Innovative multi-site photoplethysmography measurement and analysis demonstrating increased arterial stiffness in paediatric heart transplant recipients.

Objective: It has been documented that heart transplantation in children is often complicated by arterial hypertension and increased arterial stiffness. We use innovative multi-site photoplethysmography (MPPG) pulse measurement and analysis technology to assess changes in arterial stiffness in paediatric heart transplant recipients (HTRs) in comparison with healthy control (HC) children.

Approach: A group of 20 HTRs (median age 13.

Novel optical assessments of tissue composition and viability using fluorescence spectroscopy and tissue oxygenation spectrophotometry in patients with systemic sclerosis: a pilot study.

Objective: Patients with systemic sclerosis (SSc) experience significant morbidity and mortality, therefore, the development of tests to aid its early diagnosis are very important. The aim of this pilot study was to assess the diagnostic value of novel optical non-invasive skin fluorescence spectroscopy (FS) and tissue oxygen saturation (TOS) viability measurements in patients with established SSc.

Approach: Two groups were studied, comprising 14 SSc patients and nine healthy controls (93% and 73% females, respectively).

Using Lempel-Ziv Complexity to Assess ECG Signal Quality.

The poor quality of wireless electrocardiography (ECG) recordings can lead to misdiagnosis and waste of medical resources. This study presents an interpretation of Lempel-Ziv (LZ) complexity in terms of ECG quality assessment, and verifies its performance on real ECG signals. Firstly, LZ complexities for typical signals, namely high-frequency (HF) noise, low-frequency (LF) noise, power-line (PL) noise, impulse (IM) noise, clean artificial ECG signals, and ECG signals with various types of noise added (ECG plus HF, LF, PL, and IM noise, respectively) were analyzed.

Quantifying the correlation between photoplethysmography and laser Doppler flowmetry microvascular low-frequency oscillations.

Photoplethysmography (PPG) and laser Doppler flowmetry (LDF) are two recognized optical techniques that can track low-frequency perfusion changes in microcirculation. The aim of this study was to determine, in healthy subjects, the correlation between the techniques for specific low-frequency bands previously defined for microcirculation. Twelve healthy male subjects (age range 18 to 50 years) were studied, with PPG and LDF signals recorded for 20 min from their right and left index (PPG) and middle (LDF) fingers.

Novel thermal imaging analysis technique for detecting inflammation in thyroid eye disease.

Context: The disease phase in thyroid eye disease (TED) is commonly assessed by clinical investigation of cardinal signs of inflammation and using the clinical activity score (CAS). Although CAS is the current gold standard, the clinical assessment would benefit if a more objective tool were available.

Objective: The aim of this work was to explore the clinical value of a novel thermal imaging analysis technique to objectively quantify the thermal characteristics of the eye and peri-orbital region and determine the disease phase in TED.

A multi-step method with signal quality assessment and fine-tuning procedure to locate maternal and fetal QRS complexes from abdominal ECG recordings.

Non-invasive monitoring of fetal electrocardiogram (fECG) plays an important role in detecting and diagnosing fetal diseases. This study aimed to develop a multi-step method for locating both maternal and fetal QRS complexes from abdominal ECG (aECG) recordings. The proposed method included four major steps: abdominal ECG pre-processing, maternal QRS complex locating, maternal ECG cancellation and fetal QRS complex locating.

Extracting fetal heart beats from maternal abdominal recordings: selection of the optimal principal components.

This study presents a systematic comparison of different approaches to the automated selection of the principal components (PC) which optimise the detection of maternal and fetal heart beats from non-invasive maternal abdominal recordings.A public database of 75 4-channel non-invasive maternal abdominal recordings was used for training the algorithm. Four methods were developed and assessed to determine the optimal PC: (1) power spectral distribution, (2) root mean square, (3) sample entropy, and (4) QRS template.

Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation.

Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity.

Novel photoplethysmography cardiovascular assessments in patients with Raynaud's phenomenon and systemic sclerosis: a pilot study.

Objective: Multisite photoplethysmography (PPG) cardiovascular assessments can evaluate endothelial, peripheral autonomic and arterial dysfunction. The aim of this pilot study was to investigate the potential clinical utility of the technology in assessing patients with SSc and primary RP (PRP).

Methods: Multisite PPG pulse measurements, a reference ankle brachial pressure index (ABPI) and a full clinical assessment were undertaken for three subject groups: SSc, PRP and controls.

Finger microvascular responses to deep inspiratory gasp assessed and quantified using wavelet analysis.

The physiological changes following a deep inspiratory gasp (DIG) manoeuvre have been described in the literature. However, the lack of a reliable signal processing technique to visualize and quantify these physiological changes has so far limited the applicability of the test to the clinical setting. The main aim of this study was to assess the feasibility of using wavelet analysis to quantify the pulse arrival time (PAT) and its changes during the DIG manoeuvre.

Novel assessment of microvascular changes in idiopathic restless legs syndrome (Willis-Ekbom disease).

Many patients with restless legs syndrome (Willis-Ekbom disease) complain of burning sensations in their feet associated with the desire to move, such that they seek cooler environments. This pilot study aimed to characterise the microvascular skin changes in 12 patients with restless legs syndrome compared with 12 age- and sex-matched controls. Patients with moderate or severe restless legs syndrome and controls underwent detailed thermovascular assessment in a controlled temperature room at three different stages (normothermic phase 23 °C, hot phase 30 °C, cold phase 18 °C).

Chronic fatigue syndrome and impaired peripheral pulse characteristics on orthostasis--a new potential diagnostic biomarker.

Autonomic nervous system dysfunction is frequently reported in chronic fatigue syndrome (CFS) with orthostatic intolerance, a common symptom that can be objectively assessed. The frequent finding of autonomic dysfunction and symptoms on standing has the potential to provide a diagnostic biomarker in chronic fatigue. In this study we explored the clinical value of non-invasive optical multi-site photoplethysmography (PPG) technology to assess cardiovascular responses to standing.