How the New Biotoxin Illness Risk Score (BIRS) Test © Works

This new test is based on a model which was developed using logistical regression (statistical analysis) and data collected by Dr. Shoemaker's research group in an IRB approved study. The test was developed by biostatisticians and software developers, and although the analysis is complex, the web-based screening tool is very simple and easy to use. You will answer a series of about 25 questions pertaining to your symptoms. The questions are straightforward and the answers are either 'yes' or 'no'. Once the symptom questions are completed you will take an eye test known as a Visual Contrast Sensitivity(VCS) Test. You will be shown a series of images somewhat similar to the one shown below. The results of the symptoms and eye test are then loaded into the model and your Biotoxin Illness Risk Score (BIRS) is calculated. The model, which was developed using peer-reviewed and widely accepted biostatistical methodology, was developed with data collected over the past 5 years and is the first of it's kind. The model was able to destinguish Biotoxin Illness patients from Control patients with 99.6% accuracy. Please remember this is only a screening tool and your care provider will need to order labratory tests that will objectively confirm the BIRS score and make a formal diagnosis, and only then can begin treatment.

If you would like to take an on-line screening test, you will first need to create an account. Then, once logged-in you will then be able to purchase and take on-line tests under the "Testing" menu. Prices for testing packages can be seen here.

The new test offers several substantial improvements compared to the old VCS test and we are excited to share those with you. Some key features of the new test include:

  • your symptoms and and VCS test results are used to calculated an easy to understand Biotoxin Illness Risk Score(BIRS)between 1 and 100.
  • your eye test (VCS) test results are graded as a 'pass/fail' and you will also be able to view your raw VCS test results in an easy to understand graphical color-coded format.
  • your BIRS and VCS test results are trended so you and your care provider can easily track changes during treatment or re-exposure .
    • These improvements to the test will allow you much greater insight into your health, your treatment progress and/or biotoxin re-exposures.

    About the Eye (VCS )Portion of the Test

    The visual system includes a complex neurological network that involves the retina, optic nerve, brain nuclei and the visual cortex. One of the main outputs of the visual system is pattern vision. The VCS tests is an indicator of the ability to detect visual patterns. The test measures the least amount of contrast between light and dark bars (sinusoidal grating) that is needed for the viewer to detect the bars. VCS is measured at five different bar sizes (spatial frequencies) because perception of different bar sizes is mediated by different physiological components, and these components are differentially susceptible to effects from different toxic substances (10-17).

    The largest effects of biotoxins are at the mid-size bars (1-8). To measure VCS, viewers are presented a series of bar patterns at each of the five bar sizes. Viewers respond by indicating that the bars are tilted to the left, tilted to the right, are straight up and down, or that they cannot see any bars. The pattern with the lowest contrast that is correctly identified is the measure of VCS for that bar size. Upon completing the VCS test, viewers receive a message indicating that biotoxins are (positive) or are not (negative) likely to be involved in their illness. They will also be able to view their VCS test results in graphical form to help them assess progress and/or biotoxin re-exposure. The criteria for getting a "positive" VCS result is set high to avoid false positive results. This occasionally results in a false negative result; some cases of chronic-biotoxin induced illness may pass the VCS test a some times. VCS can be measured during treatment to monitor recovery.

    The results of the VCS portion of the test are graded as a pass or fail. The data is also displayed in a graph so it is easy to see which images you passes and which you failed. In this new version of the test, we have added a trending graph so that each user can quickly see how their VCS results are changing. This trending feature is of great use in monitoring progress during treatment and/or potential re-exposures. The summary reports are easy to print and bring to your physician.

    Before Taking the VCS Portion of the Test

    Note that by default you should position your eyes approximately 18 inches from the monitor. If you know that your near vision is better than 20/20 use 24 inches. If you do not know what your near vision is, please use 18 inches. We suggest that you measure a piece of string, cut it to the correct length and use it as a 'yardstick' to position yourself at the correct distance. If your head moves some during the test, that is ok. But try to remain as close to the correct distance as you can.

    Sample VCS Test Image

    You will be shown a series of images like the one below. You will cover one eye, and then look at each image, and choose which direction that the parallel lines tilt (Right, Up, Left, Not Sure). In the example image below you would click on "Left". You will be shown a number of images for that eye. When that eye is finished, you will be asked to cover the other eye and repeat the test. It's a very simple process.

    A Journey Into the Science of Vision and Why It Works

    Visual system function is a sensitive indicator of toxic effects due to factors involving exposure, measurement ability, susceptibility to toxins, and associations of visual deficits with symptomology, biochemical alterations, objective indicators of human illness and clinically recognized diseases.

    Photoreceptors transduce light to neural signals that are processed by a variety of neuronal types in multiple layers of the retina prior to transmission via the optic nerve to brain stem nuclei for further processing. Anatomically and physiologically distinct pathways relay visual signals to the visual cortex and beyond for integration and discrimination that results in perception. [click here for more...]