**3. Results**

Of the 251 ADHD patients treated with ILF neurofeedback during the entire data collection period, only 196 had pre-post QIKtest data collected. The average duration of therapy in terms of neurofeedback sessions was 38.5 (SD = 21.6), three participants dropped out of therapy.

### **3.1 Continuous performance test**

The pre-post data at T0 and T2 of 196 participants were included in the evaluation of the continuous performance test using the QIKtest device. Changes in four variables were analyzed: average reaction time (RT), variability of reaction time (VAR), omission errors (OM) and commission errors (CO). The averaged RT of the patients improved during the duration of the ILF neurofeedback training by about 21 ms - from 457 ms at T0 to 436 ms at T2 (see **Table 1**). In parallel, VAR improved as well by about 18 ms - from 122 ms at T0 to 104 ms at T2. To examine their statistical significance, the values of RT and VAR were compared separately using independent Student's *t*-tests, as a normal distribution with equal variances was given. According to the t-test results, the improvements of RT and VAR after ILF neurofeedback treatment were statistically highly significant (see **Table 1**). The third attention parameter *Therapeutic Effect of Infra-Low-Frequency Neurofeedback Training on Children… DOI: http://dx.doi.org/10.5772/intechopen.97938*


#### **Table 1.**

*Results of the continuous performance test.*

that was measured, OM, too improved from an average of 9.6 errors (SD = 15.1 errors) at T0 to 5.0 errors (SD = 9.3 errors) at T2. The test parameter that determines impulse control CO improved from 19.1 errors (SD = 17.3 errors) on average at T0 to 9.0 errors (SD = 9.0 errors) at T2. The significance of the improvements was examined statistically using a non-parametric Wilcoxon signed-rank test, because OM and CO did not follow a normal distribution. According to their Wilcoxon signed rank test results, the improvements of OM and CO after ILF neurofeedback treatment were statistically highly significant (see **Table 1**).

To investigate the relevance ("quality") of the improvements in the studied parameters of attention and impulse control in relation to mental maturity, the respective "equivalent mental age" for RT, VAR, OM and CO was determined from the corresponding norm curves of the CPT database. On average, the participating ADHD patients had an age of 12.1 years. However, their averaged performance in the CPT before the start of the ILF neurofeedback training was clearly below their averaged actual age when compared with the CPT database (see **Figure 3**): the averaged performances for the attention parameters RT, VAR and OM of the average 12.1-yearold ADHD patients corresponded to the 10.2 (RT), 10.0 (VAR) and 8.9 (OM) years age groups in the CPT database and thus, lack a mental maturity of around 2 years. For the tested parameter of impulse control, CO, the averaged performances of the ADHD patients corresponded to the 8.5 (CO) years age group in the CPT database and thus, showed an even slightly more delayed mental maturity of about 3.5 years.

#### **Figure 3.**

*Improvements of the equivalent mental age for the different test parameters of the continuous performance test.*

In terms of "equivalent mental age" that was derived from the CPT database, the ADHD patients benefited considerably from the therapy. After the ILF neurofeedback training equivalent mental age of the ADHD patients clearly increased for RT from 10.2 to 12.3 years, for VAR from 10.0 to 12.8 years, for OM from 8.9 to 10.3 years and for CO from 8.5 to 15.0 years (see **Figure 3**).
