Experimental data

From a presentation by Dr. Kakuichi Shiomi

In this report, the term of "Cerebral exponent" means the same as "Brain activity level" and CEM.

Figure 1. shows one of the results of our early experiments for measuring the chaotic characteristics of human voice. In this case, test subject - 1 had started story reading after lunch in the afternoon. The test subject - 1 felt tired and stopped reading after about 50 minutes from the start of reading. The 5 minutes average of the first Lyapunov exponent that we call cerebral exponent, that drawn by red line, had increases to the level of about 120%. And the exponent had already increased to that level about 20 minutes before the test subject noticed his tiredness himself.

Figure 1.
Click the picture to enlarge

Figure 2. shows also the other result of early experiments. In this case, the test subject - 2 read a newspaper. When the test subject read pages of politics and economy, the cerebral exponent had been kept high level comparatively. However, the cerebral exponent decreased to the level of about 70% after changing to sports pages, as if the brain of the test subject was commanded that gdescend and maintain the cerebral exponent level of 70%!h

We thought this was because there were many difficult topics in the pages of politics and economy, and the cerebral exponent of the test subject was kept high level with heavy cerebral workload.

Figure 2.

Click the picture to enlarge

Figure 3. shows the other result that I think it is very interesting.

In this case, we thought that the variation in the cerebral exponent shows mental condition of the test subject. There are 4 patterns of the variation in the figure.

  1. In the first phase, decreasing of the cerebral exponent means alleviation of initial tension.
  2. In the second phase, the cerebral exponent is gradually increasing, since the test subject got tired with reading aloud.
  3. In the third phase, there were fluctuations. The periodical fluctuation of the cerebral exponent means that the test subject was thinking that he would like to stop reading but he had to keep going.
  4. In the forth-final phase, the cerebral exponent increased suddenly, rapidly. The sudden increase of the cerebral exponent means that fatigue caused difficulty in reading.

Figure 3.

Click the picture to enlarge

Figure 4. shows the variation in the cerebral exponent of the voice of a lecturer, who is a craftsman of a winery.

He was requested to give a lecture on research and development at the winery to students of the university. In the morning, the cerebral exponent of his voice was less than 700. The cerebral exponent value of 700 is already very high, since the normal level of male voice is from 400 to 550, according to the results of our experiment. As the results, cerebral exponent value of relaxed male voice is about from 400 to 450, and relaxed female voice is about from 300 to 400.

After a lunch break, in the afternoon, his cerebral exponent was increased to more than 800. He said that he was very tired, since he had to have a lunch with a chief professor of the course, and he could not take a rest at all at a lunch break.

Figure 4.

Click the picture to enlarge

Additionally, I would like to show another interesting results of experiments. These two figures show the long-term variations in the cerebral exponent. In these experiments, test subject - 5 and 6 were requested to read a story or newspaper every morning and every evening for more than two months. As a result, we found that the test subject - 5 usually got tired in the evening.

Figure 5.

Click the picture to enlarge

As a result of personality test, the test subject - 5 is active enough but the test subject - 5 lacks cooperativeness. Then, the test subject - 5 has always got tired after work, or any event, since she is always in emotional conflict. (Figure 6)

As a result of personality test; The test subject - 6 is not so active. The test subject - 6 lacks independence. But the test subject - 6 has cooperativeness enough. Then, the test subject - 6 can always recover from her fatigue relatively easily by taking a short rest before reading. (Figure 7)

We then think that the results of the experiments were good coincidence with the result of the personality tests

Figure 6.Figure 7.

Click the pictures to enlarge

We have carried out another kind of experiment, gTen Minutes Readingh.

gTen Minutes Readingh is a protocol for diagnosis of cerebral conditions. The test subject makes 5 minutes reading with sound feedback through a headphone after 5 minutes normal reading.

Figure 8.

Click the picture to enlarge

Figure 9. shows the result of Ten Minutes Reading.

The increase of cerebral exponent of the test subject was observed after starting reading voice feedback.

Figure 9.

Click the picture to enlarge

Figure 10. shows the result of the other experiment. Each dot represents a couple of cerebral exponent, x coordinate is in case of normal reading, and y coordinate is in case of reading by closing one ear with test subjectfs finger. As a result of the experiment, in about 70% of all 41 case, the cerebral exponent of reading in case of closing ear, y coordinate, is higher than x coordinate, that of normal reading. The light dots represent the case of female voice.

Figure 10.

Click the picture to enlarge

Summary