Tinnitus is an auditory perception of sound heard by the ears or head in the absence of external source. The noises typically described as a ringing, hissing, whistling, buzzing or clicking. They may come and go, or it might hear them all the time. Some people with tinnitus report that they experience more than one type of sound.
The first step in treating tinnitus is appropriately diagnosing and measuring tinnitus. Tinnitus cases should be assessing by otorhinolaryngologist (ORL), audiologist, psychiatrists, clinical psychologists and also neurologist. For audiological part, audiologist will do routine audiological assessment, tinnitus audiometry and administration of tinnitus questionnaires.
Routine audiological assessment is the starting point to look for possible causes of tinnitus. It includes otoscopic examination, tympanometry, acoustic reflex, pure tone audiometry (PTA), and also otoacoustic emission testing. When evaluating tinnitus case, audiologist will use different sets of tests that can help to rule out or identify possible causes of tinnitus. Moreover, specific hearing markers may inform different potential treatment options for tinnitus. Tinnitus audiometry includes pitch matching, loudness matching, uncomfortable loudness level, minimum masking level (MML) and residual inhibition (RI).
Pitch and loudness matching is important to document the treatment progress and for sound therapy prescription. Pitch matching is to determine the frequency that best matches the patient’s tinnitus pitch by using the conventional audiometer. During history taking, we asked patient about type of tinnitus and start the test at nearest pitch of patient’s subjective perception. A two alternate choice method is used by presenting a tone for example 1 khz sound and 2 khz sound. This step will be repeating the above frequency at adjacent octave frequencies until a ‘close match’ to the tinnitus is identified. Besides that, loudness matching is to determine the intensity level that best matches the patient’s tinnitus loudness by using conventional audiometer. At pitch-matched frequency, the tone starts at 5db below hearing threshold, and increase by 2 db steps until the loudness of the tone is reported as same with tinnitus.
In addition, some patient with tinnitus also experience sound sensitivity or hyperacusis. Uncomfortable loudness level (UCL) helps to establish the level of sounds patient truly uncomfortable and need to be addressed as part of tinnitus management. The test should be conducted on one ear at a time from 250 Hz to 4 kHz. The test start at patient’s hearing threshold and gradually increase using 5 db steps until patient response the sound becomes uncomfortable.
Minimum masking level (MML) and residual inhibition (RI) is important to document the treatment progress and to ‘estimate’ the effectiveness of sound therapy. MML is performed in tinnitus ear starts with usual PTA to obtained white band noise (WBN) threshold. After getting the WBN threshold, the noise is increased gradually (e.g 2 db step) until the noise has fully masked patient’s tinnitus. In residual inhibition, WBN is delivered continuously to the tinnitus ear at 10 dB above minimum masking level for one minute. After one minute, the noise is terminated and the patient is asked whether tinnitus is fully gone, softer than usual or no change in tinnitus loudness. This will determine the effectiveness of sound therapy to the patient.
Tinnitus not only gives impact on hearing, it can cause negative towards physical, cognitive and also mental. The difference between tinnitus being a minor or major issue to the patient is how the tinnitus impacts of patients’ live. As such, audiologist has administered the tinnitus questionnaires to measure the subjective burden the patient experiences because of tinnitus. There are some clinical questionnaires for documenting the severity of tinnitus such as Tinnitus Function Index, Tinnitus Reaction Questionnaire (TRQ), Tinnitus Handicap Inventory (THI), Tinnitus Handicap Questionnaire (THQ), Borang Evaluasi Soal Selidik Tinnitus (BEST) – Malay tinnitus questionnaire and Depression Anxiety Stress Scales (DASS).