*4.3.3 Ictal EEG*

*Epilepsy - Advances in Diagnosis and Therapy*

patients, particularly in younger children.

component.

seizures.

a tendency to remit.

*4.3.1 Background*

nal seizures occur.

*4.3.2 Interictal abnormalities (IA)*

**4.3 Electroencephalography**

into a unilateral or generalized motor seizure.

falls or as a few jerks; erratic myoclonias are not rare.

**B.** Focal seizures, commonly CPC, are accompanied with autonomic features like pallor, cyanosis, respiratory changes, and drooling and oral automatisms, with eyelid or distal jerks. These seizures are short (few minutes) but can progress

**C.** Myoclonic seizures (MS) should manifest like massive axial movements with

**E.** Nonconvulsive status epilepticus (NCSE) or obtundation status is prolonged episodes (hours or days) of diminishing of consciousness with loss of contact or variably reduced responsiveness and somnolence, with erratic or segmental myoclonus. This NCSE may be initiated, punctuated, or terminated by GTCS or be combined with axial myoclonic, myoclonic-atonic, or clonic

**F.** Tonic seizures are rare and may be triggered by intermittent photic stimulation

Sensitivity to photic or pattern stimulation is noted in approximately 40% of

Worsening of seizures or SS may be provoked by blocking sodium channels

In adults, seizures are more frequent during sleeping, especially long-lasting clonic seizures or short tonic-clonic seizures, while MS, AA, and focal seizures have

EEG abnormalities are non-specific, but interictal EEG is useful for differential

whereas ictal recordings with EMG polygraphy document seizure polymorphism [11].

In wakefulness state background activity is normal at onset, despite the frequent seizures; diffuse or asymmetric slowing may be seen if EEG is performed immediately after a seizure or may remain on for a few days. During sleeping normal patterns, initially after the first year, there is usually a gradual slowing of the background activity, more obvious if seizures are frequent. Physiological sleep phenomena and organization mostly remain conserved, except numerous noctur-

It may be present at the beginning (22% of patients) and grow during the evolution (77%) [48]. Generalized focal and multifocal abnormalities, spikes, and spike-wave or polyspike-wave discharges, symmetric or not, predominate over the frontal and central areas, but occur over the temporal and occipital areas, too. IA is typically greater during sleeping [48, 49]. The evolution of the EEG aspects with age is not always similar and being dependent on the number and duration

diagnosis; however sequential EEG recordings may show the evolution of DS,

(IPS), visual patterns, hot water immersion, and physical effort.

AEDs, such as carbamazepine, phenytoin, lamotrigine, and vigabatrin.

**D.** Atypical absences (AA) could appear frequently linked with a myoclonic

**86**

of seizures.

