In EEG, delta waves are seen:

Ans. C. In deep sleep Type Frequency (Hz)LocationNormallyPathologicallyDeltaup to 3frontal, high amplitude (20- 200uV)Adults*deep sleep* infants* subcortical lesions* diffuse lesionsTheta4-7 HzParietal and temporal regions* young children*drowsiness (early sleep)* focal subcortical lesionsAlpha8 -12 HzParietal and occipital (50- 100 uV)* closing the eyes and by relaxation.Frequency decreases in: hypoglycemia, hypothermia, hypercapnia, GA, sleep, comaBeta12 - 30 HzFrontal region; low amplitude waves 10 uV* active, busy or anxious thinking, active concentration* sedatives