What causes diminished hearing and a throbbing sound in only my left ear which sometimes stops?

Answer 1

This is referred to as pulsatile tinnitus.

I want to give you an overview of the different kinds of problems that can cause pulsatile tinnitus (tinnitus which throbs at the same rate as your heart beat. I assume you have already determined whether this is, in fact, the case, by feeling your pulse and listening to the tinnitus at the same time).

Here's a partial list, hitting the high points:

Vascular disorders (high blood pressure; abnormal placement of vessels within the middle ear; blood vessels which are abnormally narrow; aneurysms; arteriovenous malformations).

Tumors in or near the ear that are highly vascular.

Middle ear inflammation due to acute or chronic infection, or Eustachian tube dysfunction.

The noise will be repetitive but will NOT coincide with your heartbeat, if your problem is myoclonus.

The big worry, obviously, is that the pulsatile tinnitus is related to a vascular disorder or highly vascular tumor. If you see an ENT, he/she will know how to examine you with this in mind and will know the appropriate tests that need to be done to figure this out.