|Year : 2016 | Volume
| Issue : 1 | Page : 10-13
Correlation between video-otoscopic images and tympanograms of patients with acute middle ear infection
Ching-Shiung Ting1, Kuo-Wei Huang2, Yuan-Chung Tzeng3
1 Dr. Ching-Shiung Ting's ENT Clinic; Department of ENT, Tainan Municipal Hospital, Tainan City, Taiwan
2 Department of ENT, Tainan Municipal Hospital, Tainan City, Taiwan
3 Medical Research Department of Tainan Municipal Hospital, Tainan City, Taiwan
|Date of Web Publication||16-Feb-2016|
Tainan Municipal Hospital, No. 670, Chongde Road, East District, Tainan City 701
Source of Support: None, Conflict of Interest: None
Objective: The tympanic membrane undergoes several changes in appearance in acute middle ear infection, which may be caused by a pressure change in the middle ear cavity. The tympanic membrane can be visualized through video-otoscopy, and the middle ear pressure can be detected through tympanometry. The objectives of this study were to assess the correlation between video-otoscopic images and tympanograms and to determine which of these tools can be used in diagnosing acute middle ear infection most efficiently and at an earlier stage. Materials and Methods: The study period was from April 2005 to August 2014, 900 patients, 1247 cases (693 males, 554 females), and 1951 infected ears were examined. Patients were encouraged to follow-up at our outpatient clinic where matched video-otoscopic images and tympanograms were obtained independently at each visit. A total of 4827 matched results were collected and their correlations were statistically analyzed using Pearson's Chi-square and logistic regression tests. Results:P< 0.05, determined using Pearson's Chi-square test, indicated a statistically significant correlation between video-otoscopic images and tympanograms. Furthermore, in 7.2% of the cases, video-otoscopy could be used to diagnose acute middle ear infection 1–2 visits earlier than tympanometry could, which was also confirmed by logistic regression tests. Conclusions: Handheld otoscopes coupled with video-otoscopes are more efficient than tympanometers in diagnosing any patient with a suspected acute middle ear infection. Video-otoscopy provides an opportunity for immediately observing the condition of the tympanic membrane, which is helpful for clinicians and patients.
Keywords: Correlation, Logistic regression test, Pearson's Chi-square test, Tympanogram, Video-otoscopic image
|How to cite this article:|
Ting CS, Huang KW, Tzeng YC. Correlation between video-otoscopic images and tympanograms of patients with acute middle ear infection. Indian J Otol 2016;22:10-3
|How to cite this URL:|
Ting CS, Huang KW, Tzeng YC. Correlation between video-otoscopic images and tympanograms of patients with acute middle ear infection. Indian J Otol [serial online] 2016 [cited 2020 Feb 23];22:10-3. Available from: http://www.indianjotol.org/text.asp?2016/22/1/10/176508
| Introduction|| |
Acute middle ear infection, such as acute otitis media and otitis media with effusion, induces pressure change in the middle ear cavity, which subsequently results in a change in the appearance of the tympanic membrane.
Tympanometry rapidly provides a general view of the pressure condition in the middle ear, whereas video-otoscopy provides a direct and adequate visualization of the tympanic membrane.
Numerous studies have confirmed tympanometers as tools with high sensitivity, but with relatively low specificity in diagnosing acute middle ear infection. Contrarily, both otoscopes and otomicroscopes are tools with higher sensitivity and specificity than tympanometers.
Both otomicroscopes and video-otoscopes have high magnification and bright light; however, images obtained from otomicroscopes show only a small portion of the tympanic membrane. Furthermore, an otomicroscope is highly expensive and specific training is required for operating it; a video-otoscope produces a larger, clearer image of the whole tympanic membrane along with the entire annular ligament, and manipulating it is easy, even for a general practitioner.
The objectives of the current study were to assess the correlation between video-otoscopic images and tympanograms and to determine which of these tools can be used in diagnosing acute middle ear infection most efficiently and at an earlier stage.
| Materials and Methods|| |
The study period was from April 2005 to August 2014, and 900 patients, 1247 cases, 693 males, 554 females, and 1951 infected ears were examined. These patients were included in this study based on chief complaints and handheld otoscopic examinations. Furthermore, the age distribution of the patients was from 0.5 to 76 years, and the peak ranged from 2 to 8 years old.
Each suspected case patient was encouraged to follow-up at our outpatient clinic every 3–5 days until the normal ear appearance, which is observed using a video-otoscope and tympanogram, transitioned to Type A or Type C tympanograms. Every case yielded a matched video-otoscopic image and tympanogram independently at each visit.
The tympanic membrane undergoes numerous pathological changes during acute middle ear infection. Different types of tympanic membrane appearances reflect different pressure conditions and the viscosity of content in the middle ear cavity, which may occur at different stages of middle ear infection. Therefore, we graded the video-otoscopic images according to the appearance of the tympanic membrane [Figure 1].
|Figure 1: Grades of video-otoscopic images. Upper row - left to right: Grade 0, Grade 1, Grade 2; Middle row - left to right: Grade 3, Grade 4, Grade 5; Low row - left to right: Grade 6, Grade 7|
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Grade 0 means a normal semitransparent eardrum; Grade 1 represents the presence of mucopus in the middle ear and a yellow-whitish bulged eardrum that looks like a donut; Grade 2 is similar to Grade 1, except for the appearance of a flat eardrum, which means the middle ear pressure is decreasing; Grade 3 means an acute inflammation in the middle ear cavity and eardrum, marked as a red eardrum; Grade 4 represents the presence of a serous secretion in the middle ear with an amber-colored eardrum. If the amber-colored eardrum demonstrates air-bubble or an air-fluid level, it is defined as Grade 5, which means a diminished middle ear pressure and viscosity of content; Grade 6 means fluid effusion in the middle ear; Grade 7 means an atelectasis or retracted eardrum, which indicates negative pressure with little or no content in the middle ear.
The tympanometry was performed using a GSI 37 tympanometer (Grason-Stadler Inc., Eden Prairie, Minnesota, USA). The tympanograms were classified, according to Jerger, into Types A, A+, B, and C.
A total of 4827 matched results were collected and the correlation between these matched video-otoscopic images and tympanograms were statistically analyzed using Pearson's Chi-square and logistic regression tests; the Statistical Package for the Social Sciences software, Version 18 (SPSS Inc., Chicago, Illinois, USA) was used for the analysis.
| Results|| |
This study confirms the correlation between video-otoscopic images and tympanograms; in particular, 71.4% of the Grade 0 video-otoscopic images were correlated with the Type A tympanogram, and 86.4% of the Grade 1, 72.1% of the Grade 2, 64.9% of the Grade 3, and 90.6% of the Grade 4 video-otoscopic images were correlated with the Type B tympanogram. For the Grade 5–7 video-otoscopic images, the correlation shifted from the Type B tympanogram to Type C tympanogram; in other words, 61.5% of the Grade 5 and 44.2% of the Grade 6 video-otoscopic images were correlated with the Type B tympanogram, and 63.6% of the Grade 7 were correlated with the Type C tympanogram, which may have been caused by the change in the pressure and viscosity of the middle ear. The Pearson Chi-square test revealed that P = 0.000, thus indicating a strong and statistically significant correlation between these two methods [Table 1]. We also performed further analysis using the logistic regression test, using “Grade 0 associated with Type B” as the parameter; we found higher odds ratio than parameters for every grade, particularly for Grades 1 and 4, which were 81.955 and 124.071, respectively [Table 2].
|Table 1: Analysis of correlation between 4827 matched video-otoscopic images and tympanograms using Pearson's Chi-square test|
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|Table 2: Logistic regression test among Grade 1-7 video-otoscopic images versus tympanogram B|
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We also conducted an investigation using Excel (Microsoft Inc., Seattle, Washington, USA) and the results indicated that excluding 538 infected ears who followed-up only once and 2 ears that underwent ventilation tube insertion, 102 among the remaining 1411 infected ears (7.2%) demonstrated abnormal video-otoscopic images despite showing Type A tympanogram at the initial visit; this condition then transitioned to Type B or Type C at the next 1–2 visits (days 3–6 of the follow-up), indicating that video-otoscopy can determine changes in the appearance of the tympanic membrane earlier than tympanometry can. The logistic regression test, in which “Grade 0 at the initial visit associated with Type B at the next visit” was used as the parameter, indicated that 203 infected ears that demonstrated normal tympanograms at the initial visit showed high odds ratios for Grades 1 and 4, which were 1.5 and 1.875, respectively [Table 3]. This means that for patients with normal tympanograms (despite having the Grade 1 video-otoscopic images at the initial visit), we can predict, at 1.5 times higher than normal that these tympanograms will become abnormal images at the next 1 to 2 visits. Furthermore, for the patients with the Grade 4 images, similar to the Grade 1 images, the predictions can be performed at 1.875 times higher than normal. By contrast, for the patients with Grade 0 video-otoscopic images and Type B or Type C tympanograms at the initial visit, only 13 infected ears (0.9%) transitioned to abnormal video-otoscopic images at the next visit. When “Type A at the initial visit associated with abnormal image at the next visit” was used as the parameter, no odds ratios higher than the parameter were observed for Type B and C tympanograms [Table 4].
|Table 3: Logistic regression test among 203 ears whose tympanograms were Type A, coupled with different grade of video-otoscopic images (except Grade 0) at the initial visit, to predict the association with tympanogram Type B at next visit|
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|Table 4: Logistic regression test among 141 ears whose video-otoscopic images were Grade 0, coupled with abnormal tympanograms (Type B or C) at the initial visit, to predict the association with abnormal video-otoscopic images at next visit|
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| Discussion and Conclusion|| |
Although tympanometry is a relatively reliable and fast approach for diagnosing middle ear infection, its applicability in younger patients is limited because such patients have smaller ear canals and less support. These factors cause the cartilaginous ear canal to collapse under minor pressure changes.,
According to the current study, 7.2% of cases might be misdiagnosed if only tympanometry is performed. Numerous studies have reported that Type A tympanograms are associated with the presence of middle ear effusion in 2–26% of cases,,,, which is consistent with our results; therefore, we recommend using a handheld otoscope coupled with a video-otoscope, rather than a tympanometer, to enhance the diagnostic accuracy.
Video otoscopy produces a large and clear image of the tympanic membrane that is adequately focused. The primary advantage of this method is that the entire tympanic membrane, annular ligament, and external canal can be visualized. For an ENT specialist providing primary outpatient care, video-otoscopy has the following advantages:
- It provides a direct and efficient visualization, which is favorable for teaching residents and educating patients 
- It is a tool with a relatively high sensitivity and specificity 
- There is no limit on patients' age, particularly for younger patients. Even if the patient is crying, the rigid teleotoscope can still be inserted safely into the patient's ear canal, provided that the head is strongly restrained
- The nose and throat can be inspected simultaneously, if required.
The current study confirms the correlation between video-otoscopic images and tympanograms, and also indicates that video-otoscopy can achieve an earlier diagnosis than tympanometry can in 7.2% of cases. Therefore, we recommend performing handheld otoscopy coupled with video-otoscopy, rather than tympanometry, on any patient with a suspected acute middle ear infection to prevent misdiagnosis or delayed diagnosis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]