**3. Results**

#### **3.1 Theta–beta ratio**

Theta–beta ratio (TBR) is reported to be a qEEG marker for a person's capacity to focus their attention on salient information. For this cohort, between the control block 1 and the comparison block 2 human structure–function course examinations, we have reported significant increments in voltage within the standard theta and beta EEG frequencies combined with a significant decrement in the theta–beta ratio. (TBR) These findings were associated with no significant changes in the magnitude of voltages in the standard delta and alpha bandwidths and, therefore, suggest an overall increase in attention control for the cohort.

**Figure 1** presents qEEG maps comparing the control exam (upper panel) and comparison exam (lower panel) measures of the voltages from the subject earning the highest block 2 exam score of 90%.

#### **Figure 1.**

*qEEG voltage maps for the subject with the highest exam score. Green circles indicate the scalp recording sites where the voltages are in the normal reference range (OK = normal) for each of the standard delta (1–3 Hz), theta (4–7 Hz), alpha (8–12 Hz), and beta (15–20 Hz) EEG bandwidths. Light blue (LO = low) and dark blue (VLO = very low) circles indicate voltages 1 and 2 standard deviations below the normal reference range; red (HI = high) and yellow (VHI = very high) circles are voltages 1 and 2 standard deviations above the normal reference range, respectively. Upper panel: eyes-closed control map recorded 3 days before the first control exam covering introductory material taught in the subject's first structure–function course exam. Lower panel: eyes-closed comparison map recorded 3 days before the comparison exam covering material taught in the subject's second human structure–function course exam, 5 weeks after the control recording. Theta and beta voltages are used to compute theta–beta ratio, a qEEG marker for attentional control.*

#### **3.2 Theta bandwidth changes for the subject with the highest exam score**

Five recording sites exhibit no changes from normal theta frequencies coded green, four sites show theta increases from 1 standard deviation below normal (light blue) to normal (green), seven sites show theta increases from 2 standard deviations below normal (dark blue) to 1 standard deviation below normal (light blue), and three sites show theta increases from 2 standard deviations below normal (dark blue) to normal (green). These findings are indicative of an overall increase in theta voltage for the subject with the highest exam score. The predominant change in theta is observed at 14 of 19 sites wherein increases in theta voltage are found.

#### **3.3 Beta bandwidth changes for the subject with the highest exam score**

Two recording sites exhibit no changes from normal beta frequencies coded green, five sites show beta increases from normal (green) to 1 standard deviation above normal (red), nine sites show beta increases from 1 standard deviation below normal (light blue) to 1 standard deviation above normal (red), one site shows a beta increase from 2 standard deviations below normal (dark blue) to 1 standard deviation above normal (red), and two sites shows beta increases from normal (green) to 2 standard deviations above normal (yellow). These findings are indicative of an overall increase in beta voltage for the subject with the highest exam score. The predominant change in beta is observed at 12 of 19 sites wherein increments in beta voltage are found.

*Quantitative Electroencephalography for Probing Cognitive and Behavioral Functions… DOI: http://dx.doi.org/10.5772/intechopen.107483*

### **3.4 Theta-beta ratio for the subject with the highest exam score**

The theta and beta voltage changes resulted in larger increases in beta than in theta voltage, thereby decreasing the theta-beta ratio (TBR) by 11.7% from 0.93 to 0.84. This range of TBR indicates that the subject with the highest exam score is functioning with 7%–16% more beta than theta bandwidth voltage.

**Figure 2** shows representative qEEG maps comparing the control block 1 (upper panel) and comparison block 2 (lower panel) voltage measurements from the subject earning the lowest block 2 exam score of 48%.
