Editor's note: This is a transcript of the live seminar presented on June 9, 2011. To view the course recording, register here: /audiology-ceus/course/va-selections-medical-surgical-professional-issues-ethics-preventing-medical-errors-for-audiologists-18865
Medical Errors in Audiology
Cindy Beyer, AuD: Errors in healthcare are a concern to all providers, and although those occurring in audiology are rarely life threatening, audiologists are not immune to such events. This presentation will identify common clinical errors and steps that will assist in minimizing adverse audiology outcomes. While we named the course Preventing Medical Errors for licensure purposes, the more appropriate term might be Preventing Clinical Errors since audiologists, by legal definition, do not specifically "medically" diagnose hearing loss but rather assist in the diagnosis of it. How many of you have encountered something unexpected in clinical practice: an abrasion to the ear canal, an impression that got stuck and could not be removed from the patient's ear, or perhaps PT tubes became dislodged during an impression? Were you comfortable in handling the situation? Did you learn anything that you could apply in your practice going forward? As we go about our day to day practices we are going to experience things that are unexpected. If we practice long enough and see a diverse caseload of all ages, the chances are pretty good that we are going to have at least one unexpected and undesirable patient outcome during our careers. The material in this course will attempt to share with you some of the insights and experiences that we have observed over the past two decades at HearUSA and some lessons learned along the way.
Minimize Risk
The first rule in medicine is to do the patient no harm. One of the best ways to minimize risk to our patients is to follow established clinical guidelines. Scope of practice documents have been carefully developed to assist us in delivering conscientious and appropriate care and are available through the American Academy of Audiology (AAA) and also through the American Speech-Language Hearing Association (ASHA). We would encourage you to be familiar with those and to follow established protocols. Beyond that, you may want to take a very close look at your practice or organization and detail specific procedures that will facilitate the needs of your particular practice or patient base. It is important to have a disciplined process in place where all parties involved in the delivery of the care are fully aware of the guidelines and rationales. Each person should be trained and held accountable for their actions. When we cultivate an environment of care and consideration, we become much more adept at minimizing clinical errors. With the privilege of being a licensed healthcare provider, we assume the responsibility of delivering care in a competent and disciplined manner, consistent with the rules of medicine. Some providers might question how greatly medical malpractice concerns should impact an audiology practice. Injury that occurs during the delivery of hearing care is minor when compared to those in other medical specialties, particularly in a surgical environment, for example. But it may be helpful to view the events in the context of healthcare laws, so let's consider a formal definition as we move on to discuss potential risks and liabilities.
Malpractice can be defined as either deliberate action or an act of neglect that is committed by a healthcare provider that results in injury or other adverse outcome to the patient. In our profession, these injuries can encompass a very broad spectrum from actual physical injury to the ear or perhaps even the unintentional mismanagement of a patient's hearing loss. Malpractice is further defined by how one's delivery of services matches the expected standard of care in the community. Here is an example from the Florida statutes: The prevailing professional standard of care for a given healthcare provider shall be that the level of care, skill and treatment which, in light of all of the surrounding circumstances, is recognized as acceptable and appropriate by reasonably prudent similar healthcare providers (Section 766.102 Florida Statutes). While this is a pretty general definition, malpractice could be considered anything contrary to that guideline. These are some of the things that we need to consider in order to protect our livelihoods as well as the conditions of our patients.
Here are some statistics that will help us to put the issue into a broader frame of reference. In general, medical error is an issue of importance, and it contributes not only to the unfortunate death and injury of hundreds of thousands of people, but it adds another layer of expense to an already inflated healthcare cost structure. The cost of retreating and rehabilitating, in addition to the legal burden of protecting the provider and compensating the patient and the legal team, is staggering when you take into context the fact that the vast majority of incidents are preventable. We start to recognize some of the responsibilities wherein we have to take action. Up to 100,000 people die annually due to medical errors. More people die due to medical errors than from AIDS, car accidents or breast cancer. Medical errors cost the nation almost $38 billion annually. Furthermore, up to $17 million of this cost is from preventable injuries. Seventy percent of adverse outcomes are preventable, and another 5% are potentially preventable (Fung, 2011). These data show that we need to do all we can do to minimize the risks that our patients encounter when they come to us for help.
We live in an increasingly litigious society, and the consumer is advised and solicited more and more to seek legal help when they feel something has compromised their care or if they have been treated in an unfair way. Millions of dollars are spent resolving these cases, and as healthcare providers we need to take this into consideration. It is also important to also remember that regulatory agencies, such as Centers for Medicare and Medicaid Services (CMS) and state licensing boards, continue to impose more and more responsibility on licensed providers. This is an increasing trend, that accountability for all aspects of patient care is the responsibility of the provider, and we need to be aware of that.
There are areas specific to audiology that we will address today as they relate to medical errors. We will be looking at infection control, history and documentation as part of the medical records process, cerumen removal, hearing evaluation and testing, earmold impressions, hearing aid fitting and verification, and amplification technology. Dr. Younker will then discuss electrophysiology errors.
Infection Control
It is the responsibility of any healthcare provider to try to ensure that the environment of care is safe. We need to take steps to protect our patients from the transmission of disease. Disease transmission can occur from clinician to patient, from patient to clinician and from patient to patient. Contamination can also occur from contact between our equipment and a patient. Elderly patients can present with compromised immune systems, which places them at more risk of contracting infections. The same might be said for newborns or pediatric cases. An active program for controlling infection in your practice can help to minimize the spread of infection and keeps you and your patients safe.
There are several published sources on infection control including a book by Bankaitis and Kemp (2003) entitled Infection Control in the Audiology Clinic. Hand washing is the single biggest factor in controlling the spread of infectious disease. This can be an area that is overlooked in audiology practice. There are other common errors in infection control in addition to not washing hands between patients, such as handling unclean hearing aids. It is instinctive for us to hold out our hand to take the hearing aid when the patient takes it out of the ear and hands it to us. Know this - that hearing aid is not sanitary. The proper procedure would be to retrieve the hearing aid by using a small paper cup or a sanitary wipe. Handling unclean hearing aids is something to avoid because it easily transmits bacteria from the patient's ear to your hand and then, of course, to whatever else you touch if you do not wash or disinfect your hands right away. Patient contact areas including counters, chair rails, response buttons, or any surface touched by the patient should also be disinfected between every patient contact.
Another common error in regard to infection control is the infrequent changing of ultrasonic solutions. These should be changed after every cleansing. Any type of cerumen removal tool, otolight, or impression syringe that touched a patient or bodily fluid should be disinfected before reusing. Reusing insert earphones, tympanometry tips, otoscope specula, or real-ear probes among patients is not consistent with best practices in infection control. Another error would be the improper storage of clean or dirty tympanometry tips. You want to make sure you get the dirty ones to the ultrasonic cleaner with fresh solution. When the tips have been cleaned, they need to be dried and then stored and in a covered container. Wash your hands after handling tools and equipment. You might consider hanging posters or signs around the office as reminders, or you could do a ten-minute refresher training with your staff on a monthly or quarterly basis. Ensure that diligence in infection control is ingrained and a continuous part of the clinical setting.
Documentation and Record Keeping
The next area that we will discuss is medical records. In my experience of quality and clinical oversight, the maintenance of adequate documentation is one of the largest areas where there is much room for performance improvement. I think this is likely the case with most healthcare providers. It is impossible to develop an effective plan of care for any patient without first evaluating each patient's medical and audiology history. You have to ask the right questions to be in a position to determine the most appropriate direction of care, whether that is going to be hearing aids, assistive listening products, cochlear implants or any other type of medical-surgical intervention. That is why it is important that we explore every question in the case history and then document those answers into the record accordingly. It will save time and inconvenience in the future, especially if the file is audited by your regulatory agency or maybe a health plan. HearUSA has experienced, and continues to experience, numerous audits from insurance plans and Medicaid investigators. The extent and the quality of documentation plays an important role in assessing the type of a job we are doing and how effective we are in the delivery of care. Good recordkeeping helps us stay focused and develop logical plans for patient care.
Although documentation is time consuming, there are many reasons for taking the time to do it. It is relevant to have information available when you are reviewing the file and to develop the go-forward plan. Be reminded that patient files are legal documents, and they are subject to subpoena, audit and medical records exchanges. Your records are going to be viewed by other audiologists, physicians, and possibly lawyers, so your professional name and license number is attached to every aspect of every case. People will form judgments and opinions about your professionalism based on the documentation that they see.
Be very detailed in your recordkeeping. Make sure that you are noting exact hearing aid makes, models, circuitry, features and experiences of present and past hearing aid use. Document your recommendations and your prognosis for improvement. You may find it useful to look back on that information and use it as a counseling tool for managing expectations. If medical clearance is indicated by your test results, it is important to make an effort to obtain it and document it. Even if the patient signs a clearance or a waiver form, we need to take steps to bring medical opinion into the case if it is so indicated and explain why a medical waiver might be used in the presence of data that would suggest that medical treatment is indicated. If you have a patient who is challenging, has a complex diagnosis, or one that has a history of being dissatisfied with hearing aids, make your treatment plan more involved. You may want to consider bringing in a second opinion or consulting with a colleague, but always entering all of those conditions and any special steps that you took to address those challenges into the file. If a patient has an issue and you document that complaint into the file, also document your next step to close the loop.
The American Medical Association (AMA) provides guidelines for medical records. These entries should be present in your patient encounters for every date of service: the reason for the encounter, any relevant history, physical examination findings, any prior diagnostic test results, your assessment and diagnosis, impression, and your rationale for ordering medically necessary supplies or devices. Note the patients' progress as they follow your plan of treatment; enter that subjective piece into your notes. Detail what your next steps will be as part of the care plan, even if it is a six or twelve-month re-evaluation. Always have the date of service entered into the file and have legible identity of your signature or initials. Ensure that the date of service is authenticated.
Common deficiencies include illegible notes; handwriting is very important. If you are in a solo private practice and you only have to read your own notes it may not be that big of an issue. However, it can be an obstacle if someone else tries to read your notes, such as a colleague, physician, or attorney, and they are illegible. The most common deficiency that we come across in addition to illegible notes is incomplete notes such as those with missing signatures, or changes made to the medical record using White Out. If you make a mistake or change in the notes, the proper procedure is to use a single strikethrough and then initial the change in order to maintain the integrity of the document. When we get beyond audiology colleagues, there may be some difficulty with other medical providers understanding our symbols. AS and AD and greater than (>) and less than (<) are abbreviations that are often misinterpreted. Another type of error to avoid is bias or non-professional remarks in the clinical notes. Please be cautioned against doing that. If there is something you feel that needs to be remembered but does not need to be a part of the clinical record, consider using a sticky note separate from the medical record.
Some files are very disorganized and this can lead to clinical errors. Patient files that have the papers out of order or fall out when you open the file are not aligned with best practices for documentation. Organize any such patient files where this may be the case. We do not want to be too repetitive in our notes, as standardized notes that say the same thing for each visit may not be as thorough as is needed. However, some standardization is appropriate, but there should be some particular individual notations that are included so that notes don't appear rote. I will mention that the misuse of rubber stamped or electronic signatures is something to consider. Be aware of how and by whom your signature is applied to billing and other contractual agreements.
Wrapping up this area: Obviously, failure to document the visit at all is an issue. Make sure that the notes are comprehensive so another practitioner could follow the plan of care if the patient transferred out of your practice. Printing or saving the hearing aid programming sheets is really important. From a billing perspective, especially when dealing with Medicare and Medicaid, missing physician scripts or clearance forms can be problematic, particularly if you get into an audit situation.
There are certain state requirements that we all have to meet if we dispense hearing instruments. Your state may have requirements for the sales receipt or purchase agreement. Some patients may take their cases to small claims court. We have had dozens of civil cases where there is an arbitrator, and we have to then try to defend the case. Documentation in those situations is critical, such as your ability to demonstrate that you discussed certain things like satisfaction or the terms of purchase. Sometimes you are called to court long after the incident occurs. Memory will not serve you well in those cases, but good documentation will - establish that you have a process in place and you have done everything that you could to treat the patient professionally and fairly.
Dissatisfied consumers may also file action with state licensing boards. In this case, there is usually a written document from the health department or the licensing agency to the licensee asking for a response and supporting documentation. When you review your records, remember that if something was not written down, it did not happen. The time to incorporate a solid recordkeeping system is before a problem occurs, not after. We have seen investigations where patients allege that they were not treated correctly, they were misfit, or they try to return a hearing aid a year or two after purchase. Each of these required a detailed response to certain allegations, so the clinical notes and forms were very helpful. None of the licensing investigations in which HearUSA has been involved have resulted in disciplinary action to the provider. However, it takes time, money and experience to handle those cases, and it can also mean a loss of professional dignity in some instances.
Documenting patient confirmation regarding your treatment plan and recommendations as well as the terms and agreement of the hearing aid purchase is essential. Likewise, document any instance of a patient's refusal to seek your advice or follow your recommendations. A good tip here is to always have a next scheduled appointment, no matter how far into the future that appointment may be. This helps to preserve and demonstrate continuity of care.
One of the things often discussed in our field is the use of a binaural waiver. This is used by some providers when patients use a monaural aid when binaural amplification was recommended. I have not seen any cases where a monaural user seeks to recover damages because he or she did not hear a car coming or something along those lines. I think some people may find it a little adversarial with the patient, but if you choose not to use a binaural waiver then you absolutely should have the binaural recommendation clearly documented so as not to be disputed.
Cerumen Removal
Cerumen removal is an invasive practice. It presents the possibility of clinical error and subsequent malpractice litigation. Approximately 150,000 ears are cleaned of wax each week in the United States (Hain, 2008). In most cases it is a prerequisite to comprehensive patient care within hearing care practices, but in some states it is not always included in the scope of audiology practice or it may even be specifically excluded. Ensure that you know what your state guidelines are. If it is not within your scope and an adverse event occurs during cerumen removal, your malpractice insurance may not cover it. And, of course, if it is not within our scope then according to the state, then the patient has a stronger stance in seeking compensatory damages in the event of a complication. We need to be sure anyone performing cerumen removal, ourselves or someone working with us, has the proper training and skills. Office staff definitely do not have cerumen removal in their scope, even if you have trained them.
Besides formal training, there are some personal limitations that should be recognized. You have to have good vision and dexterity to be able to safely remove wax from the ear. You also have to have the right tools and equipment. This includes a stable and effective light source. There are obviously some contraindications for cerumen removal that should be considered on a case by case basis. Some of these include effusion, hematoma, unidentifiable foreign objects or surgical modification of the ear canal. Reconsider performing this procedure if your patient has diabetes, a suppressed immune system, bleeding disorders, or a lack of muscular control where you would need to constrain them to remove the wax. Another consideration would be if the patient has a history of or any pending legal proceedings.
What we have experienced to be the most common errors in regard to cerumen removal are, first, ignoring the contraindications. One thing that we use to preserve that contraindication process is a cerumen removal consent form. It asks for the patient to not only sign and give consent to remove the wax, but it also asks them specifically if they have any of the medical conditions stated previously. It gives us some specific information to have on file, and then we have the patient's signature. Other errors we see are neglecting to clean and disinfect the cerumen tools, improper storage of tools, and canal abrasions.
In 2010, HearUSA had two adverse events related to cerumen removal. Neither of these was serious. With that said, in the 20 years that we have been collecting data on this, we do have a recent case that suggested that there was a possible tympanic membrane (TM) perforation during cerumen removal. Our process is that we routinely do a pre and post-removal tympanogram so we can identify that the TM is intact. In one case, the pre removal tympanogram was Type A. Post incident, there was a 7.0 middle ear volume with a slight amount of blood appearing in the canal. Unfortunately, that could be our first significantly adverse experience with cerumen removal in over two decades, and we do not yet know full outcome because we have not been able to follow up directly with the patient.
Common Errors in Routine Audiometry
Our routine test battery is particularly susceptible to several common place errors. Incomplete or poor case history, which can lead to errors in testing interpretation. Supervision of students and externs is another potential place for errors to occur. When students are not properly supervised they may make mistakes. Remember as a supervisor that it is your name, your license, and your responsibility to ensure proper supervision. If you are supervising students and they are testing on your behalf, you need to make sure that your documentation is well supported. Additional testing errors include choosing the wrong test due to time constraints, over masking, misinterpreting test results, and not making a referral when it is appropriate to do so. When testing children or difficult-to-test patients, it can be an error if we do not keep them on task and obtain inaccurate test results. More common testing errors are improper placement of the headphones, which is typically a reversal problem, improper placement of the bone oscillator, poor or unclear test instructions, speech recognition testing at levels that are so low that we cannot get maximum performance, and failure to perform calibrations or listening checks. Calibrations and listening checks may seem tedious but something that we need to do. Reversal of the earphones is a careless error that we have observed, some resulting in pediatric patients fit inappropriately because the earphones. Even the most routine of cases requires our diligence as audiologists, because in truth, it is sometimes the sheer repetitiveness of routine that leads us to be negligent.
In audiometry, use the cross check principle and ensure that any discrepancies are corrected. For example, if we have a Type B tympanogram and present acoustic reflexes, something is wrong there. If you have air-bone gaps try some troubleshooting measures such as checking for collapsed canals or improper headphone placement to close the gaps. Make sure all of the pieces of data tie together before we make recommendations or send the patient to the next step in the treatment process.
Hearing aid dispensing is regulated through state licensure and registration in most states, and state laws will include requirements for audiometric testing and prerequisites to a hearing aid fitting. Those will typically include pure-tone air conduction testing, speech audiometry tests and measures of middle ear involvement. Some states require that testing is performed in a soundproof booth. Some mandate probe-microphone measurements for hearing aid fittings. It is important to be familiar with your state's licensing laws are and to incorporate them actively within your practice.
We all know masking can be complicated. Inaccurate testing due to improper masking can lead to recommendations that are inappropriate. Inadequate hearing aid fittings can occur as a result. It is important for hearing aid dispensers to make sure that when there are air bone gaps the patient is referred to an audiologist. When masking is involved the diagnosis may be more complicated or a medical issue may underlie the hearing loss, whereas the scope of practice for hearing aid dispensers is limited to testing for the purposes of fitting hearing aids.
Pediatrics is a specialized population, and as such, our procedures have to be modified accordingly in order to reduce risk and prevent clinical errors. We have to think quickly and use our clinical judgment when working with a child whose cognitive function precludes most standard test protocols. If you primarily work with adults or geriatrics, it is always a good idea to get second opinions from colleagues or other specially-trained pediatric audiologists in these cases. If we are dealing with multi-handicapped children or those with limited cognitive function, we want to make sure we have good recordkeeping and that we are taking extra measures to get that additional layer of support for our data. When fitting very young children with hearing aids, we typically want to follow them very closely to monitor their hearing status, as we often do not know the long-term stability of the hearing thresholds. We want to ensure that we are making the appropriate adjustments to the hearing aids as the children grow and their testing becomes more reliable and informative. Pediatric hearing aid fittings are much different than adult fittings, and we have to take into account the flexibility needed in a hearing instrument as a child grows, as well.
Medical referrals are an important part of our care process. It is good practice that we keep the physician involved when indicated, so we want to have practice guidelines in place to avoid the over or under-referring of medical care. When we under-refer our patients for physician intervention we might deny them the opportunity for the most effective and appropriate resolution to their hearing condition. If we over refer patients for medical care, it is costly and inconvenient. Have standard procedures in place for when to bring the physician into a case in a way that makes good sense and gives the patient the best outcome.
Ear Impressions
In our experience, the taking of ear impressions is by far the riskiest procedure that audiologists perform. With proper training and experience, ear impressions can be performed safely, and it is an integral part of our practice. We need to be diligent with ear impressions because it is an invasive procedure and can have unforeseen problems. Ear impressions require a conscientious approach to inspecting the ear canal and confirming the otoblock placement to avoid damage to the ear.
There is potential for damage to outer, middle and even inner ear structures when taking deep impressions. These complications include abrasions, trauma or lesions to the TM or middle ear ossicles, removal of pressure equalization (PE) tube, perilymph fistula with resultant fluctuating progressive or long standing sensorineural hearing loss, or concussive inner ear trauma accompanied by temporary or permanent threshold shifts. In order to avoid such incidents, we have to be very careful in the way we examine the ear canal and use a bracing procedure to avoid potential injury to the ear if there is any sudden movement. This is particularly important in the pediatric population. If patients are frightened or nervous or if they have compromised neuromuscular control, they may have involuntary movements which could cause us to inflict injury during the impression process. It is also critical to visualize the ear canal pre- and post-otoblock placement. Inspect the ear canal before placing the otoblock and then take another very close look after otoblock placement to make sure that it is completely occluding the ear canal so that the impression material cannot flow around or beyond it.
I can share with you some of the data that we have from 2010. We documented 13 incidents related to ear impressions, which represents the majority of our errors and over half the total incidents that we report on an annual basis. Unfortunately, it also has the most severe and adverse of outcomes. The most common are abrasions to the ear canal or an embedded impression. Those are typically resolved without too much distress or intervention, although others were more challenging that I will share with you.
Many years ago we had a 68-year old female with mild sloping to severe sensorineural hearing loss in both ears. Post ear impression there was reported pain and bleeding. The patient subsequently sought an ear, nose, and throat (ENT) physician's attention. The surgical report we received when the patient filed suit against us enlightened us to the fact that there was impression material that had adhered to the tympanic membrane that had to be removed under general anesthesia. The patient was left with feelings of numbness in the tongue and a distorted sense of taste. The hearing tests following the incident now indicated a moderate to profound mixed hearing loss in the left ear and on going complaints of dizziness. We settled the case for $100,000. The impression material remains embedded in the ossicles, which could be visualized during otoscopy. The physician felt that it would cause additional damage to try to remove that material from the ossicles.
In this next case, the patient presented with moderate to severe hearing loss in the incident ear and severe hearing loss in the other ear. Neither the audiologist, general practitioner nor the otolaryngologist could remove the impression. Eventually it had to be removed under sedation. The impression material had obliterated the tympanic membrane. It surrounded the ossicles and then entered the Eustachian tube. They had to remove an ossicle, which was subsequently replaced, and clean out the Eustachian tube. As a result, there were significant decreases in air-conduction thresholds in this ear which left her with a severe to profound mixed hearing loss. In addition, the patient had complaints of dizziness. We settled this case for $560,000. The audiologist was reported to national databanks for loss of clinical privileges and malpractice experience. We have to report people that experience certain events into these data banks. Going forward, we are required by our malpractice carrier to develop corrective actions for cases with negative outcomes. These types of situations resulting in large payouts contribute not only to the significant distress of the patient but also to the malpractice premium.
One final case to share with you: We have a patient that has twice encountered impression difficulty with us, and then visited us a third time for another ear impression. She first visited one of our offices in New York and we took an impression. It became stuck due to insufficient packing because she had a surgically altered canal with a large mastoid bowl. Beyond the first bend, the canal opened up. In these types of ears, the impression material enters that area and when attempting to remove it through the narrow part of the ear canal, it won't work. This happened on a Friday afternoon. The patient went to her general practitioner. He could not remove it. The ENT could not remove it. She had to go through the weekend with this impression still stuck in her ear. Understandably, it caused her a significant amount of discomfort. She ended up with some related cardiac issues and had to be hospitalized where they finally removed the impression in the emergency room without further incident. The patient subsequently came back to another office in Florida, and we had the same thing happen again with a different audiologist. The impression became stuck, and the impression had to be surgically removed again. The outcome of this situation was less than $10,000, fortunately, because we had a good long standing relationship with the patient and because there was no permanent damage or even injury to the ear. There was just inconvenience, what we would call pain and suffering. Within the past few weeks she came back to our office for a third time. She wanted to purchase another set of hearing aids. At this point we asked the patient to obtain the ear impression from an ENT physician, so we could make sure that we did not have another problem with this same situation. The tip here is to make sure you get the history of the patient and observe the canal very closely, then incorporate that information into your decision-making process with careful consideration and procedure.
We know of half a dozen cases where PE tubes have been inadvertently dislodged during the course of impressions. Usually these are swim mold impressions, and all the incidents involved children. In these cases the child experiences significant pain and bleeding. The parent is distressed, naturally. The physician is then not very pleased about this, and although it typically does not lead to long-term damage, it is a traumatic experience. This event happened just recently and the audiologist reported it to us in these words:
I did not see the gap between the cotton block/canal - allowed material to blow by the block. The reason I believe it was so serious is because it was a toddler, and the canal is so small that there is little margin for error. I have been doing impressions for 25 years. I should have been even more careful, but I am not sure that would have prevented the incident. I just didn't see the gap.
The reason we share this with you is to point out that even the most experienced can make mistakes with the most routine of procedures. Be very much aware of the risk associated with earmold impressions and minimize that risk the best way that you can. The lesson is that we have to be diligent with each and every case. Do not rush. Always visualize the block placement with very good lighting. At some point, maybe we will have digital scanning of the ears. If we can look forward to that, the digital scanning topography will remove those risks of ear impressions that we have.
Technology and Programming Errors
With the introduction of programmable and digital hearing aids we were given a new world of flexibility and possibilities. With this came the added complexity of continuously-evolving features and algorithms. Undeniably, digital hearing aids are a tremendous advantage for a number of very good reasons. That is not to say that the mere use of digital amplification alone will result in an improved patient outcome. We need to employ skills and techniques to result in the patient realizing those benefits.
One of the most common mistakes made in hearing aid dispensing is the overreliance on the first-fit algorithms. One online survey showed that 70% of the responding audiologists program their hearing aids using the manufacturer's first fit settings. Another report said that less than 12% of the targets on the manufacturer's fitting software screen match what is actually measured in the patient's ear (Stender, Appleby & Hallenbeck, 2011). Software varies considerably across manufacturers. We cannot assume that the norms developed in research facilities are going to apply to our individual patients in real life situations. We have to verify hearing aid fittings objectively with probe-microphone measurements. Assess each patient's results subjectively, and use those data to make knowledgeable decisions on the patient's behalf. Using first fit as a routine procedure leads to repeat visits, unrealized expectations and creates anxiety. In these cases it is a waste of clinician time to keep adjusting and counseling when the hearing aids have not been ascertained to meet the auditory needs. If we take the proper steps and utilize the data available from the equipment and the processes that we have, our fittings will be more efficient and accurate.
Other areas of potential pitfall with hearing aid fittings are failure to take into consideration previous amplification experiences, and failure to identify the patient's primary needs and expectations. These areas have a significant influence on the type of technology we select, as well as the ways in which we apply it. The best way to make use of the technology advancements is through a disciplined process of evaluating pre- and post-hearing-aid fittings. Analyze both the subjective and the objective data. In our experience, the most common hearing aid clinical errors are not saving the program into the hearing aid and delivering factory repairs back to the patient that are not programmed appropriately. Others include programming with an inappropriate compression strategy, not ordering appropriate options, not programming additional memories correctly, not incorporating past history into programming decisions, not entering bone conduction into the fitting software for mixed or conductive losses, and, again, over-reliance on first fit algorithms.
Here is a case that we can share from several years ago. An experienced audiologist was fitting completely-in-the-canal (CIC) hearing aids to a patient. The patient preferred to get CICs, but she had a long standing perforation in her left ear and had diabetes. As a result of trying to accommodate the patient, the audiologist fit the patient with CIC hearing aids, and within 90 days the patient had a fungus in her left ear. The closing of the ear canal with no venting and the diabetic predisposition to fungus led to a very negative outcome. It took 24 doctor's visits and the refitting to a behind-the-ear (BTE) hearing aid over an eight-month period to resolve the issue. That was a significant inconvenience to the patient. Consider the expense involved in the medical visits and lost time. The question that we have to ask ourselves is, "How could this course have been altered? Is there something that we should have done differently?" Should we have refused to fit the CIC hearing aid to the perforated ear? That is a decision that is always going to be best left to the discretion of the audiologist and the patient, but at the very least, we are suggesting that the patient should have had rigorous counseling about the importance of ventilating the ear and cleaning the hearing aid. The patient should have been fully advised on the importance of sanitizing the hearing aids, and then possibly incorporating some medical intervention to ensure that the perforation stayed dry with the hearing aid use. The take away: if you are pursuing a risky fitting, take care to implement and document precautionary measures.
Verification and Validation
Verification and validation are clinical tools that ensure the functionality of hearing aids as well as individual patient benefit. Verification techniques are primarily used to determine if the hearing aid meets a particular standard and is performing appropriately. A validation technique uses functional gain, speech perception, questionnaires, or interviewing techniques to determine how much benefit one is receiving from the hearing aids; however, neither validation or verification are consistently employed by all clinicians, even though they have been found to be correlated very strongly with user satisfaction. The biggest mistake one can make in terms of verification is simply not doing it. According to a 2009 study by Consumer Reports, 66 percent of the nation's hearing aids may be set incorrectly. Many industry surveys and studies have reported that real ear measures are conducted in less than half of all hearing aid fittings (Strom, 2006; Kirkwood, 2005; Kochkin et al., 2010). In the opinion of many this is a gross negligence, and it contributes to the lack of professionalism that is perceived by the consumer. When it is done, it needs to be done in a manner that achieves the goal, not just to check it off the to-do list.
The lack of objective data to verify the fitting throws into question the validity, efficacy and legitimacy of the hearing aid fitting process. In the practice of healthcare, pre and post measurements of conditions or treatment is a universally expected process. When we perform verification, we need to hold the results to a professional standard. We need to ensure that we are using soft, medium and loud inputs and yield acceptable outputs that are within the dynamic range of the patient. We need to provide adequate audibility, maximize intelligibility and maintain a zone of comfort for those patients. Restricted dynamic ranges can create distortion with amplification, and we need to adjust the fitting accordingly. We need to verify that features such as directional microphones are working as intended. With multi memory products or other features where a specific functionality is expected, we need to verify it. We have the responsibility to demonstrate how the hearing aid is performing in different settings, not just in the universal setting. Patients are paying us a significant amount of money for our services, so it is incumbent upon us to demonstrate that the hearing aids we select and recommend are providing benefit and meeting an objective standard. This also gives us the opportunity to make modifications or provide additional counseling and instructions.
There are several things we can overlook when programming hearing instruments: failure to verify settings or multiple programs, failure to interpret the output appropriately, not including bone conduction in the real-ear targets when a conductive component exists which alters the gain, and not using a modulated speech stimulus when verifying digital products.
With reference to validation, a common deficiency is the failure to employ a standardized measure for patient feedback. It is more of an informal process when we ask the patient for feedback or input into how the hearing aid feels and sounds and operates, but the opportunity for standardizing that process and collecting data in a written format is a clear performance improvement scenario for most practices. This can be done in ways that helps make a practice grow because you can aggregate the data to make some general assumptions or you might do a unique training program one-on-one with another clinician. If you have some peer review in your practice you can develop an open environment that is based on accountability and responsiveness to consumer needs. If you find 80% of the time our patients are reporting a certain piece of information and 20% of the time they are reporting another piece of information, that can be a pretty powerful set of data that can help us to make knowledgeable decisions and improve our clinical performance.
Electrophysiology
Suzanne Younker, AuD: The ABR is a test that is highly dependent on the equipment and how we set it up. It is an easy test for the patient who simply has to lie still. The audiologist has to ensure that we have certain things in order. First, our electrode placement has to be appropriate depending on if we are doing one-channel or two-channel recordings. We need a very low impedance to collect our responses accurately so we have to prep the skin appropriately. Certainly there is a difference prepping a newborn versus an adult. I learned early in my career that over scrubbing was probably a medical error because causing red marks on newborn skin is not necessary. You do not need to scrub that hard to get good impedance.
When you are using electrophysiology to make a diagnosis, it is your responsibility to make sure that the data collection is the best that it can be. This means acknowledging that we can manipulate our parameters and settings to achieve the best possible Wave V response. You do have to be cognizant of how the rate, gain, filters, and stimuli affect the recording. Take care not to manipulate your parameters so much that you create an error in collection.
Remember that the patient needs to be calm during testing. Pay attention to the patient's state - opening their eyes or clenching teeth may cause a degradation of the morphology of the waves. Most of us today are using insert earphones or tiptrodes. Take into account that for these to be most effective, the ears need to be clear of cerumen. It does not take much cerumen to get into that insert and cause what looks like a conductive hearing loss or delayed latencies.
We have to know the middle ear status. We need to perform tympanometry prior to doing an ABR test to know how the waveforms might be affected. On a newborn who has failed a newborn hearing screening, make sure that you are collecting responses to click stimuli using rarefaction and condensation polarities. This allows you to see the cochlear microphonic and confirm the appropriate activity of the cochlea. I am on the state of Florida Children's Medical Services Audiology Review Committee, and we review pediatric audiologists in the state of Florida when they apply. We review applications and add them to a referral database for the state of Florida's Children's Medical Services. We look to see if audiologists regularly show an ABR with reversed polarity in their initial run to diagnose cochlear function and their ability to interpret those findings. That is a key component that we look for, and often times that particular piece is missed.
Identifying Wave V is a challenge in some instances. We do know with ABRs, particularly with high-frequency hearing loss, marking the IV-V complex is tricky because sometimes the waves blend together. Having an accurate marking is critical. Knowing the normative latency data in your particular clinic or population is a must. With pediatric testing, we see errors with latency and intensity. On the recording equipment, there is an initial recording delay that can be adjusted. If it is set too high, you will miss seeing the cochlear microphonic. The cochlear microphonic occurs between 0.4 and 1.5 ms, so you do not want to cut it off too early.
Here is a case study that was shared with us by another facility. The patient was a four year old male who had been using hearing aids for two years. He did not have any language that was understandable by others outside of his family. His communication was more behavioral than actual speech or language. He also had tantrums and was refusing to wear his hearing aids. He was diagnosed with an autism spectrum disorder. He had very inconsistent behaviors in the soundfield, and an ABR at the age of two suggested he had severe sensorineural hearing loss. When we look at the latency-intensity function we want to say that they probably followed Wave V and identified a Wave V that would indicate that severity of the loss. The parents continued to report that speech and behavioral therapy are not helping. There was a recommendation for a re evaluation at another facility than the original facility. Sure enough, the evaluation reports indicated poor reliability for behavioral testing. The speech awareness threshold came in at about 65 dB HL, but they were not getting consistent threshold responses. Tympanometry indicated normal middle ear function and absent acoustic reflexes. Otoacoustic emissions (OAEs) were tested and were very robust from 500 to 8000 Hz. This is a red flag. How does that happen? When the ABR was re-tested, a very clear cochlear microphonic was seen but with no waveforms. Traditionally, when you have severe sensorineural hearing loss you will not see the cochlear microphonic, thus confirming the cochlear site of lesion. This child was actually re-diagnosed with auditory neuropathy and was recommended for a cochlear implant consultation. When dealing with the infant population it is critical that we understand what we are doing, how we are doing it, why we are doing it and what are the best recommendations for a positive patient outcome.
Vestibular Cautions and Errors
When we talk about vestibular electrophysiology, we are providing physical changes to the patient that we can record. We are directly involved in the patient's physical state, and that can be an invitation for many different errors to occur. Certainly we want to make sure that we have provided those patients undergoing electronystagmography (ENG) or videonystagmography (VNG) specific instructions regarding medications. We may want them to abstain from taking certain medications if they can avoid it, avoid caffeine and limit food intake, or whatever your particular pre-testing protocol calls for. The reason for such protocols is that we do not want something interrupting the stimulus that we are trying to elicit. Again, different practices may provide different test preparation instructions, and it is important to interview your patients very explicitly prior to testing to make sure the instructions were followed. I once interviewed a patient, asking if he had had any caffeine or alcohol within the past 24 hours, and he denied it. Upon further questioning he said he did not have alcohol, but he did have a beer the night before. Taking a thorough case history and understanding what you are dealing with will obviously help you make the best recommendations and interpretation of the results.
The physical well being of the patient is certainly a primary concern. In vestibular testing, we manipulate the patient's head and body. We need to know if they have any issues with movement. Some people might be wheelchair bound or have challenges with neck or back movement. If we take the right precautions and case history, we are going to be set up to do the test appropriately. The room light needs to be the appropriate dimness for an ENG; if you are using goggles for a VNG that is not so much a concern. Be sure to assess the patient's medication intake and if they have taken something, make sure you document it.
Because vestibular testing is more of a physical type of test, we need to be aware of how we are feeling. Are we fatigued? Tired, stressed or not feeling well, might hinder your ability to move a patient rapidly or task them sufficiently. Sometimes the repetitiveness of doing these tests may lead to errors. Although we might have done hundreds of ENGs in our career, this is the one and only ENG that each patient will experience, and they are looking to you to be at your best to provide it. I think tasking is the most difficult challenge when doing ENG because some patients can fly through and count backwards by 2 from 100. Some patients cannot. We have to understand each patient's level of education and comprehension. Tasking the patient with something familiar to them is good so they will be preoccupied and not inhibit the vestibular response, especially during calorics.
The last thing regarding ENG on which I would comment is that we probably do not make enough referrals for further testing. We cannot be experts in everything. If we feel that we are not able to provide all the services required for a particular patient, referring to a nearby clinic with expertise in that area is favorable for the patient. I once tested a very dizzy patient with extreme vertigo for an ENG. I thought for sure I would be able to see something on my calorics, but all of the traditional tests came out normal. The only thing that was very odd to me was his eyes moved very rapidly every time he closed them. At the time, we did not have vertical electrodes, only horizontal, and all I was picking up was this erratic movement. I thought it was my equipment. I could not figure it out, but I knew it was something abnormal. I stated in the report that the ENG information was essentially normal, but this erratic eye movement was definitely not typical. He was eventually referred to the University of Miami and was found to have a basil cell carcinoma from heavy smoking. The moral of the story is that we do not want an error to be that we do not refer out for things that we are not comfortable with.
The patient's behavior could be a possible error, as well. Certainly they are going to have some anxiety. They may have never had an ENG before, so understanding that and being able to talk them through the test will improve the integrity of the responses we want to get. Does the patient have any neck or back injuries that will limit the range of motion required for testing? Many older patients might not be able to lay back very quickly during a Dix Hallpike maneuver. Are there visual hindrances with the goggles that may impede the patient's ability to see the target? If you are tasking a patient with hearing loss, be aware that they might not hear you well enough to answer the questions effectively, especially beyond the high noise during calorics. Consider if there might be a language barrier. If you live in a particular area where you might see a certain population, having a few key instructional phrases in the native language is a must because you do not want lack of communication to be a reason why you were unable to get the data that you need.
Eye blinks can cause errors. Knowing the difference between an eye blink and nystagmus is, in my opinion, the hardest thing for new clinicians to learn. Our computerized systems are much better at discerning that, but a clinician still needs to be knowledgeable about seeing erroneous eye movement versus true nystagmus so a misdiagnosis does not occur. You cannot rush the length of the test. Sometimes we need to take longer than we would like. We need to base the length of the test on the patient's mental and physical status, and if we do not let the recording go long enough, we might miss a delay of onset or a reversal.
Another general error possibility includes not assessing the middle ear function. This is extremely important when performing caloric irrigation. Neglecting to close the goggles for no-vision tasks would cause inaccuracies in our recordings. Perhaps we are mistaking congenital nystagmus for a spontaneous nystagmus. When the patient is not accurately positioned, we have committed a physical error. When a patient has a physical condition, it limits our ability to perform the tests the way they are intended. Tasking is an integral part of the vestibular test battery, and if you are not tasking, you cannot elicit the response. Again, knowing your patient's background is going to help you to provide the best instructions to elicit the needed responses.
Finally, observing how your patient moves and their natural physical state is important before and during the test session. As you know, patients experience vertigo because we put them in a particular position, and what do they want to do? They want to get out of that position. They want to sit up. They want to turn their head. Paying attention to each patient's physical status, instructing them and walking them through the vertigo they might experience is critical. If they move, we have just interrupted again the validity of our response.
Performing otoscopy in order to observe the angle of the canal and the best pathway to the TM is important. When you perform the calorics, it is important that you use the appropriate irrigation time, pressure and temperature. You must allow the vestibular system to rest in between irrigations. Remember that if you get absent bithermal calorics, you have to follow through with ice calorics.
Here is a case study of a 58-year-old woman with a recent onset of vertigo. Ocular motor testing results indicated poor pursuit and abnormal saccades. No spontaneous or gaze nystagmus was noted. The positional tests were unremarkable, but the calorics showed a right unilateral weakness. I believe she was given some medications, but the vertigo still persisted. She went to another facility, and they repeated the vestibular testing. This battery included VNG and platform posturography. Not every facility has posturography at their fingertips, but in this particular case it was the unilateral weakness and the abnormal saccades that triggered somebody to perform the posturography. The results from this second vestibular assessment showed corrective and slowed saccades on the VNG, but other findings were essentially normal. Posturography indicated a central pattern on the Sensory Organization Test (SOT). The conclusive diagnosis was a cerebellar disorder. This kind of disorder was one that could not have been made with the VNG alone. If you need additional resources when you are treating a patient, remember that it is okay to refer. The vestibular assessment can be very complex. We know all the pieces of the puzzle have to be in place before we can make a clear diagnosis. VNG alone is not always enough.
If you are doing Vestibular Evoked Myogenic Potentials (VEMPs), you have to watch the placement of the electrode and ensure that it is in the belly of that sternocleidomastoid muscle. We are testing an elicited response that is measured directly from that muscle, so we have to be diligent in our test preparation and setup. Remind the patient to relax. We need to observe for inconsistent muscle contraction and note when the patient becomes fatigued. VEMP can be a very demanding, physical test for the patient. They need to lift or turn their head and hold it tightly for an extended period of time, and not every patient can do that successfully. Noting the patient's fatigue is the most critical thing that can be missed and cause an error in our results.
When performing rotary chair testing, secure the patient's body and head. We want to make sure that they are locked in and are not going to fall out, especially as they become dizzy and disoriented. The head has to be in a stable, constant position and fastening it to the headrest is the best way to ensure consistent placement with the appropriate 20-degree head tilt. If the chair is not moving or broken, it can look like absent responses. Be cognizant and pay attention to all the details, even if they seem minute.
For posturography, assure that the foot placement is correct and that the harness is the correct size and is fastened appropriately. Obtain a thorough case history. If not listed on the case history, ask about previous physical injuries that would preclude an optimal testing situation. Not recognizing a patient who opens their eyes when they are supposed to be closed is an error and changes the results. Posturography may be performed on patients who are suspected of malingering. Malingerers are more likely to do poorly on the easy tasks and better at the hard tasks. It is probably hard to fake that you are going to fall when you really do not want to fall. Knowing your patient, knowing the information, and being observant will always help and avoid the errors.
Over the course of our practice, we will see many people who suffer from tinnitus. It is important that if we are not particularly experts in tinnitus management that we, again, refer to a facility or another paraprofessional that can work with these patients. It can have a significant impact on the quality of life for these patients. Another case study was provided to us where a professional audiologist was aware that a patient had tinnitus, but basically told the patient in the counseling sessions to get hearing aids and learn to live with it. The patient was very grief-stricken from his wife being recently deceased, and the tinnitus, in his mind, had increased. The tinnitus caused him such extreme disturbances almost to the point of wanting to take his own life. His daughter took him to another facility, and they did extensive counseling and found out he really needed psychological attention. . Know your strengths and weaknesses and you will definitely do your best for the patient.
In Summary
Cindy Beyer, AuD: Thank you, Suzanne. We will recap some of the generalities that we have covered, and then we will talk about a few of the things that you can do in the event that you do encounter an adverse event in your practice. We talked about working with age extremes (pediatrics versus geriatrics) and the fact that they usually require additional care and expertise. We talked about inexperienced clinicians and unsupervised externs who are likely to experience a higher degree of clinical error, and for that we need to be more watchful. For those of us who have been in the field for a while now, a lack of continuing education or quality learning experience may have left us with an inadequate field of knowledge and outdated information.
Unfamiliarity with state of the art equipment is an easy way to make errors. Some of the new pieces of equipment are very sophisticated with advanced features. It takes a certain amount of skill to be able to navigate those. If we are not completely competent or familiar with what our equipment can or cannot do, we may make errors to our patients. Any time we have fatigue or distraction, we can misdiagnose or make a clinic error. We talked about the importance of record keeping and how that could be useful in both guiding patient experiences as well as protecting us from liability.
At HearUSA, we have a systematic process of collecting data. In the past 24 years we have seen over one million patients and dispensed hundreds of thousands of hearing aids. We have a process where we centralize incident reports. We also centralize complaints and track them by frequency and type of complaint. We visit our patient care sites and do internal audits and chart reviews to quantify our performance, and as a result we have thousands of clinical and peer record review data. We have aggregated, analyzed and reported on it. We trend it over time.
What we are sharing with you today is 2010 data. We had 21 patient-care related incidents reported from our 177 locations. When compared to the almost 180,000 patient visits in a year that equals a little over one incident for every 10,000 patient encounters. It is pretty low. We have already acknowledged that audiology is a pretty low‑risk profession, but there are risks nonetheless. In total we have the 21 incidents. Thirteen of those were related to ear impressions, and most of those were abrasions to the canal. Two were cases of embedded impressions and two were trauma cases. We reported two incidents related to cerumen removal and they were both minor.
The point here is to actually measure and track the incidents. First you collect the data. Then you measure the data. Then you analyze it, trend it, and understand it. If you see anything that could be corrected through a change in a process or training programs, that is the opportunity for performance improvement. Even in the best of practices and despite our best efforts it is possible to have a negative patient outcome.
What do we do when we encounter an adverse event? One of the things that we want to do is make sure we fully document the circumstances and also the details of the event. This is going to be a very important part of the process of minimizing risk and making sure that the patient gets appropriate care, and then further making sure it does not happen again to the extent that we can control it. We need to follow up with a patient post-incident within a day or two, depending on the sequence of events, to find out what has happened. At HearUSA we use a third‑party to do that. We do not ask the clinician who was involved to make that follow‑up phone call. This is part of our data collection, however. We obtain the clinician’s viewpoint of what happened and the patient's viewpoint of what happened, and it is all documented.
During the course of the incident, demonstrate compassion and concern, and verbalize a blameless apology. “I am sorry this has happened to you. I apologize for this inconvenience.” We do not need to point fingers or try to analyze what happened in front of the patient. Just demonstrating that there is care and concern is a very, very good thing. Many states have what are called “I’m sorry” laws so that if you give an apology immediately following the event, anything else you might say cannot be used against you in a court of law. So, again, it is really important that the patient perceives that you want to help fix the problem and that you are not trying to sweep it under the rug.
A root cause analysis is a complete in‑depth investigation of what happened, why it happened, how it happened, and what the surrounding details are. At HearUSA we have a form that we complete on every incident and then we investigate thoroughly. We talk to the provider. We talk to the patient. We look at our existing processes. We look to see if there are other similar situations or incidents so that we can identify any patterns. These reporting systems place accountability where it belongs and help us identify opportunities to improve safety. Here is a tip when it comes to investigating impression incidents that you would want to include on your root cause analysis. When you are doing the documentation, include the batch and the lot numbers of your impression materials on the root cause analysis form. That may or may not be significant, but you always want to do that. There have been cases where certain batches of impression material did not cure properly, so you want to keep that as a matter of documentation.
Another thing to remember is to keep the details of the incident separate from your medical record. Do not put your root cause analysis or your incident report form into the medical record. Remember, patients have access to their medical records. You would not want internal reports to become part of the permanent patient record that is transferred or read by other providers or the patients themselves. These reports should be filed in a separate internal operating file because then it is not part of the patient record, and it is not subject to subpoena and other record-retrieval types of processes. Our advice is to air on the side of conservatism and complete a report even the mildest concerns. You will not remember details weeks down the road if something comes to pass, and therefore you will have your documentation if needed.
If you have risk management resources available to you, you will want to coordinate with them and seek their advice along with any other in-house or legal support such as the circumstances warrant. Here is a note of caution to you. Work out a mechanism of communication with your insurance company. We have learned this. If there is a patient incident and that you believed was contained and chose not to alert your malpractice carrier, they might not cover it if the patient files suit down the road. This is kind of a tricky thing. On the other hand, if you notify them of everything your rates will go up. If you do not notify them of something that is potentially litigious, they may not cover it because of the fact you did not report it to them within 30 days. You want to work out that mechanism of communication ahead of time. Sometimes we say to our insurance company, “This is for notification purposes only. We are not anticipating action by the patient. Just to be on the safe side, we are putting you on the alert that this happened.”
There are a few additional reminders about improving patient safety. It is always worthwhile to find out why the event happened. It is always worthwhile to strategize about new methodologies. Sometimes it is appropriate to develop new tools then test to measure if those strategies are, in fact, helpful in improving patient safety. Try to create a culture where people are interested in quality of care and can discuss near misses, risks and problems. We would not want to foster a culture where people avoid accountability or responsibility when things do not go quite as expected. Patient education is an important part of that process. Quality oversight is necessary. If you do not look for things, you might not find them, or when you do find them you may be too far down the road to manage them appropriately.
In closing, routine visits and procedures are not always routine. We need to take good care, and to use a disciplined process to ensure minimal risk to both patients and to ourselves. We need to handle adverse incidents with concern and professionalism to the best probable end. Train, train and re-train, and foster a culture of excellence.
References
The 2005 Florida Statues Chapter 766 Section 102. (2005). Retrieved on January 5, 2006 from www.flsenate.gov/statutes/index.cfm
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Bankaitis, A.U. & Kemp, R.J. (2005). Infection control in the audiology clinic (2nd Edition). St. Louis, MO: Auban.
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Kirkwood, D. (2005). Survey: Dispensers fitted more hearing aids in 2005 at higher prices. Hearing Journal, 59(4), 40 – 50.
Kochkin, S., Beck, D. L., Christensen, L. A., Compton-Conley, C., Fligor, B.J., Kricos, P.B., et al. (2010). MarkeTrak VIII: The impact of the hearing healthcare professional on hearing aid user success. Hearing Review, 17(4), 12 – 34.
Stanger, T. (2009, July). Hear well in a noisy world. Consumer Reports. Available from www.consumerreports.org
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Strom, K. (2006). The HR 2006 dispenser survey. Hearing Review, 13(6):16-39.
