Digital Biomarkers for the Assessment of Non-Cognitive Symptoms in Patients with Dementia with Lewy Bodies: A Systematic Review.

Background: Portable digital health technologies (DHTs) could help evaluate non-cognitive symptoms, but evidence to support their use in patients with dementia with Lewy bodies (DLB) is uncertain. Objective: 1) To describe portable or wearable DHTs used to obtain digital biomarkers in patients with DLB, 2) to assess the digital biomarkers' ability to evaluate non-cognitive symptoms, and 3) to assess the feasibility of applying digital biomarkers in patients with DLB. Methods: We systematically searched databases MEDLINE, Embase, and Web of Science from inception through February 28, 2023. Studies assessing digital biomarkers obtained by portable or wearable DHTs and related to non-cognitive symptoms were eligible if including patients with DLB. The quality of studies was assessed using a modified check list based on the NIH Quality assessment tool for Observational Cohort and Cross-sectional Studies. A narrative synthesis of data was carried out. Results: We screened 4,295 records and included 20 studies. Seventeen different DHTs were identified for assessment of most non-cognitive symptoms related to DLB. No thorough validation of digital biomarkers for measurement of non-cognitive symptoms in DLB was reported. Studies did not report on aspects of feasibility in a systematic way. Conclusions: Knowledge about feasibility and validity of individual digital biomarkers remains extremely limited. Study heterogeneity is a barrier for establishing a broad evidence base for application of digital biomarkers in DLB. Researchers should conform to recommended standards for systematic evaluation of digital biomarkers.

Differentiating anti-IgLON5 disease and Lewy body dementia: a systematic review.

BACKGROUND: Anti-IgLON5 disease is a rare but potentially reversible cause of cognitive impairment, sleep disturbances, dysautonomia, and movement disorders. It is an autoimmune encephalitis which, due to its insidious onset, could mimic neurodegenerative disorders, and multiple symptoms overlap with those seen in dementia with Lewy bodies (DLB). We hypothesized that the symptomatology and findings in patients with anti-IgLON5 disease overlapped with that of DLB. OBJECTIVES: To assess the commonality of features in anti-IgLON5 disease and DLB and identify potential red flags for anti-IgLON5 disease in patients undergoing diagnostic evaluation for DLB. METHODS: We searched in MEDLINE, Web of Science, and Embase from inception on December the 8th, 2022 with the search term "IgLON5". We performed a systematic review of case reports and case series of anti-IgLON5 disease, and two reviewers independently extracted data on symptoms and findings. Frequencies of symptoms were compared with consensus criteria for DLB. RESULTS: We included 57 studies with 127 individual case reports of anti-IgLON5 disease (mean age 63 years at diagnosis, median symptom duration 2 years). Cognitive dysfunction was reported in 45% of cases, REM-sleep behavioral disorder in 15%, and 14% had parkinsonism. Respiratory insufficiency was reported in 37%, and bulbar symptoms in 67%. CONCLUSIONS: We found a significant overlap between anti-IgLON5 disease and DLB. We propose that anti-IgLON5 disease should be considered in young patients with DLB with chorea, gaze palsy, early dysphagia, or prominent respiratory symptoms. Our study contributes to the emerging knowledge on symptoms and biomarkers in anti-IgLON5 disease.

Cerebrospinal fluid erythropoietin, oxidative stress, and cognitive functions in patients with bipolar disorder and healthy control participants: A longitudinal case-control study.

Persistent cognitive impairments occur in a large proportion of patients with bipolar disorder (BD) but their underlying pathological cellular processes are unclear. The aims of this longitudinal study of BD and healthy control (HC) participants were to investigate (i) the association of brain erythropoietin (EPO) and oxidative stress with cognitive functions and (ii) the changes in brain EPO during and after affective episodes. Participants underwent neurocognitive testing, lumbar punctures for cerebrospinal fluid (CSF) sampling and provided urine spot tests at baseline (all), after an affective episode (patients) and after one year (all). EPO was assayed in the CSF and oxidative stress metabolites related to RNA and DNA damage (8-dihydroguanosine [8-oxo-Guo], 8-hydroxy-2-deoxyguanosine [8-oxo-dG]) were assayed in the CSF and spot urine. Data was available for analyses for 60 BD and 37 HC participants. In unadjusted primary analyses, verbal memory decreased with increasing concentrations of CSF EPO and oxidative stress. In unadjusted explorative analyses, poorer verbal memory and psychomotor speed were associated with higher levels of oxidative stress. However, no associations between cognitive functions and CSF levels of EPO or oxidative stress were observed after adjustment for multiple testing. CSF EPO concentrations were unchanged during and after affective episodes. While CSF EPO correlated negatively with CSF DNA damage marker 8-oxo-dG, this association rendered non-significant after adjusting for multiple testing. In conclusion, EPO and oxidative stress do not seem to be robustly related to cognitive status in BD. Further insight into the cellular processes involved in cognitive impairments in BD is necessary to pave the way for novel therapeutic strategies to improve patients' cognitive outcomes.

Autocorrelation functions and power spectral densities of the Stokes parameters in a polarization speckle pattern.

The concept of ensemble-average polarization and coherence has been applied to studying fluctuating Stokes parameters in a polarization speckle observed when coherent light is passed through a birefringent polarization scrambler. With the aid of the ensemble-average van Cittert-Zernike theorem for the propagation of ensemble-average polar-coherence, we invesitgate the autocorrelation functions and power spectra of the Stokes parameters to expose the dependence of the polarization-related scale-size distributions on the optical geometries in which the polarization speckle arises. A generalized concept of the Stokes ensemble-average coherence areas is introduced to deal with the polarization-related average areas associated with polarization speckle.

Membrane transporters control cerebrospinal fluid formation independently of conventional osmosis to modulate intracranial pressure.

BACKGROUND: Disturbances in the brain fluid balance can lead to life-threatening elevation in the intracranial pressure (ICP), which represents a vast clinical challenge. Nevertheless, the details underlying the molecular mechanisms governing cerebrospinal fluid (CSF) secretion are largely unresolved, thus preventing targeted and efficient pharmaceutical therapy of cerebral pathologies involving elevated ICP. METHODS: Experimental rats were employed for in vivo determinations of CSF secretion rates, ICP, blood pressure and ex vivo excised choroid plexus for morphological analysis and quantification of expression and activity of various transport proteins. CSF and blood extractions from rats, pigs, and humans were employed for osmolality determinations and a mathematical model employed to determine a contribution from potential local gradients at the surface of choroid plexus. RESULTS: We demonstrate that CSF secretion can occur independently of conventional osmosis and that local osmotic gradients do not suffice to support CSF secretion. Instead, the CSF secretion across the luminal membrane of choroid plexus relies approximately equally on the Na+/K+/2Cl- cotransporter NKCC1, the Na+/HCO3- cotransporter NBCe2, and the Na+/K+-ATPase, but not on the Na+/H+ exchanger NHE1. We demonstrate that pharmacological modulation of CSF secretion directly affects the ICP. CONCLUSIONS: CSF secretion appears to not rely on conventional osmosis, but rather occur by a concerted effort of different choroidal transporters, possibly via a molecular mode of water transport inherent in the proteins themselves. Therapeutic modulation of the rate of CSF secretion may be employed as a strategy to modulate ICP. These insights identify new promising therapeutic targets against brain pathologies associated with elevated ICP.

Treatment Challenges When Stopping Denosumab.

Introduction Denosumab is commonly used to treat osteoporosis. However, discontinuation results in rebound bone loss and increased vertebral fracture risk. We report a clinical case series, illustrating the dilemma in deciding the best treatment should denosumab be stopped. Cases In eight patients aged 56-89 years, zolendronic acid after stopping denosumab resulted in BTM rises and BMD decline.  In a 68-year-old, two years of oral bisphosphonate after three years of denosumab resulted in elevated bone turnover markers (BTM) and decline in bone mineral density (BMD), necessitating a switch to zoledronic acid.  In a 79-year-old, two annual doses of zolendronic acid after three years of denosumab failed to suppress high BTM, with BMD dropping and denosumab being restarted.  In a 60-year-old, on stopping denosumab after 10 years of oral bisphosphonate, BMD remained stable despite no further therapy. Conclusion Drug holidays are not an option with denosumab, with a risk of bone loss even on transitioning to bisphosphonates. Risk is greater with longer duration of treatment6 and may be mitigated by prior bisphosphonate use. Standard dose zoledronic acid does not prevent bone loss in a significant proportion of patients. BTM may help in monitoring treatment and need for further bisphosphonates.

Speckle-displacement-based wavemeter for mode-hop and side-mode detection.

A speckle-displacement-based wavemeter is combined with a spatial-fundamental-mode-pass filter to eliminate the influence of multimode operation on the directionality of the resulting output from a distributed Bragg reflector (DBR) tapered laser. The proposed setup is characterized theoretically and experimentally, and detections of mode hops and side-mode suppression ratios (SMSRs) in the optical output are demonstrated. The laser illuminates a rough surface at an oblique angle, and a camera observes the corresponding speckle pattern from an almost identical back-scattering direction. As the wavelength of the laser shifts, the speckle pattern responds with a corresponding displacement, which is approximately linear with respect to the shift within the detection area. The wavemeter tracks continuously the shifts of the speckles pattern by tracking the peak of the covariance function of sequentially acquired images. In this way, the speckle-displacement-based wavemeter achieves a spectral resolution of 10.4 MHz. Mode hops in the laser do not cause any impeding decorrelation of the speckle patterns. Interestingly, the actual SMSR is related to the peak height and width of the absolute covariance function. A wavemeter, which is capable of measuring wavelengths, mode hops, and SMSRs, is highly useful for spectroscopy, quantum optics, nonlinear frequency conversion, and other applications requiring stable single-frequency laser light, especially when using diode lasers.

Ovarian toxicity of carboplatin and paclitaxel in mouse carriers of mutation in BRIP1 tumor suppressor gene.

More than 10% of women diagnosed with breast cancer during reproductive age carry hereditary germline pathogenic variants in high-penetrance BRCA genes or in others genes involved in DNA repair mechanisms such as PALB2, BRIP or ATM. Anticancer treatments may have an additional negative impact on the ovarian reserve and subsequently on the fertility of young patients carrying such mutations. Recently, the combination of carboplatin and paclitaxel is being recommended to these BRCA-mutated patients as neoadjuvant therapy. However, the impact on the ovary is unknown. Here, we investigated their effect of on the ovarian reserve using mice carriers of BRCA1-interacting protein C-terminal helicase-1 (BRIP1) mutation that plays an important role in BRCA1-dependent DNA repair. Results revealed that the administration of carboplatin or paclitaxel did not affect the ovarian reserve although increased DNA double-strand breaks were observed with carboplatin alone. Co-administration of carboplatin and paclitaxel resulted in a significant reduction of the ovarian reserve leading to a lower IVF performance, and an activation of the PI3K-Pten pathway, irrespective of the genetic background. This study suggests that co-administration of carboplatin and paclitaxel induces cumulative ovarian damage and infertility but a heterozygote genetic predisposition for DNA damage related to BRCA1 gene function does not increase this risk.

Comparing a Single Clinician Versus a Multidisciplinary Consensus Conference Approach for Dementia Diagnostics.

BACKGROUND: Evidence-based recommendations on the optimal evaluation approach for dementia diagnostics are limited. This impedes a harmonized workup across clinics and nations. OBJECTIVE: To evaluate the diagnostic performance of a multidisciplinary consensus conference compared to a single clinician approach. METHODS: In this prospective study, we enrolled 457 patients with suspected cognitive decline, from two European memory clinics. A diagnostic evaluation was performed at baseline independently in two ways: 1) by a single clinician and 2) at a multidisciplinary consensus conference. A syndrome diagnosis and an etiological diagnosis was made. The confidence in the diagnosis was recorded using a visual analogue scale. An expert panel re-evaluation diagnosis served as reference for the baseline syndrome diagnosis and a 12-24-month follow-up diagnosis for the etiological diagnosis. RESULTS: 439 patients completed the study. We observed 12.5%discrepancy (k = 0.81) comparing the baseline syndrome diagnoses of the single clinician to the consensus conference, and 22.3%discrepancy (k = 0.68) for the baseline etiological diagnosis. The accuracy of the baseline etiological diagnosis was significantly higher at the consensus conference and was driven mainly by increased accuracy in the MCI group. Confidence in the etiological diagnosis at baseline was significantly higher at the consensus conference (p < 0.005), especially for the frontotemporal dementia diagnosis. CONCLUSION: The multidisciplinary consensus conference performed better on diagnostic accuracy of disease etiology and increased clinicians' confidence. This highlights the importance of a multidisciplinary diagnostic evaluation approach for dementia diagnostics, especially when evaluating patients in the MCI stage.

Random object optical field diagnostics by using carbon nanoparticles.

We propose a new approach of using carbon nanoparticles for correlation optical diagnostics of а complex scalar optical field created by scattering and diffraction of radiation off a rough surface. This surface is simulated and we generate a diffraction pattern of the amplitude and phase distribution in the far field. Carbon nanoparticles of a certain size and concentration are obtained by the bottom-up methods of hydrothermal synthesis of citric acid and urea followed by centrifugation. The optical properties of carbon nanoparticles, such as luminescence and absorption in the visible spectrum that essentially differs for different wavelengths, as well as particle size of about dozen nanometers, are the determining criteria for using these particles as probes for the optical speckle field. Luminescence made it possible to register the coordinate position of carbon nanoparticles in real time. The algorithm for reconstruction of the scalar optical field intensity distribution through the analysis of the nanoparticle positions is here displayed. The skeleton of the optical speckle field is analyzed by Hilbert transform to restore the phase. Special attention is paid to the restoration of the speckle field's phase singularities.

The role of physical and cognitive function in performance of activities of daily living in patients with mild-to-moderate Alzheimer's disease - a cross-sectional study.

BACKGROUND: Several factors may play a role in the ability of patients with Alzheimer's disease to perform activities of daily living (ADL). The aim of this study was to examine the impact of different aspects of physical performance and cognitive functions on ADL in patients suffering from mild-to-moderate Alzheimer's disease. METHODS: We conducted secondary analyses on cross-sectional baseline data from the randomized controlled multicentre study "Preserving quality of life, physical health and functional ability in Alzheimer's Disease: The effect of physical exercise" (ADEX). In total, 185 AD patients (76 women and 109 men), with a mean age on 70,4 years, were included. Data from physical performance tests (Astrand cycle test, Timed up & Go (TUG), Sit to Stand test (STS)) and cognitive tests (Mini Mental Status Examination (MMSE), Symbol Digit Modalities Test (SDMT), Stroop Color and Word test (Stroop)) were used. Their associations with ADL, measured on the ADCS-ADL scale was assessed in multivariable regression analyses. RESULTS: SDMT and MMSE had significant, moderate correlations with total ADL (SDMT: r = 0.33, MMSE: r = 0.42) and instrumental ADL (SDMT: r = 0.31, MMSE: r = 0.42), but not with basic ADL. Adjusting for age and sex, the associations between SDMT and MMSE to total ADL and instrumental ADL persisted. No significant associations were found between Astrand, TUG, STS or Stroop and total ADL, basic ADL or instrumental ADL. CONCLUSION: Total ADL and instrumental ADL are associated with cognitive functions, including executive function. No significant association between examined physical performance parameters and ADL functions was observed, and consequently does not support an impact of physical function on ADL functions in patients with mild-to-moderate Alzheimer's disease and relatively well-preserved physical function. Strategies aimed to improve cognition may be better suited to improve ADL function in patients with mild-to-moderate Alzheimer's disease. TRIAL REGISTRATION: NCT01681602 . Registered 10 September 2012, retrospectively registered.

Gait Disturbances are Associated with Increased Cognitive Impairment and Cerebrospinal Fluid Tau Levels in a Memory Clinic Cohort.

BACKGROUND: Gait analysis with accelerometers is a relatively inexpensive and easy to use method to potentially support clinical diagnoses of Alzheimer's disease and other dementias. It is not clear, however, which gait features are most informative and how these measures relate to Alzheimer's disease pathology. OBJECTIVE: In this study, we tested if calculated features of gait 1) differ between cognitively normal subjects (CN), mild cognitive impairment (MCI) patients, and dementia patients, 2) are correlated with cerebrospinal fluid (CSF) biomarkers related to Alzheimer's disease, and 3) predict cognitive decline. METHODS: Gait was measured using tri-axial accelerometers attached to the fifth lumbar vertebra (L5) in 58 CN, 58 MCI, and 26 dementia participants, while performing a walk and dual task. Ten gait features were calculated from the vertical L5 accelerations, following principal component analysis clustered in four domains, namely pace, rhythm, time variability, and length variability. Cognitive decline over time was measured using MMSE, and CSF biomarkers were available in a sub-group. RESULTS: Linear mixed models showed that dementia patients had lower pace scores than MCI patients and CN subjects (p < 0.05). In addition, we found associations between the rhythm domain and CSF-tau, especially in the dual task. Gait was not associated with CSF Aß42 levels and cognitive decline over time as measured with the MMSE. CONCLUSION: These findings suggest that gait - particularly measures related to pace and rhythm - are altered in dementia and have a direct link with measures of neurodegeneration.

Selection of memory clinic patients for CSF biomarker assessment can be restricted to a quarter of cases by using computerized decision support, without compromising diagnostic accuracy.

INTRODUCTION: An accurate and timely diagnosis for Alzheimer's disease (AD) is important, both for care and research. The current diagnostic criteria allow the use of CSF biomarkers to provide pathophysiological support for the diagnosis of AD. How these criteria should be operationalized by clinicians is unclear. Tools that guide in selecting patients in which CSF biomarkers have clinical utility are needed. We evaluated computerized decision support to select patients for CSF biomarker determination. METHODS: We included 535 subjects (139 controls, 286 Alzheimer's disease dementia, 82 frontotemporal dementia and 28 vascular dementia) from three clinical cohorts. Positive (AD like) and negative (normal) CSF biomarker profiles were simulated to estimate whether knowledge of CSF biomarkers would impact (confidence in) diagnosis. We applied these simulated CSF values and combined them with demographic, neuropsychology and MRI data to initiate CSF testing (computerized decision support approach). We compared proportion of CSF measurements and patients diagnosed with sufficient confidence (probability of correct class ≥0.80) based on an algorithm with scenarios without CSF (only neuropsychology, MRI and APOE), CSF according to the appropriate use criteria (AUC) and CSF for all patients. RESULTS: The computerized decision support approach recommended CSF testing in 140 (26%) patients, which yielded a diagnosis with sufficient confidence in 379 (71%) of all patients. This approach was more efficient than CSF in none (0% CSF, 308 (58%) diagnosed), CSF selected based on AUC (295 (55%) CSF, 350 (65%) diagnosed) or CSF in all (100% CSF, 348 (65%) diagnosed). CONCLUSIONS: We used a computerized decision support with simulated CSF results in controls and patients with different types of dementia. This approach can support clinicians in making a balanced decision in ordering additional biomarker testing. Computer-supported prediction restricts CSF testing to only 26% of cases, without compromising diagnostic accuracy.

Ageing as a risk factor for neurodegenerative disease.

Ageing is the primary risk factor for most neurodegenerative diseases, including Alzheimer disease (AD) and Parkinson disease (PD). One in ten individuals aged ≥65 years has AD and its prevalence continues to increase with increasing age. Few or no effective treatments are available for ageing-related neurodegenerative diseases, which tend to progress in an irreversible manner and are associated with large socioeconomic and personal costs. This Review discusses the pathogenesis of AD, PD and other neurodegenerative diseases, and describes their associations with the nine biological hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, deregulated nutrient sensing, stem cell exhaustion and altered intercellular communication. The central biological mechanisms of ageing and their potential as targets of novel therapies for neurodegenerative diseases are also discussed, with potential therapies including NAD+ precursors, mitophagy inducers and inhibitors of cellular senescence.

Moderate- to high-intensity exercise does not modify cortical ß-amyloid in Alzheimer's disease.

INTRODUCTION: Animal models of Alzheimer's disease show that exercise may modify ß-amyloid (Aß) deposition. We examined the effect of a 16-week exercise intervention on cortical Aß in patients with mild-to-moderate Alzheimer's disease. METHODS: Thirty-six patients with Alzheimer's disease were randomized to either one hour of aerobic exercise three times weekly for 16 weeks or usual care. Pre and post intervention, 11Carbon-Pittsburgh compound B positron emission tomography was carried out to assess cortical Aß, and quantified using standardized uptake value rations (SUVRs). RESULTS: The intervention showed no effect on follow-up SUVRs in a covariance analysis with group allocation, baseline intervention SUVR, age, sex, and baseline Mini-Mental State Examination as predictors. Change in SUVRs did not correlate with changes in measures of physical or aerobic fitness. DISCUSSION: The present findings do not support an effect of exercise on Aß. However, the relatively short intervention period may account for a lack of efficacy. Further studies should test earlier and longer interventions.

Impact of a clinical decision support tool on prediction of progression in early-stage dementia: a prospective validation study.

BACKGROUND: In clinical practice, it is often difficult to predict which patients with cognitive complaints or impairment will progress or remain stable. We assessed the impact of using a clinical decision support system, the PredictND tool, to predict progression in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI) in memory clinics. METHODS: In this prospective multicenter study, we included 429 patients with SCD (n = 230) and MCI (n = 199) (female 54%, age 67 ± 9, MMSE 28 ± 2) and followed them for at least 12 months. Based on all available patient baseline data (demographics, cognitive tests, cerebrospinal fluid biomarkers, and MRI), the PredictND tool provides a comprehensive overview of the data and a classification defining the likelihood of progression. At baseline, a clinician defined an expected follow-up diagnosis and estimated the level of confidence in their prediction using a visual analogue scale (VAS, 0-100%), first without and subsequently with the PredictND tool. As outcome measure, we defined clinical progression as progression from SCD to MCI or dementia, and from MCI to dementia. Correspondence between the expected and the actual clinical progression at follow-up defined the prognostic accuracy. RESULTS: After a mean follow-up time of 1.7 ± 0.4 years, 21 (9%) SCD and 63 (32%) MCI had progressed. When using the PredictND tool, the overall prognostic accuracy was unaffected (0.4%, 95%CI - 3.0%; + 3.9%; p = 0.79). However, restricting the analysis to patients with more certain classifications (n = 203), we found an increase of 3% in the accuracy (95%CI - 0.6%; + 6.5%; p = 0.11). Furthermore, for this subgroup, the tool alone showed a statistically significant increase in the prognostic accuracy compared to the evaluation without tool (6.4%, 95%CI 2.1%; 10.7%; p = 0.004). Specifically, the negative predictive value was high. Moreover, confidence in the prediction increased significantly (∆VAS = 4%, p < .0001). CONCLUSIONS: Adding the PredictND tool to the clinical evaluation increased clinicians' confidence. Furthermore, the results indicate that the tool has the potential to improve prediction of progression for patients with more certain classifications.

Automatically computed rating scales from MRI for patients with cognitive disorders.

OBJECTIVES: The aims of this study were to examine whether visual MRI rating scales used in diagnostics of cognitive disorders can be estimated computationally and to compare the visual rating scales with their computed counterparts in differential diagnostics. METHODS: A set of volumetry and voxel-based morphometry imaging biomarkers was extracted from T1-weighted and FLAIR images. A regression model was developed for estimating visual rating scale values from a combination of imaging biomarkers. We studied three visual rating scales: medial temporal lobe atrophy (MTA), global cortical atrophy (GCA), and white matter hyperintensities (WMHs) measured by the Fazekas scale. Images and visual ratings from the Amsterdam Dementia Cohort (ADC) (N = 513) were used to develop the models and cross-validate them. The PredictND (N = 672) and ADNI (N = 752) cohorts were used for independent validation to test generalizability. RESULTS: The correlation coefficients between visual and computed rating scale values were 0.83/0.78 (MTA-left), 0.83/0.79 (MTA-right), 0.64/0.64 (GCA), and 0.76/0.75 (Fazekas) in ADC/PredictND cohorts. When performance in differential diagnostics was studied for the main types of dementia, the highest balanced accuracy, 0.75-0.86, was observed for separating different dementias from cognitively normal subjects using computed GCA. The lowest accuracy of about 0.5 for all the visual and computed scales was observed for the differentiation between Alzheimer's disease and frontotemporal lobar degeneration. Computed scales produced higher balanced accuracies than visual scales for MTA and GCA (statistically significant). CONCLUSIONS: MTA, GCA, and WMHs can be reliably estimated automatically helping to provide consistent imaging biomarkers for diagnosing cognitive disorders, even among less experienced readers. KEY POINTS: • Visual rating scales used in diagnostics of cognitive disorders can be estimated computationally from MRI images with intraclass correlations ranging from 0.64 (GCA) to 0.84 (MTA). • Computed scales provided high diagnostic accuracy with single-subject data (area under the receiver operating curve range, 0.84-0.94).

Detecting frontotemporal dementia syndromes using MRI biomarkers.

BACKGROUND: Diagnosing frontotemporal dementia may be challenging. New methods for analysis of regional brain atrophy patterns on magnetic resonance imaging (MRI) could add to the diagnostic assessment. Therefore, we aimed to develop automated imaging biomarkers for differentiating frontotemporal dementia subtypes from other diagnostic groups, and from one another. METHODS: In this retrospective multicenter cohort study, we included 1213 patients (age 67 ±â€¯9, 48% females) from two memory clinic cohorts: 116 frontotemporal dementia, 341 Alzheimer's disease, 66 Dementia with Lewy bodies, 40 vascular dementia, 104 other dementias, 229 mild cognitive impairment, and 317 subjective cognitive decline. Three MRI atrophy biomarkers were derived from the normalized volumes of automatically segmented cortical regions: 1) the anterior vs. posterior index, 2) the asymmetry index, and 3) the temporal pole left index. We used the following performance metrics: area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. To account for the low prevalence of frontotemporal dementia we pursued a high specificity of 95%. Cross-validation was used in assessing the performance. The generalizability was assessed in an independent cohort (n = 200). RESULTS: The anterior vs. posterior index performed with an AUC of 83% for differentiation of frontotemporal dementia from all other diagnostic groups (Sensitivity = 59%, Specificity = 95%, positive likelihood ratio = 11.8, negative likelihood ratio = 0.4). The asymmetry index showed highest performance for separation of primary progressive aphasia and behavioral variant frontotemporal dementia (AUC = 85%, Sensitivity = 79%, Specificity = 92%, positive likelihood ratio = 9.9, negative likelihood ratio = 0.2), whereas the temporal pole left index was specific for detection of semantic variant primary progressive aphasia (AUC = 85%, Sensitivity = 82%, Specificity = 80%, positive likelihood ratio = 4.1, negative likelihood ratio = 0.2). The validation cohort provided corresponding results for the anterior vs. posterior index and temporal pole left index. CONCLUSION: This study presents three quantitative MRI biomarkers, which could provide additional information to the diagnostic assessment and assist clinicians in diagnosing frontotemporal dementia.

Impact of a Clinical Decision Support Tool on Dementia Diagnostics in Memory Clinics: The PredictND Validation Study.

BACKGROUND: Determining the underlying etiology of dementia can be challenging. Computer- based Clinical Decision Support Systems (CDSS) have the potential to provide an objective comparison of data and assist clinicians. OBJECTIVES: To assess the diagnostic impact of a CDSS, the PredictND tool, for differential diagnosis of dementia in memory clinics. METHODS: In this prospective multicenter study, we recruited 779 patients with either subjective cognitive decline (n=252), mild cognitive impairment (n=219) or any type of dementia (n=274) and followed them for minimum 12 months. Based on all available patient baseline data (demographics, neuropsychological tests, cerebrospinal fluid biomarkers, and MRI visual and computed ratings), the PredictND tool provides a comprehensive overview and analysis of the data with a likelihood index for five diagnostic groups; Alzheimer´s disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia and subjective cognitive decline. At baseline, a clinician defined an etiological diagnosis and confidence in the diagnosis, first without and subsequently with the PredictND tool. The follow-up diagnosis was used as the reference diagnosis. RESULTS: In total, 747 patients completed the follow-up visits (53% female, 69±10 years). The etiological diagnosis changed in 13% of all cases when using the PredictND tool, but the diagnostic accuracy did not change significantly. Confidence in the diagnosis, measured by a visual analogue scale (VAS, 0-100%) increased (ΔVAS=3.0%, p<0.0001), especially in correctly changed diagnoses (ΔVAS=7.2%, p=0.0011). CONCLUSION: Adding the PredictND tool to the diagnostic evaluation affected the diagnosis and increased clinicians' confidence in the diagnosis indicating that CDSSs could aid clinicians in the differential diagnosis of dementia.

Role of temperature in de-mixing absorbance spectra composed of compound electrolyte solutions.

This work is focused on the role of temperature in the de-mixing of absorbance spectra measured in mixed aqueous Na2SO4 and NaNO3 solutions. First, the influence of temperature on the absorbance spectrum of demineralized water was determined. Second, the absorbance spectra of five separate electrolytes (NaNO2, NaNO3, CaCl2, K2CO3, and NaOH) at three temperatures (4°C, 25°C, and 50°C) for concentrations ranging from 0.0625 M to 0.5 M were examined. These five electrolytes show similar temperature dependencies. Finally, absorbance spectra of mixed solutions were investigated at temperatures of 5°C, 15°C, 25°C, 35°C, and 45°C for concentrations ranging from 0.0625 M to 0.5 M per electrolyte in the mixture. The spectral window from 650 to 1100 nm was utilized to observe the ionic and temperature influences on the vibrational modes of the OH bond in the solvent molecules. The effects of dissolving Na2SO4 and NaNO3 are nonlinearly cumulative at lower temperatures indicating extended alteration of the water structure beyond the first hydration shell. A similar trend was observed for a mixture of Na2CO3 and NaCl. Furthermore, it was found that higher temperatures are better for recovering the separate component absorption signatures of an electrolyte mixture. The near-infrared spectral regime is well suited for integrated sensing, and therefore these results can help in designing an integrated sensor to identify inorganic species in water.