Kam Mirmelstein Lemberger was the second person in the U.S. to be diagnosed in 1975 with what came to be called “ultra-audiometric hearing.”1This is a condition in which the patient's audiogram reflects inner hair cell sensitivity around 70-80 dB HL from 250 to 8000 Hz, but rises rapidly to virtually normal sensitivity between 10,000 and 15,000 Hz. This unique sensitivity was often missed and the patients were fitted, usually unsuccessfully, with hearing aids that rolled off at 3000-4000 Hz and with closed molds. The closed mold served to mask the ultra-high frequencies the patients used to support lipreading. For this and other reasons, these patients never successfully adapted to hearing aids.
The Kresge Hearing Research group at LSU's Medical School in New Orleans (Berlin, Cullen, Halpern and Killion, on loan from Knowles Electronics) first recognized the condition and built an upward-shifting translator for her that shifted low frequencies into the more sensitive high-frequency zone. The first person to be correctly diagnosed, a Gallaudet graduate who received the initial upward shifting translator, now successfully uses a cochlear implant. But Kam has continued to use the translator to this day. (See Time Magazine February 1982).
Unfortunately the translator device was aging and losing reliability. The story picks up here.
On January 16, 2009, we had our first experience with an experimental device custom-designed for Kam to manage her unusual hearing loss, residual ultra-audiometric hearing.1 This loss was originally managed by an upward-shifting translator designed by Henry Halperin, Jack Cullen, and Mead Killion to take low frequencies and shift them up into the highs.1,2 Many subsequent iterations of the device were built by Kresge engineers Pal Szabo and Han Wen to keep Kam and patients like her in usable hearing devices.
The major problem was this: Kam's hearing was normal above 10,000 Hz and any speakers used in hearing aids of the late ‘70s and early ‘80s rolled off at about 3000 to 6000 Hz. The earmolds blocked any unamplified usable sound from arriving unimpeded, so the patients simply could not hear anything usable with ordinary hearing aid systems of that time.
The beauty of the upward-shifting translators was that the BP 1912 speakers designed by Killion for Knowles Electronics had frequency response up past 12,000 Hz and could overcome the insertion loss of the mold while also giving the necessary amplification in the highs.
Over the years the translators aged (as did we all), so we needed to develop a new algorithm. The Kresge Lab let two separate contracts to private engineering companies (neither of them experienced in hearing aid work) to develop new versions. They were both unsuccessful, with the second engineer taking 4-1/2 years to produce a totally unrealistic device roughly 12 by 10 inches in size.
When Engineer #2 presented the device to Kam, Greg Siegle of General Hearing Instruments (GHI) in New Orleans was present as my consultant. Siegle, who was as taken aback as the rest of us by the sheer size of the device, suggested that he might try to make a device that would work for Kam. Keep in mind that the second engineer had taken more than 4 years to produce a huge and unwearable device. Siegle came up with a working model in 3 days!
Kam wore it from July 2008 through January 2009, giving the GHI team regular feedback through me until the final prototype was activated on January 16.
Kam's voice changes immediately when she hears well, and it was obvious that she could hear well within seconds of when the aid was turned on. I now have one deliriously happy patient who, after undergoing years of frustration and angst with poor hearing, can now hear herself and others around her with much greater ease.
The GHI team, led by Greg Siegle, Ed Desporte, Mike Major, and owner Roger Juneau, produced an exceptional device with two speakers embedded in a hard-backed shell. One speaker is designed for frequencies between 2200 Hz and about 13,000 Hz, and the other for much lower frequencies. The key ingredient to making the high-frequency segment work was the Digi-K amp and algorithm designed and built by Etymotic and used by GHI for years. The technical problems were formidable, but between the various expertises brought to bear they managed perfectly.
GHI has earned my respect for its innovative patient-centered care. They make me proud to have worked with them in New Orleans and thrilled to have them build this device for my patient and her successors.
1. Berlin CI, Wexler KF, Jerger JF, et al.: Superior ultra audiometric hearing: A new type of hearing loss which correlates highly with unusually good speech in the “profoundly deaf.” Otolaryngol
2. Collins MJ, Cullen JK, Berlin CI: Auditory signal processing in a hearing impaired subject with residual ultra audiometric hearing. Audiology