In March of 2000 S. Curran and J. Wattis published an article titled Critical flicker fusion threshold: a potentially useful measure for the early detection of Alzheimer’s disease. The full text of the article is only available via paid subscription, however, portions of its Abstract are presented below. Most curious though is why after 14 years has this method of diagnosis not become mainstream? All NuTesla instruments include the ability to measure and report a person’s Critical Flicker Fusion as a Wellness Number.

“Critical Flicker Fusion Threshold (CFFT) is a psychophysical threshold and, in psychological terms, it is regarded as a measure of information processing capacity. CFFT has previously been shown to be a valid and reliable measure in young healthy volunteers and it also has a long history of use as a psychopharmacological measure in this group. Furthermore, the test satisfies many of the requirements of an ‘ideal’ measure for monitoring change, especially in a psychopharmacological context. Despite this, CFFT has been neglected as a research tool in elderly and Alzheimer’s disease (AD) populations and was therefore investigated further in this regard. … patients with AD were found to have significantly lower CFFT and descending scores compared with healthy elderly subjects. Interestingly, descending thresholds were significantly lower than ascending thresholds in the patient group, a feature that may be a characteristic of AD. … CFFT is a quick and simple measure to administer and patients had no difficulty completing the test. Because the measure is a psychophysical threshold, it is free from educational and cultural bias and there are no floor or ceiling effects. From the results of this work, CFFT appears to be a useful research tool in AD. It may be a suitable measure for monitoring cognitive change over time, either in community studies of AD or a clinical trial context, but further work is required. The technique might also contribute to the early detection of AD. …” Copyright 2000 John Wiley & Sons, Ltd.

Clarius supports the easiest to use method of measuring Your Personal Wellness Number (Critical Flicker Fusion) as described below.
Your Rhythmedics Clarius includes the ability to measure and report your personal Wellness Number, also referred to as your Critical Flicker Fusion (CFF) number. It is recommended to read this section fully in advance of measuring your Wellness Number. After reading this section you can run the test multiple times to get familiar with the procedure.

Flicker Fusion is the rate at which a distinctly flashing on and off light appears to fuse into a constantly illuminated light. It was discovered in 1945 during testing of WWII pilots returning home after the war with Post Traumatic Stress Disorder that their recovery could be measured objectively by tracking their flicker fusion frequency, which NuTesla calls the Wellness Number. The higher the numbers the further along the pilots were in their recovery. Your wellness number is a personal indicator of your overall wellness. Due to differences in the physiology of our eyes you cannot compare your wellness number to someone else’s. This feature is intended to allow you to track your personal wellness level. The higher your wellness number, the higher your personal wellness level.

NuTesla discovered that in addition to being useful for tracking your personal wellness, your flicker fusion frequency can be used to assist in shifting your body’s frequency to a healthier state by emitting your frequency. For this reason, after following the directions below to measure and report your Wellness Number, Clarius will then use your flicker fusion frequency to run a ten minute program during which time we recommend you place Clarius under your pillow, lie down and relax to your personal frequency.

Flicker Fusion occurs when our eyes see a rapidly flashing light increase in frequency (the number of times it turns on and off in one second) until the light appears to be steadily lit, and conversely when a rapidly flashing light which appears to be lit continuously decreases in frequency until we can perceive a change in the illumination. Research going back to the early 1900’s has shown the higher a person’s flicker fusion frequency is (the more times in one second that a rapidly flashing light crosses the threshold of appearing to be steadily lit to flickering) indicated better overall wellness and lower stress levels.

There are three phases of CFF mode. The first phase is measurement, where your CFF rate is measured using a Red flashing SLED and the dome switches are used to adjust the rate up and down. The second phase is reporting the measured CFF rate as your personal 2 digit wellness number (from 10 to 99). The third phase is generating your CFF rate through the Bio-Pulse emitters to strengthen your resistance to unwanted alpha brainwave interruptions.
To activate this feature press and hold the SETUP switch for 1 second and release it. If you press and hold SETUP for 5 seconds it will cause Clarius to switch-over to the flash-drive mode discussed in a later section. The Spectrum LED will flash Red 6 times to indicate your Wellness Number testing is beginning. After these 6 flashes the Red SLED will appear to be lit continuously when it is actually flashing very rapidly.
Hold Clarius between your thumb and forefinger close to your face with the SLED directly in front of your dominant eye and your forefinger finger on the SETUP switch to press it when you see a definite flickering of the SLED. As the program runs the on and off times are lengthened and the apparently constantly lit Red SLED appears to start flickering, which to some looks like water boiling when staring directly into the Red SLED. As the frequency continues to slow this boiling appearance begins to be more pronounced where there is still no time when the SLED appears to be off. As the frequency continues to slow this flickering becomes a distinct on and off flashing.

Pressing the lower SETUP dome switch will cause the flickering to decrease one step and stops the automatic slowing of the flicker rate for measuring. Pressing and holding the lower SETUP dome switch will decrease the flickering rate more quickly.

Pressing the upper SELECT dome switch will cause the flickering to increase one step and stops the automatic slowing of the flicker rate for measuring. Pressing and holding the upper SELECT dome switch will increase the flickering rate more quickly.

Once you press either the SETUP or SELECT dome switches two things occur. First, the automatic decreasing of the flickering rate is suspended (the SLED continues to flash at that rate) and secondly, a 5 second timer starts which ends the measuring if it times out. If either switch is pressed, the flickering rate is adjust up or down accordingly and the 5 second timer is restarted. It is recommended to take some time to press and release the two switches, separately, to adjust the flickering rate up and down until you are satisfied it is at the point of fusing to a constantly on light.

After releasing both switches and the five second timer expires the measuring phase ends and Clarius will then report your Wellness Number. The Red SLED will turn off and Clarius will then report your two digit Wellness Number as two series of flashes, the first series of flashes uses the white SLED to count out the tens digit in multiples of ten (four white flashes is 40, 5 white flashes is 50) and the second series of flashes uses the green SLED to count out the ones digit (6 green flashes is 6). Adding the two series of flashes together yields your personal Wellness Number (46 or 56 from the example above). The upper limit is 89. If the ones digit is a zero it will be reported by a single flash of the Blue SLED (the tens digit cannot be zero). If you counted 5 white flashes then saw a blue flash your Wellness Number would be 50.

After flashing your wellness number Clarius flashes two purple flashes to indicate it is running a 20 minute therapy session using your personal Wellness Number. These two purple flashes occur every five seconds while your personal frequency is being emitted. After 20 minutes Clarius restarts the previously run clarity program. Record and compare your Wellness Number over time to assess your overall wellness. It is recommended to measure and record your personal Wellness Number on a regular basis to track your overall wellness, such as once a week. A higher number shows an improvement in wellness. If you do not press the SETUP switch the test will end and Clarius will start running the previous clarity program without reporting any Wellness Number.

The Table below gives a sampling of Wellness Numbers and their corresponding Flicker Fusion Frequency:
Wellness# CFF
50 14.69 Hz
51 15.16 Hz
52 15.67 Hz
53 16.21 Hz
54 16.79 Hz
55 17.42 Hz
56 18.09 Hz
57 18.81 Hz
58 19.60 Hz
59 20.46 Hz
60 21.39 Hz
61 22.41 Hz
62 23.54 Hz
63 24.78 Hz
64 26.17 Hz
65 27.71 Hz
66 29.45 Hz
67 31.43 Hz
68 33.69 Hz
69 36.30 Hz
70 39.34 Hz
71 42.95 Hz
72 47.28 Hz