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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/08/05 15:49:28」(JST)

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Tympanometry is an examination used to test the condition of the middle ear^[1] and mobility of the eardrum (tympanic membrane) and the conduction bones by creating variations of air pressure in the ear canal.

Tympanometry is an objective test of middle-ear function. It is not a hearing test, but rather a measure of energy transmission through the middle ear. The test should not be used to assess the sensitivity of hearing and the results of this test should always be viewed in conjunction with pure tone audiometry.

Tympanometry is a valuable component of the audiometric evaluation. In evaluating hearing loss, tympanometry permits a distinction between sensorineural and conductive hearing loss, when evaluation is not apparent via Weber and Rinne testing. Furthermore, in a primary care setting, tympanometry can be helpful in making the diagnosis of otitis media by demonstrating the presence of a middle ear effusion.

Operation

A tone of 226 Hz is generated by the tympanometer into the ear canal, where the sound strikes the tympanic membrane, causing vibration of the middle ear, which in turn results in the conscious perception of hearing. Some of this sound is reflected back and picked up by the instrument. Most middle ear problems result in stiffening of the middle ear, which causes more of the sound to be reflected back.

Admittance is how energy is transmitted through the middle ear. The instrument measures the reflected sound and expresses it as an admittance or compliance, plotting the results on a chart known as a tympanogram.

Normally, the air pressure in the ear canal is the same as ambient pressure. Also, under normal conditions, the air pressure in the middle ear is approximately the same as ambient pressure since the eustachian tube opens periodically to ventilate the middle ear and to equalize pressure. In a healthy individual, the maximum sound is transmitted through the middle ear when the ambient air pressure in the ear canal is equal to the pressure in the middle ear.

Procedure

After an otoscopy (examination of the ear with an otoscope) to ensure that the path to the eardrum is clear and that there is no perforation, the test is performed by inserting the tympanometer probe in the ear canal. The instrument changes the pressure in the ear, generates a pure tone, and measures the eardrum responses to the sound at different pressures. This produces a series of data measuring how admittance varies with pressure, which is plotted as a tympanogram.

Type A tympanogram
Type B tympanogram
Type C tympanogram

Tympanograms are categorized according to the shape of the plot. A normal tympanogram (left) is labelled Type A. There is a normal pressure in the middle ear with normal mobility of the eardrum and the conduction bones. Type B and C tympanograms may reveal fluid in the middle ear, perforation of the tympanic membrane, scarring of the tympanic membrane, lack of contact between the conduction bones of the middle ear or a tumor in the middle ear.

The categorising of tympanometric data should not be used as a diagnostic indicator. It is merely a description of shape. There is no clear distinction between the three types, nor the two subtypes of type A, namely A and A. Only measures of static acoustic admittance, ear canal volume, and tympanometric width/gradient compared to gender, age, and race specific normative data can be used to somewhat accurately diagnose middle ear pathology along with the use of other audiometric data (e.g. air and bone conduction thresholds, otoscopic examination, normal word recognition at elevated presentation levels, etc.).

References

^ David Jay Steele; Jeffrey Susman; Fredrick A. McCurdy (2003). Student guide to primary care: making the most of your early clinical experience. Elsevier Health Sciences. pp. 370–. ISBN 978-1-56053-545-4. Retrieved 27 June 2011.

External links

Medscape article by Kathleen C M Campbel
Impedance audiometry at Otolaryngology Online by drtbalu
Basic Multifrequency Tympanometry: The Physical Background

UpToDate Contents

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1. 小児における聴覚障害の評価 evaluation of hearing impairment in children
2. 成人における難聴の評価 evaluation of hearing loss in adults
3. 小児における急性中耳炎：診断 acute otitis media in children diagnosis
4. 小児における滲出液を伴う中耳炎（滲出性中耳炎） otitis media with effusion serous otitis media in children
5. 耳管機能障害 eustachian tube dysfunction

English Journal

Evaluation of hearing loss in patients with Graves' disease.

Berker D, Karabulut H, Isik S, Tutuncu Y, Ozuguz U, Erden G, Aydin Y, Dagli M, Guler S.Source, 2185 sk. Sogutozu Konutlar? 7B Blok No: 45, Sogutozu/ Ankara, Turkey, dberker6@yahoo.com.
Endocrine.Endocrine.2011 Aug 11. [Epub ahead of print]
Hearing loss has commonly been reported in association with thyroid disorders and during treatment with propylthiouracil. The relationship between hyperthyroidism and the auditory system has not been previously investigated. The aim of this cross-sectional, case-control study was to investigate hear
PMID 21833679

Selecting infants with OM that need referral and further assessment: Creating a case-finding instrument.

Lok W, Chenault MN, Anteunis LJ, Meesters C, Haggard MP.SourceDepartment of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands; School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, The Netherlands.
International journal of pediatric otorhinolaryngology.Int J Pediatr Otorhinolaryngol.2011 Aug 11. [Epub ahead of print]
OBJECTIVE: In the Netherlands, many children are surgically treated for OM. Recent publications question the need for surgical treatment in common uncomplicated OM, although there is certainly a subgroup of infants that do need further assessment and possible treatment. The present study explores th
PMID 21840067

Japanese Journal

ファブリー病患者における加齢と聴力障害との関係

山本浩志,坪井一哉,伊藤太
交通医学 64(3・4), 120-125, 2010-07
NAID 40018705270

Tympanometry による乳歯列期臼歯部交叉咬合の治療前後の変化

永田敦子,臼井朗,三好克己,李萌,前田隆秀
小児歯科学雑誌 46(2), 274, 2008-04-25
NAID 10024179942

Related Pictures

★リンクテーブル★

リンク元	「ティンパノメトリー」「鼓膜聴力検査」「acoustic impedance test」

「ティンパノメトリー」

Tympanometry
	Diagnostics
ICD-9-CM	95.41
MeSH	D000158
MedlinePlus	003390

　　[★]

英: tympanometry
関: インピーダンスオージオメトリー

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ティンパノメトリー : 約 4,060 件
ティンパノメトリ : 約 5,100 件
チンパノメトリー : 約 1,420 件
チンパノメトリ : 48 件

SOTO.76

型		空気圧-コンプライアンス関係	疾患
A型	AD型	ピークが高い	萎縮した鼓膜、耳小骨連鎖離断
A型	AS型	ピークが低い	耳小骨連鎖固着、耳硬化症
B型		平坦	鼓膜の癒着、滲出性中耳炎(鼓室内に液体が充満)
C型		ピークが陰圧側	耳管狭窄症、滲出性中耳炎：鼓室内が陰圧