Tinnitus Archive

Tinnitus Archive > Glossary

Glossary

barotrauma Damage to the ear caused by sudden abnormal pressure relationships affecting the external, middle, and/or inner ear. It is infrequent as a cause of tinnitus but when it does occur it may be associated with pain, hearing loss, perforated tympanic membrane, bleeding from the ear, and/or dizziness (suggestive of possible leakage of fluid from the inner ear). It can occur in connection with water sports (including diving) as well as during rapid altitude changes such as those sometimes occurring during flying in unpressurized planes.
data summary For the purposes of this Archive, statistical compilation of data involving one variable (such as a frequency histogram of patient ages) or a set of related variables (such as a comparison of the mean audiograms for several groups of patients).
dB - decibel The logarithmic unit used to specify sound pressure levels relative to a selected "reference" sound pressure. The reference sound pressures for hearing thresholds vary across the frequency range, as established by the American National Standards Institute. At any given frequency on an audiometer, the "0 dB" level is set to the reference sound pressure for that frequency.
dichotic Describes stimuli that are presented simultaneously to both ears of a given subject, with each ear receiving a different stimulus.
diotic Describes stimuli that are presented simultaneously to both ears of a given subject, with the two ears receiving identical or nearly-identical stimuli.
DX An abbreviation for the word "diagnosis" that is commonly used in medical environments. In the Tinnitus Data Registry the abbreviation DX appears as the title of the coding sheet used to acquire details of patients' medical history.
FT The sound frequency matching the perceived pitch of an individual's tinnitus.
HL - hearing level (in dB) The conventional way of expressing an individual's hearing thresholds relative to the standard reference levels on an audiometer (see definition of dB). For example, a subject with threshold 40 dB higher (worse) than 0 dB at a given frequency would be said to have a threshold of "40 dB HL" at that frequency.
LM - loudness match The dB level of an external sound that is judged by a given individual to be equivalent to the loudness of his tinnitus. In the Tinnitus Archive, LMs are commonly stated in dB SL (Sensation Level).
MML - minimum masking level The level in dB of a sound that just "covers" an individual's tinnitus (i.e. renders the tinnitus inaudible). In the Tinnitus Archive, MMLs are expressed in dB above the individual's threshold, that is in dB SL (Sensation Level).
objective tinnitus Tinnitus sounds that can be heard by an observer other than the individual experiencing the tinnitus (please also see subjective tinnitus). Objective tinnitus often has a clicking, fluttering, or pulsating quality. Low-frequency, pulsating tinnitus is often cardiovascular in origin, occurring in sychrony with the individual's pulse. In rare instances, objective tinnitus can have a high-pitched, ringing quality that may be either steady or interrupted. (For more information, please see: Sismanis, A. Pulsatile tinnitus. Otolaryngology Clinics of North America 36:389-402, 2003.)
octave confusion The tendency for an individual to confuse sounds one octave apart with each other, and to judge them as being identical. This potential confusion may occur during pitch-matching for tinnitus, where a common error is for subjects to select a frequency that is 1 octave lower than the actual pitch of their tinnitus. Testing for "octave confusion" involves presenting the tone selected as a tentative pitch match in alternation with a tone 1 octave higher, and requiring the subject to select that one of the two tones which best matches his tinnitus.
Oregon Tinnitus Data Archive The first edition of the Tinnitus Archive, published on 12.Jul.95. The data content of the first edition is now contained in Data Set 1 of the present Archive.
outlier(s) A statistical term referring to isolated data values that fall well outside the range of values measured for nearly all other data points in a given set of observations.Various conventions exist for deciding when a given data value should be considered an outlier (e.g. if it falls 4 or more standard deviations above or below the mean for that set of observations). Outliers are sometimes indicative of data-entry errors or other types of artifacts, and they need to be rechecked carefully to determine whether they are valid entries before attempting to perform statistical analyses with the data summaries in which they occur.
p value The probability that a given result obtained in a statistical test could have occurred by chance alone rather than because of a hypothesized relationship. For example, if a correlation coefficient has p < .05, we infer that the observed correlation is not likely to have been a random occurrence as the p value suggests that particular correlation would be obtained by chance alone fewer than 5 times out of 100. (Please consult a standard statistics text for computational formulas and further explanation.)
r - Pearson product-moment correlation Expresses the degree of linear relationship between two variables. (Please consult a standard statistics text for computational formulas and further explanation.)
RI - residual inhibition The occurrence, following presentation of a masking sound, of temporary diminution or complete suppression of an individual's tinnitus. Typically, the tinnitus recovers back to its normal level over a fairly short period of time such as a few minutes. RI can be either "partial" (PRI - the tinnitus is still audible but at a reduced level) or "complete" (CRI - the tinnitus appears to be totally absent). Most commonly, subjects experience brief CRI followed by more-gradually-recovering PRI.
SL - sensation level The level of an external sound, expressed in dB relative to an individual's hearing threshold for that sound. For example, a band of noise presented at 10 dB SL for a given individual is presented at 10 dB above that individual's threshold for the noise. (See also dB.)
SPL - sound pressure level (in dB) An internationally-accepted standard for measuring and stating the magnitude of sound. The reference pressure for dB SPL is an absolute pressure of 20 µPascals (µPa, formerly stated as .0002 µbar or .0002 dyne/cm-squared). (Also see dB.)
spontaneous tinnitus Brief tinnitus sensations that occur frequently in most if not all normally hearing people. The usual duration of spontaneous tinnitus sensations is on the order of 5 - 15 seconds. Typically, spontaneous tinnitus occurs in only one ear and is preceded by a brief feeling of pressure in that ear. It is usually loudest at onset and then fades away gradually until it is gone. Spontaneous tinnitus appears to have no clinical significance, and its origin and mechanism(s) are currently unknown.
subjective tinnitus Sensations of ringing, noise, or other types of sounds in the ears or head, and that are audible only to the individual experiencing the tinnitus (please also see objective tinnitus).
tinnitus Ringing or other noises in the ears or head.
Tinnitus Data Registry A research database set up in 1980 to study tinnitus. The database houses information obtained from patients attending the OHSU Tinnitus Clinic of the Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University.
tinnitus instrument A wearable device (resembling a hearing aid) that combines both a tinnitus masker and a hearing aid in the same case in order to provide effective masking for individuals who have a hearing loss as well as tinnitus, as is typical for the vast majority of individuals with clinically-significant tinnitus. (The circuitry for each device should be independent with separate ON/OFF switches and separate volume controls, otherwise the device is likely to be unsatisfactory to most users.)
tinnitus masker A device for reducing or suppressing an individual's perception of tinnitus, by presenting an external sound (usually, a broadband noise at a few dB above threshold) that tends to "cover up" or interfere with the tinnitus. Since the introduction of tinnitus maskers in the 1970's, a variety of such devices have become commercially available. Many individuals now routinely use wearable tinnitus maskers that resemble hearing aids, typically fitted binaurally if the individual has bilateral tinnitus. Another common type of masker is referred to as a "bedside masker", resembling a small table radio, which generates broadband noise. Many people have found that these devices can be set at comfortable listening levels that make it easier to sleep, by generating sounds that are pleasant to listen to and at the same time "cover" or reduce the individual's tinnitus.
tinnitus synthesizer Specialized electronic test equipment that is designed for precise testing of tinnitus to determine its pitch, obtain loudness matches at different frequencies, and evaluate the ability of the tinnitus to be reduced or suppressed by masking noise . Tinnitus synthesizers should be capable of generating tones and bands of noise over a wide frequency range, with sufficiently flexible output controls to allow independent (dichotic) or identical (diotic) stimulation of the two ears of the subject, and providing specification of the sound output levels in dB.
TMJ - temporomandibular joint The joint that connects the movable lower jaw to the fixed bone of the skull just below each ear.
TMJ syndrome A clinical syndrome consisting of pain or impaired movement of the temporomandibular joint (TMJ), often associated with clicking or other noises when the jaw is moved, and that appears to be a condition leading to or contributing to persistent tinnitus in some people. The diagnostic criteria for TMJ syndrome is a topic that is undergoing considerable debate at present, and consequently the prevalence of tinnitus attributable to TMJ syndrome is currently unknown.
tympanic membrane Eardrum
intersecting groups.gif: Certain questionnaire items permit patients to provide multiple responses (e.g. "IN THE LIST BELOW, PLEASE CHECK SOUND(S) THAT MOST CLOSELY RESEMBLE YOUR TINNITUS:"). When such items are tallied, patients with multiple tinnitus sounds will be counted multiple times, thus raising the response total to a value greater than 100% Certain questionnaire items permit patients to provide multiple responses (e.g. "IN THE LIST BELOW, PLEASE CHECK SOUND(S) THAT MOST CLOSELY RESEMBLE YOUR TINNITUS:"). When such items are tallied, patients with multiple responses can be counted multiple times (in some cases raising the column total to a value greater than 100%). In distribution tables where patients can be counted multiple times, we omit column totals.
rounding error.gif: In some cases, the total percentage for an analysis may appear to differ slightly from the expected total of 100%. Unless otherwise noted, small deviations from 100% are due to unavoidable rounding error. (Percentages for subgroups within all analyses are rounded to the nearest 0.1%.) In some cases, the total percentage for an analysis may appear to differ slightly from the expected total of 100%. Unless otherwise noted, small deviations from 100% are due to unavoidable rounding error. (Percentages for subgroups within all analyses are rounded to the nearest 0.1%.)
sample subset.gif: When the sample size for the current analysis is substantially (more than 10%) smaller than the total number of patients in the database, this will appear to flag that fact. Symbol used to indicate when the available sample size for a data summary is more than 10% smaller than the total number of patients in the Data Set.