A tympanogram is a diagnostic tool used to assess the condition of the middle ear, including the eardrum and ossicles. When a tympanogram graph appears abnormal, it may indicate issues such as fluid in the middle ear, eustachian tube dysfunction, or a perforated eardrum. Understanding these results is crucial for proper diagnosis and treatment of ear-related conditions.
This article explains how a tympanogram works, the different types of abnormal tympanograms, their causes, and the possible treatments available.
Understanding Tympanometry and Tympanogram Graphs
What Is a Tympanogram?
A tympanogram is a visual representation of how the eardrum responds to changes in air pressure. It is created using a test called tympanometry, which helps detect issues in the middle ear.
During the test:
- A small probe is placed in the ear canal.
- Air pressure is varied while a tone is played.
- The probe measures how the eardrum moves in response to these changes.
- The results are recorded as a graph, known as a tympanogram.
Normal vs. Abnormal Tympanogram Graph
A normal tympanogram (Type A) shows a peak at normal pressure levels, indicating healthy eardrum movement. An abnormal tympanogram deviates from this pattern, suggesting potential ear problems.
| Tympanogram Type | Description | Possible Causes |
|---|---|---|
| Type A (Normal) | Sharp peak at 0 daPa, indicating normal middle ear function. | No issues present. |
| Type As (Shallow) | Reduced peak, showing stiffness in the middle ear. | Otosclerosis, scarred eardrum. |
| Type Ad (Deep) | High peak, indicating excessive eardrum movement. | Ossicular chain discontinuity. |
| Type B (Flat) | No peak, suggesting no eardrum movement. | Fluid in the ear, eardrum perforation, cerumen blockage. |
| Type C (Negative Pressure) | Shifted peak to negative pressure values. | Eustachian tube dysfunction, early ear infection. |
Types of Abnormal Tympanograms and Their Causes
Type As (Shallow Tympanogram)
This tympanogram has a lower-than-normal peak, showing that the eardrum is stiff and does not move properly.
Causes
- Otosclerosis (abnormal bone growth in the middle ear).
- Thickened or scarred eardrum from previous infections.
- Stiffness in the ossicles (middle ear bones).
Symptoms
- Mild hearing loss.
- Feeling of fullness in the ear.
- Difficulty hearing soft sounds.
Treatment
- Observation if symptoms are mild.
- Surgery for otosclerosis (stapedectomy).
- Hearing aids in severe cases.
Type Ad (Deep Tympanogram)
This type has an excessively high peak, meaning the eardrum is moving too much.
Causes
- Ossicular chain discontinuity (disconnected middle ear bones).
- Thin or weakened eardrum.
- Previous trauma or infections.
Symptoms
- Conductive hearing loss.
- Feeling of “echo” in sound perception.
Treatment
- Surgical repair of ossicles.
- Hearing aids if needed.
Type B (Flat Tympanogram)
A flat tympanogram means that the eardrum is not moving at all, which can indicate fluid buildup, perforation, or blockage.
Causes
- Middle ear infection (otitis media with effusion).
- Perforated eardrum.
- Wax or foreign object blocking the ear canal.
Symptoms
- Muffled hearing.
- Ear pain or pressure.
- Fluid drainage (in case of perforation).
Treatment
- Antibiotics for infections.
- Myringotomy (surgical drainage of fluid).
- Earwax removal if blockage is the cause.
Type C (Negative Pressure Tympanogram)
A negative pressure tympanogram shows a shifted peak toward negative values, meaning there is improper air pressure in the middle ear.
Causes
- Eustachian tube dysfunction.
- Early or resolving ear infection.
- Allergies or sinus congestion.
Symptoms
- Ear popping sensation.
- Temporary hearing loss.
- Discomfort or pain.
Treatment
- Nasal decongestants or antihistamines.
- Eustachian tube exercises (e.g., swallowing, yawning).
- Tympanostomy tubes in severe cases.
How to Interpret an Abnormal Tympanogram
| Feature | Normal Tympanogram | Abnormal Tympanogram |
|---|---|---|
| Peak Shape | Sharp peak at 0 daPa | Flat, shifted, or excessively high/low peak |
| Eardrum Movement | Normal mobility | Stiff, hypermobile, or immobile |
| Possible Condition | Healthy middle ear | Infection, blockage, ossicle issues |
FAQs
What does a normal tympanogram look like?
A normal tympanogram (Type A) has a sharp peak around 0 daPa, showing that the eardrum moves properly in response to pressure changes.
What does a Type B tympanogram indicate?
A Type B tympanogram is flat, indicating fluid behind the eardrum, a perforation, or earwax blockage.
Can an abnormal tympanogram cause hearing loss?
Yes, abnormal tympanogram results often indicate conditions that can cause temporary or permanent hearing loss if untreated.
How is an abnormal tympanogram treated?
Treatment depends on the cause and may include antibiotics, surgery, or ear tube placement to restore normal ear function.
Can an abnormal tympanogram be temporary?
Yes, conditions like colds, allergies, or temporary eustachian tube dysfunction can cause abnormal tympanograms that resolve on their own.
Conclusion
An abnormal tympanogram graph can signal various middle ear problems, from infections to structural issues. Understanding the different types—Type As, Ad, B, and C—helps in diagnosing and treating ear conditions effectively. If you or someone you know has an abnormal tympanogram, consulting an audiologist or ENT specialist is crucial for proper treatment and prevention of hearing loss.