Tinnitus is commonly defined as the subjective perception of sound by an individual, in the absence of external sounds. Tinnitus is not a disease in itself but a common symptom, and because it involves the perception of sound or sounds, it is commonly associated with the hearing system. In fact, various parts of the hearing system, including the inner ear, are often responsible for this symptom. At times, it is relatively easy to associate the symptom of tinnitus with specific problems affecting the hearing system; at other times, the connection is less clear.
Most of the time, the tinnitus is subjective that is, the internal sounds can be heard only by the individual. Occasionally, tinnitus is "objective" meaning that the examiner can actually listen in with a stethoscope or an ear tube and hear the sounds the patient hears. Tinnitus may be caused by different parts of the hearing system. At times, for instance, it may be caused by excessive ear wax, especially if the wax touches the ear drum, causing pressure and changing how the ear drum vibrates. Other times, loose hair from the ear canal may come in contact with the ear drum and cause tinnitus.
Middle ear problems can also cause tinnitus, such as a middle ear infection or the buildup of new bony tissue around one of the middle ear bones which stiffens the middle ear transmission system (otosclerosis). Another cause of tinnitus from the middle ear may be muscle spasms of one of the two tiny muscles attached to middle ear bones. In this case, the tinnitus can be intermittent and at times, the examiner can also hear the patients sounds.
Most subjective tinnitus associated with the hearing system originates in the inner ear. Damage and loss of the tiny sensory hair cells in the inner ear (that can be caused by different factors) may be commonly associated with the presence of tinnitus. It is interesting to note that the pitch of the tinnitus often coincides with the area of the maximal hearing loss.`
One of the preventable causes of inner ear tinnitus is excessive noise exposure. In some instances of noise exposure, tinnitus is the first symptom before hearing loss develops, so it should be considered a warning sign and an indication of the need for hearing protection in noisy environments. Certain common medications can also damage inner ear hair cells and cause tinnitus. These include non-prescription medications such as aspirin, one of the most common and best known medications that can cause tinnitus and eventual hearing loss. As we age, the incidence of tinnitus increases. Hearing loss associated with aging (also known as presbycusis) typically involves loss of and damage to the hair cells.
A special category is tinnitus that sounds like one's heartbeat or pulse, also known as pulsatile tinnitus. At times, the presence of pulsatile tinnitus may signal the presence of a vascular tumor in the general vicinity of the middle and inner ear. When noting this type of tinnitus, it is advisable to consult a physician as soon as possible to rule out the presence of this type of vascular tumor.
Conditions that affect the hearing nerve can also cause tinnitus, the most common being benign tumors, typically originating from one of the balance nerves in close proximity to the hearing nerve. These are commonly referred to as acoustic neuroma or vestibular schwannoma. Tinnitus caused by an acoustic neuroma is usually unilateral and may or may not be accompanied initially by a hearing loss.
Tinnitus may also originate from lesions on or in the vicinity of the hearing portion of the brain, called the auditory cortex. These can be traumatic injuries with or without skull fracture, as well as whiplash-type injuries common in automobile accidents. Benign tumors known as meningiomas that originate from the tissue that protects the brain may also be a cause for tinnitus that originates from the brain.
There are a number of non-auditory conditions that can cause tinnitus, as well as lifestyle factors. Hypertension or high blood pressure, thyroid problems, and chronic brain syndromes can all cause tinnitus without any specific auditory problems. Stress and fatigue may cause tinnitus, or can contribute to an exacerbation of an existing case. Poor diet and lack of exercise that may cause blood vessel and heart problems may also either cause it or exacerbate an existing condition. It is also possible that tinnitus could be caused by food or beverage allergies, but these causes are not well documented and are difficult to sort out.
