We measured vestibular perceptual thresholds in 105 healthy humans (54F/51M) ranging from 18 to 80 years of age. Direction-recognition thresholds were measured using standard methods. The motion consisted of single cycles of sinusoidal acceleration at 0.2 Hz for roll tilt and 1.0 Hz for yaw rotation about an earth-vertical axis, inter-aural earth-horizontal translation (y-translation), inferior...

With increasing age, the cardiovascular system loses its efficiency. The goal of this work was to investigate the hemodynamic system response to a head-up tilt test in two groups of different aged people. We used a model for describing this response in the right calf based on a noninvasive, non-occlusive, bioimpedance signal measurement technique. A decrease in the bioimpedance value in the cal...

To seek possible differences in short-period temporal RR interval, P-wave and PR interval dispersion and spectral coherence in patients with a head-up tilt test positive for vasovagal syncope with or without prolonged asystole, severe symptoms and at high risk of trauma. We retrospectively reviewed 5 min ECG and blood pressure recordings obtained at baseline, at rest and during head-up tilt in ...

measurements of the tilt angle of potential fields can be a useful aid to their interpretation. there are several varieties of the methods in use, such as tilt angle, and the derivative of tilt angle. tilt angle filters are used for exact edge detection of the rectangular bodies artificially by writing a matlab code. the gravity effects of these models are computed by standard algorithms. the e...

We assessed the cerebral blood flow velocity response to head-up tilt test in patients with typical neurocardiogenic syncope compared with patients showing postural tachycardia. Fifty patients (21 men) with history of orthostatic intolerance, younger than 50 years (mean 27 +/- 10), participated in the study. Transcranial Doppler sonography of the middle cerebral artery, heart rate and brachial ...

To explore the effect of posture on muscle performance, we tested the effects of body tilt angle on the strength, endurance, and fatigue of, and blood flow into, the plantar flexors. Human subjects were fixed to a tilt table that could tilt them from the horizontal (0 degrees ) to upright (90 degrees ) position and enabled force to be applied to a footplate through isometric action of the right...

There has been a great deal of interest in the therapeutic role of beta-adrenergic blockade in patients suffering from vasovagal syncope. The efficacy of beta-blockers in these patients may be due to blunting of elevated catecholamine levels that precede vasovagal syncope (1). Notwithstanding the widespread use of beta-blockers in the past, some studies on chronic beta-blocker use have been les...

Autonomic dysfunction seems to play a central role in the pathophysiology of neurocardiogenic syncope (NCS) but conflicting data have recently become available. We evaluated autonomic nervous system (ANS) function (heart rate variability (HRV), systolic blood pressure variability (SBPV) and baroreceptor gain (BRG)) and non-invasive haemodynamics (cardiac output and total peripheral resistance) ...

Head-up tilt testing potentiated by sublingual nitroglycerin (NTG), advocated by an Italian group, is a simple and safe but still not a standardized, diagnostic tool for the investigation of syncope. In fact, owing to its rapid spread, the original protocol received, often arbitrarily, many subsequent modifications. We now define the best methodology of the test on strictly evidence-based crite...

Autonomic nervous system Posture Blood pressure Head up tilt Original Article AIMS: Orthostatic stress is commonly utilized to evaluate the cardiovascular autonomic function. This is done by Head Up Tilt (HUT).. Tilt table test is a standardized, physiological, clinically relevant stimulus that challenges the cardiovascular regulation. By the performance of head up tilt, it is possible to asses...