The activity of delta waves is considered to be more among infants since they spend more amount of time with slow wave sleep and hence delta waves are considered as principal wave form of infants. The analysis of waking EEG of newborn infant states that delta wave activity could be dominant during that age and appears among 5-year olds or waking EEG. The delta wave activity at time of slow wave sleep will get reduced during adolescence with reduction of twenty percent reported between age group of 11-14 years. The delta waves are considered to decrease during lifespan and lot of declination will be during the middle of forties. During the age of seventy five, delta waves and stage four sleep will be completely absent. Apart from that, there is a reduction in delta waves incidence at the time of slow wave sleep and occurrence of sequential delta wave activity will be seen commonly among adults and it will enhance with age.