Chapter One:

[1]. Sensorineural, or nerve-related hearing loss, refers to damage either to the tiny hair cells in the inner ear or to the nerve pathways that carry sound signals from the inner ear to the brain. This type of loss is unlike the less common conductive hearing loss due to problems with the actual structure of the ear canal or the eardrum. Some of the most common causes of sensorineural nerve damage are a side effect of certain strong antibiotics, other ototoxic medications, such as what my mother took when pregnant with me, viruses, and Meniere’s disease. In older people this type of hearing loss is found to be caused by a lifetime of overexposure to loud sound.

[2]. If the lowest decibel range with which a person can hear sound falls between 26 and 40 decibels (dB), their hearing loss is considered mild. If a person’s lowest perceptible sounds fall between 41 and 55dB, the hearing loss is moderate. Between 56 and 70 is moderate to severe, and between 71 and 90 is considered severe. And if someone can hear only sounds louder than 90 dB, their hearing loss is profound. Hearing loss tends to be greater in the higher frequencies. Unfortunately, as speech falls within the mid to high frequency range, even a person with mild or moderate overall hearing loss can have trouble comprehending speech.

[3]. It was important for me to be fitted with a hearing aid right away to stimulate my remaining ear fibers with sound. This would have put the nerves to work, preventing them from irreversibly atrophying further through lack of use. Because I was already four years old when I got my first hearing aid, my auditory nerves had probably already irreversibly atrophied to some extent. For this reason, the audiologist recommended wearing a custom-made mold made for each ear and alternating ears every six weeks to give each ear some experience with hearing. The hearing aid, as big as a deck of cards, would clip onto my undershirt and connect via a cord to the mold which would fit snugly into one of my ears. This was 1954, and at the time, wearing two big clunky hearing aids at once was considered too cumbersome for a young, active child. I was eleven years old before the development of the much smaller, behind-the-ear power hearing aids, making it possible to wear two aids at once.

Chapter Seven:

[1]. For centuries, the first hearing devices were long ear trumpets. They didn’t actually amplify sound but functioned by collecting sound and funneling it down an increasingly narrow tube into the ear. With the Age of Invention and the advent of electricity, all this changed; in 1876 Alexander Graham Bell was awarded a patent for producing a simple receiver that could turn electricity into sound. Then the following year Thomas Edison, who himself had hearing loss, received a patent for inventing a carbon transmitter for the telephone, which amplified the electric signal and increased the overall decibel level by about 15dB. While this volume is not sufficient for most hearing loss, which needs an amplification of at least 30dB, the development of the carbon transmitter resulted in technology that led to carbon hearing aids. These employed a microphone made with a carbon block with cups filled with tiny carbon granules, allowing for currents that amplified the sound to an earpiece.

However, the sound was very scratchy due to the carbon granules, and they also produced a limited frequency range. They were used from 1902 until the 1920s when vacuum tubes were able to increase the amplification up to 70dB. These contraptions, though, were the size of a small bookshelf, and so were totally impractical. By the late 1930s technology improved enough for the development of the first truly wearable hearing aids. These hearing aids had an earpiece (a mold made to fit the outer ear), wire, and receiver worn clipped to the wearer’s clothing. The battery pack, however, was large, and had to be strapped to the user’s leg.

World War II was a time of tremendous technological innovation, and finally hearing aids were developed with circuit boards and button-sized batteries that allowed all the components to be combined into one unit, about the size of a deck of cards. The units were connected to the earpiece with a thick wire and were the type of hearing aids I had in my early childhood. However, these aids simply amplified the sound evenly across all frequencies, regardless of the level of one’s loss at various frequency levels. (The ability to adjust the volume at different frequency levels would come decades later with the advent of digital hearing aids.) And there wasn’t yet the ability to put a cap on the amount of volume at a given frequency level, so very loud sounds were extremely painful. That explained why I found very loud noises so distressing. Ironically, extreme loud noises while wearing hearing aids are a real problem for people with severe hearing loss because of the level of amplification required.

Chapter Eight:

[1]. In 1948, Bell Laboratories developed transistors, which led to a major improvement in hearing aids. Transistors replaced the vacuum tubes; they were small, required less battery power, and had less distortion. Eventually these aids were made small enough that two could be worn, one behind each ear. However, digital hearing aids with microprocessors allowing for audio signals to be separated into different frequency bands that offered fine-tune programming were still decades away.

Chapter Fifteen:

[1]. In 1997 my mother, Marianne Gerhart, was interviewed about her life growing up in Nazi Germany by the United States Holocaust Memorial Museum. The video interview can be accessed online through the following link: https://collections.ushmm.org/search/catalog/irn508410