Membrane Compliance Research Articles

Evaluation of Hearing Loss: Understanding Audiologic Testing to Refine Image Interpretation.

The standard of reference for diagnosing and characterizing hearing loss is audiologic testing. The results of audiologic testing inform the imaging algorithm and the differential diagnosis for the underlying cause. Pure-tone audiometry tests the ability to hear tones across different frequencies, and the results are displayed as an audiogram. Tympanometry measures tympanic membrane compliance as a function of pressure to generate a tympanogram. Acoustic reflex testing helps differentiate third window lesions from other causes of conductive hearing loss. Clinical and audiologic assessment of sensorineural hearing loss helps in differentiating cochlear from retrocochlear causes. Symmetrical sensorineural hearing loss is typical of cochlear disease. Asymmetry increases the likelihood of a retrocochlear lesion, the most common of which among adults is vestibular schwannoma. Unlike patients with sensorineural hearing loss, who commonly have normal imaging studies, patients with conductive hearing loss are expected to have abnormal temporal bone CT studies. By incorporating the results of audiologic testing into their evaluation, radiologists can perform a more informed and more intentional search for the structural cause of hearing loss. The authors describe several audiogram configurations that suggest specific underlying mechanisms of conductive hearing loss. By providing a practical and accessible summary of the basics of audiologic testing, the authors empower the radiologist to leverage relevant clinical information and audiologic test results to interpret temporal bone imaging more confidently and more accurately, particularly temporal bone CT in the setting of conductive hearing loss. ©RSNA, 2024.

Interpretation of the nine-step test for Eustachian tube function should consider mastoid cavity volume.

The modified nine-step test is a classical method for evaluating Eustachian tube function. However, clinical interpretation of the increased maximal difference in middle ear pressure (mdMEP) in the modified nine-step test is unknown. We hypothesised that the different reservoir effects of the mastoid cavity can bias the results of the modified nine-step test. A total of 108 consecutive participants (216 ears) were retrospectively screened. Of these, 55 participants (82 ears) who met the inclusion/exclusion criteria were enrolled. The volumetric results of the mastoid cavity, parameters of the modified nine-step test (mdMEP, middle ear pressure, tympanic membrane compliance), and demographic data were analysed. A significant negative correlation was found between mdMEP and mastoid cavity volume (R = .467, p < .001). Ears with mdMEP >70 daPa showed poor pneumatization in the mastoid cavity, with volumes less than 3000 mm3 (10th percentile of all ears analysed). Ears with mastoid cavity volumes lower than the 25th percentile showed a significantly higher mdMEP (p < .001). Patients with mastoid cavity volumes higher than the 75th percentile were significantly younger (p < .001). Multivariate regression analysis for mdMEP showed a good fit (R = .854) using factors including middle ear pressure, admittance and, most importantly, the reciprocal of mastoid volume (Beta = 0.752, p < .001). The mdMEP, the main parameter of the modified nine-step test, was negatively correlated with the mastoid cavity volume. Therefore, the results of the modified nine-step test should be interpreted with consideration of mastoid cavity volume.

Method for measuring the membrane penetration of triaxial specimens based on an external circular array of laser displacement sensors

In triaxial tests, membrane penetration is an important factor influencing the accuracy of volume change and pore pressure measurement. To measure and evaluate the membrane penetration of specimens made of gravelly sandy soils, a method using a newly developed measurement system based on an external circular array of laser displacement sensors is proposed in this paper. A series of experimental studies were conducted on the effects of several factors on membrane penetration. The result shows that there is a linear correlation between the unit membrane compliance and the effective confining pressure on a semilog plot. In addition, as the gravel content increases, the membrane penetration increases, but this trend weakens with increasing relative density. Notably, when the characteristic particle size is the same, the membrane penetration will be greater for more broadly graded soils. Moreover, the error caused by the thickness of the membrane increases as the diameter-to-thickness ratio decreases.

Effects of membrane compliance on the normal-scale triaxial cyclic liquefaction test results of saturated coral sand

Correctly evaluating the membrane penetration and compliance effects in the element liquefaction test of saturated coral sand is important for test result applications. Therefore, the penetration volume measurement and triaxial cyclic liquefaction testing of saturated coral sand and quartz sand samples with the same grading and relative density were conducted for relatively loose and dense states, and the liquefaction resistance test results before and after membrane compliance correction were analyzed. The results showed that under the same conditions, the influence of the penetration and compliance of coral sand samples was more significant than that of the quartz sand samples. The general practice of ignoring the effect of membrane compliance in normal-scale triaxial tests is inapplicable in coral sand tests and will result in relatively unsafe analysis results.

Diagnostic Value of the Air-Bone Threshold Gap in Stapes Fixation

Introduction: The Carhart notch is a well-known sign of stapes fixation. However, previous studies have reported that the Carhart notch is not specific to stapes fixation and is also present in other middle ear diseases. Therefore, this study investigated the diagnostic value of threshold gap between air conduction and bone conduction (ABG) for stapes fixation, instead of the bone conduction dip representing the Carhart notch. Methods: A total of 199 ears that underwent exploratory tympanotomy were enrolled in this retrospective study. They were categorized into three groups according to surgical findings: stapes fixation (SF), other ossicle fixation (OF), and chain disconnection (CD). Preoperative pure-tone audiograms and impedance audiograms were compared between the groups. Results: The incidence of the Carhart notch did not differ between the groups. The ABG at 2,000 Hz showed a good diagnostic performance for distinguishing between the SF and CD groups (area under the curve, AUC = 0.816, p < 0.001), but poor performance for distinguishing between the SF and OF groups (AUC = 0.662, p = 0.003). Bone conduction at 2,000 Hz showed a moderate performance for distinguishing between the SF and CD groups (AUC = 0.707, p < 0.001) and did not show statistically significant results for distinguishing between the SF and OF groups (AUC = 0.594, p = 0.080). The tympanic membrane compliance was significantly higher in the CD group than in the SF group (p = 0.001). Conclusions: The Carhart notch was not a specific finding of SF. The sensitivity and specificity of ABG ≤15 dB at 2,000 Hz for distinguishing between SF and CD were 60.4% and 89.2%, respectively. To prepare for surgical interventions in patients with conductive hearing loss but a normal tympanic membrane, clinicians should comprehensively consider these results.

Impact of endolymphatic hydrops on DPOAE in subjects with normal to mild hearing loss.

The increased endolymph volume affects a shift in the organ of Corti and basilar membrane in ears with endolymphatic hydrops (EH), which might affect distortion-product otoacoustic emissions (DPOAE) by altering the operating point of the outer hair cells. We investigated how changes in DPOAE are related to the distribution site of EH. Prospective study. Among 403 patients with hearing or vestibular symptoms who underwent contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of EH and subsequent DPOAE testing, subjects whose hearing levels on pure tone audiometry were ≤35dB at all frequencies were included in this study. In patients with EH on MRI, the presence and amplitude of DPOAE were evaluated between groups with hearing levels of ≤25dB at all frequencies versus hearing levels of >25dB at one or more frequencies. There were no differences in the distribution of EH between groups. The amplitude of DPOAE had no clear correlation with the presence of EH. However, in both groups, there was a significantly higher probability of the presence of a DPOAE response from 1001 to 6006Hz in cases with EH in the cochlea. Among patients whose hearing levels were ≤35dB at all frequencies, better responses on DPOAE testing were found in subjects with EH in the cochlea. Alteration of DPOAEs in the early stages of hearing impairment could indicate morphological changes in the inner ear with altered basilar membrane compliance due to EH. 4.

Bats actively modulate membrane compliance to control camber and reduce drag.

ABSTRACTBat wing skin is exceptionally compliant and cambers significantly during flight. Plagiopatagiales proprii, arrays of small muscles embedded in the armwing membrane, are activated during flight and are hypothesized to modulate membrane tension. We examined the function of these muscles using Jamaican fruit bats, Artibeus jamaicensis. When these muscles were paralyzed using botulinum toxin, the bats preferred flight speed decreased and they were unable to fly at very low speeds. Paralysis of the plagiopatagiales also resulted in increased armwing camber consistent with a hypothesized role of modulating aeroelastic interactions. Other compensatory kinematics included increased downstroke angle and increased wingbeat amplitude. These results are consistent with the bats experiencing increased drag and flight power costs associated with the loss of wing-membrane control. Our results indicate that A. jamaicensis likely always employ their wing membrane muscles during sustained flight to control camber and to enhance flight efficiency over a wide flight envelope.

Large Scale Direct Shear Box Tests on Gravels

The determination of shear strength characteristics of gravelly soils is difficult through the use of conventional small scale, triaxial or simple shear testing devices in the laboratory due to membrane compliance and boundary effects; or due to inconsistent penetration resistances measured as part of standard or cone penetration testing in the field. These limitations require the use of available empirical or semi-empirical relationships or the execution of large scale laboratory or field tests. In the literature there exists inconsistent, and large range of recommendations for shear strength parameters. Within the confines of this study, direct shear box test results performed on poorly- (GP) and well-graded (GW) gravel samples with initial void ratio ranging from 0.42 to 0.53 are presented, which are tested under effective normal stresses ranging from 77 to 205 kPa. The estimated peak secant-angles of shearing resistances vary in the range of 49 to 54 degrees. On the basis of volumetric change vs. shear strain responses, the peak angle of dilation and elastic Poisson’s ratio are estimated to vary in the range of 10-16 degrees and 0.28-0.39, respectively. These estimated values are compared with available literature.

Ambient Pressure Tympanometry Wave Patterns in Patients With Superior Semicircular Canal Dehiscence.

Importance: Superior semicircular canal dehiscence (SSCD) is a treatable condition, but current diagnostic modalities have numerous limitations. Clinicians would benefit from an additional tool for diagnostic workup that is both rapid and widely available.Objective: To assess the utility of ambient pressure tympanometry (APT) in the diagnostic workup of SSCD by determining the sensitivity and specificity of APT for SSCD in comparison to other diagnostic modalities.Design: Retrospective cohort study of patients who underwent APT and temporal bone computerized tomography (CT) scans from May 2017 to July 2018.Setting: Tertiary referral center.Participants: APT was performed as part of routine audiological testing on adult patients. We retrospectively analyzed all patients who received both APT and temporal bone CT scans, and divided ears into SSCD and non-SSCD groups based on the presence or absence of radiographic SSCD. Ears with other radiographic findings that could affect tympanic membrane compliance were excluded.Exposures: All patients in this study underwent APT and temporal bone CT scans. Some patients also underwent pure tone audiometry and vestibular evoked myogenic potentials (VEMPs).Main Outcomes and Measures: The primary outcome measures were sensitivity, specificity, and risk ratio of APT for SSCD. Secondary outcome measures include sensitivity of VEMPs and supranormal hearing thresholds.Results: We describe 52 patients (70 ears) who underwent APT and CT imaging (mean age 47.1 years, 67.1% female). APT detected SSCD with 66.7% sensitivity and 72.1% specificity. In symptomatic patients, sensitivity was 71.4% and specificity was 75%. VEMPs performed best at detecting SSCD when defining a positive test as oVEMP amplitude >17 μV, with a sensitivity of 68.2%, similar to APT (p > 0.99). The combination of APT and VEMPs increased sensitivity to 88.9%, better than APT alone (p = 0.031) and trending toward better than VEMPs alone (p = 0.063).Conclusions and Relevance: Rhythmic wave patterns on APT are associated with SSCD and may raise suspicion for this condition in conjunction with consistent results on other diagnostic modalities. Although clinical utility requires confirmation in a larger prospective study, APT is a simple, rapid, and widely available tool warranting further study.

Rhythmic Wave Patterns on Ambient Pressure Tympanometry in Patients With Objective Tinnitus-associated Pathologies.

To introduce the concept of ambient pressure tympanometry (APT) and its association with pathologies that may present with objective tinnitus. Retrospective case series. Tertiary referral center. Audiologists performed APT on adult patients as part of routine audiological testing. Ears with myoclonus and patulous Eustachian tube (PET) were identified via review of patient history and physical examination. All other conditions were verified via computed tomography (CT) temporal bone imaging. Ears with conditions that could impair tympanic membrane compliance, such as otosclerosis or tympanic membrane perforation, were excluded. APT findings were analyzed via a novel algorithm. A radiographic finding associated with objective tinnitus was confirmed in 67 ears that underwent CT imaging; 45 (67%) of these ears displayed rhythmic APT wave patterns. These included 28 ears with superior semicircular canal dehiscence, 4 ears with sigmoid sinus dehiscence, 6 ears with internal carotid artery dehiscence, 4 ears with glomus tumor, and 3 ears with encephalocele. In addition, we identified three ears with myoclonus and one ear with PET. In a subset of 30 ears with objective tinnitus symptoms that underwent CT imaging, 22 displayed rhythmic waves; of these 22 ears, 20 (91%) had a radiographic finding associated with objective tinnitus. Rhythmic APT wave patterns are common and may be associated with numerous temporal bone pathologies that may present with objective tinnitus. APT is a simple, rapid, and widely available tool that warrants further study to determine its value in screening of these otologic conditions.

Preventing loss of mechanosensation by the nuclear membranes of alveolar cells reduces lung injury in mice during mechanical ventilation.

The nuclear membrane acts as a mechanosensor that drives cellular responses following changes in the extracellular environment. Mechanically ventilated lungs are exposed to an abnormally high mechanical load that may result in clinically relevant alveolar damage. We report that mechanical ventilation in mice increased the expression of Lamin-A, a major determinant of nuclear membrane stiffness, in alveolar epithelial cells. Lamin-A expression increased and nuclear membrane compliance decreased in human bronchial epithelial cells after a mechanical stretch stimulus and in a murine model of lung injury after positive-pressure ventilation. Reducing Lamin-A maturation by depletion of the protease-encoding gene Zmpste24 preserved alveolar nuclear membrane compliance after mechanical ventilation in mice. Ventilator-induced proapoptotic gene expression changes and lung injury were reduced in mice lacking Zmpste24 compared to wild-type control animals. Similarly, treatment with the human immunodeficiency virus protease inhibitors lopinavir and ritonavir reduced the accumulation of Lamin-A at nuclear membranes and preserved nuclear membrane compliance after mechanical ventilation, mimicking the protective phenotype of Zmpste24-/- animals. These results show that the pathophysiological response to lung mechanical stretch is sensed by the nuclear membranes of lung alveolar cells, and suggest that protease inhibitors might be effective in preventing ventilator-induced lung injury.

A new method for eliminating membrane compliance in cyclic triaxial tests on gravelly soils

A new computer controlled flow pump is developed to continuously mitigate the adverse effects of membrane compliance in conjunction with implementation of image processing for volume change measurement. The flow pump eliminates the membrane compliance by injecting or pumping out the required volume of water into or from the gravelly specimens to compensate for the erroneous volume change associated with the membrane compliance during undrained cyclic triaxial tests. This error is compounded in gravelly soils due to the large size of the grains and voids. In order to measure the volume of the specimen during the isotropic consolidation stage and calibrate the flow pump for cyclic loading, an image processing technique was used for measuring the volume change during the isotropic consolidation stage of loading while calculating membrane compliance associated with the amount of input water from the flow pump into the specimen. The results of image processing show that the increase in density of the specimens leads to an increase in the ratio of volumetric skeletal strains to axial strains and a decrease in the normalized membrane penetration. The study yields promising results for minimizing the errors associated with membrane compliance during undrained cyclic loading on gravels.

Instabilities in Blistering

Blistering occurs when a thin solid layer locally separates from an underlying substrate through cracking of a bulk material, delamination of a composite material, or peeling of a membrane adhered to the substrate by a thin layer of viscous fluid. In this last scenario, the expansion of the newly formed blister by fluid injection occurs via a displacement flow, which peels apart the adhered surfaces through a two-way interaction between flow and deformation. Such blisters are prone to fluid and solid mechanical instabilities. If the injected fluid is less viscous than the fluid already occupying the gap, patterns of short and stubby fingers form on the propagating fluid interface. This process is regulated by membrane compliance, which if increased delays the onset of fingering to higher flow rates and reduces finger amplitude. Suppression is mediated by the locally tapered geometry of the blister near the fluid interface, which is imposed by the underlying blistering flow. Buckling/wrinkling instabilities of the delaminated layer arise for sufficiently thin membranes and can interact with the fluid mechanical fingering instability.

Middle Ear Function and Pathophysiology in Andean Children Living at High Altitudes.

Counter, S. Allen, Leo H. Buchanan, Fernando Ortega, Anthony B. Jacobs, and Göran Laurell. Middle ear function and pathophysiology in Andean children living at high altitudes. High Alt Med Biol. 18:163-170, 2017.-The extent of altitude-related middle ear disorders in children native to high altitudes is unclear. This study examined middle ear pathophysiology in two groups of children living in high-altitude Ecuadorian Andean communities by investigating middle ear pressure (MEP), tympanic membrane compliance (TMC), and ear canal volume (ECV) using tympanometry, and by otological examination. Altitude I Group lived at 2850 m, and Altitude II Group resided at around 4000 m. The two high-altitude groups were compared with a reference group of children residing at sea level. Mean MEP was -3.6 daPa (SD: 39.2), 3.5 daPa (SD: 28.7), and 1.3 daPa (SD: 13.6) for Altitude I Group, Altitude II Group, and the Sea Level Group, respectively. The MEP was not significantly different among the three groups. Mean TMC was 0.63 cm3 (SD: 0.51), 0.60 cm3 (SD: 0.43), and 0.60 cm3 (SD: 0.24) for Altitude I Group, Altitude II Group, and the Sea Level Group, respectively. The TMC was not significantly different among the three groups. Mean ECV was 1.1 (SD: 0.26), 1.2 (SD: 0.26), and 1.0 (SD: 0.23) for Altitude I Group, Altitude II Group, and the Sea Level Group, respectively. The difference in ECV between Altitude I Group and Altitude II Group was significant (p = 0.043), as was the difference between Altitude II Group and the Sea Level Group (p = 0.001). ECV did not differ significantly between Altitude I Group and the Sea Level Group. Otological examination revealed a low incidence of ear canal and middle ear pathology. In conclusion, tympanometric and otological findings did not reveal a high incidence of middle ear pathophysiology in children living at altitudes as high as around 4000 m.

Evaluation of a novel extra-cardiac Fontan procedure with implantation of a biocompatible membrane

Fontan operation is a final palliative surgical treatment for patients with a single ventricle (SV) physiology. One of the common disadvantages of Fontan operation is to generate a non-pulsatile flow instead of the normal pulsatile flow produced by contraction of the ventricle. Theoretically, in SV patients, maintaining the antegrade flow through pulmonary valve can produce flow pulsatility in the right and left pulmonary arteries. However, it not only increases the energy loss in the Fontan of total cavopulmonary pathway (TCPC), but also imposes an extra load on pulmonary arteries as well as the ventricle.In this study, the potential capability of pulmonary valve of the patient that can be used to increase the pulsatility of blood flow in pulmonary arteries, as a novel concept, is introduced and evaluated by using numerical simulation. In this approach, the main pulmonary artery of the patient is repaired and a flexible membrane is constructed by sewing the leaflets of pulmonary valve (three cups) together, through Fontan surgery. This membrane would fluctuate by high gradient pressure that is imposed from univentricular heart in each cardiac cycle. Alternatively, more dilatable materials, as flexible artificial membranes, are also considered to examine the effect of membrane's compliance on blood flow in pulmonary arteries. In this work, we have used the flow solid interaction (FSI) simulation to investigate the effect of mechanical properties of the membrane material on the pulsatility of velocity profiles.

Side-specific mechanical properties of valve endothelial cells.

Aortic valve endothelial cells (ECs) function in vastly different levels of shear stress. The biomechanical characteristics of cells on each side of valve have not been investigated. We assessed the morphology and mechanical properties of cultured or native valve ECs on intact porcine aortic valve cusps using a scanning ion conductance microscope (SICM). The autocrine influence of several endothelial-derived mediators on cell compliance and the expression of actin were also examined. Cells on the aortic side of the valve are characterized by a more elongated shape and were aligned along a single axis. Measurement of EC membrane compliance using the SICM showed that the cells on the aortic side of intact valves were significantly softer than those on the ventricular side. A similar pattern was seen in cultured cells. Addition of 10(-6) M of the nitric oxide donor sodium nitroprusside caused a significant reduction in the compliance of ventricular ECs but had no effect on cells on the aortic side of the valve. Conversely, endothelin-1 (10(-10)-10(-8) M) caused an increase in the compliance of aortic cells but had no effect on cells on the ventricular side of the valve. Aortic side EC compliance was also increased by 10(-4) M of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester. Immunofluorescent staining of actin filaments revealed a great density of staining in ECs on the ventricular surface. The expression of actin and the relative membrane compliance of ECs on both side of the valve were not affected by ventricular and aortic patterns of flow. This study has shown side-specific differences in the biomechanics of aortic valve ECs. These differences can have important implications for valve function.

Long-Term, High-Frequency Tympanometry and Audiometry Results after Cartilage and Fascia Tympanoplasty

Long-Term, High-Frequency Tympanometry and Audiometry Results after Cartilage and Fascia Tympanoplasty

Static analysis of hydrostatic conical bearings using flow resistance network method

Purpose – This paper aims to study the static characteristics of the hydrostatic conical journal bearings by utilizing single-action membrane restrictors to compensate the working pressures of recesses. Design/methodology/approach – The flow resistance network method is used to analyze the influences of load capacity and static stiffness of bearing with the design parameters, including the number of recesses, radial eccentricity ratio, axial displacement ratio, restriction constant, membrane compliance, length-diameter ratio, circumferential land width ratio, axial land width ratio and half of cone angle. Findings – This study shows the infinite stiffness of the oil produced in the first and second recesses while single-action membrane restriction constant of 2 and 3, respectively, as well as in the fourth recess while single-action membrane restriction constant of 0.01 and 0.1, respectively. Research limitations/implications – This article provides the hydrostatic conical bearings in static and unbiased states for analyses of design parameters. The analyses ignore dynamic pressure effect and do not use the Reynolds equation, and assuming that each oil recesses pressure is constant. Practical implications – The influences of the design parameters including the number of recesses, membrane restriction, membrane compliance, length-diameter ratio, half of con-angle, circumferential land width ratio, and axial land width ratio are discussed to the load capacity and static stiffness of conical bearing. Originality/value – Based on the characteristics of the conical bearing through analysis, this article suggests the front bearing with hard membrane restrictor (capillary) and the back bearing with soft membrane restrictor are the most appropriate for axial stiffness.

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network.

Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network including a rat, a reservoir, a pinch valve, and a peristaltic pump. To demonstrate the proposed method, a twin-shaped microfluidic device, which is composed of two half-circular chambers, two side channels with multiple indicating channels, and one bridge channel, was carefully designed. Based on the microfluidic device, three sequential flow controls were applied to identify viscosity and flow rate of blood, with label-free and sensorless detection. The half-circular chamber was employed to achieve mechanical membrane compliance for flow stabilization in the microfluidic device. To quantify the effect of flow stabilization on flow fluctuations, a formula of pulsation index (PI) was analytically derived using a discrete fluidic circuit model. Using the PI formula, the time constant contributed by the half-circular chamber is estimated to be 8 s. Furthermore, flow fluctuations resulting from the peristaltic pumps are completely removed, especially under periodic flow conditions within short periods (T < 10 s). For performance demonstrations, the proposed method was applied to evaluate blood viscosity with respect to varying flow rate conditions [(a) known blood flow rate via a syringe pump, (b) unknown blood flow rate via a peristaltic pump]. As a result, the flow rate and viscosity of blood can be simultaneously measured with satisfactory accuracy. In addition, the proposed method was successfully applied to identify the viscosity of rat blood, which circulates in a complex fluidic network. These observations confirm that the proposed method can be used for simultaneous measurement of viscosity and flow rate of whole blood circulating in the complex fluid network, with sensorless and label-free detection. Furthermore, the proposed method will be used in evaluating variations in the viscosity of human blood during cardiopulmonary bypass procedures or hemodialysis.

Using optical profilometry to characterize cell membrane roughness influenced by amyloid-beta 42 aggregates and electric fields

The membrane roughness of Neuro-2a neroblastoma cells is measured by using noninterferometric wide-field optical profilometry. The cells are treated with the fibril and oligomer conformers of amyloid-beta (Aβ) 42, which is a peptide of 42 amino acids related to the development of Alzheimer's disease. We find that both the Aβ42 fibrils and Aβ42 oligomers reduced the cell membrane roughness, but the effect of Aβ42 oligomers was faster and stronger than that of the fibrils. We also apply direct-current electric field (dcEF) stimulations on the cells. A dcEF of 300 mV/mm can increase the membrane roughness under the treatment of Aβ42. These results suggest that Aβ42 can decrease the membrane compliance of live neuroblastoma cells, and dcEFs may counteract this effect.