Datalogging is an advanced hearing instrument feature that collects and stores information in the hearing instrument. Datalogging systems are capable of tracking information about the acoustical environment in which the hearing instrument was worn. For example, how often was the patient in a noisy environment?¹ Datalogging is useful in hearing instrument fine-tuning due to the fact that it shows how the patient actually uses the instrument in real life.²

What Datalogging is Not
Datalogging provides the most benefit in fine-tuning during the first few weeks after the initial fitting. However, in general, it is not practical to store and then review data that has been collected over several months. Although datalogging can add a great deal to the fine-tuning process, it is not a substitute for the patient’s reported subjective experiences with the hearing instrument. 

Additionally, the logged data is usually not available for viewing within the first 8 hours after the datalogging function is initialized. The reason for this is that environmental data is quite variable and a minimum of 8 hours is required to obtain a reliable estimate of long-term conditions in the sound environment.  

Patients may be concerned that datalogging can act as a sort of “spy” system, recording conversations and personal details about their activities. The hearing care professional should take care to thoroughly explain datalogging and assure the patient that the system does not do any acoustical recording of conversation. The only things that are recorded are classification of the acoustical environment and information about how the hearing instrument itself is operating. Appropriate counseling should be sufficient to dispel patient fears. It is also possible to disable the datalogging in the fitting software, if desired.  

Benefits of Datalogging
With the help of datalogging, patient comments such as “I wore the instrument sometimes” or “Sounds are too loud” become more transparent to the hearing care professional when the comments are compared to actual data from the hearing instrument. Datalogging can make the fine-tuning process easier and more efficient, saving valuable clinical time.

We all know that first fittings are only a starting point, based on statistical averages and best estimates of the fitting parameters needed for each patient. Datalogging provides individual patient data that cannot be obtained in any other way. Knowledge of the patient’s typical listening environments provides critical information for programming changes.³ Tracking the patient’s manipulation of instrument controls, such as volume control changes, can highlight the need for adjustment of the gain and frequency response. In short, the more individual information we can obtain about the patient’s real life use of the hearing instrument, the more easily we can adjust the system to meet the patient’s individual needs.⁴

Datalogging Systems in Use Today
There are presently a number of hearing instruments on the market that offer datalogging. In addition to tracking information on the acoustical environment, some datalogging systems also track the duration of program use, along with the listener’s manipulation of instrument controls. The most advanced systems generate proposals for fine-tuning changes and/or counseling suggestions.  

In order to be practical, datalogging should be organized in such a way that the information is accessible to the hearing care professional. Too much information can be confusing, especially if the practical value is not obvious. An effective datalogging system should do more than just collect data for its own sake.

A New Datalogging System
A new premium hearing instrument, the Bernafon ICOS, incorporates an enhanced form of datalogging called the ICOS Tracker. The development of this datalogging system focused on user-friendliness and effective support for fine-tuning. The system stores data about program use, volume control changes, the sound environment in which the instrument was worn, and feedback (if present).

Information about the patient’s program use and frequency of changes reflects the patient’s real-life use of the hearing instrument. This information can help the dispensing professional to determine whether the system has been optimized with programs consistent with the expectations of the patient in every situation.

Volume Control (VC) tracking is invaluable due to the fact that the VC acts as the patients’ personal fine-tuning tool and is directly linked to their listening needs (Figure 1). If the VC is changed too often, this indicates that gain and/or frequency response settings should be adjusted.

Information about the listening environments the patient encounters is also important. How much gain does the patient prefer in each environment? Is the instrument set to comfortable levels in the presence of soft and loud sounds? Is the patient making many changes at medium input levels in an attempt to better understand speech? Not only does the ICOS Tracker help to answer these questions, but also when indicated, it will make fine-tuning proposals (Figure 2). These proposals are not merely gain changes, but may involve adjustments to features such as noise reduction, as well as frequency response changes to enhance speech intelligibility.

Feedback Tracking
Feedback Tracking is unique to the ICOS Tracker (Figure 3). For the first time, the hearing care professional can obtain information about how often, and under what conditions, feedback might occur during the daily use of the instrument. Feedback Tracking looks at how often the feedback canceller was active, the frequency region at which cancellation occurred, and whether the actual response of the hearing instrument is consistent with the software reference curve. From these data, the dispensing professional can determine whether the amount of feedback cancellation is appropriate. For example, if the feedback risk is low, then the gain could be increased or a larger vent could be used. If the risk of feedback is high in a specific frequency region, the system software will propose a gain reduction only in that frequency region to avoid unnecessarily reducing the gain in unaffected regions.

An ongoing comparison with the feedback threshold reference curve in the software (either predicted or measured) assesses the appropriateness of the feedback canceller settings. For instance, if the patient has altered the conditions under which the original measurements were made (for example, by wearing a hat), the system will indicate that a new reference curve should be measured.

Clinical Trial of New Datalogging System
A study was undertaken with 19 subjects to evaluate ICOS. The average age of the subjects was 64 years old; there were 11 experienced users, and 8 new users. The majority (15 subjects) of the fittings were binaural while 4 of the fittings were monaural. The average hearing thresholds can be seen in Figure 4.  

Part of this investigation with 13 of the 19 subjects involved examining the effectiveness of the fine-tuning suggestions presented by the ICOS Tracker. These 13 subjects were studied due to the fact that their hearing instruments had volume controls and that the logged data was reliably collected. The question that was asked during this investigation was “Would fine tuning with the ICOS Tracker reduce the volume control use for these test subjects after a follow up session?”

The ICOS hearing instruments were fit according to the patient’s audiogram, individual goals for amplification from the Lifestyle Profile, and experience with amplification.  The system logged data for 2 weeks on average before follow up. The patients then returned for a follow up visit where the logged data was downloaded from the hearing instruments and the fine-tuning suggestions, if generated, were applied.

Figure 5 shows the difference in the number of volume control changes before and after optimization with the ICOS Tracker in the Audio Navigation Program. The Audio Navigation Program is designed to reflect the most common listening situations that a patient finds him/herself in during the day. A 49% decrease in overall volume control use was seen for these patients after the use of the datalogging system for fine tuning.

When the data are analyzed further by environment (Figure 6), it can be seen that the overall dB offset from the default (power on) level also decreased. The volume control use for speech in noise showed a 60% decrease while volume control use in loud noise showed a 65% decrease. In quiet there was a 38% decrease while for speech in quiet there was a 63% decrease.

Therefore, it can be concluded that the patients decreased their use of the volume control and the amount of volume control adjustment (dB) was also decreased. It can be inferred that the subjects were more satisfied with their hearing instruments in more environments and did not feel the need to adjust their volume controls. Clearly the ICOS Tracker has contributed to the fitting process.

Conclusions
Datalogging is a hearing instrument feature that is here to stay. Access to objective data about the patient’s individual listening environments and use of the hearing instrument gives hearing care professionals a tremendous advantage in the fine-tuning process. Insight into the patient’s actual manipulation of the instrument controls yields valuable clues to help to quickly identify where programming adjustments are needed. Counseling can be more effective when there is better information about the interaction between the hearing instrument and the patient. Datalogging complements the patient’s self reports of their progress, resulting in a more complete picture of the real-life effects of amplification on their hearing ability.  

The ICOS Tracker represents the next generation in datalogging with targeted fine-tuning proposals. These proposals have been shown to reduce the volume control use by patients in a variety of listening environments. The system also includes Feedback Tracking to analyze the risk of feedback while patients go about their daily activities. The enhanced functions in the system are designed to make the datalogging in ICOS even more effective as a fine-tuning tool.

References
1. Flynn MC. Datalogging: A new paradigm in the hearing instrument fitting process. The Hearing Review. 2005;12(3):52-57. Online access at www.hearingreview.com archives: March 2005.

2. Fabry DA, Tchors J. Datalogging: A clinical tool for meeting individual patient needs. The Hearing Review. 2005;12(1):32-36. Online access at www.hearingreview.com archives: Jan 2005.

3. Jenstad LM, Van Tasell DJ, Ewert C.  Hearing Aid Troubleshooting Based on Patients Descriptions. J Am Acad Audiol. 2003;14(7):347-360.

4 Flynn MC. Envirograms: Bringing greater utility to datalogging. The Hearing Review. 2005; 12(12):32-38. Online access at www.hearingreview.com archives: Nov 2005.