Enhancing stroke rehabilitation with whole-hand haptic rendering:development and clinical usability evaluation of a novel upper-limb rehabilitation device

Introduction: There is currently a lack of easy-to-use and effective robotic devices for upper-limb rehabilitation after stroke. Importantly, most current systems lack the provision of somatosensory information that is congruent with the virtual training task. This paper introduces a novel haptic robotic system designed for upper-limb rehabilitation, focusing on enhancing sensorimotor rehabilitation through comprehensive haptic rendering. Methods: We developed a novel haptic rehabilitation device with a unique combination of degrees of freedom that allows the virtual training of functional reach and grasp tasks, where we use a physics engine-based haptic rendering method to render whole-hand interactions between the patients’ hands and virtual tangible objects. To evaluate the feasibility of our system, we performed a clinical mixed-method usability study with seven patients and seven therapists working in neurorehabilitation. We employed standardized questionnaires to gather quantitative data and performed semi-structured interviews with all participants to gain qualitative insights into the perceived usability and usefulness of our technological solution. Results: The device demonstrated ease of use and adaptability to various hand sizes without extensive setup. Therapists and patients reported high satisfaction levels, with the system facilitating engaging and meaningful rehabilitation exercises. Participants provided notably positive feedback, particularly emphasizing the system’s available degrees of freedom and its haptic rendering capabilities. Therapists expressed confidence in the transferability of sensorimotor skills learned with our system to activities of daily living, although further investigation is needed to confirm this. Conclusion: The novel haptic robotic system effectively supports upper-limb rehabilitation post-stroke, offering high-fidelity haptic feedback and engaging training tasks. Its clinical usability, combined with positive feedback from both therapists and patients, underscores its potential to enhance robotic neurorehabilitation.</p

<i>In vivo</i> laser speckle contrast imaging of microvascular blood perfusion using a chip-on-tip camera

Laser speckle contrast imaging (LSCI) is an important non-invasive capability for real-time imaging for tissue-perfusion assessment. Yet, the size and weight of current clinical standard LSCI instrumentation restricts usage to mainly peripheral skin perfusion. Miniaturization of LSCI could enable hand-held instrumentation to image internal organ/tissue to produce accurate speckle-perfusion maps. We characterized a 1mm 2 chip-on-tip camera for LSCI of blood perfusion in vivo and with a flow model. A dedicated optical setup was built to compare chip-on-tip camera to a high specification reference camera (GS3) for LSCI. We compared LSCI performance using a calibration standard and a flow phantom. Subsequently the camera assessed placenta perfusion in a small animal model. Lastly, a human study was conducted on the perfusion in fingertips of 13-volunteers. We demonstrate that the chip-on-tip camera can perform wide-field, in vivo, LSCI of tissue perfusion with the ability to measure physiological blood flow changes comparable with a standard reference camera.</p

Digest of Russian Space Life Sciences, issue 33

This is the thirty-third issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 55 papers published in Russian journals. The abstracts in this issue have been identified as relevant to the following areas of space biology and medicine: biological rhythms, body fluids, botany, cardiovascular and respiratory systems, developmental biology, endocrinology, equipment and instrumentation, gastrointestinal system, genetics, hematology, human performance, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, psychology, radiobiology, and reproductive system

Functional characterization of the transcription factor early growth response 1 (Egr1) in arteriogenesis

The number of patients suffering from obstructive arterial disease is still increasing. Stimulation of a patient’s collateralization (arteriogenesis), though an auspicious therapeutic approach, is still not part of current therapy regimes. Further studies on the molecular level are needed to understand the genetic regulation in this process. The transcription factor early growth response 1 (Egr1) was shown to partic-ipate in leukocyte recruitment and cell proliferation in vitro. This work contributes to the acquisition of new insights into its mode of action in vivo. Using a model of peripheral arteriogenesis, Egr1 was found significantly upregulated in growing col-laterals of wild-type mice (WT), both on mRNA (2.24fold) and protein level (2.3fold). Egr1 stained positive in EC and vSMCs of collaterals as well as in nerves. In LDI measurements conducted over the period of 21 days evidenced a delayed perfusion recovery after femoral artery ligation in Egr1-/- mice compared to WT mice (day7: 0.46±0.05 in Egr1-/- vs. WT (0.73±0.04), day 14: 0.65±0.02 in Egr1-/- vs. 0.88±0.04 in WT and day 21: 0.79 ±0.03 in Egr1-/- vs. 0.96±0.02 in WT). Under baseline conditions, Egr1-/- showed increased levels of monocytes (521.89±52.9 cells/µl vs. 326.56±21.6 cells/µl in WT) and granulocytes (811.79±79.96 cells/µl vs. WT 559.88±34.57 cells/µl) in the circulation but reduced levels in adductor muscles (18.14±2.73 cells/µl vs. 51.22±4.38 cells/µl in WT) as evidenced by FACS analyses. After femoral artery ligation, more macrophages were detected in the perivascular space of collateral arteries in Egr1-/- (8.10±0.99 per vessel) vs. WT (6.12±0.45 per vessel) mice. The mRNA of leukocyte recruitment mediators monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1) and urokinase plasminogen activator (uPA) were found upregulated in both groups. Whereas other Egr family members (Egr2-4) did not show an upregulation in WT collateral arteries, they were found significantly upregulated in Egr1-/- mice suggesting a mechanism of counter-balancing Egr1 deficiency. A closer look at cell cycle regulators revealed that cyclin E and cdc20 were found upregulated in WT as well as in Egr1-/- mice. However, cyclin D1 was hardly detectable under Egr1 deficiency conferring Egr1 an unique role for cyclin D1 transcription. vSMC phenotype switch is a critical step towards vSMC proliferation and therefore arteriogenesis. In this context, the downregu-lation of alpha smooth muscle actin (αSM-actin) and of the transcriptional repressor, splicing factor-1 (SF-1) has been shown to be critical in vitro. During arteriogenesis, SF-1 has been found downregulat-ed in collaterals of WT mice but was 1.64fold upregulated in Egr1-/-. Similar was true for αSM-actin. Whereas in WT mice αSM-actin is downregulated at 12h after ligation Egr1 deficient mice evidenced an upregulation of αSM-actin. The strong upregulation of the nonselective proliferation marker ki67 in WT mice was not detectable under Egr1 deficiency evidencing furthermore a delay in vascular cell proliferation. Conclusion: Compensation for deficiency of Egr1 function in leukocyte recruitment can be mediated by other transcription factors; however, Egr1 is indispensable for effective vascular cell cycle progression and phenotype switch in arteriogenesis

Electrophysiology

The outstanding evolution of recording techniques paved the way for better understanding of electrophysiological phenomena within the human organs, including the cardiovascular, ophthalmologic and neural systems. In the field of cardiac electrophysiology, the development of more and more sophisticated recording and mapping techniques made it possible to elucidate the mechanism of various cardiac arrhythmias. This has even led to the evolution of techniques to ablate and cure most complex cardiac arrhythmias. Nevertheless, there is still a long way ahead and this book can be considered a valuable addition to the current knowledge in subjects related to bioelectricity from plants to the human heart