Remote Orthotic Fabrication Method Using Small Three-Dimensional Printers and Computed Tomography Data:A Technical Report.

INTRODUCTION: Computer-aided design and manufacturing (CAD/CAM) methods have gained prominence in early orthotic provision.　This study introduces an innovative approach using compact three-dimensional (3D) printers and computed tomography data to generate segmented body models for traditional Damen corset orthoses.　The goals included evaluating the comfort and fit of orthoses and assessing the effectiveness of our approach for prosthetic companies with limited financial resources. MATERIALS AND METHODS: Lumbar and thoracolumbar orthoses were crafted via CAD/CAM.　Four healthy patients wore the orthoses, with whom immediate and 1-week comfort and fit assessments were conducted.　A prosthetist assessed fit, and the Japanese edition of OPUS-CSD, the Orthotics Prosthetics Users' Survey-Client Satisfaction with Device, was used for subjective assessment of comfort and fit. RESULTS: The fit evaluations were satisfactory for all patients with positive predefined criteria.　Questionnaire responses confirmed high satisfaction and comfort, confirming a successful orthosis fit. CONCLUSION: We established an orthotic fabrication method using CAD/CAM methods with 3D printers.　Additionally, we confirmed the comfort and fit of the corsets so produced.　The initial cost of 3D printers is lower than that of traditional carving machines, enabling even small-scale orthotic fabrication facilities to utilize CAD/CAM methods.　Further research and refinements of this manufacturing approach are expected to expand its applicability.

Ground-truth effects in learning-based fiber orientation distribution estimation in neonatal brains.

Diffusion Magnetic Resonance Imaging (dMRI) is a noninvasive method for depicting brain microstructure in vivo. Fiber orientation distributions (FODs) are mathematical representations extensively used to map white matter fiber configurations. Recently, FOD estimation with deep neural networks has seen growing success, in particular, those of neonates estimated with fewer diffusion measurements. These methods are mostly trained on target FODs reconstructed with multi-shell multi-tissue constrained spherical deconvolution (MSMT-CSD), which might not be the ideal ground truth for developing brains. Here, we investigate this hypothesis by training a state-of-the-art model based on the U-Net architecture on both MSMT-CSD and single-shell three-tissue constrained spherical deconvolution (SS3T-CSD). Our results suggest that SS3T-CSD might be more suited for neonatal brains, given that the ratio between single and multiple fiber-estimated voxels with SS3T-CSD is more realistic compared to MSMT-CSD. Additionally, increasing the number of input gradient directions significantly improves performance with SS3T-CSD over MSMT-CSD. Finally, in an age domain-shift setting, SS3T-CSD maintains robust performance across age groups, indicating its potential for more accurate neonatal brain imaging.

A water-soluble caveolin-1 peptide inhibits psoriasis-like skin inflammation by suppressing cytokine production and angiogenesis.

The plasma membrane protein caveolin-1 (CAV-1) regulates signaling by inhibiting a wide range of kinases and other enzymes. Our previous study demonstrated that the downregulation of CAV-1 in psoriatic epidermal cells contributes to inflammation by enhancing JAK/STAT signaling, cell proliferation, and chemokine production. Administration of the CAV-1 scaffolding domain (CSD) peptide suppressed imiquimod (IMQ)-induced psoriasis-like dermatitis. To identify an optimal therapeutic peptide derived from CAV-1, we have compared the efficacy of CSD and subregions of CSD that have been modified to make them water soluble. We refer to these modified peptides as sCSD, sA, sB, and sC. In IMQ-induced psoriasis-like dermatitis, while all four peptides showed major beneficial effects, sB caused the most significant improvements of skin phenotype and number of infiltrating cells, comparable or superior to the effects of sCSD. Phosphorylation of STAT3 was also inhibited by sB. Furthermore, sB suppressed angiogenesis both in vivo in the dermis of IMQ-induced psoriasis mice and in vitro by blocking the ability of conditioned media derived from CAV-1-silenced keratinocytes to inhibit tube formation by HUVEC. In conclusion, sB had similar or greater beneficial effects than sCSD not only by cytokine suppression but by angiogenesis inhibition adding to its ability to target psoriatic inflammation.

Novel and reappraised wide-band EEG findings in migraineurs: Its correlation with several clinical variables.

OBJECTIVE: Cortical spreading depolarization is one possible pathogenesis of migraine, of which slow neurophysiological change is barely recorded in conventional EEG settings. Using wide-band EEG conditions, we reappraised the features of EEG in migraineurs, including subdelta-band EEG changes. METHODS: This retrospective study included 144 patients with migraine. We delineated EEG of focal delta slow (FDS) (1-4 Hz) by time constant (TC) 0.3 s and focal subdelta slow (FSDS) (< 1 Hz) by TC 2 s. Relationships between clinical variables and EEG findings were evaluated. RESULTS: Of 144 patients, 39 had aura and 105 did not. FSDS and FDS were observed in 38 and 58 patients, respectively. No EEG was recorded during the aura. In multivariate analysis with the phase of migraine, family history, age, and percentage of sleep during EEG recording, the phase of migraine was related to the occurrence of FSDS (postdrome vs interictal, prodrome, and headache respectively (OR = 49.00 [95% CI = 3.89-616.66], 46.28 [2.99-715.78], 32.79 [2.23-481.96], p = 0.0026, 0.0061, 0.011). FDS was clinically unremarkable for differential evaluation. CONCLUSIONS: Wide-band EEG abnormality in migraineurs, i.e., FSDS, can be affected by migraine phase. SIGNIFICANCE: Wide-band EEG finding could be a biomarker related to clinical variables in migraines.

Comparison of ultrasonic diagnosis of cesarean scar defects at different timepoints following cesarean section.

Background: Cesarean scar defect (CSD) is a potential complication following cesarean section (CS), which has significant clinical implications, and is usually clinically diagnosed by ultrasound. However, the optimal timing for ultrasound diagnosis of CSD after CS has not been well established. This study aimed to evaluate the appropriate time for the diagnosis of CSD after CS by ultrasonography. Methods: The prospective study involved 120 women who delivered by elective CS with single birth and term birth from January 2021 to June 2022. Sample enrollment was consecutive in the study. Each woman underwent 3 ultrasound examinations for CSD diagnosis at 6 weeks, 6 months, and 12 months postpartum according to a modified Delphi method. The ultrasound indicators about the incision situation were recorded and statistically analyzed. Paired 4-fold table chi-square test was used to evaluate the consistency between the 3 diagnoses. The diagnostic sensitivity and specificity were calculated using a 4-cell table. According to whether the diagnosis was consistent to that at 6 or 12 months, the 120 cases at week 6 were separated into a consistent group and inconsistent group for statistical evaluation of the ultrasound indicators. Additionally, the menstrual duration of the included women was also recorded to analyze the correlation to ultrasound indicators of CSD at 6 months postpartum using the Person correlation coefficient. Results: The included 120 women were divided into normal (3-7 days, n=52) and prolonged menstrual period (>7 days, n=68) groups. The 2 groups had no statistical differences in age, body mass index (BMI), gestational week of delivery, assisted reproduction rates, or postpartum complications. Among the 120 women, 100, 66, and 61 women were diagnosed as CSD at 6 weeks, 6 months, and 12 months postpartum, respectively. The results indicated that the diagnostic results of 6 weeks were inconsistent with those of 6 or 12 months postpartum, but the last 2 diagnostic results were consistent. The diagnostic sensitivity of 6 months was 100% and the specificity was 91.53% [95% confidence interval (CI): 85.84-95.26%]. Further, significant differences were found in depth of the defect, and the thickness (T) and ratio of residual muscle between the inconsistent group and the consistent group at 6 weeks. The patients could be considered self-recovered from CSD at 6 months when the defect depth was equal to or less than 4.04±0.82 mm at 6 weeks after CS. Additionally, in the CSD group at 6 months, the length (r=0.828, P<0.001), depth (r=0.784, P<0.001), width (r=0.787, P<0.001) of the defect, the T (r=0.831, P<0.001) and ratio of residual muscle (r=0.821, P<0.001) were strongly correlated with menstrual duration. Conclusions: CSD evaluation at week 6 after CS may cause misdiagnosis or overdiagnosis. The diagnosis of CSD was suggested to be made following 6 months or longer postpartum.

Molecular mechanism of co-stimulatory domains in promoting CAR-T cell anti-tumor efficacy.

Chimeric antigen receptor (CAR)-engineered T cells have been defined as 'living drug'. Adding a co-stimulatory domain (CSD) has enhanced the anti-hematological effects of CAR-T cells, thereby elevating their viability for medicinal applications. Various CSDs have helped prepare CAR-T cells to study anti-tumor efficacy. Previous studies have described and summarized the anti-tumor efficacy of CAR-T cells obtained from different CSDs. However, the underlying molecular mechanisms by which different CSDs affect CAR-T function have been rarely reported. The role of CSDs in T cells has been significantly studied, but whether they can play a unique role as a part of the CAR structure remains undetermined. Here, we summarized the effects of CSDs on CAR-T signaling pathways based on the limited references and speculated the possible mechanism depending on the specific characteristics of CAR-T cells. This review will help understand the molecular mechanism of CSDs in CAR-T cells that exert different anti-tumor effects while providing potential guidance for further interventions to enhance anti-tumor efficacy in immunotherapy.

The effect of P2X7 antagonism on subcortical spread of optogenetically-triggered cortical spreading depression and neuroinflammation.

Migraine is a neurological disorder characterized by episodes of severe headache. Cortical spreading depression (CSD), the electrophysiological equivalent of migraine aura, results in opening of pannexin 1 megachannels that release ATP and triggers parenchymal neuroinflammatory signaling cascade in the cortex. Migraine symptoms suggesting subcortical dysfunction bring subcortical spread of CSD under the light. Here, we investigated the role of purinergic P2X7 receptors on the subcortical spread of CSD and its consequent neuroinflammation using a potent and selective P2X7R antagonist, JNJ-47965567. P2X7R antagonism had no effect on the CSD threshold and characteristics but increased the latency to hypothalamic voltage deflection following CSD suggesting that ATP acts as a mediator in the subcortical spread. P2X7R antagonism also prevented cortical and subcortical neuronal activation following CSD, revealed by bilateral decrease in c-fos positive neuron count, and halted CSD-induced neuroinflammation revealed by decreased neuronal HMGB1 release and decreased nuclear translocation of NF-kappa B-p65 in astrocytes. In conclusion, our data suggest that P2X7R plays a role in CSD-induced neuroinflammation, subcortical spread of CSD and CSD-induced neuronal activation hence can be a potential target.

A common problem between gynecology, obstetrics, and reproductive medicine: Cesarean section scar defect.

Approximately 60% of patients undergoing Cesarean sections may develop Cesarean Scar Defect (CSD), presenting a significant clinical challenge amidst the increasing Cesarean section rates. This condition, marked by a notch in the anterior uterine wall, has evolved as a notable topic in gynecological research. The multifactorial origins of CSD can be broadly classified into labor-related factors, patients' physical conditions, and surgical quality. However, conflicting influences of certain factors across studies make it challenging to determine effective preventive strategies. Additionally, CSD manifests with diverse symptoms, such as abnormal uterine bleeding, dysmenorrhea, chronic pelvic pain, dyspareunia, secondary infertility, and Cesarean scar pregnancy. Some symptoms are often attributed to other diagnoses, leading to delayed treatment. The quandary of when and how to manage CSD also adds to the complexity. Despite the development of various therapies, clear indications and optimal methods for specific conditions remain elusive. This longstanding challenge has troubled clinicians in both identifying and addressing this iatrogenic disease. Recent studies have yielded some compelling consensuses on various aspects of CSD. This review aims to consolidate the current literature on every facet of CSD. We hope to raise awareness among clinicians about this clinical problem, encouraging more relevant research to unveil the complete picture of CSD.

Beyond the surface: how ex-vivo diffusion-weighted imaging reveals large animal brain microstructure and connectivity.

Diffusion-weighted Imaging (DWI) is an effective and state-of-the-art neuroimaging method that non-invasively reveals the microstructure and connectivity of tissues. Recently, novel applications of the DWI technique in studying large brains through ex-vivo imaging enabled researchers to gain insights into the complex neural architecture in different species such as those of Perissodactyla (e.g., horses and rhinos), Artiodactyla (e.g., bovids, swines, and cetaceans), and Carnivora (e.g., felids, canids, and pinnipeds). Classical in-vivo tract-tracing methods are usually considered unsuitable for ethical and practical reasons, in large animals or protected species. Ex-vivo DWI-based tractography offers the chance to examine the microstructure and connectivity of formalin-fixed tissues with scan times and precision that is not feasible in-vivo. This paper explores DWI's application to ex-vivo brains of large animals, highlighting the unique insights it offers into the structure of sometimes phylogenetically different neural networks, the connectivity of white matter tracts, and comparative evolutionary adaptations. Here, we also summarize the challenges, concerns, and perspectives of ex-vivo DWI that will shape the future of the field in large brains.

Hypersensitivity of Intrinsically Photosensitive Retinal Ganglion Cells in Migraine Induces Cortical Spreading Depression.

Migraine is a complex disorder characterized by episodes of moderate-to-severe, often unilateral headaches and generally accompanied by nausea, vomiting, and increased sensitivity to light (photophobia), sound (phonophobia), and smell (hyperosmia). Photophobia is considered the most bothersome symptom of migraine attacks. Although the underlying mechanism remains unclear, the intrinsically photosensitive retinal ganglion cells (ipRGCs) are considered to be involved in photophobia associated with migraine. In this study, we investigated the association between the sensitivity of ipRGCs and migraines and cortical spreading depression (CSD), which may trigger migraine attacks. The pupillary responses closely associated with the function of ipRGCs in patients with migraine who were irradiated with lights were evaluated. Blue (486 nm) light irradiation elicited a response from ipRGCs; however, red light (560 nm) had no such effect. Melanopsin, a photosensitive protein, phototransduces in ipRGCs following blue light stimulation. Hypersensitivity of ipRGCs was observed in patients with migraine. CSD was more easily induced with blue light than with incandescent light using a mouse CSD model. Moreover, CSD was suppressed, even in the presence of blue light, after injecting opsinamide, a melanopsin inhibitor. The hypersensitivity of ipRGCs in patients with migraine may induce CSD, resulting in migraine attacks.

Outcome of Patients With Systolic Heart Failure Who Underwent Sympathectomy for Ventricular Arrhythmia.

Cardiac sympathetic denervation (CSD) is a surgical procedure increasingly used for managing ventricular arrhythmia refractory to conventional medical therapy. Long-term outcomes of CSD in patients with systolic heart failure has not been well studied. This observational study aimed to evaluate the medical co-morbidities and outcomes of patients with systolic heart failure who underwent CSD performed as treatment for ventricular arrhythmia refractory to conventional therapy. A retrospective analysis in adult patients with ventricular arrhythmia and systolic heart failure who underwent unilateral or bilateral CSD at a single center was performed. Unadjusted Kaplan-Meier survival curves were constructed to evaluate survival after CSD. Between June 1, 2011 and March 31, 2021, 32 adult patients (age 62 ± 11.6 years, 88% male, left ventricular ejection fraction 22% ± 8.2%) with systolic heart failure underwent unilateral left (n = 4), unilateral right (n = 1), or bilateral CSD (n = 27). Mean survival after CSD was 613 ± 745 days, and the mean time from CSD to death was 291 ± 447 days. The cumulative probability of survival 1 year after CSD was 61.4%. In this single-center observational study, CSD performed for refractory ventricular arrhythmia showed favorable survival in patients with systolic heart failure. In conclusion, this study lays the groundwork for a more in-depth analysis of the potential survival benefits of CSD in this patient group.

Improving the ferroelectric properties of Lu doped Hf0.5Zr0.5O2thin films by capping a CeOxlayer.

Lu doped Hf0.5Zr0.5O2(HZO) ferroelectric films were prepared on Pt/TiN/SiO2/Si substrate by chemical solution deposition method, and an interfacial engineering strategy for improving the ferroelectric property was explored by capping the Lu doped HZO films with a cerium oxide layer. Compared with the Lu doped HZO film without the CeOxcoating layer, the Lu doped HZO film with the CeOxcoating layer has a larger remanent polarization (2Pr= 34.72µC cm-2) and presents weaker wake-up behavior, which result from the higher orthogonal phase ratio and the lower oxygen vacancy of the CeOxcoated Lu doped HZO film. In addition, the CeOxcoating can remarkably improve the fatigue resistance and retention performance of the Lu doped HZO films. It is hoped that the results can provide an effective approach for the realization of high-performance and highly reliable hafnium oxide based ferroelectric thin films.

The Role of Astrocytes in Migraine with Cortical Spreading Depression: Protagonists or Bystanders? A Narrative Review.

Cortical spreading depression (CSD) is a slow wave of cortical depolarization closely associated with migraines with an aura. Previously, it was thought that CSD depolarization was mainly driven by neurons, with characteristic changes in neuronal swelling and increased extracellular potassium (K+) and glutamate. However, the role of astrocytes, a member of the neurovascular unit, in migraine with CSD has recently received increasing attention. In the early stages of CSD, astrocytes provide neurons with energy support and clear K+ and glutamate from synaptic gaps. However, in the late stages of CSD, astrocytes release large amounts of lactic acid to exacerbate hypoxia when the energy demand exceeds the astrocytes' compensatory capacity. Astrocyte endfoot swelling is a characteristic of CSD, and neurons are not similarly altered. It is primarily due to K+ influx and abnormally active calcium (Ca2+) signaling. Aquaporin 4 (AQP-4) only mediates K+ influx and has little role as an aquaporin. Astrocytes endfoot swelling causes perivascular space closure, slowing the glymphatic system flow and exacerbating neuroinflammation, leading to persistent CSD. Astrocytes are double-edged swords in migraine with CSD and may be potential targets for CSD interventions.

Galanin diminishes cortical spreading depolarization across rodents - A candidate for treatment?

Galanin (Gal) is a neuropeptide with the potential to ameliorate cortical spreading depolarization (CSD), an electrophysiological phenomenon occurring after brain injury or in migraine aura. Gal is expressed in all cortical neurons both in rat and in mouse cortices. Here we investigated whether the effect of Gal on CSD previously described in the rat is conserved in the mouse cortex. In rats, the topical application of Gal to the cortex for 1 h did not induce any change in CSD amplitudes, propagation velocity, or threshold of elicitation. Rather, topical application of Gal for 3 h was necessary to obtain a significant decrease in these CSD parameters and to develop a remarkable increase in the KCl threshold to elicit a CSD in rat cortex. In contrast, the topical application of Gal on cortical surface for 1 h in mice was sufficient to significantly attenuate CSD amplitudes and increase threshold. A thinner cortex, a faster diffusion or different affinity/expression of receptors for Gal are possible reasons to explain this difference in the time course between rats and mice. Our data are relevant to postulate Gal as a potential target for inhibition of CSD under pathological situations such as stroke or ischemia. SIGNIFICANCE STATEMENT: The neuropeptide Galanin (Gal) is expressed in all neurons throughout the cerebral cortex, both in rats and mice, and is able to reduce or even inhibit Cortical Spreading Depolarization, thus, Gal has the potential to control neuronal excitability that may identify Gal as a target in drug development against CSD.

Thermal modal analysis of hypersonic composite wing on transient aerodynamic heating.

Considering the influence of thermal stress and material property variations, this study employs the Navier-Stokes equations and Fourier heat conduction law to establish a semi-implicit time-domain numerical analysis method for hypersonic aerothermal-structural coupling. Study the temporal variation pattern of different regions of the composite material wing under aerodynamic heating. Using the obtained transient temperature field of the wing, the thermal modal of the wing at different time points is calculated using the finite element method. Additionally, it conducts an analysis and discussion on the factors influencing the thermal modal. Composites can be effectively utilized as thermal protection materials for aircraft. During the aerodynamic heating process, the leading edge temperature reaches thermal equilibrium first, followed by the trailing edge, and the belly plate experiences a slower thermal response. Temperature rise significantly affects higher-order modes, with the change in material properties during the early stages of heating being the dominant factor. This leads to a faster decrease in natural frequency. As heat conduction progresses, the influencing factors of thermal stresses gradually increase, and the natural frequency decreases slowly or even rises.

Post-COVID reactivation of latent Bartonella henselae infection: a case report and literature review.

Cat scratch disease (CSD) is caused by Bartonella henselae (B. henselae) and presents as lymphadenopathy following close contact with cats. However, in context of the global COVID-19 pandemic, clinical manifestations of CSD may vary, posing new challenges for healthcare professionals. Here we describe a case of a 54-year-old male with painful left upper arm mass, which gradually resolved until he was infected with COVID-19. The mass then rapidly progressed before admission. Meanwhile, pulmonary symptoms including pleural effusion emerged simultaneously. The cause was undetermined with routine blood culture and pathological test until the next generation sequencing (NGS) confirmed the presence of B. henselae. We believe this case is the first to report localized aggravation of CSD after COVID-19 infection and hopefully, offers treatment experience for clinicians worldwide.

Exploration of the influence of the quantification method and reference scheme on feedback-related negativity and standardized measurement error of feedback-related negativity amplitudes in a trust game.

Various approaches have been taken over the years to quantify event-related potential (ERP) responses and these approaches may vary in their utility connecting empirical research and scientific claims. In this work we compared different quantification methods as well as the influence of three reference methods (linked mastoids, average reference, and current source density) on the resulting ERP amplitude. We use the experimental effects and effect sizes (Cohen's d) to evaluate the different methodological variants and we calculate intraclass correlation coefficients (ICC). In addition, the bootstrapped standard error of the means (SME, Luck et al., 2021), which was recently suggested as a quality criterion for ERP research, is used for this purpose. Our example for an ERP is the feedback-related negativity (FRN) to feedback about trustee behavior in a trust game with participants in the trustor position. We found that the quantification methods concerning the FRN influenced the absolute value of condition effects in the experimental paradigm. Yet, the patterns of effects were detected by all chosen methods, except for the 'individual difference wave'-based peak window approach. In addition, our findings stress the importance of checking the reference electrodes concerning effects of the experimental conditions. Furthermore, interactions of topographical distribution and reference choice should be considered. Finally, we were able to show that the SME is lower for more datapoints that are given in the quantification period of the FRN, and higher for more negative FRN amplitudes. These biases may lead to divergence of SME and effect size detection. Therefore, if the SME was used to compare different processing choices one should consider controlling for these important aspects of the data and possibly include other quality criteria like effect sizes.

Constrained spherical deconvolution on diffusion-weighted images of dolphin brains.

Invasive neuronal tract-tracing is not permitted in very large or endangered animals. This is especially the case in marine mammals like dolphins. Diffusion-weighted imaging of fiber tracts could be an alternative if feasible even in brains that have been fixed in formalin for a long time. This currently is a problem, especially for detecting crossing fibers. We applied a state-of-the-art algorithm of Diffusion-weighted imaging called Constrained Spherical Deconvolution on diffusion data of three fixed brains of bottlenose dolphins using clinical human MRI parameters and were able to identify complex fiber patterns within a voxel. Our findings indicate that in order to maintain the structural integrity of the tissue, short-term post-mortem fixation is necessary. Furthermore, pre-processing steps are essential to remove the classical Diffusion-weighted imaging artifacts from images: however, the algorithm is still able to resolve fiber tracking in regions with various signal intensities. The described imaging technique reveals complex fiber patterns in cetacean brains that have been preserved in formalin for extended periods of time and thus opens a new window into our understanding of cetacean neuroanatomy.

In vivo microstructural heterogeneity of white matter and cognitive correlates in aging using tissue compositional analysis of diffusion magnetic resonance imaging.

BACKGROUND: Age-related cognitive decline is linked to changes in the brain, particularly the deterioration of white matter (WM) microstructure that accelerates after the age of 60. WM deterioration is associated with mild cognitive impairment and dementia, but the origin and role of white matter signal abnormalities (WMSA) seen in standard MRI remain debated due to their heterogeneity. This study explores the potential of single-shell 3-tissue constrained spherical deconvolution (SS3T-CSD), a novel technique that models diffusion data in terms of gray matter (TG ), white matter (Tw ), and cerebrospinal fluid (TC ), to differentiate WMSA from normal-appearing white matter and better understand the interplay between changes in WM microstructure and decline in cognition. METHODS: A total of 189 individuals from the GENIC cohort were included. MRI data, including T1-weighted and diffusion images, were obtained. Preprocessing steps were performed on the diffusion MRI data, followed by the SS3T-CSD. WMSA were segmented using FreeSurfer. Statistical analyses were conducted to assess the association between age, WMSA volume, 3-tissue signal fractions (Tw , TG , and TC ), and neuropsychological variables. RESULTS: Participants above 60 years old showed worse cognitive performance and processing speed compared to those below 60 (p < .001). Age was negatively associated with Tw in normal-appearing white matter (p < .001) and positively associated with TG in both WMSA (p < .01) and normal-appearing white matter (p < .001). Age was also significantly associated with WMSA volume (p < .001). Higher processing speed was associated with lower Tw and higher TG , in normal-appearing white matter (p < .01 and p < .001, respectively), as well as increased WMSA volume (p < .001). Similarly, lower MMSE scores correlated with lower Tw and higher TG in normal-appearing white matter (p < .05). High cholesterol and hypertension were associated with higher WMSA volume (p < .05). CONCLUSION: The microstructural heterogeneity within normal-appearing white matter and WMSA is associated with increasing age and cognitive variation, in cognitively unimpaired individuals. Furthermore, the 3-tissue signal fractions are more specific to potential white matter alterations than conventional MRI measures such as WMSA volume. These findings also support the view that the WMSA volumes may be more influenced by vascular risk factors than the 3-tissue metrics. Finally, the 3-tissue metrics were able to capture associations with cognitive tests and therefore capable of capturing subtle pathological changes in the brain in individuals who are still within the normal range of cognitive performance.