Progress of near-infrared spectroscopy and topography for brain and muscle clinical applications

This review celebrates the 30th anniversary of the first in vivo near-infrared (NIR) spectroscopy (NIRS) publication, which was authored by Professor Frans Jobsis. At first, NIRS was utilized to experimentally and clinically investigate cerebral oxygenation. Later it was applied to study muscle oxidative metabolism. Since 1993, the discovery that the functional activation of the human cerebral cortex can be explored by NIRS has added a new dimension to the research. To obtain simultaneous multiple and localized information, a further major step forward was achieved by introducing NIR imaging (NIRI) and tomography. This review reports on the progress of the NIRS and NIRI instrumentation for brain and muscle clinical applications 30 years after the discovery of in vivo NIRS. The review summarizes the measurable parameters in relation to the different techniques, the main characteristics of the prototypes under development, and the present commercially available NIRS and NIRI instrumentation. Moreover, it discusses strengths and limitations and gives an outlook into the "bright" future

Progressive Muscle Fatigue Induces Loss in Muscle Force and Persistent Activation of Frontal Cortex as Measured by Multi-Channel fNIRT

The effect of fatiguing skeletal muscle exercise on brain, and in particular on ipsi- and ontralateral frontal cortex (FC) has not been fully clarified. The aim of this study was to investigate by functional near-infrared topography (fNIRT) the FC oxygenation response to a prolonged fatiguing rhythmic handgrip exercise performed at the maximal voluntary contraction separately with right or left hand. fNIRT is a not harmful and non-invasive optical technique allowing the simultaneous acquisition of oxygenated and deoxygenated hemoglobin concentration ([O2Hb], [HHb]) changes on the scalp. By using a 8-channel fNIRT (NIRO-200 with multi-fiber adapter, Hamamatsu Photonics) we demonstrated a significant [O 2Hb] increase, accompanied by a smaller and delayed significant [HHb] decrease, in all measurements points of both hemispheres. A significant hemisphere x task execution modality interaction was revealed only for [O2Hb] increase of the right FC during the right handgrip exercise (p= 0.008). A significant hemisphere x task execution modality interaction was found only for [HHb] decrease of the left FC during the left handgrip exercise (p<0.001). These results provide further evidence that FC plays a role in maintaining strength of the forearm muscles and ensuring a correct execution of motor tasks which require a fine motor control and coordination

Detecting Mental Calculation Related Frontal Cortex Oxygenation Changes for Brain Computer Interface Using Multi-Channel Functional Near Infrared Topography

Multi-channel functional near infrared topography (fNIRT) is a non-harmful, non-invasive and safe optical imaging technique that allows the simultaneous acquisition of oxygenated and deoxygenated hemoglobin concentration changes on the scalp. This study was aimed at investigating the potential use of fNIRT in association with a cognitive system, namely the working memory, for brain-computer interface (BCI). By using a 8-channel fNIRT system (NIRO-200 with multi-fiber adapter, Hamamatsu Photonics), we demonstrated in eight subjects that the mental calculation provokes over the frontal cortical region a significant increase in oxygenated hemoglobin and a concomitant smaller and delayed significant decrease in deoxygenated hemoglobin in all measurements points of both hemispheres. This result indicates that cortical regions involved in higher cognitive functions may serve as a readily self-controllable input for BCI fNIRT based applications

Pulse oximetry in primary care: factors affecting accuracy and interpretation

The COVID-19 pandemic saw a rapid increase in the use of pulse oximetry devices (PODs) in primary care to triage and monitor large numbers of patients and to help decide which patients required admission to hospital. In the UK, this included providing 300 000 PODs to patients as part of the ‘virtual ward’ programme and there have been calls to extend the use of remote monitoring to patients with other medical conditions.1–3 However, the increased use of pulse oximetry has been accompanied by growing concern over the potential for PODs to produce inaccurate oxygen saturation (SpO2) readings and the effect that this could have on critical decisions regarding the management of patients. This article discusses the factors that can lead to inaccurate SpO2 readings and the implications that this could have for both GPs and patients

Spatial distribution of vastus lateralis blood flow and oxyhemoglobin saturation measured at the end of isometric quadriceps contraction by multichannel near-infrared spectroscopy.

Muscle blood flow (MBF) and muscle oxygen saturation (SmO(2)) were measured at eight locations (four proximal, four distal) over a 4 x 8 cm(2) area of the vastus lateralis at rest and immediately after isometric, maximal quadriceps contraction using multichannel, frequency-domain, near-infrared spectroscopy. A venous occlusion was applied 20 s before the end of the exercise, so that the venous-occlusion-induced increase in total hemoglobin was recorded without any delay after the end of the exercise. Therefore, we were able to investigate the relationship between the exercise-induced changes in vastus lateralis MBF and SmO(2). After exercise, MBF increased significantly at each measured location. Comparing the MBF values measured at the end of exercise in the proximal and distal regions, we observed that only one proximal region had a significantly higher MBF than the corresponding distal one. The maximum desaturation measured during exercise was positively correlated with the postexercise to pre-exercise MBF ratio in both the proximal (P=0.016) and distal (P=0.0065) regions. These data confirm that frequency-domain tissue oximeters are noninvasive, powerful tools to investigate the spatial and temporal features of muscle blood flow and oxygenation, with potential applications in areas of pathophysiology

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Evaluation of the Skin Blood Flow Contribution to the Non-Invasive Measurement of Muscle Oxygenation by Near Infrared Spectroscopy

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Il memoir nella Germania del dopo Muro. Le scritture di Christa Wolf, Monika Maron, Claudia Rusch

Edward Said parla nei suoi saggi di "teoria viaggiante" a indicare che la teoria migra e muta in relazione ai contesti nei quali viene, di volta in volta, riapplicata. Questo modello teorico rappresenta il punto di partenza attraverso cui il presente lavoro intende analizzare il fenomeno della scrittura memoiristica nella Germania del dopo Muro. Partendo dal presupposto teorico che molte delle scritture autonarrative sorte dopo la Wende possano essere collocate nell'alveo del genere più "resistenziale" (rispetto all'autobiografia classica) del memoir, nei tre capitoli che riguardano le pratiche e le esperienze di scrittura memoiristica, saranno analizzate le opere di tre autrici nate nella RDT in epoche diverse e con un livello di impegno politico nel paese molto eterogeneo: Christa Wolf, Monika Maron, Claudia Rusch