Other People’s Ideas
Calvin Staples, MSc, will be selecting some of the more interesting blogs from HearingHealthMatters.org which now has almost a half a million hits each month. This blog is the most well read and best respected in the hearing health care industry and Calvin will make a regular selection of some of the best entries for his column, Other People’s Ideas.
“Other people's ideas” is the name of my new blog summary for Canadian Audiologist. I am honoured that this journal has asked me to review, and select some weekly blogs at www.hearinghealthmatters.org. I find them very useful clinically and a great stepping stone to greater academic work. Audiologists tend to spend a majority of their days testing hearing and fitting hearing aids so I thought this first blog would focus on what a majority of audiologists do regularly. Enjoy the blogs!
ROCKVILLE, MD–The U.S. Food and Drug Administration (FDA) issued a draft guidance document on November 7 designed to clarify “the distinction between hearing aids and personal sound amplification products (PSAPs), as well as the regulatory controls that apply to each.” It invited public response to the draft by February 5, 2014.
Entitled “Regulatory Requirements for Hearing Aid Devices and Personal Sound Amplification Products,” the document was published in the wake of numerous complaints from hearing aid manufacturers and dispensers about products being sold under the guise of “personal sound amplification products” (PSAPs) that really should be categorized and regulated as hearing aids since they are clearly being marketed to people looking for help with a hearing loss.
The existing 2009 FDA guidance document, states, “PSAPs are intended to amplify environmental sound for non-hearing impaired consumers. They are not intended to compensate for hearing impairment.”
The manufacture, marketing, and distribution of hearing aids by licensed professionals are strictly regulated by both federal and state agencies, while PSAPs can be sold by anyone online, by mail order, or over the counter with minimal regulation.
In issuing the draft document, which would supersede the 2009 guidance, the FDA explained that it “has become aware of a lack of clarity regarding how the agency defines a hearing aid versus a personal sound amplification product (PSAP), which has also led, in some cases, to inappropriate application of regulatory requirements for such products.”
It added, “These inconsistent interpretations of the definitions may inadvertently result in hearing-impaired consumers bypassing safeguards that were implemented to promote the prompt diagnosis of treatable medical conditions causing hearing loss. To ensure consistent interpretation, consistent application of relevant regulatory requirements, and adequate protection of the public health, FDA seeks to further clarify the definitions of hearing aids and PSAPs.”
The draft document is in large part unchanged from the existing guidance. However, it includes a number of additions, including to the section about PSAPs. Along with re-stating that they are intended for “non-hearing impaired consumers,” the 2013 version expands this section to underscore the differences between PSAPs, which are not medical devices, and hearing aids, which are.
It states that PSAPs “are intended to accentuate sounds in specific listening environments, rather than for everyday use in multiple listening situations.”
It continues, “Examples of situations in which PSAPs typically are used include hunting (listening for prey), bird watching, listening to lectures with a distant speaker, and listening to soft sounds that would be difficult for normal hearing individuals to hear (e.g., distant conversations).
“Examples of listening situations that are typically associated with and indicative of hearing loss include: difficulty listening to another person nearby, difficulty understanding conversations in crowded rooms, difficulty understanding movie dialogue in a theater, difficulty listening to lectures in an otherwise quiet room, difficulty hearing the phone or doorbell ring, or difficulty in listening situations in which environmental noise might interfere with speech intelligibility. Products making these or similar claims should not be considered PSAPs. In addition, products that are sold as an “over-the-counter” alternative or substitute for a hearing aid should not be considered PSAPs.”
No “enforcement required”
One of the crucial similarities between the 2009 and the 2013 documents is that neither one requires the FDA to enforce it.
The current guidance says, “FDA’s guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the agency’s current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited.”
The 2013 draft states, “This draft guidance, when finalized, will represent the Food and Drug Administration’s (FDA’s) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public.”
Anyone wishing to suggest changes in the draft guidance or to offer other comments has until February 4. Written comments can be mailed to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. Those wishing to e-mail their comments should go to www.regulations.gov.
Implications and case management considerations for hearing care professionals
The World Health Organization (2012) estimates 35 million children have disabling hearing loss (greater than 30 dB) worldwide. In many of these cases, the hearing loss occurs with no previous family history and without a genetic cause. This includes viruses acquired in utero (before birth), at birth, and in childhood. Some of these cases can be prevented, while others can only be treated after the fact to reduce the long-term damage. In this article, we specifically examine some of the more common viruses and virus-related conditions that are associated with childhood hearing loss.
Because it is well known that there are far-reaching implications of childhood hearing loss, we’ll also consider current practice standards for identification and management of these children. Early identification and effective management of childhood hearing loss is critical for developing the best possible communicative, educational and social outcomes for children with hearing loss secondary to these conditions.
This condition is not a virus itself, but rather the secondary result of a virus, such as influenza or chicken pox. It can lead to inflammation in a child’s middle ear due to fluid buildup. Otitis media with effusion affects nearly 75% of children between one and three years old, and is the most common cause of hearing loss in children. It is important to note that otitis media episodes peak between ages 6 and 18 months (Slavin et al., 2005), a critical time period for auditory, speech-language and cognitive growth.
Most episodes of otitis media cause temporary conductive hearing loss (usually mild to moderate in degree). Hearing loss associated with otitis media is often fluctuating, varying in degree within and between episodes. It can also affect just one ear. This fluctuant characteristic, potential unilaterality and the frequency with which a child contracts otitis media have implications that may reach beyond just a sensory impairment. The American Academy of Audiology (1992) suggests this can contribute to the lack of a stable auditory base, which normally serves as the very foundation of communication and attention behaviours.
Treatment for otitis media can range from observation or antibiotics to surgical placement of ventilation tubes. Children considered at risk for otitis media should be screened for hearing, middle ear function and speech-language development. This includes children with history of contracting otitis media prior to age 6 months and those in multi-child daycare settings. Other risk factors include Native American children, those with cleft lip/palate, and those that present with Down syndrome. The American Academy of Pediatrics recommends hearing testing for children with otitis media that has persisted for three months or longer and that the placement of tympanostomy tubes are the preferred surgical intervention, when indicated.
Meningitis is an inflammation of the meniges, the membranes that cover the brain and spinal cord. It can be acquired directly or as a secondary infection from group B strep disease, a condition that can be transferred to babies before or during birth. In children, meningitis is the most common cause of acquired bilateral sensorineural hearing loss (Morzaria et al., 2004). Meningitis is extremely dangerous if left untreated, particularly within the first 24 to 48 hours of the illness.
Permanent sensorineural hearing loss in cases of bacterial meningitis is estimated to occur in between 5 and 35% cases (Fortnum, 1992) and can range from mild unilateral to severe and bilateral. It most often manifests in the early stages of the infection and immediate medical intervention can lower the risk of permanent hearing loss. The does not belie the need for continued audiological monitoring of these children, as there are some cases where the hearing loss can be delayed in onset. From an audiological perspective, treatment can be complicated in cases when the hearing loss is of sufficient severity to indicate cochlear implant candidacy. The potential for rapid cochlear ossification in post-meningitic children can affect success of implantation (Durisin et al., 2010).
If a child experiences a high fever that comes on suddenly, flulike symptoms, and a rash, immediate medical treatment is indicated.
Routine immunizations are available to guard against meningitis. Some of the viruses associated with meningitis are very common. Therefore, good hygiene practices and avoiding those infected can prevent the spread of the virus.
Measles, Mumps, and Rubella (MMR)
These viruses are all associated with sudden hearing loss. Once commonly acquired during childhood, vaccinations are now routinely given to protect against contracting them or infecting infants in utero.
Measles is an extremely contagious and dangerous virus that can lead to serious complications, including swelling of the brain, clotting disorders, seizures and even death if left untreated. Sensorineural hearing loss secondary to measles infection is usually permanent, moderate to profound in degree, and affects both ears (bilateral).
Mumps affects salivary glands and is characterized by visible lower facial swelling. It can lead to serious complications, including encephalitis (swelling of the brain) and possible temporary or permanent hearing loss. Hearing loss secondary to mumps is often unilateral (affecting only one ear) and can be profound in degree.
Congenital rubella syndrome, like CMV (see below), is passed from an infected mother to her baby. A mother’s infection during the first trimester presents the most risk. Hearing loss associated with congenital rubella can cause severe and bilateral hearing loss.
There have been rare cases where hearing loss is suspected to be caused by the actual vaccine against MMR. This risk can be weighed against the vaccine’s very effective prevention of these life-threatening diseases. Parents should be encouraged to discuss the potential risks specific to their child with their pediatrician prior to immunization.
Cytomegalovirus (CMV) is actually a very common virus to which many adults have already been exposed and experience no symptoms. CMV can be dangerous when infecting a pregnant woman for the first time, particularly during the first half of pregnancy. 40 percent of these cases will result in transplacental transmission of the virus to the baby and approximately 10 percent of them will exhibit symptoms of CMV at birth (Duff, 2010). Symptoms can include intrauterine growth retardation, hyperbilirubinemia, microcephaly, mental retardation, seizures and hearing loss. Infection can also be passed from mother to infant via contaminated blood or body fluids during birth or through breast milk; however these cases rarely result in any significant complications.
Thirty to fifty percent of infants with symptomatic congenital CMV and even about 10% of those that are asymptomatic at birth will develop hearing loss (Dahle et al., 2000). Hearing loss secondary to congenital CMV infection does not follow any common pattern with respect to degree or configuration. It can also be progressive, fluctuant or delayed in onset from the time of infection. The American Academy of Pediatrics recommends that children with congenital CMV infection should have their hearing tested every six months. They further suggest that at times when a change in hearing status is documented in a child the schedule for monitoring hearing change to every three months. The potential for progression of the hearing loss in this population should influence the hearing care practitioner’s choice in amplification, ensuring technology is flexible enough to accommodate the fluctuating or progressive tendencies in these children.
There is no vaccine against CMV at this time, but practicing good hygiene before and during pregnancy, including regular hand washing, safe sex, and taking extreme care if exposed to the blood and bodily fluids of others (particularly young children), can help reduce the odds of initial infection.
The viruses described in this article together account for the majority of non-syndromic, acquired hearing loss in children. It is critical that hearing care professionals serving the pediatric population be aware of these common viruses and the potential for hearing loss in those affected. This information can assist in making clinical decisions regarding audiological assessment and treatment plans.
Robert H. Margolis, PhD, University of Minnesota and Audiology
TEST YOUR KNOWLEDGE
- Who was the German inventor of the electrically driven tuning fork in 1863?
- What is this device, designed in 1879? (Image at right).
- What Iowa native received an Academy Award in 1959 for introducing sound to movies?
- Who was awarded the Nobel Prize in 1914 while a prisoner in a Russian POW Camp. He finished his career at the University of Uppsala.
- Who was hired in 1917 at the University of Iowa to develop hearing tests and test patients?
- This device was developed in 1919 by Schwarz (Germany), and commercialized by Medico-Technical Company in Berlin. What is this, and why was it unique? (Image at right).
- What was the price, and how many of the Western Electric 1A audiometers were sold (1922)?
- What was the first widely-used audiometer?
- Who published the first detailed paper on audiometric methods?
- The son of a prominent otolaryngologist claimed to have coined the word “audiometer.” Who was that person?
- Who published their “Manual for Rehabilitation of Aural Casualties” in 1944?
- The scientific basis of the Hughson-Westlake method, and recommended use for clinical audiometry, was published by?
- In what year was the first ANSI Standard Method for Manual Pure Tone Audiometry published?
- Who wrote: “The number of audiometric examinations made today has grown to such a magnitude that it is only natural that some of the techniques…should become automated?”
- Hermann Ludwig Ferdinand von Helmholtz invented the electrically driven tuning fork in 1863. It helped lead the way to electric measurement of hearing sensitivity. He was a German physician and physicist who made significant contributions to several widely varied areas of modern science. In physiology and psychology, he is known for his mathematics of the eye, theories of vision, ideas on the visual perception of space, color vision research, and on the sensation of tone, perception of sound, and empiricism. In physics, he is known for his theories on the conservation of energy, work in electrodynamics, chemical thermodynamics, and on a mechanical foundation of thermodynamics. As a philosopher, he is known for his philosophy of science, ideas on the relation between the laws of perception and the laws of nature, the science of aesthetics, and ideas on the civilizing power of science. His first important scientific achievement, an 1847 physics treatise on the conservation of energy, was written in the context of his medical studies and philosophical background.
- This is the Hughes Audiometer, developed in 1879 by David Edward Hughes. (a) and (c) are the two primary coils, and (b) is the secondary coil. A Hughes carbon microphone was attached to the clock. Of this device, Benjamin Ward Richardson (England), wrote: “The world of … medicine… is under a deep debt to Professor Hughes for his simple and beautiful instrument which I have christened the audimeter, or less accurately but more euphoniously, the audiometer.” (Proc. Royal Soc. Med., 1879).
- Lee de Forest received an Academy Award in 1959 for introducing sound to movies. He was an American inventor with over 180 patents to his credit. He named himself the “Father of Radio,” with this famous quote, “I discovered an Invisible Empire of the Air, intangible, yet solid as granite,” In 1906 De Forest invented the Audion, the first triodevacuum tube and the first electrical device that could amplify a weak electrical signal and make it stronger. The Audion and vacuum tubes developed from it established the field of electronics and dominated it for 40 years, making possible radio broadcasting, television, and long-distance telephone service, among many other applications. For this reason De Forest has been called one of the fathers of the “electronic age.” De Forest is also credited with one of the principal inventions that brought sound to motion pictures, most notable his Phonofilm process, a way to make the movies talk by adding a synchronized optical soundtrack to the film. For that 1920 invention, the first sound-on-film process, he received in 1959 an honorary Oscar from the Academy of Motion Picture Arts and Sciences. The inscription read: “Academy Honorary Award to Lee de Forest for his Pioneer Invention which brought Sound to the Motion Picture. Academy of Motion Picture Arts and Sciences, 1959.”
- Robert Bárány (Austria). In 1903, he accepted a post as demonstrator at the Otological Clinic under Professor Politzer. He followed up the theories of Flourens, Purkinje, Mach, Breuer and others, and clarified the physiology and pathology of the human vestibular apparatus. He was awarded the Nobel Prize for his work in this field in 1914. The news of this award reached Bárány in a Russian prisoner-of-war camp; he had been attached to the Austrian army as a civilian surgeon and had tended soldiers with head injuries, which fact had enabled him to continue his neurological studies on the correlation of the vestibular apparatus, the cerebellum and the muscular apparatus. Following the personal intervention of Prince Carl of Sweden on behalf of the Red Cross, he was released from the prisoner-of-war camp in 1916 and was presented with the Nobel Prize by the King of Sweden in Stockholm. Audiology remembers him also as the inventor of the Noise Box for audiometric masking in 1908.
- C.C. Bunch, in 1917. He developed the first sweep frequency audiometer.
- This was the first electronic audiometer with masking, an interrupter key to switch the test tone on and off in order to prevent auditory fatigue, and a Politzer balloon attached to a “pneumatic earphone” for threshold measurements under condition of altered air pressure in the external auditory canal (1919).
- This is the Western Electric 1A audiometer. This was the first electronic audiometer commercialized in the U.S. The price was $1500 and 25 were sold (1922). This was designed and developed by E.P. Fowler and R.L. Wegel.
- The first widely-used audiometer was the Western Electric 2A audiometer (1923). It ran on dry cells and was designed to meet clinical needs. In the early instruments, normal threshold values for each test frequency had to be established first to provide a reference. The instrument was limited to 8 frequencies at octave intervals between 64 Hz and 8,192 Hz. The intensity range was limited, and an additional booster amplifier was needed to determine the threshold of feeling.
- Dr. Isaac Jones (American otologist) and Dr. Vern Knudsen (American physicist) published the first detailed paper on audiometric methods in Laryngoscope, 1924.
- Maico (Medical Acoustic Instrument Company) was founded by Leland Watson. His claim to have coined the word “audiometer” is in question based on the 1879 comment by Benjamin Ward Richardson when speaking about the Hughes hearing measurement device (See number 2).
- Walter Hughson, M.D., and Harold Westlake, Ph.D., wrote about this in Supplement to the Transactions of the American Academy of Ophthalmology and Otolaryngology, 1944.
- Raymond Carhart, Ph.D. and James Jerger, Ph.D, published their paper in the Journal of Speech and Hearing Disorders, 1959. This continues to be the preferred method for hearing threshold determination.
- The first ANSI Standard Method for Manual Pure Tone Audiometry was published in 1978.
- This statement is attributed to Wayne Rudmose. He authored Chapter 2, Automatic Audiometry, in Modern Developments in Audiology, 1963, edited by James Jerger, PhD