Subjective tinnitus is the most frequent type of tinnitus. It may have many possible causes, but most commonly it results from hearing loss. When the tinnitus is caused by disorders of the inner ear or auditory nerve it is called otic (from the Greek word for ear). These otological or neurological conditions include those triggered by infections, drugs, or trauma. A frequent cause is traumatic noise exposure that damages hair cells in the inner ear.
Prolonged exposure to loud sound or noise levels can lead to tinnitus. Ear plugs or other measures can help with prevention. Employers may use hearing loss prevention programs to help educate and prevent dangerous levels of exposure to noise. Groups like NIOSH and OSHA help set regulations to ensure employees, if following the protocol, should have minimal risk to permanent damage to their hearing.
Besides being an annoying condition to which most people adapt, persistent tinnitus may cause anxiety and depression in some people. Tinnitus annoyance is more strongly associated with the psychological condition of the person than the loudness or frequency range. Psychological problems such as depression, anxiety, sleep disturbances, and concentration difficulties are common in those with strongly annoying tinnitus. 45% of people with tinnitus have an anxiety disorder at some time in their life.
Boosting your immune system may also stop ringing in your ears. This will help to protect you from infections and diseases that may increase the level of unwanted sound. Also, an improvement in your health can mean an improvement in your tinnitus. Have a healthy lifestyle, which especially includes a healthy diet, proper and regular exercise, and enough sleep at night.
The accepted definition of chronic tinnitus, as compared to normal ear noise experience, is five minutes of ear noise occurring at least twice a week. However, people with chronic tinnitus often experience the noise more frequently than this and can experience it continuously or regularly, such as during the night when there is less environmental noise to mask the sound.
TTTS was originally described by Dr I. Klockhoff (9-12), and has been proposed by Patuzzi, Milhinch and Doyle (13) and Patuzzi (7) as the neurophysiological mechanism causing most of the persistent ASD symptoms. TTTS is an involuntary condition where the centrally mediated reflex threshold for tensor tympani muscle activity becomes reduced as a result of anxiety and trauma, so it is continually and rhythmically contracting and relaxing, aggravated by intolerable sound exposure1. This appears to initiate a cascade of physiological reactions in and around the ear, which can include: tympanic membrane flutter; alterations in ventilation of the middle ear cavity leading to a sense of blockage or fullness, as well as muffled/echoey/distorted hearing; irritation of the trigeminal nerve innervating the tensor tympani muscle, leading to frequent neuralgic pain; and symptoms consistent with temporomandibular disorder (TMD).
Sound waves reach the outer ear and are conducted down the ear canal to the eardrum, causing it to vibrate. The vibrations are transferred by the 3 tiny ear bones of the middle ear to the fluid in the inner ear. The fluid moves hair cells (stereocilia), and their movement generates nerve impulses which are then taken to the brain by the cochlear nerve. The auditory nerve takes the impulses to the brainstem, which sends the impulses to the midbrain. Finally, the signal goes to the auditory cortex of the temporal lobe to be interpreted as sound.
^ Jump up to: a b c Han BI, Lee HW, Kim TY, Lim JS, Shin KS (March 2009). "Tinnitus: characteristics, causes, mechanisms, and treatments". Journal of Clinical Neurology. 5 (1): 11–19. doi:10.3988/jcn.2009.5.1.11. PMC 2686891. PMID 19513328. About 75% of new cases are related to emotional stress as the trigger factor rather than to precipitants involving cochlear lesions.
Watery or serous discharge may be due to local inflammation and sometimes due to fungal infections. More purulent discharge, which is often yellow to brown with an offensive odor, may arise with bacterial infections. A more sticky, mucoid discharge is seen with a CSF leak and perforated eardrum. Blood-tinged discharge may be seen in more severe infections and injury.
Fluctuating sensorineural hearing loss may be from unknown cause or associated with Ménière’s disease. Symptoms of Meniere’s disease are hearing loss, tinnitus (ringing in the ears), and vertigo. Ménière’s disease may be treated medically with a low-sodium diet, diuretics, and corticosteroids. If the vertigo is not medically controlled, then various surgical procedures are used to eliminate the vertigo.
Hearing loss is categorized by severity, type, and configuration. Furthermore, a hearing loss may exist in only one ear (unilateral) or in both ears (bilateral). Hearing loss can be temporary or permanent, sudden or progressive. The severity of a hearing loss is ranked according to ranges of nominal thresholds in which a sound must be so it can be detected by an individual. It is measured in decibels of hearing loss, or dB HL. There are three main types of hearing loss: conductive hearing loss, sensorineural hearing loss, and mixed hearing loss. An additional problem which is increasingly recognised is auditory processing disorder which is not a hearing loss as such but a difficulty perceiving sound. The shape of an audiogram shows the relative configuration of the hearing loss, such as a Carhart notch for otosclerosis, 'noise' notch for noise-induced damage, high frequency rolloff for presbycusis, or a flat audiogram for conductive hearing loss. In conjunction with speech audiometry, it may indicate central auditory processing disorder, or the presence of a schwannoma or other tumor.
Hyperactivity and deep brain stimulation. Researchers have observed hyperactivity in neural networks after exposing the ear to intense noise. Understanding specifically where in the brain this hyperactivity begins and how it spreads to other areas could lead to treatments that use deep brain stimulation to calm the neural networks and reduce tinnitus.
It is estimated that half of cases of hearing loss are preventable. About 60% of hearing loss in children under the age of 15 can be avoided. A number of preventive strategies are effective including: immunization against rubella to prevent congenital rubella syndrome, immunization against H. influenza and S. pneumoniae to reduce cases of meningitis, and avoiding or protecting against excessive noise exposure. The World Health Organization also recommends immunization against measles, mumps, and meningitis, efforts to prevent premature birth, and avoidance of certain medication as prevention. World Hearing Day is a yearly event to promote actions to prevent hearing damage.
Besides research studies seeking to improve hearing, such as the ones listed above, research studies on the deaf have also been carried out in order to understand more about audition. Pijil and Shwarz (2005) conducted their study on the deaf who lost their hearing later in life and, hence, used cochlear implants to hear. They discovered further evidence for rate coding of pitch, a system that codes for information for frequencies by the rate that neurons fire in the auditory system, especially for lower frequencies as they are coded by the frequencies that neurons fire from the basilar membrane in a synchronous manner. Their results showed that the subjects could identify different pitches that were proportional to the frequency stimulated by a single electrode. The lower frequencies were detected when the basilar membrane was stimulated, providing even further evidence for rate coding.
Spontaneous otoacoustic emissions (SOAEs), which are faint high-frequency tones that are produced in the inner ear and can be measured in the ear canal with a sensitive microphone, may also cause tinnitus. About 8% of those with SOAEs and tinnitus have SOAE-linked tinnitus,[need quotation to verify] while the percentage of all cases of tinnitus caused by SOAEs is estimated at about 4%.
Exposure to loud noise. Loud noises, such as those from heavy equipment, chain saws and firearms, are common sources of noise-related hearing loss. Portable music devices, such as MP3 players or iPods, also can cause noise-related hearing loss if played loudly for long periods. Tinnitus caused by short-term exposure, such as attending a loud concert, usually goes away; both short- and long-term exposure to loud sound can cause permanent damage.