Acute Encephalopathy Workup for a Patient With a History of Lupus Cerebritis and Unremarkable Inflammatory Markers: A Case Report.

Lupus is a relatively rare disease; however, many of the patients diagnosed with lupus experience an acute confusional state. Despite the prevalence, lupus cerebritis remains a diagnosis of exclusion due to the number of differential diagnoses of the cause of acute confusional state and unreliable clinical markers. This case report highlights the significant duration it takes to work up a broad differential before initiating treatment for lupus. Our case involves a 65-year-old woman with a documented history of lupus, who presented with acute encephalopathy. Following the comprehensive diagnostic investigation, the patient was treated with high-dose steroids that resolved the patient's symptoms. This report considers the option of empiric steroid treatment in the setting of acute encephalopathy in individuals with a history of lupus cerebritis with inconclusive test results.

Photobiomodulation Can Enhance Stem Cell Viability in Cochlea with Auditory Neuropathy but Does Not Restore Hearing.

Sensorineural hearing loss is very difficult to treat. Currently, one of the techniques used for hearing rehabilitation is a cochlear implant that can transform sound into electrical signals instead of inner ear hair cells. However, the prognosis remains very poor if sufficient auditory nerve cells are not secured. In this study, the effect of mouse embryonic stem cells (mESC) and photobiomodulation (PBM) combined treatment on auditory function and auditory nerve cells in a secondary neuropathy animal model was investigated. To confirm the engraftment of stem cells in vitro, cochlear explants were treated with kanamycin (KM) to mimic nerve damage and then cocultured with GFP-mESC. GFP-mESCs were observed to have attached and integrated into the explanted samples. An animal model for secondary neurodegeneration was achieved by KM treatment and was treated by a combination therapy of GFP-mESC and NIR-PBM at 8 weeks of KM treatment. Hearing recovery by functional testing using auditory brain stem response (ABR) and eABR was measured as well as morphological changes and epifluorescence analysis were conducted after 2 weeks of combination therapy. KM treatment elevated the hearing threshold at 70-80 dB and even after the combination treatment with GFP-mESC and PBM was applied, the auditory function was not restored. In addition, the stem cells transplanted into cochlea has exponentially increased due to PBM treatment although did not produce any malignancy. This study confirmed that the combined treatment with mESC and PBM could not improve hearing or increase the response of the auditory nerve. Nevertheless, it is noteworthy in this study that the cells are distributed in most cochlear tissues and the proliferation of stem cells was very active in animals irradiated with PBM compared to other groups wherein the stem cells had disappeared immediately after transplantation or existed for only a short period of time.

Assessing the manufacturable 32-channel cochlear electrode array: evaluation results for clinical trials.

Reliability evaluation results of a manufacturable 32-channel cochlear electrode array are reported in this paper. Applying automated laser micro-machining process and a layer-by-layer silicone deposition scheme, authors developed the manufacturing methods of the electrode array for fine patterning and mass production. The developed electrode array has been verified through the requirements specified by the ISO Standard 14708-7. And the insertion trauma of the electrode array has been evaluated based on human temporal bone studies. According to the specified requirements, the electrode array was assessed through elongation & insulation, flexural, and fatigue tests. In addition, Temporal bone study was performed using eight fresh-frozen cadaver temporal bones with the electrode arrays inserted via the round window. Following soaking in saline condition, the impedances between conducting wires of the electrode array were measured over 100 kΩ (the pass/fail criterion). After each required test, it was shown that the electrode array maintained the electrical continuity and insulation condition. The average insertion angle of the electrode array inside the scala tympani was 399.7°. The human temporal bone studies exhibited atraumatic insertion rate of 60.3% (grade 0 or 1). The reliability of the manufacturable electrode array is successfully verified in mechanical, electrical, and histological aspects. Following the completion of a 32-channel cochlear implant system, the performance and stability of the 32-channel electrode array will be evaluated in clinical trials.

Fractal analysis: Left ventricular trabecular complexity cardiac MRI adds independent risks for heart failure with preserved ejection fraction in participants with end-stage renal disease.

PURPOSE: To measure left ventricular (LV) trabecular complexity by fractal dimension (FD) in patients with end-stage renal disease (ESRD), and assess whether FD was an independent risk factor for heart failure with preserved ejection fraction (HFpEF), or a significant predictor for adverse outcome in this population. METHODS: The study retrospectively enrolled 104 participants with ESRD who underwent 3.0 T cardiac magnetic resonance imaging (MRI) from June 2018 to November 2020. LV trabeculation was quantified with fractal analysis of short-axis cine slices to estimate the FD. Logistic regression analyses were used to evaluate FD and cardiac MRI parameters and to find independent risk predictors. Cox proportional hazard regression was used to investigate the association between FD and MACE. RESULTS: LV FD was higher in in the HFpEF group than those in the non-HFpEF group, with the greatest difference near the base of the ventricle. Age, minimum left atrial volume index, and LV mean basal FD were independent predictors for HFpEF in patients with ESRD. Combining the mean basal FD with typical predictive factors resulted in a C-index (0.902 vs 0.921), which was not significantly higher. Same improvements were found for net reclassification improvement [0.642; 95% confidence interval (CI), 0.254-1.029] and integrated discrimination index (0.026; 95% CI, 0.008-0.061). Participants with a LV global FD above the cutoff value (1.278) had higher risks of MACE in ESRD patients. CONCLUSIONS: LV trabecular complexity measured by FD was an independent risk factor for HFpEF, and a significant predictor for MACE among patients with ESRD.

Texture analysis of native T1 images as a novel method for non-invasive assessment of heart failure with preserved ejection fraction in end-stage renal disease patients.

OBJECTIVES: To explore the diagnostic potential of texture analysis applied to native T1 maps obtained from cardiac magnetic resonance (CMR) images for the assessment of heart failure with preserved ejection fraction (HFpEF) among patients with end-stage renal disease (ESRD). METHODS: This study, conducted from June 2018 to November 2020, included 119 patients (35 on hemodialysis, 55 on peritoneal dialysis, and 29 with kidney transplants) in Renji Hospital. Native T1 maps were assessed with texture analysis, using a freely available software package, in participants who underwent cardiac MRI at 3.0 T. Four texture features, selected by dimension reduction specific to the diagnosis of HFpEF, were analyzed. Multivariate logistic regression was performed to examine the independent association between the selected features and HFpEF in ESRD patients. RESULTS: Seventy-six of 119 patients were diagnosed with HFpEF. Demographic, laboratory, cardiac MRI, and echocardiogram characteristics were compared between HFpEF and non-HFpEF groups. The four texture features that were analyzed showed statistically significant differences between groups. In multivariate analysis, age, left atrial volume index (LAVI), and sum average 4 (SA4) turned out to be independent predictors for HFpEF in ESRD patients. Combining the texture feature, SA4, with typical predictive factors resulted in higher C-index (0.923 vs. 0.898, p = 0.045) and a sensitivity and specificity of 79.2% and 95.2%, respectively. CONCLUSIONS: Texture analysis of T1 maps adds diagnostic value to typical clinical parameters for the assessment of heart failure with preserved ejection fraction in patients with end-stage renal disease. KEY POINTS: • Non-invasive assessment of HFpEF can help predict prognosis in ESRD patients and help them take timely preventative measures. • Texture analysis of native T1 maps adds diagnostic value to the typical clinical parameters for the assessment of HFpEF in patients with ESRD.

Increased Resting-State Positron Emission Tomography Activity After Cochlear Implantation in Adult Deafened Cats.

OBJECTIVES: Cochlear implants are widely used for hearing rehabilitation in patients with profound sensorineural hearing loss. However, Cochlear implants have variable. RESULTS: and central neural plasticity is considered to be a reason for this variability. We hypothesized that resting-state cortical networks play a role in conditions of profound hearing loss and are affected by cochlear implants. To investigate the resting-state neuronal networks after cochlear implantation, we acquired 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) images in experimental animals. METHODS: Eight adult domestic cats were enrolled in this study. The hearing threshold of the animals was within the normal range, as measured by auditory evoked potential. They were divided into control (n=4) and hearing loss (n=4) groups. Hearing loss was induced by co-administration of ethacrynic acid and kanamycin. FDG-PET was performed in a normal hearing state and 4 and 11 months after the deafening procedure. Cochlear implantation was performed in the right ear, and electrical cochlear stimulation was performed for 7 months (from 4 to 11 months after the deafening procedure). PET images were compared between the two groups at the three time points. RESULTS: Four months after hearing loss, the auditory cortical area's activity decreased, and activity in the associated visual area increased. After 7 months of cochlear stimulation, the superior marginal gyrus and cingulate gyrus, which are components of the default mode network, showed hypermetabolism. The inferior colliculi showed hypometabolism. CONCLUSION: Resting-state cortical activity in the default mode network components was elevated after cochlear stimulation. This suggests that the animals' awareness level was elevated after hearing restoration by the cochlear implantation.

Synaptic Remodeling of the Auditory Cortex Following Bilateral Blindness: Evidence of Cross-modal Plasticity.

We aimed to evaluate structural dynamic changes of neurons in the auditory cortex after visual deprivation. We longitudinally tracked dendritic spines for 3 weeks after visual deprivation in vivo using a two-photon microscope. GFP-labeled dendritic spines in the auditory cortex were serially followed after bilateral enucleation. The turnover rate, density, and size of the spines in the dendrites were evaluated 1, 2, and 3 weeks after visual deprivation. The turnover rate of the dendritic spines in the auditory cortex increased at 1 week (20.1±7.3%) after bilateral enucleation compared to baseline (12.5±7.9%); the increase persisted for up to 3 weeks (20.9±11.0%). The spine loss rate was slightly higher than the spine gain rate. The average spine density (number of spines per 1 µm of dendrite) was significantly lower at 2 weeks (2W; 0.22±0.06 1/µm) and 3 W (0.22±0.08 1/µm) post-nucleation compared to baseline (0.026±0.09 1/µm). We evaluated the change of synaptic strength in the stable spines at each time point. The normalized spine size in the auditory cortex was significantly increased after bilateral blindness at 1 W postoperatively (1.36±0.92), 2 W postoperatively (1.40±1.18), and 3 W postoperatively (1.36±0.88) compared to baseline. Sensory deprivation resulted in remodeling of the neural circuitry in the spared cortex, via cross-modal plasticity in the direction of partial breakdown of synapses, and enhanced strength of the remaining synapses.

Auditory Cortical Plasticity and Reorganization in Rats With Single-Sided Deafness During Early Developmental Period.

OBJECTIVE: We aimed to examine the serial change of sound-specific auditory cortical activation patterns in age-matched normal hearing (NH) and young single-sided deafness (YSSD) rats to understand the critical period that influences a benefit of a binaural hearing. METHOD: Experiments were performed on the age-matched 64 Sprague-Dawley rats; NH group = 45 rats, and YSSD group = 19 rats. NH rats were evaluated the multi-unit neural activities from the age of post-14 days (P14ds) to P73ds by week interval. For YSSD group, left-side cochlear ablations were done at the age of P10ds, and multineural recordings were implemented at the post-deafening (PD) 2 weeks (W), PD4W, PD6W, and PD8W, with age matching. After craniotomy, tungsten wire-based 16-channel microelectrode array was inserted to the surface of the auditory cortex. Gaussian white sound stimulation was introduced to the right ear every 500 ms, and analyses were performed of the Peri-stimulus time histogram. The parameters, including peak latency, peak amplitude, total responsive area, and index of contralaterality, were evaluated. RESULTS: In NH group, larger peak amplitude and total responsive area and shorter peak latency of the contralateral hemisphere to sound stimulation were observed in all ages. Interestingly, YSSD group demonstrated that total reactive area in the contralateral side was significantly smaller than that in the ipsilateral side at PD2W and PD4W, indicating the disappearance of contralateral dominance within PD4W. Subsequently, monaural stimulation from the hearing ear exclusively activated the contralateral hemisphere at PD6W and PD8W. CONCLUSION: Early onset of unilateral deafening leads to the alternation of contralateral dominance in the early period, replaced by faster and massive reorganization toward the ipsilateral cortex. But, gradual adaptation in the contralateral side was exclusively observed. Given the short critical period in the young SSD model, early intervention may be crucial for the development of binaural hearing if SSD occurs early in life.

CNT bundle-based thin intracochlear electrode array.

OBJECTIVE: It is known that the insertion of the intracochlear electrode is critical procedure because the damage around cochlear structures can deteriorate hearing restoration. To reduce the trauma during the electrode insertion surgery, we developed a thin and flexible intracochlear electrode array constructed with carbon nanotube (CNT) bundles. METHODS: Each CNT bundle was used for an individual electrode channel after coated with parylene C for insulation. By encapsulating eight CNT bundles with silicone elastomer, an 8-channel intracochlear electrode array was fabricated. The mechanical and electrochemical characteristics were assessed to evaluate the flexibility and feasibility of the electrode as a stimulation electrode. The functionality of the electrode was confirmed by electrically evoked auditory brainstem responses (eABR) recorded from a rat. RESULTS: The proposed electrode has a thickness of 135 µm at the apex and 395 µm at the base. It was demonstrated that the CNT bundle-based electrodes require 6-fold the lower insertion force than metal wire-based electrodes. The electrode impedance and the cathodic charge storage capacitance (CSCc) were 2.70 kΩ âˆ -20.4° at 1 kHz and - 708 mC/cm2, respectively. The eABR waves III and V were observed when stimulation current is greater than 50 µA. CONCLUSION: A thin and flexible CNT bundle-based intracochlear electrode array was successfully developed. The feasibility of the proposed electrode was shown in terms of mechanical and electrochemical characteristics. A proposed CNT bundle-based intracochlear electrode may reduce the risk of trauma during electrode insertion surgery.

Neural Plastic Changes in the Subcortical Auditory Neural Pathway after Single-Sided Deafness in Adult Mice: A MEMRI Study.

Single-sided deafness (SSD) induces cortical neural plastic changes according to duration of deafness. However, it is still unclear how the auditory cortical changes accompany the subcortical neural changes. The present study aimed to find the neural plastic changes in the cortical and subcortical auditory system following adult-onset single-sided deafness (SSD) using Mn-enhanced magnetic resonance imaging (MEMRI). B57BL/6 mice (postnatal 8-week-old) were divided into three groups: the SSD-4-week group (postnatal 12-week-old, n = 11), the SSD-8-week group (postnatal 16-week-old, n = 11), and a normal-hearing control group (postnatal 8-week-old, n = 9). The left cochlea was ablated in the SSD groups. White Gaussian noise was delivered for 24 h before MEMRI acquisition. T1-weighted MRI data were analyzed from the cochlear nucleus (CN), superior olivary complex (SOC), lateral lemniscus (LL), inferior colliculus (IC), medial geniculate body (MG), and auditory cortex (AC). The differences in relative Mn2+-enhanced signal intensities (Mn2+SI) and laterality were analyzed between the groups. Four weeks after the SSD procedure, the ipsilateral side of the SSD showed significantly lower Mn2+SI in the CN than the control group. On the other hand, the contralateral side of the SSD demonstrated significantly lower Mn2+SI in the SOC, LL, and IC. These decreased Mn2+SI values were partially recovered at 8 weeks after the SSD procedure. The interaural Mn2+SI differences representing the interaural dominance were highest in CN and then became less prominently higher in the auditory neural system. The SSD-8-week group still showed interaural differences in the CN, LL, and IC. In contrast, the MG and AC did not show any significant intergroup or interaural differences in Mn2+SI. In conclusion, subcortical auditory neural activities were decreased after SSD, and the interaural differences were diluted in the higher auditory nervous system. These findings were attenuated with time. Subcortical auditory neural changes after SSD may contribute to the change in tinnitus severity and the outcomes of cochlear implantation in SSD patients.

Disappearance of contralateral dominant neural activity of auditory cortex after single-sided deafness in adult rats.

Hearing loss in mature ears can cause functional reorganization of the auditory cortex. The functional reorganization is speculated to negatively affect the outcome of hearing rehabilitation. Therefore, once hearing loss occurs, it is important to provide auditory input before extensive reorganization in the auditory pathways. We investigated the neural plasticity in auditory cortex after single-sided deafness (SSD) in an adult rat model. The animals were divided into two groups: a normal hearing (NH) and the SSD group. The neural recordings of the SSD group were conducted at different time points (2, 4, 6 and 8 weeks) after cochlear ablation. The multi-unit activity was discriminated on the sum of spikes, peak amplitude, onset latency, peak latency, and responsive area based on the peak amplitude. The auditory cortical reorganization was observed after SSD. The contralateral dominance of peak amplitude and latency that normally occur in NH group were not present in the SSD group, replaced by higher amplitude and faster response in ipsilateral cortex. According to serial recordings at different time points after SSD, different phases in the response of the auditory cortex were speculated. Compared with normal hearing, alteration of contralateral dominance was observed because of the functional reorganization of the auditory cortex after SSD.

Thermally evaporated indium-free, transparent, flexible SnO2/AgPdCu/SnO2 electrodes for flexible and transparent thin film heaters.

We investigated the characteristics of themally evaporated SnO2/Ag-Pd-Cu (APC)/SnO2 multilayer films for applications as damage-free, indium-free, flexible, and transparent electrodes for high performance flexible and transparent thin film heaters (TFHs). The top and bottom SnO2 layers and APC interlayer were prepared by a multi-source evaporation process, and the effect of the thickness of each layer on the resistivity, optical transmittance, and mechanical flexibility of the SnO2/APC/SnO2 electrodes was investigated in detail. Based on a figure of merit value, we obtained a SnO2/APC/SnO2 electrode with a low sheet resistance of 9.42 Ohm/square and a high optical transmittance of 91.14%. In addition, we examined the mechanical properties of the SnO2/APC/SnO2 electrode using various bending tests such as inner bending, outer bending, dynamic fatigue, and a twisting test. By comparing the crack shape of the SnO2/APC/SnO2 electrode bent beyond the critical bending radius (2~3 mm), we suggest a possible crack formation mechanism for the SnO2/APC/SnO2 electrodes. Furthermore, we evaluated the feasibility of the SnO2/APC/SnO2 electrodes for flexible and transparent TFHs. By correlating the sheet resistance of the SnO2/APC/SnO2 electrode and the performance of TFHs, we show the importance of transparent electrodes for high performance flexible and transparent TFHs.

Extended use of systemic steroid is beneficial in preserving hearing in guinea pigs after cochlear implant.

CONCLUSION: Seven-day administration of systemic steroids was more effective in preserving hearing for 12 weeks after cochlear implantation (CI) than a 3-day delivery. OBJECTIVES: To determine the effectiveness of extended delivery of systemic steroids to preserve hearing in guinea pigs after CI. METHODS: Dexamethasone (4 mg/ml) was delivered parenterally via a mini-osmotic pump for either 3 or 7 days. A dummy CI electrode was inserted via cochleostomy approach in 8-week-old guinea pigs. Auditory thresholds were assessed from tone burst auditory brainstem responses (2, 8, 16, 24, and 32 kHz) at 1 day prior to CI, and 1, 4, and 12 weeks after implantation. Histologic evaluation of the cochleae was carried out. RESULTS: No differences were observed in hearing thresholds among groups before CI. Significant hearing preservation was achieved at 8, 16, 24, and 32 kHz only in the 7-day infusion group compared with the control group at 1 week after CI. The same trend was maintained at 4 weeks (16, 24 kHz) and 12 weeks (16, 24, and 32 kHz). Histologic review of the 7-day infusion group revealed less fibrosis and ossification in the scala tympani and the preservation of more spiral ganglion cells, compared with the control group.

An improved speech processing strategy for cochlear implants based on an active nonlinear filterbank model of the biological cochlea.

The purpose of this study was to improve the speech processing strategy for cochlear implants (CIs) based on a nonlinear time-varying filter model of a biological cochlea. The level-dependent frequency response characteristic of the basilar membrane is known to produce robust formant representation and speech perception in noise. A dual resonance nonlinear (DRNL) model was adopted because it is simpler than other adaptive nonlinear models of the basilar membrane and can be readily incorporated into the CI speech processor. Spectral analysis showed that formant information is more saliently represented at the output of the proposed CI speech processor compared to the conventional strategy in noisy conditions. Acoustic simulation and hearing experiments showed that the DRNL-based nonlinear strategy improves speech performance in a speech-spectrum-shaped noise.

An improved speech processor for cochlear implant based on active nonlinear model of biological cochlea.

The purpose of this study was to improve speech perception performance of cochlear implant (CI) under noise by a speech processing strategy based on nonlinear time-varying filter model of biological cochlea, which is beneficial in preserving spectral cues for speech perception. A dual resonance nonlinear model was applied to implement this feature. Time-frequency analysis indicated that formant information was more clearly represented at the output of CI speech processor, especially under noise. Acoustic simulation and hearing experiment also showed the superiority of the proposed strategy in that vowel perception score was notably enhanced. It was also observed that the AN responses to the stimulation pulses produced by the proposed strategy encode the formant information faithfully. Since the proposed strategy can be employed in CI devices without modification of hardwares, a significant contribution for the improvement of speech perception capability of CI implantees is expected.