Most tinnitus is subjective, meaning that only you can hear the noise. But sometimes it's objective, meaning that someone else can hear it, too. For example, if you have a heart murmur, you may hear a whooshing sound with every heartbeat; your clinician can also hear that sound through a stethoscope. Some people hear their heartbeat inside the ear — a phenomenon called pulsatile tinnitus. It's more likely to happen in older people, because blood flow tends to be more turbulent in arteries whose walls have stiffened with age. Pulsatile tinnitus may be more noticeable at night, when you're lying in bed and there are fewer external sounds to mask the tinnitus. If you notice any new pulsatile tinnitus, you should consult a clinician, because in rare cases it is a sign of a tumor or blood vessel damage.
The patients were assessed at the start of the study for their hearing ability and the severity of their tinnitus. The researchers assessed the degree of severity using established questionnaires, which looked at health-related quality of life, the psychological distress associated with tinnitus and how far it impaired their functioning. Using this information, researchers divided participants into four groups ranked on the severity of their condition.
Acoustic qualification of tinnitus will include measurement of several acoustic parameters like frequency in cases of monotone tinnitus or frequency range and bandwidth in cases of narrow band noise tinnitus, loudness in dB above hearing threshold at the indicated frequency, mixing-point, and minimum masking level. In most cases, tinnitus pitch or frequency range is between 5 kHz and 10 kHz, and loudness between 5 and 15 dB above the hearing threshold.
Note however that tinnitus nearly always consists of fairly simple sounds -- for example, hearing someone talking that no one else can hear would not ordinarily be called tinnitus -- this would be called an auditory hallucination. Musical hallucinations in patients without psychiatric disturbance is most often described in older persons, years after hearing loss.
As an initial test of our treatment, we first conducted a small pilot study to see if there were measurable benefits within 3 to 6 months of using this therapy. While we did not inform participants of whether they would receive a treatment or unaltered music, every participant in fact received a treatment. Participants reported a drop in scores on the Tinnitus Handicap Inventory (THI) within 3 months of using their personalized sound therapy for about 2 hours a day. THI is a psychometrically robust and validated questionnaire that assesses the impact of tinnitus on daily living and the degree of distress suffered by the tinnitus patient. Furthermore, we saw increased benefits after 6 months of treatment use (Figure 1). This data suggested that our treatment may be engaging brain plasticity in a positive manner, thereby gradually reducing tinnitus over time. Armed with this information, we designed a more rigorous trial that is very uncommon among research in tinnitus therapies.
An assessment of hyperacusis, a frequent accompaniment of tinnitus, may also be made. The measured parameter is Loudness Discomfort Level (LDL) in dB, the subjective level of acute discomfort at specified frequencies over the frequency range of hearing. This defines a dynamic range between the hearing threshold at that frequency and the loudnes discomfort level. A compressed dynamic range over a particular frequency range is associated with subjectve hyperacusis. Normal hearing threshold is generally defined as 0–20 decibels (dB). Normal loudness discomfort levels are 85–90+ dB, with some authorities citing 100 dB. A dynamic range of 55 dB or less is indicative of hyperacusis.
Often people bring in very long lists of medications that have been reported, once or twice, to be associated with tinnitus. This unfortunate behavior makes it very hard to care for these patients -- as it puts one into an impossible situation where the patient is in great distress but is also unwilling to attempt any treatment. Specialists who care for patients with ear disease, usually know very well which drugs are problems (such as those noted above), and which ones are nearly always safe.
A common cause of tinnitus is inner ear hair cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can "leak" random electrical impulses to your brain, causing tinnitus.