The overall goal of this procedure is to treat sudden sensory neuro-hearing-loss patients using a neuro-rehabilitation approach. This method can help answer key questions in the fields of otolaryngology, neurology, and rehabilitation therapy. The main advantage of this technique is that we can provide a safe, easy, inexpensive, and effective treatment option for patients with sudden sensory neuro-hearing-loss.
So, this method can provide insight into hearing loss. It also can be applied to other diseases such as tinnitus and disease. Demonstrating the procedure will be Kenichi Sekiya, an otolaryngologist studying with us.
Begin by obtaining an ear mold, portable music player, close type headphone, equalizer, and headphone amplifier. Prepare libraries of different types of music on the portable music player. Transfer music from CDs by placing the CD in the computer's CD-ROM drive and then use a sound-editing application to download the audio by selecting File and Extract Audio from CD.Next, confirm that the music covers a wide frequency range.
Select an entire wave form by clicking Edit, Select Entire Wave, then click Window and Frequency Analysis. View frequency along the horizontal axis and amplitude along the vertical axis in the Frequency Analysis panel. Finally, transfer the music files from the computer to a portable music player via a connection cable.
Use a pure tone audiometer to measure air and phone conductance hearing threshold levels in both ears by using a step size of five decibels in accordance with the modified Hughson-Westlake procedure. To measure hearing thresholds, begin by setting the frequency control of an audiometer to 1, 000 hertz. Then place headphones on the patient.
Monaurally, play sound to the intact ear with an intensity level of 50 decibels by pressing the Sound Presentation button for one second to give the patient the 1, 000-hertz tone. Wait for them to respond by either pressing a button or raising their hand. If the patient responds to the tone, continue to present softer tones, decreasing by 10 decibels each time until the patient cannot respond any longer.
If the patient does not respond to the initial 1, 000-hertz tone, present louder tones, increasing by five decibels each time until the patient is able to respond. Note the softest intensity level that the patient is able to respond to. To establish the hearing threshold at 1, 000 hertz, repeat the sound presentation at 1, 000 hertz until the same intensity level is noted by the patient three times.
Then, test frequencies at 2, 000, 4, 000, and 8, 000 hertz in the same manner. Next, retest the hearing threshold at 1, 000 hertz. Confirm that this threshold is within five decibels of the previously determined threshold at 1, 000 hertz.
Following this, individually test frequencies at 500, 250, and 125 hertz. Next, test the affected ear by only playing sound through the speaker of the affected ear. Repeat the threshold procedure in the same order for all the frequencies listed here.
Present a narrow-band masking noise to the untested ear, using the plateau method. If the difference between left and right hearing thresholds equals or exceeds 25 decibels at the lower frequencies or is greater than or equal to 40 decibels at or above 1, 000 hertz. To measure bone conduction hearing thresholds, place a bone conduction vibrator on the patient to test the intact and affected ear.
Apply a narrow-band masking noise to the untested ear in order to avoid cross-talk. Finally, plot hearing threshold levels on an audiogram form. First, plug the outer canal of the unaffected ear using an ear mold.
Tightly pack the ear mold into the outer canal to ensure that no space exists in the external auditory meatus. Then ask the patient to put on close type headphones. Monaurally play the selected music into the affected ear while the speaker on the other ear is kept silent.
Use an equalizer to modulate the sound level of each frequency according to a half gain"rule which states that the gain level is equal to half the amount of hearing level differences between ears at each frequency. Ask the patient to perform fine adjustments of the sound level and equalizer settings in order to make the music sound as natural and comfortable as possible. Then ask the patients whether they perceive the music with the affected ear in order to confirm that cross-hearing does not occur.
Inform the patients that they are permitted to receive standard therapy for sudden sensory neuro-hearing loss, or SSHL, in addition to this CIST protocol. Ask the patient to listen to music for six hours per day using the close type headphones. Allow patients to perform other tasks and segment the time spent listening to music if they choose.
Additionally, instruct patients to use the ear mold every day until they leave the hospital. Finally, every two days measure the air-conduction threshold levels of the affected ear, as previously described in the Measure Hearing Threshold Levels"section. Adjust volume and equalizer settings according to the half gain"rule and at the patient's comfort discretion.
In this protocol, a novel neuro-rehabilitation approach is tested on patients with SSHL. The canal of the intact ear of SSHL patients is plugged in order to motivate active listening using the affected ear and to promote cortical reorganization. At baseline, both the control group and the group with CIST therapy indicated no differences in hearing level.
However, after treatment, the second and third examinations were conducted and showed that hearing in the affected ear had improved at all frequencies for both groups. Furthermore, significant differences of hearing levels between the affected and intact ears were observed between the two groups at the second and third examination. Once mastered, this technique can be done easily and safely.
While attempting this procedure, it is important to remember to avoid noise trauma and cross-hearing. Other therapies, like corticosteroids, can be performed in addition to this procedure. After its development, this procedure paves the way for researchers in the field of neuroscience to explore behavioral therapies against diseases that are related to maladaptive cortical reorganization.
After watching this video, you should have a good understanding of how to perform the constraint-induced sound therapy for sudden sensory neuro-hearing-loss.
