[Show abstract][Hide abstract] ABSTRACT: Diplacusis is defined as the phenomenon of hearing the same tone at different pitches in the two ears. Although binaural pitch-matching using method-of-adjustment has been employed in most studies, it is sometimes hard for subjects with impaired hearing to judge ‘equal pitch’ as one frequency. To resolve this problem, a modified pitch-matching test, in which the relation of pitch sensation between the two ears was assessed as a matched frequency ‘range’ using the randomized maximum likelihood sequential procedure, was developed. Eight subjects with unilaterally impaired hearing, as well as eight normal subjects, were examined to evaluate this new test procedure. In the present method, matched frequency is assessed as a frequency range, in which subjects cannot judge whether the pitch of the signal in one ear is higher or lower than that in the opposite ear. This method appeared to be useful for assessing the characteristics of diplacusis in subjects with impaired hearing as well as in normal subjects. Sumario La diploacusia se define como el fenómeno de percibir un mismo tono como frecuencias diferentes en los dos oídos. Aunque se ha utilizado en muchos estudios la equiparación binaural del tono por el método del ajuste, a veces es difícil que los sujetos con trastornos auditivos juzguen un “tono igual” como una misma frecuencia. Para solucionar este problema, se desarrolló una prueba modificada de equiparación de tonos, en la cuál la relación de sensación tonal entre los dos oídos se evaluó como un rango de frecuencias, utilizando procedimientos secuenciales aleatorios de máxima similitud. Se examinaron ocho sujetos con hipoacusia unilateral y ocho con audición normal para evaluar este nuevo procedimiento. Con este método, la equiparación de la frecuencia se evalúa como un rango de frecuencias, en el que los sujetos no pueden juzgar si el tono de la señal en un oído es más alto o más bajo que en el oído opuesto. Este método parece ser útil para evaluarlas características de la diploacusia en sujetos con trastornos auditivos, así como en sujetos normales.
International Journal of Audiology 07/2009; 42(6):297-302. DOI:10.3109/14992020309101321 · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position.
The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved.
The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression.
The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.
[Show abstract][Hide abstract] ABSTRACT: Computed tomography (CT) in the sitting position was useful for detecting patulous Eustachian tube (ET).
Tertiary referral center.
Eighty-seven patients divided into two groups. The patulous ET group consisted of 111 ears of 67 patients with patulous ET. The control group consisted of 30 ears of 20 patients without symptoms characteristic of patulous ET or abnormal findings in ET function tests.
CT was performed under the resting condition and during Valsalva maneuver (Valsalva condition). The multiplanar reconstruction technique was used to reconstruct 1-mm-thick gapless images parallel to and perpendicular to the ET long axis. The open tubal distance (OTD) and average ET-gram were examined.
The OTD was significantly longer in the patulous ET group than in the control group under both resting and Valsalva conditions (both p < 0.001). The OTD was also significantly longer under the Valsalva condition than under the resting condition in both groups (p < 0.01 in the patulous ET group, p < 0.001 in the control group). The average ET-gram showed an occlusive zone in the cartilaginous portion medial to the isthmus under both the resting and Valsalva conditions in the control group (n = 30). However, the occlusive zone could not be observed under either the resting or Valsalva conditions in the patulous ET group (n = 111). Completely patent (open) ET was observed with continuous hyperlucency from the pharyngeal to the tympanic orifices in 88 of 111 patients in the patulous ET group, but in none of the control group, indicative of 100% specificity.
Computed tomography in the sitting position employing Valsalva maneuver is useful for the diagnosis of patulous ET.
[Show abstract][Hide abstract] ABSTRACT: Binaural unmasking refers to the improvement in intelligibility under conditions of masking when a tone is presented out of phase rather than in phase. In the present study, binaural unmasking was evaluated using auditory-evoked magnetoencephalography (MEG) in eight healthy right-handed volunteers (7 males and 1 female, mean age 25.9 years). Peak latency and amplitude of the N1m response to tone bursts of 250 Hz (n = 8), 1000 Hz (n = 3), and 4000 Hz (n = 3) were measured under S0N0 (binaural phase difference was zero radian (in phase) for both stimulus sound and masker noise) and SpiN0 (binaural phase difference was pi radian (out of phase) for stimulus sound and zero radian for masker noise) conditions. The level of tone bursts was swept by 5 or 10 dB steps from the level of 20 dB above the psychophysical threshold under the S0N0 condition until no significant auditory-evoked field could be observed. Identical background noise was presented to both ears continuously at 50 dB SPL. N1m responses to stimuli at or above the psychophysical threshold were found bilaterally in all subjects except one who had only right hemispheric N1m. N1m response for the SpiN0 stimulus had larger amplitude and shorter latency than that for the S0N0 stimulus in each hemisphere and at each sound level. Neuromagnetic binaural unmasking was greatest around the threshold level, corresponding to psychophysical binaural unmasking; became smaller with greater stimuli, indicating the suprathreshold unmasking effect; and disappeared at around 15-20 dB above the threshold. Psychophysical binaural unmasking can be quantitatively evaluated by MEG in the auditory cortex level of the bilateral hemispheres.
[Show abstract][Hide abstract] ABSTRACT: Diplacusis is defined as the phenomenon of hearing the same tone at different pitches in the two ears. Although binaural pitch-matching using method-of-adjustment has been employed in most studies, it is sometimes hard for subjects with impaired hearing to judge 'equal pitch' as one frequency. To resolve this problem. a modified pitch-matching test, in which the relation of pitch sensation between the two ears was assessed as a matched frequency 'range' using the randomized maximum likelihood sequential procedure, was developed. Eight subjects with unilaterally impaired hearing, as well as eight normal subjects, were examined to evaluate this new test procedure. In the present method, matched frequency is assessed as a frequency range, in which subjects cannot judge whether the pitch of the signal in one ear is higher or lower than that in the opposite ear. This method appeared to be useful for assessing the characteristics of diplacusis in subjects with impaired hearing as well as in normal subjects.
International Journal of Audiology 09/2003; 42(6):297-302. · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It is well known that sound presented in the contralateral ear can elicit the activity of the olivocochlear (OC) efferent. In the present study, the effects of the addition of contralateral noise on the psychophysical measurements of auditory thresholds were investigated in human subjects with normal hearing. The results obtained in the present study indicate that the addition of contralateral noise at a level of only 20 or 30 dB sound pressure level (SPL) may cause a significant elevation of the auditory threshold in the mid-frequency area (usually 2-3 dB). When the level of contralateral noise was elevated, the elevation of the auditory threshold tended to be larger and the affected frequency area became wider. Although other factors that elevate the auditory thresholds, such as cross-talk effects and the acoustic reflex of the middle ear muscles, may be involved in the above-mentioned paradigm, especially when higher levels of contralateral noise are used, it is important to know the degree of OC-mediated threshold elevation in usual audiometric measurement.
The Tohoku Journal of Experimental Medicine 08/2003; 200(3):129-35. DOI:10.1620/tjem.200.129 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report a case of intramuscular hemangioma in the sternocleidomastoid muscle in a 12-year-old female. The tumor had slowly enlarged up to 35mm length in the left sternocleidomastoid muscle. MRI was a useful tool for both diagnosis and therapeutic planning. The tumor with surrounding muscle tissue was surgically excised, without excess bleeding. After the surgery, neither deformity nor functional problems of the neck have appeared in follow up.
[Show abstract][Hide abstract] ABSTRACT: Dynamic changes in the pharyngeal airway of patients with obstructive sleep apnea syndrome (OSAS) were evaluated by quantitating the findings of real-time imaging performed during wakefulness and spontaneous sleep by means of dynamic magnetic resonance imaging (MRI). Six patients with OSAS and 3 non-OSAS subjects, selected prospectively and randomly, underwent polysomnography and dynamic MRI. The cross-sectional areas of the soft palate and oropharynx and the anterior-posterior airway dimensions seen during wakefulness and spontaneous sleep were calculated by US National Institutes of Health imaging software. On the basis of a case control study, comparisons were made with age-matched and body mass index-matched obese non-OSAS snorers. Spontaneous sleep caused significant obstruction and narrowing of various sites of the pharyngeal airway in the OSAS patients, but not in the non-OSAS subjects. During wakefulness, the non-OSAS subjects showed no marked narrowing of the pharyngeal airways, whereas a transient but significant narrowing was observed in the OSAS patients. The mean values of both the cross-sectional area and the anterior-posterior diameter at the soft palate were significantly reduced by spontaneous sleep in the OSAS patients. Dynamic MRI in awake OSAS patients shows promise as a routine diagnostic tool for localizing the upper airway collapse for appropriate selection of surgical therapy.
The Annals of otology, rhinology, and laryngology 03/2001; 110(2):183-9. DOI:10.1177/000348940111000215 · 1.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent apneas during sleep, resulting in repetitive hypoxemia. The present study retrospectively analyzed subjective and objective assessments of the patients with OSAS in a relatively long-term follow-up. From February 1986 to August 1996, 53 patients received surgical treatment for OSAS and snoring. Thirty-seven (27 males and 10 females) out of 53 patients completed the questionnaire and postoperative sleep study was obtained in 6 patients. In 20 children (<15 years), snoring, sleep apnea, and daytime sleepiness completely disappeared in 12, 19, and 16, and improved in 8, 1, and 4, respectively. These findings confirm that tonsillectomy and/or adenoidectomy in children may be the first selection for treatment. In 17 adults, snoring, sleep apnea, and daytime sleepiness completely disappeared in 2, 5, and 8, improved in 11, 8, and 7, and was unchanged in 4, 4, and 1, respectively. The apnea index in adults was significantly decreased in both early and late postoperative periods. These results suggest that surgery is a satisfactory alternative for adult patients if performed accurate preoperative diagnosis of the localization of the airway collapse and careful long-term follow-up.
The Tohoku Journal of Experimental Medicine 12/2000; 192(3):165-72. DOI:10.1620/tjem.192.165 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The contraction of the stapedius muscle during the effort of vocalization was examined by measurement of acoustic compliance in subjects who had undergone laryngectomy or tracheostomy. No significant level of persistent compliance change was recorded in any of the subjects, indicating the absence of effective contraction of the stapedius during the vocalization effort. In two subjects who use an electrolarynx, although no significant compliance change resulted from the simple vocalization effort without the electrolarynx (no actual vocalized sound), a remarkable level of persistent compliance change was observed during the vocalization using the electrolarynx. These results seem to indicate that a simple vocalization effort without actual voice cannot elicit effective contraction of the middle ear muscles, and that sound generation during vocalization is essential for effective contraction of the middle ear muscles during vocalization, at least in some human subjects.
Hearing Research 12/2000; 149(1-2):248-52. DOI:10.1016/S0378-5955(00)00192-1 · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of the addition of contralateral noise on the level of distortion product otoacoustic emissions (DPOAEs) were examined. In the present study, the DPOAEs were recorded for a relatively long period (2 minutes), and the time-course of the effects of contralateral sound on the level of DPOAEs were considered. In general, the addition of the contralateral noise resulted in suppression of the level of DPOAEs. The time-course of this suppression appeared to depend on the level of the contralateral noise. When the level of the contralateral noise was low, the suppression of the level of DPOAEs seemed to be largely unchanged for at least 2 minutes. In contrast, when a relatively high level of contralateral noise was used, the suppression of the level of DPOAEs decreased with time.
The Tohoku Journal of Experimental Medicine 07/2000; 191(2):71-8. DOI:10.1620/tjem.191.71 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of the addition of contralateral noise on the psychophysical tuning curve (PTC) were examined in subjects with normal hearing. The masking threshold of the tail part of the PTC tended to decrease with the addition of contralateral noise, although the threshold reduction was usually less than 5 dB. On the other hand, the effects of contralateral noise were relatively small around the tip of the PTC contour. Focusing on the effects of contralateral noise on the masking threshold at the tail part of the PTC, the effects of changing the time between initiation of masking the tone and the presentation of the masked probe tone on the threshold reduction at the tail part of the PTC were also observed. The results indicate that the reduction of the masking threshold by the addition of contralateral noise tended to be larger when the presentation of the signal tone was delayed after the onset of the masker. Usually, when the signal tone was presented under conditions of the forward masking paradigm, the reduction of the threshold was most remarkable. Results obtained in the present study are discussed based on the known characteristics of the olivocochlear (OC)-efferent fibers activated by contralateral noise.
Hearing Research 05/2000; 142(1-2):63-70. DOI:10.1016/S0378-5955(00)00010-1 · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A 12-year-old female patient presented with unilateral sensorineural hearing loss. Distortion-product otoacoustic emission testing failed to reveal any measurable emissions in the affected side. MR imaging did not reveal labyrinthine malformation. Three-dimensional Fourier transformation-constructive interference in steady-state MR images showed a thin cochlear branch. We speculated that mumps infection or developmental malformation caused the unilateral sensorineural hearing loss.
American Journal of Neuroradiology 03/2000; 21(2):328-30. · 3.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Signal perception ability under conditions of a narrow band masker in subjects with hearing aids was examined using a theoretical model of the auditory nerve fibre (ANF) with a deteriorated tuning curve in addition to measurements of actual masking function in subjects wearing hearing aids. The results obtained indicate that the apparent masking function could be affected by the frequency-gain character as well as by the degree of compression. Usually, the compression-type of amplification with flat and/or high-frequency weighted characteristics improves not only the apparent thresholds but also the apparent masked thresholds under conditions of lower frequency masking. On the other hand, a low-frequency masker amplified by a higher gain with low-frequency weighted amplification could cause larger upward-masking effects on the signal perception of the higher frequency signal in some conditions. The present study may contribute to our understanding of the underlying mechanisms of the effects of different amplification by the aid.
[Show abstract][Hide abstract] ABSTRACT: DFN3, an X chromosome-linked nonsyndromic mixed deafness, is caused by mutations in the BRN-4 gene, which encodes a POU transcription factor. Brn-4-deficient mice were created and found to exhibit profound deafness. No gross morphological changes were observed in the conductive ossicles or cochlea, although there was a dramatic reduction in endocochlear potential. Electron microscopy revealed severe ultrastructural alterations in cochlear spiral ligament fibrocytes. The findings suggest that these fibrocytes, which are mesenchymal in origin and for which a role in potassium ion homeostasis has been postulated, may play a critical role in auditory function.
[Show abstract][Hide abstract] ABSTRACT: The effects of the cut-off frequency of the filtered broadband stimuli on the human acoustic reflex (AR) were examined to observe the relation between the area of excitation in the cochlea and the AR response. The results obtained have indicated that all the input from the cochlear region does not equally contribute to trigger the AR equally; i.e., there is a lesser contribution from the frequency region below 700 Hz.
The Tohoku Journal of Experimental Medicine 07/1998; 185(2):131-7. DOI:10.1620/tjem.185.131 · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Thirty patients suffering from habitual snoring were subjected to laser-assisted uvulopalatoplasty with a KTP/532 laser under local anesthesia. The patients selected for the present study had no complaints of severe sleep apnea. The surgical procedure included bilateral vertical incision through the palate at the base of the uvula with or without removal of the lower half of the uvula. Ninety-three percent of the patients showed apparent improvement of snoring following the operation. However, other sleep-related symptoms such as sleep quality and daytime sleepiness were not significantly improved. No major or critical complications such as massive bleeding and asphyxia occurred. Post-operative pain on deglutition disappeared in most patients 2 weeks after the operation. This procedure is safe, minimally invasive and effective for habitual snoring without apnea.