Tinnitus, generally known as “ringing in the ears” is the perception of noise in the ears when no outside source exists. Tinnitus affects approximately 17% of Americans, usually without any apparent reason. Sufferers describe hearing noises such as buzzing, ringing, tones, crickets, whooshing, and pulsing. Many encounter tinnitus symptions 24 hours a day, 7 days a week, which leads to sleep issues, emotional distress, and other associated problems.
Tinnitus AssessmentsWhen assessing tinnitus, it is always a good idea to begin with the Basic Comprehensive Audiometric however, many individuals experiencing tinnitus also have hyperacusis (sensitivity to loud sounds) and/or misophonia (extreme dislike of sound); therefore, it is generally recommended that a modified test battery be incorporated when testing patients suffering from tinnitus. A modified test battery will assist with patient comfort during audiometric testing and typically eliminate supra-threshold (significantly above threshold) testing, such as Loudness Discomfort Level testing (LDLs). The Basic Audiometric Evaluation is also useful in ruling out any medical considerations, such as acoustic tumors that may be causing the tinnitus. Most audiometric tests are appropriate for tinnitus patients, although careful consideration should be made for acoustic reflex or decay testing, as the presentation level of these signals can exceed tolerance levels for many tinnitus sufferers. Often times extended high-frequency threshold testing (> 8kHz) is recommended to better understand and characterize the tinnitus, although a specialized high-frequency audiometer is needed to do this. Otoacoustic Emissions (OAEs) can also be used to investigate the function of the cochlea.
Tinnitus: Minimum Masking Levels (MMLs)
Also known as Minimum Suppression Levels (MSLs) this test refers to the minimum level of noise (or any sound) that results in making the tinnitus completely inaudible or the least amount of noise needed to “mask” the tinnitus. To determine the MML threshold in dB HL, first obtain threshold of audibility for the white noise, then increase level of white noise in 1dB steps until patient reports tinnitus is inaudible. This could be as little as 10dB SL. Sensation Level (SL) is the dB amount obtained above threshold. For patients experiencing binaural tinnitus, present white noise binaurally to obtain MML in dB SL; monaural tinnitus patients should receive white noise presented in the affected ear for MML information. MMLs can help monitor changes and improvements throughout Tinnitus Retraining Therapy, as a reduction of the MML (requiring less noise to mask the tinnitus) over time can imply improvement to tinnitus perception and detuning of neural patterns from tinnitus detection.
Tinnitus Pitch (Frequency) Matching
Pitch matching refers to matching the perceived tinnitus to a specific frequency, using a pure-tone or narrow-band noise. If the patient describes tinnitus as a ringing, use pure tone frequency matching, if the patient describes tinnitus as a noise, use Narrow-band frequency matching. Present tone or noise above threshold and increase in 1dB steps until a frequency match is reported. Pitch matching can be useful in helping to characterize the psycho acoustic properties of the tinnitus, but may not tell you much about the tinnitus itself. Recording and monitoring these results can help identify changes to the perception of the tinnitus,
but consider test/retest reliability issues. Pitch matching results can help with the TSG settings should frequency shaping of the TSG noise signal be preferred over a white-noise broad-band signal.
Tinnitus Loudness (Intensity) Matching
Loudness matching refers to matching the perceived tinnitus to a specific intensity. Loudness matching can be useful in helping to characterize the psycho acoustic properties of the tinnitus, but is not highly relevant to the severity of the tinnitus. Recording and monitoring these results can help identify changes to the perception and/or habituation of the tinnitus, but consider tesVretest reliability issues. Loudness matching results can be helpful with the TSG volume settings. Loudness and frequency matching is usually only a few dB above the patient’s audiometric threshold. Proceed to increase or decrease presentation level until an intensity level/match is reported.
Residual Inhibition Testing
Residual Inhibition (RI Testing) typically results from a perceived decrease or elimination of tinnitus after exposure to a supra-threshold sound for a period of time greater than 1 minute. This typically results after audiometric testing or LDL testing; therefore, if this test will be performed, it should be performed after the MML test and never on the same day as fitting a sound generator device for Sound Therapy or Tinnitus Retraining Therapy. The length of time that residual inhibition can last will vary from person to person. Caution should be taken when testing for Rl as an increase in tinnitus perception can occur.
The mixing/blending point refers to the point at which the tinnitus and white noise generated from a Sound Therapy device such as the Live TS are perceived to mix or blend together without over-masking or completely masking the tinnitus. This measurement is important for identifying the suggested volume setting of a Sound Therapy device.
Hearing Aids For Treatment of Tinnitus
Clinical evidence shows that the use of hearing aids in tinnitus patients provides two benefits:
- It makes the patient less aware of the tinnitus
- It improves communication by reducing the annoying sensation that sounds and voices are masked by the tinnitus.
Hearing loss reduces stimulation from external sounds resulting in increased awareness of tinnitus and deprivation of input may change the function of structures of the auditory pathways. Tinnitus is often caused by expression of neural plasticity evoked by deprivation of auditory input.
With hearing aid amplification, external sounds can provide sufficient activation of the auditory nervous system to reduce the tinnitus perception and it may elicit expression of neural plasticity that can reprogram the auditory nervous system and thereby have a long-term beneficial effect on tinnitus by restoring neural function.
To obtain the best results, hearing aids should be fitted to both ears, use an open ear aid with the widest amplification band, and disabled noise reducing controls. In some cases a combination device would be preferable. The conditions required in order to obtain good results include not only the use of devices, but above all, their adaptation to the needs of the single patient, by counseling and customization. Wearing the hearing aid must become second nature to the patient even though it is only one element of the tinnitus therapy.