With the advances in pediatric neuroscience, pediatric EEG has become an important investigation. In my article I had discussed interpretational of common neurological disorders.

Major Frequence Ranges of Rhythms :

Electrical activity from the brain consists primarily of rhythms and these rhythms are named according to their frequency in cycles per second (C/sec), also called Hertz Hz).

• Delta refers to all rhythms less than 4 c/sec
• Theta is between 4 to <8 c/sec
• Alpha is between 8 to 13 c/sec.
• Beta is> 13 c/sec.
  Normal Background Rhythms-Introduction
  Usually, there is one dominant frequency that is called the 'background rhythm'.

1. Background rhythm in wake

In infants = 4 to 5 c/sec. (Delta and Theta waves)
In children = 5 to 8 c/sec. (Theta)
In adults = 8 to 10 c/sec. (Alpha)

2. Background rhythm is sleep

In light sleep = 5 to 6 c/sec. (Theta)
In deep sleep = 2 to 3 c/sec. (Delta)

(A) Abnormal Patterns - Introduction:
Abnormal patterns are mainly divided into two types:

1. Slow waves and
2. Spikes (or-sharp waves)

Also, depression of normal rhythm's may be abnormal.

(I) Slow Waves:

Slow waves are rhythms appearing especially during wakefulness that are slower than in the normal. Abnormal slow waves appear when the brain cells are damaged.

(II) Paroxysms: Spikes (Sharp Waves):

The spike (or Sharp wave) is a suddenly appearing electrical explosion that looks like a spike of large nail, spikes are <70 m sec and sharp wave 70 to 200 m sec in duration. These two patterns signify an epileptogenic region of the brain.

(III) Depression of normal Rhythms - Decreased amplitude of any normal rhythms.

Diffuse slow - suggestive of metabolic, toxic, infectious etiologies.
Focal slow-very slow - space occupying lesion.

B) Summary of Abnormal EEG Patterns and associated clinical conditions:
SHARP PAROXYSMALACTIVITY-NEONATAL:

1. Multi focal spikes - (non specific) Seizures.
2. Repetitive spike-Clonic seizure
3. Slow delta discharge-tonic seizure

POST NATAL:

1. Hypsarrhythmias-Infantile spasms.
2. Slow (1 to 2/sec.) spike and wave-Lennox-Gastaut syndrome (tonic seizure)
3. 3.3/sec.spike and wave complex-absence (Multiple spike-generalized tonic clonic seizure)
4. Occipital spikes - Visual perceptual disorders
5. Centro temporal sharp waves-benign epilepsy of childhood.
6. Periodic Lateralized epileptiform discharge - Cerebrovascular emboli and also epilepsia partialis continua, meta static to mores.
7. Temporal sharp waves

Posterior	Mid temporal	Anterior
Seizures	Navigate Symptoms & Seizures	P Psychomotor & generalized
		Tonic clonic seizures

© META BOLIC, INFECTONS AND TOXIC ETIOLOGIES:
These are diffuse slow waves, decreased frequency of back ground rhythm.

(D) VASCULAR:

• Carotid-Frontal and temporal slow waves
  
• Vertibrobasilar-Temporal and occipital show waves and low amplitude
  
• Haemorrhage-SharrJwaves or spikes with slow waves
  
• Space occupying lesion-highly localized abnormal slow waves.

(E) MENTAL & LEARNING DISABVITIES:
Occipital slow waves and extreme spindles.

(F) SENILITY:
Decreased frequency-of back ground rhythm and temporal slow waves on the left side of brain.

Mahapedicon 2005 - Conference Abstracts.Pediatric Oncall [serial online] 2006 [cited 15 July 2006(Supplement 7)];3. Available from:
http://www.pediatriconcall.com/fordoctor/Conference_abstracts/
MAH_PEDICON2006/eeg1_in_pediatrics.asp