Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
The 2 most common conditions in Neurology which can cause trasient neurological symptoms include seizures and migraines.
An aura is the perceptual disturbance experienced by some migraine suffers and epilepsy patients. It often manifests as the perception of a strange light, strange sensations, an unpleasant smell or confusing thoughts or experiences. For patients these are often warning sensations that a migraine or a seizure is coming on.
Are these symptoms followed by a headache??
A lot of times people can have migraines with out the actual headache. In other words they just have an aura. The same thing can be seen with seizures. The feeling of "deja vu" and flashes of light again have been well defined with seizures.
In answer to your question, No. One does not need to convulse in order to have seizures. These symptoms on their own can be because of seizures, and they basically arise due to underlying abnormal brain electrical activity.
I strongly advise you to go see a neurologist. An EEG or Electroencephalogram ( Brain wave testing) is a simple test which can rule seizures in or out. It would especially be helpful if they catch an episode while you are hooked up to the EEG. If the EEG is negative then they can look at other causes such as migraines.
I hope this helps. Good luck!
Thank you for your time and your thorough and helpful answer. I really appreciate it and will discuss it with my doctor.