Tinnitus is a perception of a sound in one or both ears or in the head when no external sound is present. It is often described as ringing in the ears but also as hissing, roaring, whistling etc. - but common to all - as a completely different sound as previously experienced from their external environment.
It can be intermittent or continuous; occasional or long term symptom.
Objective tinnitus has mostly physical/physiological origin e.g. noise injury or arterial aneurysm in the brain. It is thereby only a symptom and not a disease itself. The sound can be heard by an observer (with using an stethoscope or other sound recording device). It is treated by eliminating the cause.
At subjective tinnitus no sound can be detected by an observer. An abnormal auditory nerve activity is the only recordable change. It is a standalone disturbance which is not physical/physiological but rather arise from psychic tension. Medications or other physical measures rarely help. Personal approach toward the patient (understanding, discussion) is needed.
What cannot be considered as tinnitus:
-any external sound
-sounds caused by change in external air pressure (at diving or quick changes in altitude (car on mountain road, plane...)
-"voices" as psychiatric patients describe them.