The twilight learning can create a memory directly from the outside, which is also one of the electromagnetic manipulations. This technique can be conducted without a help of the wave, though it is definitely within in a sphere of the brainwave study.
When you are under a light sleep, i.e. under a REM sleep, the window is open for a direct access to the long-term memory. If you are whispered something during this state, it is remembered as a long-term memory. It can be achieved just by one-time whispering, but you eventually feel it as more real when this operation has continued for several days.
This manipulation can be exercised just by the electromagnetic wave. The REM sleep is identified by the brainwave state dominated by the theta wave and the operative can send a thought at this time moment by an ultra-long wave. In this way, it is remembered as a long-term memory, which is felt as a real experience after several days of the operation.
This electromagnetic operation can be recurred to work this manipulation effectively that you experience the same dream continuously. If you assume this manipulated thought as an experience, it is quite critical as you might believe you have done a wrong thing in the past even though not.
It is an extreme case, but you might be more easily manipulated to judge others or situations under wrong information created by the twilight learning. If you have a distorted perception or feeling for the specific event, you are more likely controlled by the spy. If this is the case, you might conduct a crime in the future, not a wrong memory of the past.
You better recollect your memory often to avoid this electromagnetic manipulation. The externally created memory has a specific feature that there is no real viewpoint of yours or you know something which is improbable to experience. If you can make it clear at this point, you have a feeling that it is not an experience even if it is left in the long-term memory, eventually getting away from the manipulation.