Q. "My 7-year old son wakes up periodically in the middle of the night. We find him sitting bolt upright, staring straight ahead, and screaming at the top of his lungs. He sounds like he's being viciously attacked. This goes on for a while, during which we try to console him. He goes back to sleep without knowing we were even there. If we decide to awaken him, he appears confused, and doesn't remember his dreams".

A. Your little boy doesn't remember his dream because he wasn't dreaming. It sounds as if he's experiencing night terrors.

When we first fall asleep, we enter stage one sleep. We then progress through stages two and three until, after about an hour and a half, we enter our the deepest sleep, stage four. Scientists can recognise these stages by our brain-wave (EEG) patterns.

What is surprising is that we don't dream during the four stages. If someone awakens during them, the most they can say is that they were "thinking".

Following stage four is "rapid eye movement" (REM" sleep. This is a totally different stage, and it is here that we start dreaming. If you were to watch someone, you would see the eyes darting back and forth. Dreams last for 45 minutes or so, and then we go back to non-REM sleep for about an hour. The pattern goes on throughout the night, and the non-REM stages get lighter. That is what the old saying "an hour before midnight is worth two after" pertains to.

Nightmares occur while we are dreaming. They can be as real and as frightening as a Hollywood thriller.

Night terrors, on the other hand, occur in stage four sleep. This is also the stage in which sleepwalking and talking occur. The reason they occur is unknown, and most children grow out of them. They may be worse at times of stress.

Hearing your child screaming in terror is distressing to you and the rest of the family, but luckily your child is in no danger. Your best strategy, if you can handle it, is to just leave him be. You've already said that he goes back to sleep on his own. Use the same methods for sleepwalkers as well. Determine that he isn't in danger of falling downstairs or out a window, or any other harm, and he'll soon return to bed.

Night terrors usually occur in children from 3 to 6 years of age, but sometimes go a little later. They are not an indication of any problem. You would actually be better to get your own rest during these occurrences, difficult as it sounds.