Learning context shapes bimanual control strategy and generalization of novel dynamics.

Bimanual movements are fundamental components of everyday actions, yet the underlying mechanisms coordinating adaptation of the two hands remain unclear. Although previous studies highlighted the contextual effect of kinematics of both arms on internal model formation, we do not know how the sensorimotor control system associates the learned memory with the experienced states in bimanual movements. More specifically, can, and if so, how, does the sensorimotor control system combine multiple states from different effectors to create and adapt a motor memory? Here, we tested motor memory formation in two groups with a novel paradigm requiring the encoding of the kinematics of the right hand to produce the appropriate predictive force on the left hand. While one group was provided with training movements in which this association was evident, the other group was trained on conditions in which this association was ambiguous. After adaptation, we tested the encoding of the learned motor memory by measuring the generalization to new movement combinations. While both groups adapted to the novel dynamics, the evident group showed a weighted encoding of the learned motor memory based on movements of the other (right) hand, whereas the ambiguous group exhibited mainly same (left) hand encoding in bimanual trials. Despite these differences, both groups demonstrated partial generalization to unimanual movements of the left hand. Our results show that motor memories can be encoded depending on the motion of other limbs, but that the training conditions strongly shape the encoding of the motor memory formation and determine the generalization to novel contexts.

Writing while walking: The impact of cognitive-motor multi-tasking on collision avoidance in human locomotion.

BACKGROUND: When moving in public space, individuals are challenged with having to master multiple cognitive and motor demands, either simultaneously or in short succession. Empirical evidence suggests that cognitive-motor multi-tasking during walking may impact one or both, cognitive and motor performance. These performance changes may result from unintentional task-interference effects, but also from strategic behavioral changes to cope with the multiple task demands. Strategic changes in human walking behavior have been uncovered in experimental scenarios, in which individuals avoid colliding with other individuals or objects in the environment. However, whether collision avoidance behavior is sensitive to cognitive-motor multi-task demands has remained underexplored, yet. Thus, with this study, we aimed at systematically studying cognitive-motor multi-task effects on collision avoidance during human locomotion. METHODS: Ten healthy participants (23.9 ± 4.3 years, 4 female) were walking at their preferred speed from a predefined start to end position under four experimental conditions: walking only (BL), walking while having to avoid a collision with another person (IO), writing a text message on a mobile phone while walking (cognitive-motor dual-task, DT), and writing while walking with collision avoidance demand (multi-task, MT). Parameters quantifying locomotor as well as collision avoidance behavior (path length, walking speed, minimum distance, path and speed adjustment) were assessed using optical motion tracking. In addition, performance in the writing task (errors, writing speed) was examined. RESULTS: Participants' locomotor behavior was significantly affected by experimental conditions, with additive effects of multi-task demands on both path length (BL = DT < IO < MT) and walking speed (BL > IO > DT > MT). Further, participants showed an increased error rate and writing speed in the writing task when walking as compared to when standing still, independent of the presence of an interferer. Importantly, collision avoidance behavior was selectively influenced by cognitive-motor multi-task demands, with an increased minimum distance to the other person in the MT-condition, but no differences in path or speed adjustment. DISCUSSION: Our results suggest significant multi-tasking effects of writing a message on the mobile phone while walking on both locomotor behavior and writing task performance. Collision avoidance behavior seems to be selectively affected by multi-task demands, reflected in an increased minimum passing distance, without overt changes in path or speed adjustments. This may be indicative for a strategic change in collision avoidance behavior towards a more cautious strategy to account for altered attention allocation and less visual feedback when writing while walking.

The influence of the COVID-19 pandemic on the prescription of multiple sclerosis medication in Germany.

BACKGROUND: Real-word evidence from diverse data sources is increasingly important in terms of generating rapid insights to effectively manage patient populations, especially during major public health disruptions such as the ongoing COVID-19 pandemic. Patients with chronic and inflammatory diseases - such as multiple sclerosis (MS) - were reported to experience potentially negative effects due to the use of immunosuppressive drugs in combination with a COVID-19 infection. In this research, we explored the impact of the COVID-19 pandemic on medication use in patients with MS in Germany. METHODS: Patient-level pharmacy dispensing data from the Permea platform - covering approximately 44% of all community pharmacy dispensing in Germany - were analysed from 2019 - 2021. Longitudinal use patterns of MS medication and antidepressants and patient demographics were assessed. Daily variation in MS medication use was specifically studied around the dates of the first and second lockdowns in Germany. RESULTS: We included data from 539,400 prescriptions which included at least 1 MS drug. The medication data showed a stable level of monthly prescriptions for MS medication at 2.02 ± 0.03 prescriptions per pharmacy during the study period. Although there was a sharp increase in daily prescriptions before the first lockdown (from an average 660.08 ± 137.59 daily prescriptions in the observed period to a maximum dispensing number of 998 daily prescriptions), the overall number of prescriptions remained at pre-pandemic levels (603 ± 90.31 daily prescriptions in 2019). Similar trends were observed for monthly co-prescribed antidepressant use per pharmacy (0.10 ± 0.01 in 2019-0.11 ± 0.02 in 2020). CONCLUSION: Throughout the COVID-19 pandemic, the use of MS medications and co-prescribed antidepressants was stable. These insights from real-world data demonstrate the value of evidence-based insights for managing patient care.