Orthostatic Test

A proper evaluation requires measurements of a patient under at least two different conditions. The method used here is to examine a patient both at rest and during physical activity. This can be accomplished by having a patient engage in some activity where the general response of a healthy person is known.

Based on the patient’s reaction, a more accurate assessment of ANS is possible. Intellewave uses a very popular method of ANS provocation – the Orthostatic Test, which is simply a transition from a supine to a standing position. Any physical or mental dysfunction will be exhibited as an inadequate ANS response during this test.

There are 3 result pages for Orthotest:

  1. Cluster Analysis
  2. Spectrum
  3. 3D Spectrum

Cluster Analysis Chart

The chart displays clusterization of Integrated HF and Integrated LF components. The horizontal or X-axis shows the level of intensity of Integrated HF component. The vertical or Y-axis shows the intensity of the Integrated LF component

The goal of cluster analysis is to translate the results of the Power Spectrum analysis into the format of clusterization chart. A point on the chart reflects a distribution of intensities of Integrated HF and Integrated LF components of Spectral function.

Each Cluster Analysis Chart has a light-blue and a green point. The light-blue point indicates the Integrated HF and Integrated LF distribution during the first main stage of the test, the green point reflects the frequency distribution during the second main stage of the test.

For Orthotest, the blue point refers to the Supine Stage of the test, and the green point refers to the Upright Stage of the test. There is also a red point in the chart for Ortho test. The red point, or Point of Average, shows an average for the two main stages. Coordinates of the Point of Average are displayed below the graph.

The diagram displayed in the left part of the panel describes the transition stage of a test. Transition stage is the part of the test during which R-R intervals activity changes noticeably, while the patient performs a transition between the  Supine to Upright. The transition period description contains a part of the rhythm graphic strip during a transition, minimum, and maximum HR during this period and calculated 30/15 Ratio.


The Spectrum page for Orthostatic test includes the description of 2 stages of the test:

1. Description of the Supine stage of the test is displayed on the left side of the panel

2. Description of the Upright stage of the test is displayed on the right side of the panel.

To generate a spectrum, Intellewave uses Fast Fourier Transform (FFT). The spectral function shown on the Spectrum Chart consists of 96 harmonics. Spectral analysis of the wave “portrait”, which appears in the rhythm graphic strip panel allows Intellewave to identify two main components:
– Low frequency: 0.033 – 0.15 Hz.
– High frequency: 0.15 – 0.5 Hz.

On the horizontal or X-axis, the frequency in Hertz is shown. On the vertical or Y-axis, the amplitude of spectral harmonics is shown (S, msec2). The low and high-frequency bands can be easily identified on the chart. The vertical lines between different frequency bands show the harmonic for this frequency and an order of the harmonic is written above.

The maximums of the spectral function are shown by green triangles for each range if present.


This page displays a movable 3D chart of the Spectral function. Frequency (in Hz) is shown on the horizontal, or X-axis, and the amplitude of spectral harmonics (S, msec2) is shown on the vertical or Y-axis. Different frequency ranges are displayed in different colors. Two different stages of a test are displayed next to each other when the chart is viewed from the top.