Characterization of unipolar electrogram morphology: A novel tool for quantifying conduction inhomogeneity

Aims: Areas of conduction inhomogeneity (CI) during sinus rhythm may facilitate the initiation and perpetuation of atrial fibrillation (AF). Currently, no tool is available to quantify the severity of CI. Our aim is to develop and validate a novel tool using unipolar electrograms (EGMs) only to quantify the severity of CI in the atria....

Atrial extrasystoles enhance low-voltage fractionation electrograms in patients with atrial fibrillation

BACKGROUND AND AIMS: Atrial extrasystoles (AES) provoke conduction disorders and may trigger episodes of atrial fibrillation (AF). However, the direction- and rate-dependency of electrophysiological tissue properties on epicardial unipolar electrogram (EGM) morphology is unknown. Therefore, this study examined the impact of spontaneous AES on...

Closing the loop: Novel quantitative fMRI approach for manipulation of the sensorimotor loop in tremor

Tremor is thought to be an effect of oscillatory activity within the sensorimotor network. To date, the underlying pathological brain networks are not fully understood. Disentangling tremor activity from voluntary motor output and sensorimotor feedback systems is challenging. To better understand the intrinsic sensorimotor fingerprint...

Directionality of corticomuscular coupling in essential tremor and cortical myoclonic tremor

Objective: A role of the motor cortex in tremor generation in essential tremor (ET) is assumed, yet the directionality of corticomuscular coupling is unknown. Our aim is to clarify the role of the motor cortex. To this end we also study ‘familial cortical myoclonic tremor with epilepsy’ (FCMTE) and slow repetitive voluntary movements with a...

Distinct cortical activity patterns in Parkinson's disease and essential tremor during a bimanual tapping task

Background: Parkinson's disease (PD) and essential tremor (ET) are neurodegenerative diseases characterized by movement deficits. Especially in PD, maintaining cyclic movement can be significantly disturbed due to pathological changes in the basal ganglia and the cerebellum. Providing external cues improves timing of these movements in PD and...

Deficits in tapping accuracy and variability in tremor patients

Background: The basal ganglia and cerebellum are brain structures involved in movement initiation, execution and termination. They are thought to be involved in the tremor generation and movement deficits in Parkinson's disease (PD) and essential tremor (ET). Especially in PD, maintaining cyclic movement, such as walking or tapping can be...

A Power Spectral Density-Based Method to Detect Tremor and Tremor Intermittency in Movement Disorders

There is no objective gold standard to detect tremors. This concerns not only the choice of the algorithm and sensors, but methods are often designed to detect tremors in one specific group of patients during the performance of a specific task. Therefore, the aim of this study is twofold. First, an objective quantitative method to detect...

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Akoestische emissie metingen aan een op trek belast GLARE-3 paneel: Vergelijking van PAC SPARTAN-SU en MISTRAS 2001 apparatuur

Dit rapport beschrijft de resultaten van akoestische emissie (AE) metingen aan een op trek belast GLARE-3 paneel. De metingen zijn verricht in het kader van een evaluatie van AE-apparatuur. Hierbij is een vergelijking gemaakt tussen de van Fokker Aircraft B.V. geleende PAC SPARTAN-SU apparatuur en de door ANRU Physical Acoustics ter beschikking...

Nortec-30 eddyscan inspection of F-28 fuselage lap joint specimens

This report describes an evaluation of the Nortec-30 Eddyscan for the inspection of fuselage lap joints. The evaluation makes use of calibration specimens representing countersunk and dimpled longitudinal lap joints in F-28 fuselage structure. These calibration specimens have artificial defects representing fatigue cracks initiated in or near...

Eddy current detection of pitting corrosion around fastener holes

An evaluation of the eddy current technique for the detection and depth assessment of corrosion around fastener holes in F-16 lower wing skins is described. The corrosion type in this structure is pitting corrosion at the countersink edge of the fastener holes. Due to a corrosion clean-up limit of only 1.5 - 2.5 %, a maximum thickness reduction...

In-service detection of impact damage in composite materials

Impact damage is the type of in-service damage most significantly affecting the structural strength of composite aircraft components. The structure should be designed in such a way, however, that only visually detectable impact damage is possibly significant. When visible impact damage has been detected, the internal damage should be further...

Characterization of inspection performance

For a characterization of inspection performance it is necessary to consider both the probability of detection (POD) of defects in flawed specimens, and the probability of recognition (POR) of unflawed specimens. Different aspects of this characterization will be discussed in this paper using the magnetic inspection results of a NLR test...

Reliability of nondestructive inspection

This report describes the concept of reliability of nondestructive inspection (NDI) and reviews the different aspects involved. First, the probability of detection (POD) of flaws in flawed specimens is discussed. To provide a measure of confidence in an estimated POD, lower botind values of this probability at a given confidence level are...