The Valsalva maneuver revisited by wavelets.

The Valsalva maneuver is an autonomic test that evokes short sharp cardiovascular fluctuations mediated by the autonomic nervous system. Numerous spectral analysis methods have been proposed to analyze biological signals. When applied to heart rate (HR) variability, two major bands related to autonomic influence have been defined: LF (mainly sympathetic) and HF (parasympathetic).

Wavelet analysis of autonomic outflow of normal subjects on head-up tilt, cold pressor test, Valsalva manoeuvre and deep breathing.

Non-invasive autonomic evaluation has used fast Fourier transform (FFT) to assign a range of low (LF) and high frequencies (HF) as markers of sympathetic and parasympathetic influences, respectively. However, FFT cannot be applied to brief transient phenomena, such as those observed on performing autonomic tests where the acute changes of cardiovascular signals (blood pressure and heart rate) that represent the first and most important stage of the autonomic performance towards a new state of equilibrium occur. Wavelet analysis has been proposed as a method to overcome and complement information taken exclusively in the frequency domain.

Hereditary sensory neuropathy type 1 in a Portuguese family-electrodiagnostic and autonomic nervous system studies.

Hereditary sensory and autonomic neuropathy type 1 (HSAN 1) is a dominantly inherited disorder; its gene locus is mapped on chromosome 9q22. Three different missense mutations (C133Y, C133W and V144D) have been described in 11 families from Australia, England and Austria. Common clinical features have been found in these families.

Sympathetic sudomotor function and amyotrophic lateral sclerosis.

Introduction: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neuron cells in the cerebral cortex, brain stem and spinal cord. Autonomic nervous system involvement is not a recognized feature of the disease; nonetheless, autonomic dysfunction has been reported in severely affected patients. The aim of this study was to evaluate sympathetic sudomotor function in ALS patients, employing the sweat imprint test.