"We don't know at this time the extent to which external environmental sounds are heard by the fetus," he said.

There is little evidence that these vibratory sensations make any significant contribution to the external sound.

In the case of a room inside a castle, it would automatically filter out external sounds such as cars, birds, and pedestrians.

"They cancel out the external sound, and that would be protective."

In other words, people with Tinnitus perceive sound when no environmental or external sounds are present.

- Patients can use external sounds to exert some control over their tinnitus.

That is, increasing the level of external sounds within safe limits can help patients learn to pay less attention to their tinnitus.

Either way, the complete absence of external sound was uncanny.

Therefore, external sounds were not likely to be incorporated into an ongoing dream.

The sound perceived may range from a quiet background noise to one that can be heard even over loud external sounds.