I have been around occupational Audiology for a long time. As a software developer, I have seen a lot of interesting innovations over the years, both in audiometers and in software. I have written software to communicate with just about every audiometer that is out there and some old ones that are no longer being sold. Lately, I have been getting some questions and recommendations on tablet-based audiometers. Specifically, audiometers based on the iPad tablet. There seems to be a lot of interest on the subject, so I wanted to offer my opinion on these new testing devices and methods, utilizing my 25 years of experience in the field.
- The tablets used for testing are off the shelf devices that can be purchased rather inexpensively and replaced quickly if one were to fail.
- They are light and portable. This makes them ideal for testing when a booth is not an option.
- They do not need a PC or laptop to function. The software is downloaded onto the tablet, the headphones are plugged in and the subject interacts with the tablet during the test. With so few moving parts or equipment to setup, one could be setup and testing in minutes.
- They are modern, and attractive to younger nurses and technicians. Hey, as a developer, I love gadgets. I have been using tablets since the original iPad, and I think they do a fabulous job for certain tasks.
- They are generally only used for open room testing. Since the testing apps on these devices are made to interact directly with the subject, the technician needs to be looking over their shoulder to observe when the subject is having issues with the test. Open room testing, while sometimes necessary, will (in my opinion) yield poorer test results than a test performed in a sound booth. While special headphones can mitigate some of the problems, other issues such as visual distractions can detract from the quality of the test.
- Manual testing is awkward. In order to do manual testing, the technician must take over the tablet, and request that the subject raise their hand when they hear the tones. Just like it was done some 30 years ago. The technician would then enter the response on the tablet. Hearing testing technicians still must be CAOHC certified to do manual testing, and it is best practice to have CAOHC training for all hearing testing technicians how do any type of testing. Automatic or manual.
- With tablets, daily calibration checks must be done on a person. Modern hearing conservation programs with traditional audiometers have a bio-acoustic simulator that is used every morning to check for issues with the audiometer and cabling. This simulator responds at preset values and the results are compared with the values from the last annual audiometer calibration. Tablet audiometers cannot be hooked up to a simulator, so a human subject must be used to do the daily calibration checks. Just like it was done over 30 years ago before modern audiometers and simulators were made available. This daily calibration check is in the OSHA 1910.95 standard and is required to be performed every 24 hours. Testing a human subject for the calibration check is time consuming, and error prone.
- For the annual audiometer calibration, the tablet and headphone must be sent off to be calibrated, or a replacement headset along with the calibration “numbers” must be sent to the client. Sending the audiometer and headset off for calibration means downtime for the client. Getting a replacement headset that was calibrated on another tablet, may be fine, or it may not be. It all depends on how close the audio calibration values are between the client tablet and the one the calibration was performed on. Any differences can mean STS’s and possible recordable shifts.
- These tablets are intended for purposes other than occupational hearing testing. The manufacturer can at any time change the specifications, ports or software. Or, they could discontinue the device all together. Traditional audiometers are made to be used for years, and most last well over 20 years. That cannot be said for any tablet that I know of.
- It is difficult to incorporate a tablet audiometer with existing hearing conservation programs. Our clients use our state of the art hearing conservation program that can communicate with most audiometers and HR software programs. Because tablet-based audiometers have no way of connecting to an existing company HR or hearing database, one must import and export demographics and hearing data to and from the tablet.
- From the studies I have seen, the accuracy is “within 10dB” of a standard audiometer. In my opinion this is unacceptable. Occupational audiological testing has an accuracy of 5dB. When I read a specification that says “within 10dB”, that means it is less than 10dB but greater than 5dB. A Standard Threshold Shifts occur when there is a 10dB average shift (with or without aging) against the baseline. This “accuracy” issue has the possibility of generating STS’s when comparing the results of a tablet audiometer test and a baseline done on a traditional audiometer. You can’t get around the fact that a tablet audiometer is less accurate than a traditional audiometer.
- Beware of companies advertising their tablet audiometers ability for open room testing. For any audiometer to be used in an open room environment, the noise level must be constantly monitored with a Type II microphone. To my knowledge, none of the current mass market tablets have a built in Type II microphone. Specifically, the iPad, the most common tablet used as a tablet-based audiometer, does not have a Type II microphone built in. This means that to have a valid open room test with the iPad that meets the 1910.95 OSHA standard, you will need either an external type II microphone, or a separate device to monitor the noise levels.
- Also, beware claims that “this is an OSHA approved device”. OSHA does not approve devices, they are regulatory agency only.
In my opinion, and with the consultation of my Doctors of Audiology, I cannot recommend tablet-based audiometers to our clients at this time. As a Hearing Conservation consulting company that has been in business for 20 years, our clients rely on us to provide sound and accurate advice on their hearing conservation programs. In many cases, our Audiologists act as the Professional Supervisor of our clients audiometric monitoring programs. We would be negligent in our responsibilities if we allowed one of our clients to suffer a negative audit because we did not warn them about the potential issues in tablet-based audiometers.
Before you make the decision to purchase a tablet-based audiometer, ask the company these four questions:
- Is the microphone on the tablet a Type II microphone? If not, an external Type II microphone is required by OSHA fore open room hearing testing.
- Will the tablet audiometer work with my existing hearing conservation software?
- Can I use a bio-acoustic simulator (bio-Betty) for my daily calibration checks?
- How accurate is the tablet in comparison to a standard audiometer?