"So at least now I know how to deal with things myself, what I can do if it gets really bad again"-experiences with a long-term cross-sectoral advocacy care and case management for severe multiple sclerosis: a qualitative study.

BACKGROUND: Persons with severe Multiple Sclerosis (PwsMS) face complex needs and daily limitations that make it challenging to receive optimal care. The implementation and coordination of health care, social services, and support in financial affairs can be particularly time consuming and burdensome for both PwsMS and caregivers. Care and case management (CCM) helps ensure optimal individual care as well as care at a higher-level. The goal of the current qualitative study was to determine the experiences of PwsMS, caregivers and health care specialists (HCSs) with the CCM. METHODS: In the current qualitative sub study, as part of a larger trial, in-depth semi-structured interviews with PwsMS, caregivers and HCSs who had been in contact with the CCM were conducted between 02/2022 and 01/2023. Data was transcribed, pseudonymized, tested for saturation and analyzed using structuring content analysis according to Kuckartz. Sociodemographic and interview characteristics were analyzed descriptively. RESULTS: Thirteen PwsMS, 12 caregivers and 10 HCSs completed interviews. Main categories of CCM functions were derived deductively: (1) gatekeeper function, (2) broker function, (3) advocacy function, (4) outlook on CCM in standard care. Subcategories were then derived inductively from the interview material. 852 segments were coded. Participants appreciated the CCM as a continuous and objective contact person, a person of trust (92 codes), a competent source of information and advice (on MS) (68 codes) and comprehensive cross-insurance support (128 codes), relieving and supporting PwsMS, their caregivers and HCSs (67 codes). CONCLUSIONS: Through the cross-sectoral continuous support in health-related, social, financial and everyday bureaucratic matters, the CCM provides comprehensive and overriding support and relief for PwsMS, caregivers and HCSs. This intervention bears the potential to be fine-tuned and applied to similar complex patient groups. TRIAL REGISTRATION: The study was approved by the Ethics Committee of the University of Cologne (#20-1436), registered at the German Register for Clinical Studies (DRKS00022771) and in accordance with the Declaration of Helsinki.

"Such an institution represents the circle of life" - bringing an inpatient hospice into an academic setting: a pre-implementation exploratory study.

BACKGROUND: To combine the benefits of hospice and palliative care, the integration of both seems self-evident. Aim of this study was to explore clinical staff's and volunteers' expectations and concerns of the first university hospice in Germany planning for implementation. METHODS: Staff and volunteers of the Department of Palliative Medicine of the University Hospital in Cologne received questionnaires and were interviewed following three themes of interest: opportunities, challenges, general criteria. Questionnaire results were analyzed descriptively using mean ± SD and percentages, open-ended questions and interviews were analysed using content analysis. RESULTS: A total of 28/100 questionnaires was returned (n = 17 clinical staff, n = 11 volunteers) and 18 interviews conducted. The majority of both clinical staff and volunteers estimated the need for a university inpatient hospice as rather to very high (64.7% and 81.8%, respectively). Our findings revealed that most clinical staff and volunteers anticipated improvements with the intended university inpatient hospice, although their expectations were divided between both hope and concern while adhering to legal and general requirements, which they feared might oppose such a project. Participants expressed concern about leadership and staffing plans, albeit most pronounced among clinical staff. Nursing staff repeatedly articulated concerns about being interchanged between the palliative care ward and the intended inpatient hospice while they had explicitly chosen to work in palliative medicine. CONCLUSIONS: The overall high level of anticipated progress and excitement is very encouraging. Albeit serious concerns were mentioned, our results indicate that all participants believe in a positive impact and highlight the need of developing a solid concept. In order to implement such a hospice within a university setting, it is important to consider multilevel contextual factors such as system-level factors (funding, external and internal regulations), organization-level factors (leadership, staff motivation), and patient-level factors (adaptability to patients' needs). Our findings illustrate the importance of understanding the context of practice before implementation. Our pre-implementation study helps identify critical views from staff members and volunteers that may hinder or advance the implementation. TRIAL REGISTRATION: The study was registered at the German Clinical Trials Register (#DRKS00021258) on April 17th 2020.

Cultural adaptation of the Integrated Palliative care Outcome Scale for neurological symptoms.

OBJECTIVES: Standardized measures for assessing neurological patients needing palliative care remain scarce. The Integrated Palliative care Outcome Scale for neurological patients in its short form (IPOS Neuro-S8) helps assess and identify patients' symptom burden and needs early but has not yet been validated in German. The aim was to culturally adapt and translate the IPOS Neuro-S8 into the German health-care context and evaluate its face and content validity. METHODS: Cultural adaptation study following the first 6 out of 8 phases of the Palliative care Outcome Scale measures manual: (1) conceptual definition, (2) forward translation to German, (3) backward translation to English, (4) expert review, (5) cognitive debriefing, (6) proofreading. Neurological patients needing palliative care and clinical staff of the Department of Palliative Medicine or Neurology of the University Hospital of Cologne were included. Data were analyzed using thematic content analysis and descriptive statistics. RESULTS: A total of 13 patients and 16 clinical staff participated in this study. The expert review panel (phase 4) consisted of 11 additional members. While patients (n = 9) and clinical staff (n = 11) confirmed that the IPOS Neuro-S8 is an intelligible tool that is well accepted (phase 5), some linguistic and cultural differences were found between the original English and German versions. These mainly concerned the items mouth problems and spasms. SIGNIFICANCE OF RESULTS: The German version of the IPOS Neuro-S8 has demonstrated face and content validity and captures relevant symptoms of neurological patients needing palliative care. Its psychometric properties, including construct and criterion validity, will be investigated next.

Availability as key determinant in the palliative home care setting from the patients' and family caregivers' perspectives: A quantitative-qualitative-content analysis approach.

OBJECTIVE: A sense of security is important in palliative home care. Yet, knowledge about which components contribute most to feeling secure from the patients' and family caregivers' perspectives, especially since the introduction of specialist palliative home care, is sparse. The goal of the current study was to determine the key components contributing to a sense of security and how they relate to each other as experienced by patients and family caregivers in specialist and generalist palliative home care. METHODS: The current sub-study, as part of a larger study, was performed in different regions in Germany. Palliative care patients and family caregivers of at least 18 years of age, being cared for at home were interviewed using semi-structured interview guides following a three-factor model and analyzed by using a combined quantitative-qualitative-content approach. RESULTS: One hundred and ninty-seven patients and 10 carers completed interviews between December 2017 and April 2019. The majority of patients were diagnosed with an oncological disease. Sense of security was mentioned particularly often suggesting its high relevance. We identified nine subcategories that were all mentioned more frequently by specialist than generalist palliative home care recipients in the following order of priority and relation: (i) patient-centeredness: availability, provision of information/education, professional competence, patient empowerment, and trust (ii) organizational work: comprehensive responsibility, external collaboration, and internal cooperation, and (iii) direct communication. SIGNIFICANCE OF RESULTS: The work of specialist palliative home care services in particular was perceived as very effective and beneficial. Our findings confirm a previously developed three-factor model allowing for generalizability and revealed that availability was most important for improving the sense of security for effective palliative home care.

Validation of a palliative care outcome measurement tool supplemented by neurological symptoms (HOPE+): Identification of palliative concerns of neurological patients.

BACKGROUND: There is growing interest to integrate palliative care and its structures into the care of neurological patients. However, in Germany there is no comprehensive assessment tool capturing the symptoms of patients with advanced neurological diseases. AIM: To validate a newly developed palliative care measurement tool based on an extension of the validated core documentation system Hospice and Palliative Care Evaluation considering additional neurological issues (HOPE+). DESIGN: Prospective, observational study using HOPE+ and as external criteria, the Eastern Cooperative Oncology Group (ECOG) performance status and the 12 months "surprise" question (12-SQ) in a neurological population, and assessment for its construct validity and diagnostic accuracy. SETTING/PARTICIPANTS: All newly admitted patients to the Department of Neurorehabilitation, Dr. Becker Rhein-Sieg-Clinic aged 18-100 years (#DRKS00010947). RESULTS: Data from 263 patients (63 ± 14 years of age) were analyzed. HOPE+ revealed a moderately correlated six-factor structure (r = -0.543-0.525). Correlation analysis to evaluate discriminant validity using ECOG as external criterion was high (rs(261) = 0.724, p < 0.001) and confirmed for severely affected patients by adding the 12-SQ ("No"-group: 48.00 ± 14.92 vs "Yes"-group: 18.67 ± 7.57, p < 0.009). Operating characteristics show satisfactory diagnostic accuracy (area under the curve: 0.746 ± 0.049, 95% confidence interval = 0.650-0.842). CONCLUSION: HOPE+ demonstrates promising psychometric properties. It helps to assess palliative care issues of patients in neurological settings and, in combination with the 12-SQ, conceivably conditions when to initiate the palliative care approach in a population underrepresented in palliative care structures so far.

Development of a Long-Term Cross-Sectoral Case and Care Management Manual for Patients With Severe Multiple Sclerosis and Their Caregivers.

PURPOSE/OBJECTIVES: Care and case management (CCM) aims to provide optimal care for patients and their caregivers on an individual and superordinate level of health care providers and authorities. To facilitate a clear and systematic CCM process as part of a clinical study intervention, a semistructured manual is the prerequisite. PRIMARY PRACTICE SETTINGS: The ongoing COCOS-MS (Communication, Coordination and Security for People with Multiple Sclerosis) study is a randomized controlled Phase II clinical intervention study. The CCM manual is being tested on the intervention group consisting of severely affected individuals with multiple sclerosis (MS; Expanded Disability Status Scale [EDSS] >5) and their caregivers receiving CCM for 12 months in addition to standard care. The intervention comprises monthly personal visits and weekly telephone calls during which the CCM manual is applied. FINDINGS/CONCLUSIONS: The CCM manual has been developed on the basis of previous literature and well-established questionnaires following theoretical aspects and prior scientific work covering individual domains of life of people with MS. Within the COCOS-MS study, its feasibility is being tested meticulously. It allows for a standardized assessment while being tailored to the individual. At the end of the intervention period, it will be analyzed statistically and qualitatively. Consequently, conclusions can be drawn as to whether the CCM manual is feasible or has to be adapted for use in standard care after analyzation. IMPLICATIONS FOR CASE MANAGEMENT PRACTICE: The CCM manual serves as a tool for the continuous, long-term, cross-sectoral care for patients suffering from severe MS and their caregivers. The manual provides guidance in adequately addressing patients' complex symptoms, problems, and needs, as well as assessing existing resources both at the individual patient level and at a superordinate level.

Concordance of Intrinsic Brain Connectivity Measures Is Disrupted in Alzheimer's Disease.

Background: Recently, a new resting-state functional magnetic resonance imaging (rs-fMRI) measure to evaluate the concordance between different rs-fMRI metrics has been proposed and has not been investigated in Alzheimer's disease (AD). Methods: 3T rs-fMRI data were obtained from healthy young controls (YC, n = 26), healthy senior controls (SC, n = 29), and AD patients (n = 35). The fractional amplitude of low-frequency fluctuations (fALFF), regional homogeneity (ReHo), and degree centrality (DC) were analyzed, followed by the calculation of their concordance using Kendall's W for each brain voxel across time. Group differences in the concordance were compared globally, within seven intrinsic brain networks, and on a voxel-by-voxel basis with covariates of age, sex, head motion, and gray matter volume. Results: The global concordance was lowest in AD among the three groups, with similar differences for the single metrics. When comparing AD to SC, reductions of concordance were detected in each of the investigated networks apart from the limbic network. For SC in comparison to YC, lower global concordance without any network-level difference was observed. Voxel-wise analyses revealed lower concordance in the right middle temporal gyrus in AD compared to SC and lower concordance in the left middle frontal gyrus in SC compared to YC. Lower fALFF were observed in the right angular gyrus in AD in comparison to SC, but ReHo and DC showed no group differences. Conclusions: The concordance of resting-state measures differentiates AD from healthy aging and may represent a novel imaging marker in AD.

Serum cortisol is negatively related to hippocampal volume, brain structure, and memory performance in healthy aging and Alzheimer's disease.

Objective: Elevated cortisol levels have been frequently reported in Alzheimer's disease (AD) and linked to brain atrophy, especially of the hippocampus. Besides, high cortisol levels have been shown to impair memory performance and increase the risk of developing AD in healthy individuals. We investigated the associations between serum cortisol levels, hippocampal volume, gray matter volume and memory performance in healthy aging and AD. Methods: In our cross-sectional study, we analyzed the relationships between morning serum cortisol levels, verbal memory performance, hippocampal volume, and whole-brain voxel-wise gray matter volume in an independent sample of 29 healthy seniors (HS) and 29 patients along the spectrum of biomarker-based AD. Results: Cortisol levels were significantly elevated in patients with AD as compared to HS, and higher cortisol levels were correlated with worse memory performance in AD. Furthermore, higher cortisol levels were significantly associated with smaller left hippocampal volumes in HS and indirectly negatively correlated to memory function through hippocampal volume. Higher cortisol levels were further related to lower gray matter volume in the hippocampus and temporal and parietal areas in the left hemisphere in both groups. The strength of this association was similar in HS and AD. Conclusion: In AD, cortisol levels are elevated and associated with worse memory performance. Furthermore, in healthy seniors, higher cortisol levels show a detrimental relationship with brain regions typically affected by AD. Thus, increased cortisol levels seem to be indirectly linked to worse memory function even in otherwise healthy individuals. Cortisol may therefore not only serve as a biomarker of increased risk for AD, but maybe even more importantly, as an early target for preventive and therapeutic interventions.

Communication, Coordination, and Security for People with Multiple Sclerosis (COCOS-MS): a randomised phase II clinical trial protocol.

INTRODUCTION: Patients with multiple sclerosis (MS) have complex needs that range from organising one's everyday life to measures of disease-specific therapy monitoring to palliative care. Patients with MS are likely to depend on multiple healthcare providers and various authorities, which are often difficult to coordinate. Thus, they will probably benefit from comprehensive cross-sectoral coordination of services provided by care and case management (CCM). Though studies have shown that case management improves quality of life (QoL), functional status and reduces service use, such benefits have not yet been investigated in severely affected patients with MS. In this explorative phase ll clinical trial, we evaluated a CCM with long-term, cross-sectoral and outreaching services and, in addition, considered the unit of care (patients and caregivers). METHODS AND ANALYSIS: Eighty patients with MS and their caregivers will be randomly assigned to either the control (standard care) or the intervention group (standard care plus CCM (for 12 months)). Regular data assessments will be done at baseline and then at 3-month intervals. As primary outcome, we will evaluate patients' QoL. Secondary outcomes are patients' treatment-related risk perception, palliative care needs, anxiety/depression, use of healthcare services, caregivers' burden and QoL, meeting patients' and caregivers' needs, and evaluating the CCM intervention. We will also evaluate CCM through individual interviews and focus groups. The sample size calculation is based on a standardised effect of 0.5, and one baseline and four follow-up assessments (with correlation 0.5). Linear mixed models for repeated measures will be applied to analyse changes in quantitative outcomes over time. Multiple imputation approaches are taken to assess the robustness of the results. The explorative approach (phase ll clinical trial) with embedded qualitative research will allow for the development of a final design for a confirmative phase lll trial. ETHICS AND DISSEMINATION: The trial will be conducted under the Declaration of Helsinki and has been approved by the Ethics Commission of Cologne University's Faculty of Medicine. Trial results will be published in an open-access scientific journal and presented at conferences. TRIAL REGISTRATION NUMBER: German Register for Clinical Studies (DRKS) (DRKS00022771).

Two Decades of Brain Tumour Imaging with O-(2-[18F]fluoroethyl)-L-tyrosine PET: The Forschungszentrum Jülich Experience.

O-(2-[18F]fluoroethyl)-L-tyrosine (FET) is a widely used amino acid tracer for positron emission tomography (PET) imaging of brain tumours. This retrospective study and survey aimed to analyse our extensive database regarding the development of FET PET investigations, indications, and the referring physicians' rating concerning the role of FET PET in the clinical decision-making process. Between 2006 and 2019, we performed 6534 FET PET scans on 3928 different patients against a backdrop of growing demand for FET PET. In 2019, indications for the use of FET PET were as follows: suspected recurrent glioma (46%), unclear brain lesions (20%), treatment monitoring (19%), and suspected recurrent brain metastasis (13%). The referring physicians were neurosurgeons (60%), neurologists (19%), radiation oncologists (11%), general oncologists (3%), and other physicians (7%). Most patients travelled 50 to 75 km, but 9% travelled more than 200 km. The role of FET PET in decision-making in clinical practice was evaluated by a questionnaire consisting of 30 questions, which was filled out by 23 referring physicians with long experience in FET PET. Fifty to seventy per cent rated FET PET as being important for different aspects of the assessment of newly diagnosed gliomas, including differential diagnosis, delineation of tumour extent for biopsy guidance, and treatment planning such as surgery or radiotherapy, 95% for the diagnosis of recurrent glioma, and 68% for the diagnosis of recurrent brain metastases. Approximately 50% of the referring physicians rated FET PET as necessary for treatment monitoring in patients with glioma or brain metastases. All referring physicians stated that the availability of FET PET is essential and that it should be approved for routine use. Although the present analysis is limited by the fact that only physicians who frequently referred patients for FET PET participated in the survey, the results confirm the high relevance of FET PET in the clinical diagnosis of brain tumours and support the need for its approval for routine use.

Differential neural structures, intrinsic functional connectivity, and episodic memory in subjective cognitive decline and healthy controls.

The neural correlates of subjective cognitive decline (SCD; i.e., without objectifiable deficit) remain to be elucidated. Possible causes of SCD include early neurodegeneration related to Alzheimer's disease or functional and structural changes related to sub-clinical depression. We investigated the relationship between episodic memory performance or memory complaints and structural or functional magnetic resonance imaging (MRI) measures in participants with SCD (n=18) but without psychiatric disorders and healthy controls (n=31). In SCD, memory complaints were not associated with memory performance but with sub-clinical depression and executive functions. SCD-associated memory complaints correlated with higher amygdala and parahippocampal gyrus (specifically subiculum) gray matter density. In controls, but not in SCD, mesiotemporal gray matter density and superior frontal gyrus functional connectivity predicted memory performance. In contrast, in SCD, only a trend toward a correlation between memory performance and gray matter density in the parietooccipital lobes was observed. In our memory-clinic sample of SCD, we did not observe incipient neurodegeneration (limited to structural and functional MRI) but rather sub-clinical depression underlying subjective cognitive complaints.

Spatial distributions of cholinergic impairment and neuronal hypometabolism differ in MCI due to AD.

Elucidating the relationship between neuronal metabolism and the integrity of the cholinergic system is prerequisite for a profound understanding of cholinergic dysfunction in Alzheimer's disease. The cholinergic system can be investigated specifically using positron emission tomography (PET) with [11C]N-methyl-4-piperidyl-acetate (MP4A), while neuronal metabolism is often assessed with 2-deoxy-2-[18F]fluoro-d-glucose-(FDG) PET. We hypothesised a close correlation between MP4A-perfusion and FDG-uptake, permitting inferences about metabolism from MP4A-perfusion, and investigated the patterns of neuronal hypometabolism and cholinergic impairment in non-demented AD patients. MP4A-PET was performed in 18 cognitively normal adults and 19 patients with mild cognitive impairment (MCI) and positive AD biomarkers. In nine patients with additional FDG-PET, the sum images of every combination of consecutive early MP4A-frames were correlated with FDG-scans to determine the optimal time window for assessing MP4A-perfusion. Acetylcholinesterase (AChE) activity was estimated using a 3-compartmental model. Group comparisons of MP4A-perfusion and AChE-activity were performed using the entire sample. The highest correlation between MP4A-perfusion and FDG-uptake across the cerebral cortex was observed 60-450 s after injection (r = 0.867). The patterns of hypometabolism (FDG-PET) and hypoperfusion (MP4A-PET) in MCI covered areas known to be hypometabolic early in AD, while AChE activity was mainly reduced in the lateral temporal cortex and the occipital lobe, sparing posterior midline structures. Data indicate that patterns of cholinergic impairment and neuronal hypometabolism differ significantly at the stage of MCI in AD, implying distinct underlying pathologies, and suggesting potential predictors of the response to cholinergic pharmacotherapy.

The "Surprise Question" in Neurorehabilitation-Prognosis Estimation by Neurologist and Palliative Care Physician; a Longitudinal, Prospective, Observational Study.

Background: The 12-months "surprise" question (12-SQ) for estimating prognosis and the need for integrating palliative care (PC) services has not yet been investigated for neurological patients. Objective: Test the value of the 12-SQ on a sample of neurorehabilitation patients. Methods: All patients newly registered in the Department of Neurorehabilitation, Dr. Becker Rhein-Sieg-Clinic (8/2016-03/2017) were asked to participate. The treating neurorehabilitation physicians (NP) and an external consulting PC physician (PCP) independently estimated patients' prognosis using the 12-SQ; while symptom burden was independently assessed using the standardized palliative outcome measurement HOPE-SP-CL, a set of additional neurological issues, and ECOG. Follow-up with consenting patients 12 months later was via telephone. Descriptive and inferential statistics were utilized in data analysis. Results: Of 634 patients, 279 (44%) patients (male: 57.7%, female: 42.3%; mean age: 63 ± 14) (or, alternatively, their legal representative) consented and were assessed at baseline. Per patient NP and PCP both answered the 12-SQ with "Yes" (164), with "No" (42), or had different opinions (73). The "No" group displayed the highest symptom burden on all three measures for both disciplines. Overall, PCP scored higher (i.e., worse) than NP on all measures used. Follow-up was possible for 236 (drop-out: 15.4%) patients (deceased: 34 (14.4%), alive: 202 (85.6%)). Baseline scores on all measures were higher for deceased patients compared to those still living. Prognostic characteristics were: sensitivity: NP 50%, PCP 67.6%; specificity: NP 86.1%, PCP 70.3%, p < 0.001; positive predictive value: NP 37.8%, PCP 27.7%; negative predictive value: NP 91.1%, PCP 92.8%; area under the curve: NP 0.68, PCP 0.69; success rate: NP 80.9%, PCP 69.9%, p = 0.002. Regression analysis indicated that age, dysphagia and overburdening of family (NP answering the 12-SQ), dysphagia and rehabilitation phase (PCP answering the 12-SQ) were associated with increased likelihood of dying within 12 months. Without the 12-SQ as relevant predictor, age, dysphagia and ECOG were significant predictors (NP and PCP). Conclusion: Combining the 12-SQ with a measurement assessing PC and neurological issues could potentially improve the 12-SQ's predictive performance of 12-month survival and help to identify when to initiate the PC approach. Clinical experiences influence assessment and prognosis estimation.

On the Extraction and Analysis of Graphs From Resting-State fMRI to Support a Correct and Robust Diagnostic Tool for Alzheimer's Disease.

The diagnosis of Alzheimer's disease (AD), especially in the early stage, is still not very reliable and the development of new diagnosis tools is desirable. A diagnosis based on functional magnetic resonance imaging (fMRI) is a suitable candidate, since fMRI is non-invasive, readily available, and indirectly measures synaptic dysfunction, which can be observed even at the earliest stages of AD. However, the results of previous attempts to analyze graph properties of resting state fMRI data are contradictory, presumably caused by methodological differences in graph construction. This comprises two steps: clustering the voxels of the functional image to define the nodes of the graph, and calculating the graph's edge weights based on a functional connectivity measure of the average cluster activities. A variety of methods are available for each step, but the robustness of results to method choice, and the suitability of the methods to support a diagnostic tool, are largely unknown. To address this issue, we employ a range of commonly and rarely used clustering and edge definition methods and analyze their graph theoretic measures (graph weight, shortest path length, clustering coefficient, and weighted degree distribution and modularity) on a small data set of 26 healthy controls, 16 subjects with mild cognitive impairment (MCI) and 14 with Alzheimer's disease. We examine the results with respect to statistical significance of the mean difference in graph properties, the sensitivity of the results to model and parameter choices, and relative diagnostic power based on both a statistical model and support vector machines. We find that different combinations of graph construction techniques yield contradicting, but statistically significant, relations of graph properties between health conditions, explaining the discrepancy across previous studies, but casting doubt on such analyses as a method to gain insight into disease effects. The production of significant differences in mean graph properties turns out not to be a good predictor of future diagnostic capacity. Highest predictive power, expressed by largest negative surprise values, are achieved for both atlas-driven and data-driven clustering (Ward clustering), as long as graphs are small and clusters large, in combination with edge definitions based on correlations and mutual information transfer.

Functional Disintegration of the Default Mode Network in Prodromal Alzheimer's Disease.

Neurodegenerative brain changes can affect the functional connectivity strength between nodes of the default-mode network (DMN), which may underlie changes in cognitive performance. It remains unclear how the functional connectivity strength of DMN nodes differs from healthy to pathological aging and whether these changes are cognitively relevant. We used resting-state functional magnetic resonance imaging to investigate the functional connectivity strength across five DMN nodes in 25 healthy controls (HC), 28 subjective cognitive decline (SCD) participants, and 25 prodromal Alzheimer's disease (AD) patients. After identifying the ventral medial prefrontal cortex (vmPFC), posterior cingulate cortex (PCC), retrosplenial cortex (RSC), inferior parietal lobule, and the hippocampus we investigated the functional strength between DMN nodes using temporal network modeling. Functional coupling of the vmPFC and PCC in prodromal AD patients was disrupted. This vmPFC-PCC coupling correlated positively with memory performance in prodromal AD. Furthermore, the hippocampus de-coupled from posterior DMN nodes in SCD and prodromal AD patients. There was no coupling between the hippocampus and the anterior DMN. Additional mediation analyses indicated that the RSC enables communication between the hippocampus and DMN regions in HC but none of the other two groups. These results suggest an anterior-posterior disconnection and a hippocampal de-coupling from posterior DMN nodes with disease progression. Hippocampal de-coupling already occurring in SCD may provide valuable information for the development of a functional biomarker.

Aberrant functional connectivity differentiates retrosplenial cortex from posterior cingulate cortex in prodromal Alzheimer's disease.

The posterior cingulate cortex (PCC) is a key hub of the default mode network, a resting-state network involved in episodic memory, showing functional connectivity (FC) changes in Alzheimer's disease (AD). However, PCC is a cytoarchitectonically heterogeneous region. Specifically, the retrosplenial cortex (RSC), often subsumed under the PCC, is an area functionally and microanatomically distinct from PCC. To investigate FC patterns of RSC and PCC separately, we used resting-state functional magnetic resonance imaging in healthy aging participants, patients with subjective cognitive impairment, and prodromal AD. Compared to the other 2 groups, we found higher FC from RSC to frontal cortex in subjective cognitive impairment but higher FC to occipital cortex in prodromal AD. Conversely, FC from PCC to the lingual gyrus was higher in prodromal AD. Furthermore, data indicate that RSC and PCC are characterized by differential FC patterns represented by hub-specific interactions with memory and attentions scores in prodromal AD compared to cognitively normal individuals, possibly reflecting compensatory mechanisms for RSC and neurodegenerative processes for PCC. Data thus confirm and extend previous studies suggesting that the RSC is functionally distinct from PCC.

Illness versus substance use effects on the frontal white matter in early phase schizophrenia: A 4Tesla (1)H-MRS study.

OBJECTIVE: Young adults with early phase schizophrenia often report a past or current pattern of illicit substance use and/or alcohol misuse. Still, little is known about the cumulative and separate effects of each stressor on white matter tissue, at this vulnerable period of brain development. METHODS: Participants involved 24 healthy controls with a past or current history of sustained illicit drug use and/or alcohol misuse (users), 23 healthy controls without such history (normative data), and 27 users with early phase schizophrenia. (1)H-MRS data were acquired from a large frontal volume encompassing 95% of white matter, using a 4Tesla scanner (LASER sequence, TR/TE 3200/46ms). RESULTS: Reduced levels of choline-containing compounds (Cho) were specific to the effect of illness (Cohen's d=0.68), with 22% of the variance in Cho levels accounted for by duration of illness. Reduced levels of myoInositol (d=1.10) and creatine plus phosphocreatine (d=1.07) were specific to the effects of illness plus substance use. Effect of substance use on its own was revealed by reductions in levels of glutamate plus glutamine (d=0.83) in control users relative to normative data. CONCLUSIONS: The specific effect of illness on white matter might indicate a decreased synthesis of membrane phospholipids or alternatively, reduced membrane cellular density. In terms of limitations, this study did not include patients without a lifetime history of substance use (non-users), and the specific effect of each substance used could not be studied separately.

Consolidation in older adults depends upon competition between resting-state networks.

Memory encoding and retrieval problems are inherent to aging. To date, however, the effect of aging upon the neural correlates of forming memory traces remains poorly understood. Resting-state fMRI connectivity can be used to investigate initial consolidation. We compared within and between network connectivity differences between healthy young and older participants before encoding, after encoding and before retrieval by means of resting-state fMRI. Alterations over time in the between-network connectivity analyses correlated with retrieval performance, whereas within-network connectivity did not: a higher level of negative coupling or competition between the default mode and the executive networks during the after encoding condition was associated with increased retrieval performance in the older adults, but not in the young group. Data suggest that the effective formation of memory traces depends on an age-dependent, dynamic reorganization of the interaction between multiple, large-scale functional networks. Our findings demonstrate that a cross-network based approach can further the understanding of the neural underpinnings of aging-associated memory decline.

Sensitivity to white matter FMRI activation increases with field strength.

Functional magnetic resonance imaging (fMRI) activation in white matter is controversial. Given that many of the studies that report fMRI activation in white matter used high field MRI systems, we investigated the field strength dependence of sensitivity to white matter fMRI activation. In addition, we evaluated the temporal signal to noise ratio (tSNR) of the different tissue types as a function of field strength. Data were acquired during a motor task (finger tapping) at 1.5 T and 4 T. Group and individual level activation results were considered in both the sensorimotor cortex and the posterior limb of the internal capsule. We found that sensitivity increases associated with field strength were greater for white matter than gray matter. The analysis of tSNR suggested that white matter might be less susceptible to increases in physiological noise related to increased field strength. We therefore conclude that high field MRI may be particularly advantageous for fMRI studies aimed at investigating activation in both gray and white matter.