Brief Answer:
You probably did not respond to verbal message.

Detailed Answer:
Hi,

Welcome to HealthCareMagic.com I am Dr.J XXXXXXX Anto Bruno Mascarenhas. I have gone through your query with diligence and would like you to know that I am here to help you.

Let us first see the basics

1
Alertness varies according to the stimulus in different persons

Some People are very alert to objects in games e.g. a baseball being hurled at them, but are slow to respond to oral commands or dialogues.
Some People are very alert to oral commands or dialogues and will immediately reply, but may not be able to tackle a tennis ball coming at them
Some People are fast at both
Some People are slow at both

2
Even among the same person, alertness varies according to time

A professional Tennis Player or Baseball Player, may not be as alert in his game after a 12 hour drive as compared to how he will be after getting up and warming up

In Your case,
You can respond quickly to a ping pong ball and you are very good at the game
But
When other doctors and nurses observed you over the years, they write down: "patient has a flat affect"
It just means that you are very good and have high alert levels for Objects and games, but when some one is talking to you, you do not respond immediately

Now Coming to the EEG

During EEG, the technician must have spoken to you asking you to do something
But
You must have been preoccupied with your thoughts, or concentrating on the lights of other equipments in the room that you failed to hear what the technician said

The EEG technician would not know that you were intently watching something
He just assumed that you did not reply properly because you were drowsy

Q1
Could untreated depression or schizophrenia show "drowsy brainwaves" when the patient feels as wide and awake he or she could every be.
A1
I don't think that it is drowsy brain waves
It is more likely that that you were slow to respond as your attention was on something else during hat time

Hope you found the answer helpful.

If you need any clarification / have doubts / have additional questions / have follow up questions, then please do not hesitate in asking again. I will be happy to answer your questions.

Best Wishes for Speedy Recovery
Let me know if I can assist you further.
Take care.

-oOo-

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