**3. Results**

EEG before administration of Dep can be described as the deceleration of the background EEG due to augmentation of the high-amplitude poly- and monomorphic waves within the low-frequency range. Quantitative spectral analysis (brain mapping) of interictal EEG revealed that, in the total EEG spectrum, the most dominant are the oscillations of 3–8 Hz with a prevalent amplitude of 60–120 μv.

Dep reduced the amplitude in the low-frequency range (p < 0.05).

#### **3.1 Qualitative EEG study**

The qualitative analysis revealed that the Dep therapy reduced the number of spontaneous paroxysmal discharge (by 76%) in the resting EEG and suppressed primarily the typical epileptiform complexes of spike-waves (SW) (3/s) (absence) [30, 31].

#### **3.2 Quantitative EEG study**

The quantitative analysis showed reduction of frequency (p < 0.05).

The Aps dynamics revealed the reduction of the incidence of low-frequency waves (p < 0.05), especially this effect was more prominent for the theta range.

Following the initial reduction of APs' alpha activity, especially in the occipital region (p < 0.05), this index did not show any further decline (p < 0.05).

Dep treatment produced a decreased brain activity within the range of beta (p < 0.05) [32].

The presence of a rhythmic monomorphic mid−/high-amplitude theta waves despite clinical improvements (seizure-free and no epileptiform EEG correlates) can provoke seizures after the Dep withdrawal. Seizures recurred due to not only Dep withdrawal but also due to dose reduction in patients. This aggravation of epilepsy was found in 64% of patients [33–35]. The rhythmic monomorphic mid−/ high-amplitude theta waves can be observed using brain mapping and power spectra. Such a pattern is not visible in the visual EEG observation.

Dep therapy did not show a EEG clinical aggravation that was diagnosed with the criteria of Genton and McMenamin [33].

Dep treatment decreased the number of seizures. The clinical signs and EEG pattern are described in **Table 2**.


**Table 2.**

*Clinical outcome and EEG record in 46 patients.*
