A common medical symptom in which ear of a person hears ringing sound persistently can come from a slew of different problems such as disease or injuries, said medical experts.

Now researchers have found the reason why Tinnitus can be so hard to treat. According to Live Science, the find was made from the University of Iowa and was published in Current Biology.

Researchers during the study used a brain-monitoring technique which is usually used to treat epilepsy to map the process of tinnitus.

Furthermore, researchers during study measured brain activity during bouts of tinnitus, comparing stronger and weaker occurrences of the condition.

They even measured the results against brain patterns seen when the volunteers were exposed to a sound meant to mimic the symptom.

The most important finding made by researchers was that activity that was directly linked to tinnitus was very wide and spanned a large proportion of the part of the brain.

Researchers found that the brain in contrast responded to a sound they played that mimicked tinnitus were localized to just a tiny area.

This clearly showed that tinnitus not only fills in the sounds missing after hearing damage, but it also spreads into other areas of the brain.

Tinnitus is the perception of a sound that is often described as ringing, which is really not there, said researchers.

In experts view the study and its endings are very important when looking at the future of tinnitus treatment. Because so many pathways in the brain are activated by the condition, therefore it can be difficult for medicines or other treatments to reduce the symptom.

Neurofeedback, in which patients learn to control their brainwaves, is often utilized to control the persistent ringing, they added.