in space or the exploration of unfamiliar environments. Future studies should compare the effects on spatial updating during seated and free-floating conditions, and determine at which g-threshold decrements in spatial updating performance emerge

A Scoping Review on Shoulder Injuries of Wheelchair Tennis Players:Potential Risk-Factors and Musculoskeletal Adaptations

Wheelchair tennis players are prone to develop shoulder injuries, due to the combination of wheelchair propulsion, overhead activities and daily wheelchair activities. A methodical literature search was conducted to identify articles on shoulder complaints in wheelchair tennis, wheelchair sports and tennis. The aims were to identify (1) type of shoulder complaints; (2) possible risk factors for the development of shoulder injuries; (3) musculoskeletal adaptations in the shoulder joint in wheelchair tennis players. Fifteen papers were included in this review, five on wheelchair tennis, three on wheelchair sports and seven on tennis. Type of shoulder complaints were acromioclavicular pathology, osteoarthritic changes, joint effusion and rotator cuff tears. Possible risk factors for the development of shoulder injuries in wheelchair tennis are overhead movements, repetitive activation of the anterior muscle chain and internal rotators, as well as a higher spinal cord injury level. Muscular imbalance with higher values for the internal rotators, increase in external range of motion, decrease in internal range of motion and reduced total arc of motion were the most common proposed musculoskeletal adaptations due to an unbalanced load. These presented risk factors and musculoskeletal adaptations might help researchers, coaches and wheelchair tennis players to prevent shoulder injuries