scholarly journals Near-infrared spectroscopy in evaluating psychogenic pseudosyncope—a novel diagnostic approach

QJM ◽  
2019 ◽  
Vol 113 (4) ◽  
pp. 239-244
Author(s):  
P Claffey ◽  
L Pérez-Denia ◽  
G Rivasi ◽  
C Finucane ◽  
R A Kenny
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Saturation Index ◽  
Diagnostic Algorithm ◽  
Cerebral Hypoperfusion ◽  
P Value ◽  
Non Invasive ◽  
Eyes Closed

Abstract Background Psychogenic pseudosyncope (PPS), a conversion disorder and syncope mimic, accounts for a large proportion of ‘unexplained syncope’. PPS is diagnosed by reproduction of patients’ symptoms during head-up tilt (HUT). Electroencephalogram (EEG), a time consuming and resource intensive technology, is used during HUT to demonstrate absence of cerebral hypoperfusion during transient loss of consciousness (TLOC). Near-infrared spectroscopy (NIRS) is a simple, non-invasive technology for continuous monitoring of cerebral perfusion. We present a series of patients for whom PPS diagnosis was supported by NIRS during HUT. Methods Eight consecutive patients with suspected PPS referred to a syncope unit underwent evaluation. During HUT, continuous beat-to-beat blood pressure (BP), heart rate (HR) and NIRS-derived tissue saturation index (TSI) were measured. BP, HR and TSI at baseline, time of first symptom, presyncope and apparent TLOC were measured. Patients were given feedback and followed for symptom recurrence. Results Eight predominantly female patients (6/8, 75%) aged 31 years (16–54) were studied with (5/8, 63%) having comorbid psychiatric diagnoses, and (5/8, 63%) presenting with frequent episodes of prolonged TLOC with eyes closed (6/8, 75%). All patients experienced reproduction of typical events during HUT. Systolic BP (mmHg) increased from baseline (129.7 (interquartile range [IQR] 124.9–133.4)) at TLOC (153.0 (IQR 146.7–159.0)) (P-value = 0.012). HR (bpm) increased from baseline 78 (IQR 68.6–90.0) to 115.7 (IQR 93.5–127.9) (P-value = 0.012). TSI (%) remained stable throughout, 71.4 (IQR 67.5–72.9) at baseline vs. 71.0 (IQR 68.2–73.0) at TLOC (P-value = 0.484). Conclusions NIRS provides a non-invasive surrogate of cerebral perfusion during HUT. We propose HUT incorporating NIRS monitoring in the diagnostic algorithm for patients with suspected PPS.

scholarly journals The Use of Near-Infrared Spectroscopy and/or Transcranial Doppler as Non-Invasive Markers of Cerebral Perfusion in Adult Sepsis Patients With Delirium: A Systematic Review

2021 ◽  
pp. 088506662199709
Author(s):  
Michael D. Wood ◽  
J. Gordon Boyd ◽  
Nicole Wood ◽  
James Frank ◽  
Timothy D. Girard ◽  
...  
Keyword(s):  
Systematic Review ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Transcranial Doppler ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Cochrane Library ◽  
Delirium Assessment ◽  
Non Invasive ◽  
The Impact

Background: Several studies have previously reported the presence of altered cerebral perfusion during sepsis. However, the role of non-invasive neuromonitoring, and the impact of altered cerebral perfusion, in sepsis patients with delirium remains unclear. Methods: We performed a systematic review of studies that used near-infrared spectroscopy (NIRS) and/or transcranial Doppler (TCD) to assess adults (≥18 years) with sepsis and delirium. From study inception to July 28, 2020, we searched the following databases: Ovid MedLine, Embase, Cochrane Library, and Web of Science. Results: Of 1546 articles identified, 10 met our inclusion criteria. Although NIRS-derived regional cerebral oxygenation was consistently lower, this difference was only statistically significant in one study. TCD-derived cerebral blood flow velocity was inconsistent across studies. Importantly, both impaired cerebral autoregulation during sepsis and increased cerebrovascular resistance were associated with delirium during sepsis. However, the heterogeneity in NIRS and TCD devices, duration of recording (from 10 seconds to 72 hours), and delirium assessment methods (e.g., electronic medical records, confusion assessment method for the intensive care unit), precluded meta-analysis. Conclusion: The available literature demonstrates that cerebral perfusion disturbances may be associated with delirium in sepsis. However, future investigations will require consistent definitions of delirium, delirium assessment training, harmonized NIRS and TCD assessments (e.g., consistent measurement site and length of recording), as well as the quantification of secondary and tertiary variables (i.e., Cox, Mxa, MAPOPT), in order to fully assess the relationship between cerebral perfusion and delirium in patients with sepsis.

P5678Near-infrared spectroscopy (NIRS) in the evaluation of psychogenic pseudosyncope - Moving towards a simplified diagnostic pathway

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
P Claffey ◽  
L Perez-Denia ◽  
G Rivasi ◽  
A Ungar ◽  
C Finucane ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Diagnostic Yield ◽  
Case Series ◽  
Cerebral Hypoperfusion ◽  
Tilt Test ◽  
Eyes Closed ◽  
Unexplained Syncope

Abstract Background Psychogenic pseudosyncope (PPS) is a conversion disorder that often mimics syncope, is commonly referred to cardiology clinics and accounts for a large proportion of patients admitted with “unexplained syncope”. Unlike syncope, PPS is characterized by normal blood pressure (BP) and heart rate (HR) values at TLOC inferring the absence of cerebral hypoperfusion. The current gold standard for the diagnosis of PPS is the reproduction of patients' symptoms during a head-up tilt test (HUTT) with concurrent electroencephalogram (EEG) monitoring showing normal haemodynamic and brainwave measurements. However, EEG is time consuming, resource intensive and many syncope units lack ready access, thereby solely relying on absence of peripheral haemodynamic changes to diagnose PPS. Purpose Near-infrared spectroscopy (NIRS) is a non-invasive technology used for continuous monitoring of cerebral oxygenation. Measuring adequacy of tissue oxygenation is an appropriate surrogate for cerebral perfusion. In this study, we present a case series of patients for whom the diagnosis of PPS was confirmed by NIRS during TLOC. We propose use of NIRS in routine clinical assessment of suspected PPS. Methods We describe nine consecutive patients with suspected PPS referred to a dedicated syncope unit for investigation of recurrent unexplained syncope. All patients underwent evaluation in accordance with European Society of Cardiology guidelines including HUTT. Continuous beat-to-beat BP and HR measurements were recorded using finger plethysmography. In addition, continuous NIRS-derived tissue saturation index (TSI) - a measure of percentage oxygenation - was recorded using an optical sensor applied to the left lateral forehead to assess cerebral perfusion. Absolute values of BP, HR and TSI at baseline, time of first symptom onset, presyncope and apparent TLOC were recorded. The evaluation was diagnostic for PPS when apparent TLOC occurred in the absence of typical haemodynamic or cerebral perfusion changes. Results The median age was 35 years (range 14–54). Clinical features were consistent with those previously described in PPS literature - female preponderance, comorbid psychiatric diagnosis, frequent attack history, with prolonged TLOC and eyes closed during events. During HUTT, all patients experienced an apparent TLOC which they recognised as reproductive of typical events. BP and HR measurements increased significantly at time of TLOC. There was no significant change in TSI at any of the time points throughout HUTT. (Figure 1 shows averaged absolute values of systolic and diastolic BP, HR and TSI with median values represented by thickened lines.) Figure 1. Measurements during HUTT Conclusion NIRS is readily available, easily accessible and provides an appropriate surrogate measure of cerebral perfusion during HUTT. We propose that HUTT incorporating concurrent NIRS monitoring will enhance diagnostic yield and patient management providing important biofeedback.

scholarly journals Brain–Computer Interfacing Using Functional Near-Infrared Spectroscopy (fNIRS)

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 389
Author(s):  
Kogulan Paulmurugan ◽  
Vimalan Vijayaragavan ◽  
Sayantan Ghosh ◽  
Parasuraman Padmanabhan ◽  
Balázs Gulyás
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Brain Function ◽  
Near Infrared ◽  
Functional Near Infrared Spectroscopy ◽  
Non Invasive ◽  
Neuron Function ◽  
Brain Computer Interfacing ◽  
The Brain ◽  
Computer Interfacing

Functional Near-Infrared Spectroscopy (fNIRS) is a wearable optical spectroscopy system originally developed for continuous and non-invasive monitoring of brain function by measuring blood oxygen concentration. Recent advancements in brain–computer interfacing allow us to control the neuron function of the brain by combining it with fNIRS to regulate cognitive function. In this review manuscript, we provide information regarding current advancement in fNIRS and how it provides advantages in developing brain–computer interfacing to enable neuron function. We also briefly discuss about how we can use this technology for further applications.

scholarly journals An Overview of Near Infrared Spectroscopy and Its Applications in the Detection of Genetically Modified Organisms

2021 ◽  
Vol 22 (18) ◽  
pp. 9940
Author(s):  
Soo-In Sohn ◽  
Subramani Pandian ◽  
Young-Ju Oh ◽  
John-Lewis Zinia Zaukuu ◽  
Hyeon-Jung Kang ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Food Systems ◽  
Near Infrared ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Genetically Modified Crops ◽  
Non Invasive ◽  
Agriculture And Food ◽  
Non Destructive

Near-infrared spectroscopy (NIRS) has become a more popular approach for quantitative and qualitative analysis of feeds, foods and medicine in conjunction with an arsenal of chemometric tools. This was the foundation for the increased importance of NIRS in other fields, like genetics and transgenic monitoring. A considerable number of studies have utilized NIRS for the effective identification and discrimination of plants and foods, especially for the identification of genetically modified crops. Few previous reviews have elaborated on the applications of NIRS in agriculture and food, but there is no comprehensive review that compares the use of NIRS in the detection of genetically modified organisms (GMOs). This is particularly important because, in comparison to previous technologies such as PCR and ELISA, NIRS offers several advantages, such as speed (eliminating time-consuming procedures), non-destructive/non-invasive analysis, and is inexpensive in terms of cost and maintenance. More importantly, this technique has the potential to measure multiple quality components in GMOs with reliable accuracy. In this review, we brief about the fundamentals and versatile applications of NIRS for the effective identification of GMOs in the agricultural and food systems.

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