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Background: Although many studies have suggested that air cells may play an important role in sigmoid sinus diverticulum and/or dehiscence (SSDD)-induced pulsatile tinnitus (PT), the exact effects remain unclear. This study aims to quantitatively investigate the effect of different degrees of pneumatization of temporal bone on sound transmission from the sigmoid sinus to the tympanic cavity., Methods: In the clinical study, 25 patients were enrolled to measure the sound intensity and frequency of SSDD-induced PT. In the experimental study, sound inputs at different frequencies at the dehiscent sigmoid plate were measured and compared among realistic object models of different degrees of pneumatization, when sound intensity in the tympanic cavity was fixed as the level of the PT sound intensity sensed by patients., Results: The sound intensity sensed by PT patients was 34.0 ± 13.0 dB SPL, which represented the sound intensity in the tympanic cavity transmitted from the dehiscent sigmoid plate. In the experimental study, when sound received in the tympanic cavity was fixed at 34 dB SPL, the mean inputs of sound intensity at the dehiscent sigmoid plate were 46.9, 46.2, 45.2, 47.1, 57, 57.4, and 74.1 dB SPL in a hypo-pneumatized model; 42.6, 43, 41.5, 43.2, 47.3, 58.2, and 78.8 dB SPL in a moderately pneumatized model; 52.6, 52.8, 48.1, 61, 64.2, 82.4, and >87.3 dB SPL in a well-pneumatized model; and 47.2, 46.2, 45.4, 49.4, 54.9, 66.6, and 77.7 dB SPL in hyper-pneumatized model, with increased sound frequencies (125-8000 Hz). The mean sound transmission distances were 41.7 mm, 45.2 mm, 47.6 mm, and 48.4 mm in successively better pneumatized models., Conclusion: Sound reduces while passing through air cells and attenuation is lowest in the moderately pneumatized temporal bone, followed by the hypo- and hyper-pneumatized temporal bones, and the highest in the well-pneumatized temporal bone. Lower-frequency sound attenuation (≤1000 Hz) is less than that of higher-frequency sound (>1000 Hz).

Objective: This study is to investigate the hemodynamic changes of pulsatile tinnitus (PT) patients induced by sigmoid sinus wall anomalies (SSWA)., Study Design: Prospective study., Setting: Tertiary referral university hospital., Patients: Fifteen unilateral PT patients with SSWA identified on computed tomography images and surgery and 15 age-, sex-, and body mass index-matched healthy volunteers underwent velocity-encoded, cine magnetic resonance imaging., Intervention: Hemodynamic data in sigmoid sinus were obtained from velocity-encoded, cine magnetic resonance imaging, and compared between PT patients and controls., Main Outcome Measures: Heart rate was recorded. Cross-sectional area (CSA), peak positive velocity (PPV), average positive flow volume per beat (APFV/beat), average flow volume per beat (AFV/beat), peak negative velocity (PNV), and average negative flow volume per beat (ANFV/beat) were measured. Average flow volume per minute (AFV/min), average positive flow volume per minute (APFV/min), average negative flow volume per minute (ANFV/min), average positive velocity (APV), average negative velocity (ANV), and regurgitation fraction (RF) were calculated., Results: APV at PT side of patients was 13.4 ± 3.3 cm/s, which was significantly slower than that at corresponding side of controls (15.8 ± 2.6 cm/s). PNV and RF at PT side of patients were 21.0 ± 15.4 cm/s and 2.4% respectively, which were significantly higher than those values at corresponding side of controls (both of them were 0). HR, CSA, PPV, APFV/beat, APFV/min, AFV/beat, AFV/min, ANV, ANFV/beat, and ANFV/min were 69.8 ± 9.4 beat/min, 48.4 ± 17 mm, 31.4 ± 5.9 cm/s, 5.4 ± 1.8 ml/beat, 373.9 ± 117.7 ml/min, 5.1 ± 2.0 ml/beat, 352.0 ± 134.6 ml/min, 2 (0-4.9) cm/s, 1 (0-2.7) ml/beat, and 4.1 (0-141.3) ml/min at PT side of patients, and 67.4 ± 7.8 beat/min, 38.2 ± 18 mm, 29.9 ± 3.9 cm/s, 5.3 ± 2.0 ml/beat, 350.3 ± 125.3 ml/min, 5.1 ± 1.9 ml/beat, 340.5 ± 117.9 ml/min, 0 (0-2.1) cm/s, 0 (0-0.8) ml/beat, and 0 (0-55.4) ml/min at corresponding side of controls. These hemodynamics were not significantly different between groups., Conclusion: APV, PNV, and RF changes take place in SSWA patients, which may be associated with the occurrence of PT and have the potential value to improve accurate etiological diagnosis and predict treatment success.

Pulsatile tinnitus (PT) is a common symptom in otology. In some cases, the venous flow in the sigmoid sinus (SS) is the source of PT. It is suggested that the venous sound is propagated into the tympanic cavity through the air pathway of temporal bone air cells (TBAC). The hyperpneumatization of TBAC was hypothesized as a direct pathology of PT through amplifying the venous sound, but there is no quantitative analysis. This study aims to quantify the relationship between the venous sound amplification and the pneumatization grade of TBAC. The acoustic numerical simulation and statistical analysis were performed based on the radiology data of 21 pulsatile tinnitus patients. The TBAC of these patients were classified into hypopneumatization, normal pneumatization and hyperpneumatization grades according to three standards. The in vitro acoustic experiment was done as the validation of simulation. It is indicated that the SS standard is effective for the clinical evaluation of venous sound amplification. The TBAC amplifies the venous sound due to the acoustic resonance at the first mode frequency, regardless of the pneumatization grades. The normal pneumatic TBAC exhibits the highest sound amplification effect on the venous sound amongst the three grades, contributing mostly to PT, but would not induce PT without any other causes.

Pulsatile tinnitus (PT), characterized as pulse-synchronous, is generally objective. Sigmoid sinus (SS) venous sound is widely suggested to be a possible sound source of PT. The dehiscence and thinness of SS cortical plate (CP) was commonly reported as PT pathology in previous studies, but lack quantitative or biomechanical analysis. In this study, it was aimed to quantify the relationship between venous sound and CP dehiscence/thinness using in vitro experiment. The in vitro models of SS and CP were established based on 3D-printing, with the developed pulsatile venous flow in the SS model. The generated sound signal and the vibration response at the dehiscent/thinned area were analyzed. The sound signal generated in the normal-sized dehiscence model was pulse-synchronous within 100--400 Hz, which had similar acoustic characteristics as the clinical PT sounds. It was concluded that the pulsatile venous sound is produced at TS-SS junction in case of CP dehiscence. The CP, even a thinned one can effectively diminish the venous sound and sound-generating pulsatile vibration at TS-SS junction. The CP dehiscence would induce pulse-synchronous and high pressure venous sound, as well as pulse-synchronous vibration above 20 Hz, regardless of the dehiscence size. On the contrary, the CP thinness would not induce obvious venous sound or pulsatile vibration above 20 Hz., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

During the past several years, the rapid development of neuroimaging techniques has contributed greatly in the noninvasive imaging studies of tinnitus. The aim of the present study was to explore the brain anatomical alterations in patients with right-sided unilateral pulsatile tinnitus (PT) in the early stage of PT symptom using voxel-based morphometry (VBM) analysis. Twenty-four patients with right-sided pulsatile tinnitus and 24 age- and gender-matched normal controls were recruited to this study. Structural image data preprocessing was performed using VBM8 toolbox. Tinnitus Handicap Inventory (THI) score was acquired in the tinnitus group to assess the severity of tinnitus and tinnitus-related distress. Two-sample t -test and Pearson's correlation analysis were used in statistical analysis. Patients with unilateral pulsatile tinnitus had significantly increased gray matter (GM) volume in bilateral superior temporal gyrus compared with the normal controls. However, the left cerebellum posterior lobe, left frontal superior orbital lobe (gyrus rectus), right middle occipital gyrus (MOG), and bilateral putamen showed significantly decreased brain volumes. This was the first study which demonstrated the features of neuroanatomical changes in patients with unilateral PT during their early stages of the symptom.

Unilateral pulsatile tinnitus (PT) was proved to be a kind of disease with brain functional abnormalities within and beyond the auditory network (AN). However, changes in patterns of the lateralization effects of PT are yet to be established. Relationship between the AN and other brain networks in PT patients is also a scientific question need to be answered. In this study, we recruited 23 left-sided, 23 right-sided PT (LSPT, RSPT) patients and 23 normal controls (NC). We combined applied independent component analysis and seed-based functional connectivity (FC) analysis to investigate alteration feature of the FC of the AN by using resting-state functional magnetic resonance imaging (rs-fMRI). Compared with NC, LSPT patients demonstrated disconnected FC within the AN on both sides. Disrupted network integrity between AN and several brain functional networks, including executive control network, self-perceptual network and the limbic network, was also demonstrated in LSPT patient group bilaterally. In contrast, compared with NC, RSPT demonstrated decreased FC within the AN on the left side, but significant increased FC within the AN on the right side (symptomatic side). Enhanced FC between AN and executive control network, self-perceptual network and limbic network was also found mainly on the right side in patients with RSPT. Positive FC between the auditory network and the limbic network may be a reason to explain why RSPT patients are willing to be in the clinic. Briefly, LSPT exhibit disrupted network integrity in brain functional networks. But RSPT is featured by enhanced FC within AN and between networks, especially on the right (symptomatic) side. Corroboration of featured FC helps to reveal the pathophysiological changing process of the brain in patients with PT, providing imaging-based biomarker to distinguish PT from other kind of tinnitus., (Copyright © 2017 Elsevier Inc. All rights reserved.)

We herein report a newly described cause of venous pulsatile tinnitus: protrusion of an aberrant sylvian vein into the tympanum. A 60-year-old woman presented with a 4-month history of objective persistent pulsatile tinnitus in the right ear with no other complaints. The pulsatile tinnitus diminished with rotation of the head to the right side or by compression of the right cervical vascular structures. The frequency and intensity of the tinnitus were 125 Hz and 20 dB HL, respectively. Audiometry and otoscopic examination findings were normal. Radiologic examination showed that the right sylvian vein protruded into the tympanum through the dehiscent anterior cortical plate of the tympanum.

Abnormal neural activities can be revealed by resting-state functional magnetic resonance imaging (rs-fMRI) using analyses of the regional activity and functional connectivity (FC) of the networks in the brain. This study was designed to demonstrate the functional network alterations in the patients with pulsatile tinnitus (PT). In this study, we recruited 45 patients with unilateral PT in the early stage of disease (less than 48 months of disease duration) and 45 normal controls. We used regional homogeneity (ReHo) and seed-based FC computational methods to reveal resting-state brain activity features associated with pulsatile tinnitus. Compared with healthy controls, PT patients showed regional abnormalities mainly in the left middle occipital gyrus (MOG), posterior cingulate gyrus (PCC), precuneus and right anterior insula (AI). When these regions were defined as seeds, we demonstrated widespread modification of interaction between the auditory and non-auditory networks. The auditory network was positively connected with the cognitive control network (CCN), which may associate with tinnitus related distress. Both altered regional activity and changed FC were found in the visual network. The modification of interactions of higher order networks were mainly found in the DMN, CCN and limbic networks. Functional connectivity between the left MOG and left parahippocampal gyrus could also be an index to reflect the disease duration. This study helped us gain a better understanding of the characteristics of neural network modifications in patients with pulsatile tinnitus., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Sigmoid sinus cortical plate dehiscence (SSCPD) is common in pulsatile tinnitus (PT) patients, and is treated through SSCPD resurfacing surgery in clinic, but the bio-mechanism is not clear as so far. This study aimed to clarify the bio-mechanism of PT sensation induced by SSCPD, and quantify the relationship of cortical plate (CP) thickness and PT sensation intensity. It was hypothesized that SSCPD would induce PT through significantly amplifying sigmoid sinus (SS) venous sound in this study. Finite element (FE) analysis based on radiology data of typical patient was used to verify this hypothesis, and was validated with clinical reports. In cases with different CP thickness, FE simulations of SS venous sound generation and propagation procedure were performed, involving SS venous flow field, vibration response of tissue overlying dehiscence area (including SS vessel wall and CP) and sound propagation in temporal bone air cells. It was shown in results that SS venous sound at tympanic membrane was 56.9dB in SSCPD case and -45.2dB in intact CP case, and was inaudible in all thin CP cases. It was concluded that SSCPD would directly induce PT through significantly amplifying SS venous sound, and thin CP would not be the only pathophysiology of PT. This conclusion would provide a theoretical basis for the design of SSCPD resurfacing surgery for PT patients with SSCPD or thin CP., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: Previous studies demonstrated altered regional neural activations in several brain areas in patients with pulsatile tinnitus (PT), especially indicating an important role of posterior cingulate cortex (PCC). However, few studies focused on the degree of functional connectivity (FC) of this area in PT patients. In this study, we will compare the FC of PCC in patients affected with this condition and normal controls by using resting-state functional magnetic resonance imaging (fMRI)., Methods: Structural and functional MRI data were obtained from 36 unilateral PT patients with single etiology and 36 matched healthy controls. FC feature of the region of interest (PCC) were characterized using a seed-based correlation method with the voxels in the whole-brain., Results: Compared with healthy controls, patients showed significant decreased FC to the right middle temporal gyrus (MTG), right thalamus and bilateral insula. By contrast, PCC demonstrated increased functional connectivity between the precuneus, bilateral inferior parietal lobule and middle occipital gyrus. We also found correlations between the disease duration of PT and FC of PCC-right MTG (r=-0.616, p<0.001)., Conclusions: Unilateral PT patients could have abnormal FC to the PCC bilaterally in the brain. PCC, as a highly integrated brain area, is an example of nucleus that was involved in mediation between different neural networks. It might be a modulation core between visual network and auditory network. The decreased FC of MTG to PCC may indicate a down regulation of activity between PCC and auditory associated brain cortex. Decreased FC between limbic system (bilateral AI) and PCC may reflect the emotional message control in patient group. This study facilitated understanding of the underlying neuropathological process in patients with pulsatile tinnitus., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT) patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF) in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027-0.073 Hz, and slow-5, 0.010-0.027 Hz, which are more sensitive to subcortical and cortical neurological signal changes, resp.) were analyzed to examine the intrinsic brain activity in detail. Compared to controls, PT patients had increased ALFF values mainly in the PCu, bilateral IPL (inferior parietal lobule), left IFG (inferior frontal gyrus), and right IFG/anterior insula and decreased ALFF values in the multiple occipital areas including bilateral middle-inferior occipital lobe. For the differences of the two frequency bands, widespread ALFF differences were observed. The ALFF abnormalities in aMPFC/ACC, PCu, right IPL, and some regions of occipital and parietal cortices were greater in the slow-5 band compared to the slow-4 band. Additionally, the THI score of PT patients was positively correlated with changes in slow-5 and slow-4 band in PCu. Pulsatile tinnitus is a disease affecting the neurological activities of multiple brain regions. Slow-5 band is more sensitive in detecting the alternations. Our results also indicated the importance of pathophysiological investigations in patients with pulsatile tinnitus in the future.

Background: Although some features of dehiscent sigmoid plates as a cause of pulsatile tinnitus (PT) have been reported, detailed imaging findings have not been evaluated., Purpose: To retrospectively evaluate the computed tomography (CT) features of dehiscent sigmoid plates associated with PT., Material and Methods: The CT images of 23 PT patients were assessed to evaluate the features of the dehiscent sigmoid plates, lateral sinuses, and temporal bone pneumatization., Results: A total of 31 defects were found on the PT side. Twenty-five defects involved the superior curve or the descending segment, four involved above both sites, and only two involved the inferior curve. Twenty-six defects involved the anterior border or the anterolateral border, and only five involved the lateral border of the sigmoid sinus. The dehiscent sigmoid plate was on the dominant side in all 18 patients with a unilateral dominant lateral sinus, and on the right side in two patients and on the left side in three patients with co-dominant lateral sinuses. Fourteen patients had hyperpneumatization and nine had good pneumatization of temporal bone. Fifteen of the 17 patients with resolution of PT after surgery had a single defect. Four of the six patients with persistence of PT after surgery had more than one defect., Conclusion: Sigmoid plate dehiscence often involves the anterior or anterolateral border of the superior curve or the descending segment of the sigmoid sinus on the side of the dominant lateral sinus, which often coexists with extensive pneumatization of the temporal bone., (© The Foundation Acta Radiologica 2014.)

Introduction: The mechanism of occurrence of sigmoid sinus dehiscence/diverticulum (SSDD) in pulsatile tinnitus (PT) patients remains under debate. Its association with idiopathic intracranial hypertension (IIH) lacks evidence, which is important for therapeutic planning and improving the clinical outcome. This study aimed to evaluate the association between SSDD and IIH by comparing the prevalence of several established imaging features of IIH between PT patients with SSDD and healthy volunteers., Methods: Thirty-three unilateral PT patients with SSDD identified on CT images and 33 age- and sex-matched healthy volunteers underwent T1-weighted volumetric magnetic resonance imaging (MRI). The optic nerve, pituitary gland, transverse sinus, and ventricles were assessed. The prevalence of established IIH imaging features was compared between the two groups. Furthermore, the PT patients were divided into two subgroups: PT patients with dehiscence only and PT patients with diverticulum. The same statistical analysis was performed on each pathophysiologic entity respectively., Results: The PT patients with SSDD showed a significantly higher prevalence of empty sella (P < 0.001), flattened posterior sclera (P = 0.001), vertical tortuosity of the optic nerve (P = 0.001), protrusion of the optic nerve (P = 0.006), transverse sinus stenosis (P = 0.011), and distension of the optic nerve sheath (P = 0.000). There were no significant differences between the PT and control groups in the maximum widths of the third and fourth ventricles and the lateral ventricle size. In contrast to controls, the imaging findings persisted in both of pathophysiologic entities, except for transverse sinus stenosis., Conclusions: Several IIH imaging features occur more frequently in PT patients with SSDD than in healthy individuals, which suggests a potential correlation between SSDD with PT and IIH.

Background and Purpose: The imaging features of sigmoid plate dehiscence-induced pulsatile tinnitus have been presented. The origin of the sigmoid plate dehiscence, however, remains unclear. Our aim was to assess the prevalence and extent of sigmoid plate dehiscence on computed tomography (CT) images in multiple age groups to determine whether this condition is more likely to be congenital or acquired., Materials and Methods: We retrospectively reviewed contrast-enhanced CT images of sigmoid plates of temporal bones in 504 patients. Each temporal bone was characterized as normal or dehiscent. Patients were then subcategorized into four age groups, and the prevalence and extent of dehiscent sigmoid plates in each group were calculated and compared., Results: Overall, 80 patients had sigmoid plate dehiscence, nine of whom had it bilaterally. In successively older age groups, the prevalences of sigmoid plate dehiscence were 18.9%, 20.1%, 14.5%, and 12.7%, respectively. Respective average anteroposterior bony defect diameters were 3.7±1.7, 3.0±1.3, 3.1±1.5, and 3.0±1.1 mm. Respective average vertical bony defect diameters were 3.6±2.3, 2.6±1.2, 3.2±1.5, and 3.0±1.7 mm. The prevalence and extent of sigmoid plate dehiscence were not statistically different among the four age groups., Conclusions: The similar radiologic prevalence and extent of dehiscent sigmoid plates among the age groups suggest that the dehiscence is more commonly a congenital than an acquired condition., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Previous studies have found a link between tinnitus and cognitive impairment, even leading to dementia. However, the mechanisms underlying this association are not clear. The purpose of this study was to explore intrinsic network changes in tinnitus and hearing loss patients with cognitive disorders. We included 17 individuals with bilateral idiopathic tinnitus, hearing loss, and cognitive impairment (PA) and 21 healthy controls. We identified resting-state networks (RSNs) and measured intra-network functional connectivity (FC) values via independent component analysis (ICA). We also evaluated correlations between RSNs and clinical characteristics. Compared with the healthy controls, the PA group showed decreased connectivity within the ventral attention network, dorsal attention network (DAN), visual network, left frontoparietal network, right frontoparietal network, sensorimotor network, and increased connectivity within the executive control network. MoCA (Montreal Cognitive Assessment) scores were negatively correlated with the FC values for left calcarine within the DAN. We identified abnormal intrinsic connectivity in several brain networks, mainly involving cognitive control, vision, sensorimotor function, and the cerebellum, in tinnitus patients with cognitive impairment. It may be possible to use the FC strength of the left calcarine within the DAN as an imaging marker to predict cognitive impairment in tinnitus patients. [ABSTRACT FROM AUTHOR]