A speech audiogram plays human speech through headphones instead of sounds. This can be words or numbers that are repeated. The speech audiogram is an important way to screen for hearing disorders and is also used when fitting hearing aids.
What is the speech audiogram?
The speech audiogram is an important way to investigate hearing disorders and is also used in the fitting of hearing aids. The speech audiogram is similar to a sound chart. However, the speech audiogram does not play sounds or tones for the test person to perceive, but numbers, words or individual syllables. Since these sounds are played at fixed volumes, the speech audiogram is a good method for determining speech comprehension. A speech diagram, also known as a speech intelligibility test, shows the difference in the subject’s perception between current hearing and speech comprehension. Testing by a speech diagram can be done in different ways. There are so-called syllable tests, word tests and sentence tests. The different tests allow a good clarification of how high the hearing ability and the equally important speech comprehension are pronounced. In the syllable test, individual syllables, usually meaningless, are played back and repeated by the test person. In the so-called Freiburg word test, monosyllabic nouns and number words are played over headphones or loudspeakers. Number words should be easy to understand and recognized as correct even at a low sound pressure level. People with hearing loss may not understand all words that are monosyllabic even at a good level and with a sound perception disorder present. The tests focus on two-syllable, often four-syllable number words or single-syllable words such as farm, slope, or ring. By grouping the words, hearing loss can be measured in the area of numbers, but also in a discrimination loss. The sentence test with complete sentences better reflects everyday situations.
Function, effect, and goals
The speech chart is used especially to clarify suspected hearing loss and other disorders in the auditory area. The necessary tests serve as a guide to how much the affected person hears or understands. The increase of the volume ends as soon as the test person can repeat the played words, numbers or syllables without errors. If the errors persist despite a higher volume, the test person switches to the next higher volume. The volume required for the person to understand is an important value for the ENT specialist. Through the speech audiogram measurement performed, the specialist then determines whether unilateral or bilateral hearing aid fitting is required. The speech audiogram varies from individual to individual and takes between ten to 20 minutes. In the number test, ten groups of ten numbers each in the two-digit range are played, and in the word test, 20 groups of 20 single-syllable nouns each are played. The number of correctly understood words is the percentage of the total number of words tested for intelligibility and discrimination. The order in which the word groups are played is irrelevant. However, it is important for the correct performance of the language chart to test a complete group. Each group is matched in terms of the composition of the sounds it contains to ensure a qualitative auditory test. If the words are mixed, the balance decreases and the validity of the test is reduced. The speech audiogram starts at a speech sound level ten to 20 decibels above that of the hearing loss, at 1,000 Hz. If more than half of the numbers played are correctly understood, testing of the next group follows at a speech sound level reduced by ten decibels and vice versa. The monosyllabic words, because they are more difficult to understand, are played at a speech sound level of about 30 to 40 decibels above the level where a good half or more of the monosyllables are still correctly understood. Experience has shown that it is advisable not to start too quietly during the monosyllabic test. Under certain circumstances, this could cause the patient to tire early on or lose interest in the important examination at an early stage.The main goal in the monosyllabic test is to find the appropriate speech sound level at which the monosyllabic can be understood or to reach an optimal value, which cannot be increased according to the current test results. At least three groups should be tested in the one-silver test to achieve a good result. It does not really require 100 percent comprehension. If the result is 95 percent, it is okay to accept the word as fully understood, because due to internal or external influences it is sometimes possible that just one word is not understood. In hearing aid fitting, the test is important to learn how far this speech sound level can be increased until the discomfort limit is reached. This tolerance test indicates the range in which someone has their maximum speech understanding, which for someone with normal hearing is between 50 and 100 decibels.
Risks, side effects, and dangers
The risks of using the speech chart are the patient themselves and possible interference that could skew the test result. The patient must actively cooperate with the language chart and not be tempted by lack of interest or commitment, lack of time or the like to take the tests performed and words, numbers or syllables announced in the process less seriously. This can be stressful for people who fear a possible hearing disorder or hearing aid fitting. In addition, the devices used must be functioning properly for the speech chart to be conducted correctly – only then can a meaningful measurement and resulting measures be meaningful.
