Hideko Heidi Nakajima

Hideko Heidi Nakajima


Prominent publications by Hideko Heidi Nakajima

KOL Index score: 14521

OBJECTIVES: Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an air-bone gap at the low frequencies on audiometric testing. The mechanism causing such a gap has not been well elucidated. We investigated middle ear sound transmission in patients with LVAS, and present a hypothesis to explain the air-bone gap.

METHODS: Observations were made on 8 ears from 5 individuals with LVAS. The diagnosis of LVAS was made by computed tomography in all cases. Investigations ...

Known for Bone Gap |  Aqueduct Syndrome |  Large Vestibular |  Low Frequencies |  Middle Ear
KOL Index score: 13753

OBJECTIVE: The goal of the present study was to investigate the clinical utility of measurements of ear-canal reflectance (ECR) in a population of patients with conductive hearing loss in the presence of an intact, healthy tympanic membrane and an aerated middle ear. We also sought to compare the diagnostic accuracy of umbo velocity (VU) measurements and measurements of ECR in the same group of patients.

DESIGN: This prospective study comprised 31 adult patients with conductive hearing ...

Known for Conductive Hearing Loss |  Umbo Velocity |  Ossicular Discontinuity |  Preliminary Study |  Canal Reflectance
KOL Index score: 13336

HYPOTHESIS: Round window (RW) stimulation with a floating mass transducer (FMT) can be studied experimentally and optimized to enhance auditory transduction.

BACKGROUND: The FMT (MED-EL Vibrant Soundbridge) has been recently implanted in patients with refractory conductive or mixed hearing loss to stimulate the RW with varying degrees of success. The mechanics of RW stimulation with the FMT have not been studied in a systematic manner.

METHODS: In cadaveric human temporal bones, ...

Known for Floating Mass Transducer |  Window Stimulation |  Fmt Rw |  Temporal Bone |  Sound Pressure
KOL Index score: 12645

OBJECTIVE: This study compares measurements of ear-canal reflectance (ECR) to other objective measurements of middle ear function including audiometry, umbo velocity (VU), and tympanometry in a population of strictly defined normal-hearing ears.

DESIGN: Data were prospectively gathered from 58 ears of 29 normal-hearing subjects, 16 females and 13 males, aged 22 to 64 yr. Subjects met all of the following criteria to be considered as having normal hearing: (1) no history of significant ...

Known for Umbo Velocity |  Canal Reflectance |  Normal Hearing |  Middle Ear |  1 Khz
KOL Index score: 12572

We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. The technique we employ, which exploits microscale fiberoptic pressure sensors, enables the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. In our results, the sound pressure in scala vestibuli (PSV) was much ...

Known for Sound Pressure |  Temporal Bone |  Scala Vestibuli |  Stapes Velocity |  Round Window
KOL Index score: 12531

HYPOTHESIS: A superior semicircular canal dehiscence affects hearing by introducing a third window into the inner ear that 1) lowers cochlear input impedance, 2) shunts air-conducted sound away from the cochlea resulting in conductive hearing loss, and 3) improves bone-conduction thresholds by increasing the difference in impedance between the vestibule and the round window.

BACKGROUND: Superior semicircular canal dehiscence has been linked to a "conductive" hearing loss characterized by ...

Known for Semicircular Canal |  Window Ear |  Conducted Sound |  Chinchilla Model |  Loss Conductive
KOL Index score: 11875

After initially successful preservation of residual hearing with cochlear implantation, some patients experience subsequent delayed hearing loss. The etiology of such delayed hearing loss is unknown. Human temporal bone pathology is critically important in investigating the etiology, and directing future efforts to maximize long term hearing preservation in cochlear implant patients. Here we present the temporal bone pathology from a patient implanted during life with an Iowa/Nucleus ...

Known for Cochlear Implantation |  Delayed Loss |  Hearing Preservation |  Hair Cells |  Temporal Bone
KOL Index score: 11136

The cochlea is normally driven with "forward" stimulation, in which sound is introduced to the ear canal. Alternatively, the cochlea can be stimulated at the round window (RW) using an actuator. During RW "reverse" stimulation, the acoustic flow starting at the RW does not necessarily take the same path as during forward stimulation. To understand the differences between forward and reverse stimulation, we measured ear-canal pressure, stapes velocity, RW velocity, and intracochlear ...

Known for Forward Stimulation |  Round Window Rw |  Stapes Velocity |  Ear Canal |  Scala Tympani
KOL Index score: 10082

Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the ...

Known for Canal Dehiscence |  Intracochlear Sound |  Cochlear Partition |  Differential Pressure |  Effects Scd
KOL Index score: 9501

Superior canal dehiscence (SCD) is a defect in the bony covering of the superior semicircular canal. Patients with SCD present with a wide range of symptoms, including hearing loss, yet it is unknown whether hearing is affected by parameters such as the location of the SCD. Our previous human cadaveric temporal bone study, utilizing intracochlear pressure measurements, generally showed that an increase in dehiscence size caused a low-frequency monotonic decrease in the cochlear drive ...

Known for Canal Dehiscence |  Sound Pressure |  Patients Scd |  Hearing Loss |  Superior Semicircular
KOL Index score: 9377

Superior canal dehiscence (SCD) is caused by an absence of bony covering of the arcuate eminence or posteromedial aspect of the superior semicircular canal. However, the clinical presentation of SCD syndrome varies considerably, as some SCD patients are asymptomatic and others have auditory and/or vestibular complaints. In order to determine the basis for these observations, we examined the association between SCD length and location with: (1) auditory and vestibular signs and symptoms; ...

Known for Evoked Myogenic |  250 Hz |  Superior Canal Dehiscence |  Symptoms Patients |  Scd Syndrome
KOL Index score: 8172

OBJECTIVES/HYPOTHESIS: Preoperative clinical diagnosis of malleus fixation can be difficult. "Fixation" of the malleus can be caused by various disorders or diseases: fibrous tissue, bony spurs, and neo-osteogenesis around the malleus head or stiffening of the anterior malleal ligament. The conductive hearing loss produced by these disorders or diseases has not been well characterized. The study goals were 1) to determine the effects of various types of malleus fixation using a cadaveric ...

Known for Stapes Fixation |  Umbo Velocity |  Malleus Head |  Conductive Humans |  Anterior Malleal Ligament
KOL Index score: 7532

A human temporal-bone preparation was used to determine the effects of various degrees of artificial ossicular fixation on the sound-induced velocity at the input-side (the umbo of the malleus) and the output-side (the stapes) of the ossicular chain. Construction of various degrees of attachment between an ossicle and the surrounding temporal bone provided a range of reduction in ossicular mobility or "fixations". The results demonstrate different effects of the fixations on the umbo and ...

Known for Ossicular Chain |  Middle Ear |  Umbo Stapes |  Conductive Humans |  Temporal Bone
KOL Index score: 7000

OBJECTIVES/HYPOTHESIS: Although the theoretical risk of elevated temperatures during endoscopic ear surgery has been reported previously, neither temperature change nor heat distribution associated with the endoscope has been quantified. In this study, we measure temperature changes during rigid middle ear endoscopy in a human temporal bone model and investigate whether suction can act as a significant cooling mechanism.

STUDY DESIGN: Human temporal bone model of endoscopic middle ear ...

Known for Ear Surgery |  Temporal Bone |  Light Source |  Elevated Temperatures |  Endoscopic Middle
KOL Index score: 6847

Current clinical practice cannot distinguish, with any degree of certainty, the multiple pathologies that produce conductive hearing loss in patients with an intact tympanic membrane and a well-aerated middle ear without exploratory surgery. The lack of an effective non-surgical diagnostic procedure leads to unnecessary surgery and limits the accuracy of information available during pre-surgical consultations with the patient. A non-invasive measurement to determine the pathology ...

Known for Conductive Hearing Loss |  Acoustic Immittance |  Middle Ear |  Differential Diagnosis |  Temporal Bone


Hideko Heidi Nakajima: Influence Statistics

Sample of concepts for which Hideko Heidi Nakajima is among the top experts in the world.
Concept World rank
frequencies promontory velocity #1
surgically stiffened rw #1
impedances ear #1
drive cochlear #1
transmission mechanisms stimuli #1
intracochlear pressures velocities #1
new technique stimulation #1
volume velocity flow #1
oval window vibrates #1
pressures scala #1
input pressure drive #1
ear airconduction #1
hearing rw reinforcement #1
ear low frequencies #1
cochlear drive #1
velocity cochlear #1
rw sound #1
infrasound transmission #1
pressure eac #1
ear canal cochlea #1
years scala #1
velocities stapes #1
reinforcement hearing #1
microphone fully #1
implantable acoustic #1
reduced stapes motion #1
rw reinforcement #1
baha bandwidth #1
pressure scala vestibuli #1
twowindow #1
psv pst #1
cochlear pressures #1
decrease pdiff #1
compliant round window #1
sound transmission ear #1
simple twowindow #1
physiological leakage impedance #1
impedance scd #1
stimuli sophisticated models #1
sv scala #1
effects scd #1
scalae pressures #1

Key People For Umbo Velocity

Top KOLs in the world
John J Rosowski
middle ear tympanic membrane sound pressure
William Tower PEAKE
middle ear tympanic membrane malleus fixation
Saumil N Merchant
middle ear temporal bone tympanic membrane
Michael E Ravicz
middle ear sound pressure tympanic membrane
Richard L Goode
middle ear tympanic membrane stapes footplate
Hideko Heidi Nakajima
middle ear umbo velocity superior canal dehiscence

Hideko Heidi Nakajima:Expert Impact

Concepts for whichHideko Heidi Nakajimahas direct influence:Umbo velocity,  Middle ear,  Conductive hearing loss,  Acoustic trauma,  Temporal bone,  Superior canal dehiscence,  Superior canal,  Stapes velocity.

Hideko Heidi Nakajima:KOL impact

Concepts related to the work of other authors for whichfor which Hideko Heidi Nakajima has influence:Middle ear,  Round window,  Tympanic membrane,  Canal dehiscence,  Bone conduction,  Otoacoustic emissions,  Ossicular chain.



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Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States | Harvard Medical School and Massachusetts Eye and Ear | Massachusetts Eye and Ear, Boston, MA, USA | Department of Otolaryngology-Head and Nec

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