Hydroacoustic Sonification and Flow Pattern Investigation of Venous Pulsatile Tinnitus Using MEMS Hydrophone Sensing and Dye Flow Visualization Techniques: Pilot 3D Printing, Computational Fluid Dynamics, and Psychoacoustic Study

Abstract

indicates the hearing-related reference pressure in air in the unit of dB SPL (ref = 20 μPa). # indicates the pressure gradient from the inlet to the outlet of the transverse-sigmoid sinus.* The f requency matching was perfor med using 1/3 octave nar row-band noise with center f requency of 125/250/500/750/1000 Hz.

Time Series and Mel-frequency Cepstrum Coefficient Analyses of Venous Pulsatile Tinnitus Vascular Sound and Flow Velocity Sensed by Transcranial/Retroauricular Doppler Ultrasound Approaches

“…(6,15) Thus, if surgical reduction of the flow velocity is prioritized, the endoluminal stenting technique may be more suitable than the transtemporal technique since expanding the sinus lumen endoluminally is less likely to perniciously augment the intracranial pressure. (7,16,17) In contrast to transverse sinus stenting, using the transtemporal compression technique to reduce the flow velocity should prevent overcompressing the sinus lumen to avoid the iatrogenic cause of intracranial hypertension. (16) Nonetheless, the flow volume and/or flow velocity can be effectively redistributed or reduced locally after external compression, whereas local compression over the prominent transverse-sigmoid junction will not significantly impair bilateral flow dynamics in vivo.…”

“…This has been confirmed by some test subjects who found 1/3 octave narrow-band noise with 1 kHz center frequency resembling their PT during psychoacoustic frequency matching. (7)…”

“…(5,6) Vibroacoustic and hydroacoustic generation of sound are two major acoustic sources of venous PT associated with SSWAs. (7,8) As the sigmoid plate becomes dehiscent, the sound of sigmoid sinus vascular wall displacement (vibroacoustic source) secondary to flow impingement and blood flow motion (hydroacoustic source) is transmitted to the inner ear via the air-conduction transmission route. (9) Although the clinical association among SSWAs, transverse sinus stenosis, and idiopathic intracranial hypertension has been increasingly investigated and identified by clinicians, (4) no conclusion has been drawn on the correlation between hemodynamics and the acoustic production of PT.…”

“…(11) Doppler ultrasound examination of venous flow can be used to capture the in vivo hydroacoustic source of PT. (7,12) Since the depth and width of flow sampling are adjustable, different directions and locations of blood flow can be detected. (10) In previous studies, the vascular sound sampled at the upper IJV exhibited high accordance with participants' subjective perception of PT in terms of rhythm and frequency.…”

Retroauricular/Transcranial Color-Coded Doppler Ultrasound Approach in Junction With Ipsilateral Neck Compression on Real-Time Hydroacoustic Variation of Venous Pulsatile Tinnitus

“…In addition to the volumetric asymmetry and high sinus flow velocity that are commonly discovered in PT subjects with SSWAs, some authors also speculated that a regional complex vortical flow structure might engender PT ( Hsieh and Wang, 2020 ; Mu et al, 2020 ; Li et al, 2021 ). Considering that (a) the velocity profile varies among individuals with venous PT and (b) vortical flow structure emanates from the transverse–sigmoid junction with or without diverticulum ( Mu et al, 2020 ; Ding et al, 2021 ; Hsieh et al, 2021a ; Li et al, 2021 ; Qiu et al, 2021b ), it is, however, unclear how the velocity and diverticular vortex affect the hydroacoustic production of PT and how fluctuations in the cross-sectional area of the transverse–sigmoid sinus lumen affect the flow acoustics.…”