Which tympanometer is optimal for an outpatient primary care setting?
Four models out of 16 made the cut for best in field.
- Four tympanometers are suitable for outpatient primary care, and each has positive and negative attributes. The Earscan was rated easiest to use and provided the most consistent data.
In a primary care setting where patient volume, time constraints, and provider turnover are on the increase, you need dependable biomedical equipment that produces quality data and is easy to use, ergonomic, and affordable. This is certainly true of the tympanometer, which is used to measure mobility and impedance of the tympanic membrane and ossicles, provide an objective measurement of the middle ear, augment visual and pneumatic otoscopy, and confirm and document otitis media with effusion (OME) and acute otitis media (AOM).1-3 Our study aimed to determine which tympanometer is optimal in the outpatient primary care setting.
Based on objective and subjective analysis, the Earscan appears to be an excellent choice for outpatient primary care, though users also liked the MT 10 and GSI 37.
Four units made initial cut
Of 16 tympanometers we found through a review of market literature, an Internet search, and audiology recommendations, 4 met the minimum requirements (TABLE 1)—Earscan (www.microaud.com), GSI 37 (www.viasyshealthcare.com), MicroTymp 2 (www.welchallyn.com) and MT 10 (www.interacoustics-us.com).
TABLE 1
Tympanometers had to meet these minimum requirements to be considered
| 1. COMPLIANCE |
| Pressure measurement: +200 to –300 daPa |
| Sound frequency: 226 Hz ±3% |
| Sound amplitude: 85 dB SPL ±3dB |
| 2. PRESSURE PUMP |
| Accuracy: ±15% or 10 daPa (or better) |
| Positive to negative pressure sweep |
| 3. DATA DISPLAY |
| Screen size: 2.5 cm × 2.5 cm |
| Horizontal axis (pressure): +200 to –300 daPa |
| Vertical axis (volume): 1.0 to 2.5 cm3 displayed |
| 4. PRICE |
| <$3000 list price per unit |
| 5. SIZE AND ERGONOMICS |
| Main box or docking station: dimensions < 30 cm × 23 cm × 10 cm; weight <2.7 kg |
| Handheld component: dimensions < 10 cm × 25 cm × 13 cm; weight <500 g |
What we looked for in our in-depth evaluation
We evaluated the tympanometers with formal objective testing, clinical use, subjective user rating, and feature comparison.
We assessed reproducibility with a volume calibration tool (in vitro), and with intra- and inter-device testing (in vivo) on volunteers. The tympanometers were also compared side by side in a clinical setting on adults and children with and without ear disease.
Eight evaluators with various clinical and technical backgrounds were our subjective raters. They used a Likert scale survey to rate the following tympanometer attributes: appearance, size, safety, durability, capabilities, ergonomics of physical design, ease of use (overall operations, specific control features), screen information layout, LCD screen/monitor, printing, maintenance, software interface, data quality and reliability, and accessories. Participants independently reviewed the tympanometers and were blinded to others’ evaluations.
We prioritized categories as high, medium, or low importance. Finally, important features of each unit were identified and verified.
Our rankings
Earscan comes out on top
Formal testing, clinical use, and feature comparison suggest the Earscan is the tympanometer best suited for primary care (see “How the units compared”).
The Earscan delivered high-quality data with excellent results in reproducibility testing for volume, pressure, and compliance. It proved reliable in the clinical setting with positive comments from participants.
Ergonomics. The Earscan was rated the easiest to use and the simplest to obtain a probe tip-ear seal. The Earscan has a small cylindrical probe affixed to a pressure/sound tube that attaches to the control unit. Anecdotally, these kinds of box-and-tube tympanometers provide the best seal and true readings. The probe is small, lightweight, and well suited for the clinician’s hand and patient’s ear so the tip-ear seal is easily viewed during the procedure. The tips are malleable, beveled, and tapered to provide an excellent fit in the ear canal.
The control unit is a reasonable size with finger-sized buttons and a viewable screen. It is simple to turn the unit on, press the Impedance button and perform the exam. The unit displays understandable feedback as to status.
Construction. The air pump, tone inducer, tubing, probe, and compliance pressure sensor are sturdy and yield consistent results. The unit is rugged and portable making it popular for occupational health.
Features. The Earscan is affordable and comes with additional functionality of audiometry and acoustic reflex testing. It has RS232 serial port capability to facilitate printer and limited computer integration.
Drawbacks. The unit is powered by a 120-volt adapter, making it less convenient than a handheld tympanometer. It may not be reasonable to carry the Earscan from one exam room to another. The Earscan has an older appearance with sealed buttons that are encased and provide little tactile feedback.
