Prescription medication use in the 10 years prior to diagnosis of young onset Alzheimer's disease: a nationwide nested case-control study.

BACKGROUND: Patients with young onset Alzheimer's disease (YOAD) face long diagnostic delays. Prescription medication use may provide insights into early signs and symptoms, which may help facilitate timely diagnosis. METHODS: In a register-based nested case-control study, we examined medication use for everyone diagnosed with YOAD in a Danish memory clinic during 2016-2020 compared to cognitively healthy controls. Prescription medication use were grouped into 13 overall categories (alimentary tract and metabolism, blood and blood forming organs, cardiovascular system, dermatologicals, genitourinary system and sex hormones, systemic hormonal preparations, antiinfectives for systemic use, antineoplastic and immunomodulating agents, musculo-skeletal system, nervous system, antiparasitic products, respiratory system, and sensory organs). Further stratifications were done for predetermined subcategories with a use-prevalence of at least 5% in the study population. Conditional logistic regression produced odds ratios, which given the use of incidence-density matching is interpretable as incidence rate ratios (IRRs). The association between prescription medication use and subsequent YOAD diagnosis was examined in the entire 10-year study period and in three time-intervals. RESULTS: The study included 1745 YOAD cases and 5235 controls. In the main analysis, several overall categories showed significant associations with YOAD in one or more time-intervals, namely blood and blood forming organs and nervous system. Prescription medication use in the nervous system category was increased for YOAD cases compared to controls already 10->5 years prior to diagnosis (IRR 1.17, 95% CI 1.05-1.31), increasing to 1.57 (95% CI 1.39-1.78) in the year preceding diagnosis. This was largely driven by antidepressant and antipsychotic use, and especially prominent for first-time users. CONCLUSIONS: In this study, medication use in several categories was associated with YOAD. Onset of treatment-requiring psychiatric symptoms such as depression or psychosis in mid-life may serve as potential early indicators of YOAD.

Diagnostic accuracy of the Brief Assessment of Impaired Cognition case-finding instrument in a general practice setting and comparison with other widely used brief cognitive tests-a cross-validation study.

BACKGROUND AND PURPOSE: The aim of this study was to examine the discriminative validity of the Brief Assessment of Impaired Cognition (BASIC) case-finding instrument in a general practice (GP) setting and compare it with other widely used brief cognitive instruments. METHODS: Patients aged ≥70 years were prospectively recruited from 14 Danish GP clinics. Participants were classified as having either normal cognition (n = 154) or cognitive impairment (n = 101) based on neuropsychological test performance, reported instrumental activities of daily living, and concern regarding memory decline. Comparisons involved the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Rowland Universal Dementia Assessment Scale (RUDAS), the Mini-Cog, the 6-item Clock Drawing Test (CDT-6) and the BASIC Questionnaire (BASIC-Q). RESULTS: BASIC demonstrated good overall classification accuracy with an area under the receiver operating characteristic curve (AUC) of 0.88 (95% confidence interval [CI] 0.84-0.92), a sensitivity of 0.72 (95% CI 0.62-0.80) and a specificity of 0.86 (95% CI 0.79-0.91). Pairwise comparisons of the AUCs of BASIC, MMSE, MoCA and RUDAS produced non-significant results, but BASIC had significantly higher classification accuracy than Mini-Cog, BASIC-Q and CDT-6. Depending on the pretest probability of cognitive impairment, the positive predictive validity of BASIC varied from 0.83 to 0.36, and the negative predictive validity from 0.97 to 0.76. CONCLUSIONS: BASIC demonstrated good discriminative validity in a GP setting. The classification accuracy of BASIC is equivalent to more complex, time-consuming instruments, such as the MMSE, MoCA and RUDAS, and higher than very brief instruments, such as the CDT-6, Mini-Cog and BASIC-Q.

Subclinical epileptiform discharges in Alzheimer's disease are associated with increased hippocampal blood flow.

BACKGROUND: In epilepsy, the ictal phase leads to cerebral hyperperfusion while hypoperfusion is present in the interictal phases. Patients with Alzheimer's disease (AD) have an increased prevalence of epileptiform discharges and a study using intracranial electrodes have shown that these are very frequent in the hippocampus. However, it is not known whether there is an association between hippocampal hyperexcitability and regional cerebral blood flow (rCBF). The objective of the study was to investigate the association between rCBF in hippocampus and epileptiform discharges as measured with ear-EEG in patients with Alzheimer's disease. Our hypothesis was that increased spike frequency may be associated with increased rCBF in hippocampus. METHODS: A total of 24 patients with AD, and 15 HC were included in the analysis. Using linear regression, we investigated the association between rCBF as measured with arterial spin-labelling MRI (ASL-MRI) in the hippocampus and the number of spikes/sharp waves per 24 h as assessed by ear-EEG. RESULTS: No significant difference in hippocampal rCBF was found between AD and HC (p-value = 0.367). A significant linear association between spike frequency and normalized rCBF in the hippocampus was found for patients with AD (estimate: 0.109, t-value = 4.03, p-value < 0.001). Changes in areas that typically show group differences (temporal-parietal cortex) were found in patients with AD, compared to HC. CONCLUSIONS: Increased spike frequency was accompanied by a hemodynamic response of increased blood flow in the hippocampus in patients with AD. This phenomenon has also been shown in patients with epilepsy and supports the hypothesis of hyperexcitability in patients with AD. The lack of a significant difference in hippocampal rCBF may be due to an increased frequency of epileptiform discharges in patients with AD. TRIAL REGISTRATION: The study is registered at clinicaltrials.gov (NCT04436341).

Risk of Major Types of Dementias Following Hospital-Diagnosed Infections and Autoimmune Diseases.

Background: Population-based studies have shown an increased risk of dementia after infections, but weaker links were reported for autoimmune diseases. Evidence is scarce for whether the links may be modified by the dementia or exposure subtype. Objective: We aimed to investigate the association between infections and/or autoimmune diseases and rates of major types of dementias in the short- and long terms. Methods: Nationwide nested case-control study of dementia cases (65+ years) diagnosed in Denmark 2016-2020 and dementia-free controls. Exposures were hospital-diagnosed infections and autoimmune diseases in the preceding 35 years. Two groups of dementia cases were those diagnosed in memory clinics (MC) and those diagnosed outside memory clinics (non-memory clinic cases, NMC). Results: In total, 26,738 individuals were MC and 12,534 were NMC cases. Following any infection, the incidence rate ratio (IRR) for MC cases was 1.23 (95% CI 1.20-1.27) and 1.70 for NMC cases (1.62-1.76). Long-term increased rates were seen for vascular dementia and NMC cases. IRRs for autoimmune diseases were overall statistically insignificant. Conclusions: Cases with vascular dementia and not Alzheimer's disease, and a subgroup of cases identified with poorer health have increased long-term risk following infections. Autoimmune diseases were not associated with any type of dementia. Notably increased risks (attributed to the short term) and for NMC cases may indicate that immunosenescence rather than de novo infection explains the links. Future focus on such groups and on the role of vascular pathology will explain the infection-dementia links, especially in the long term.

The cingulate island sign in a mixed memory clinical cohort: Prevalence and diagnostic accuracy.

INTRODUCTION: Visual rating of the cingulate island sign (CIS) on [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) has a high specificity for dementia with Lewy bodies (DLB) in selected cohorts such as DLB versus Alzheimer's disease (AD). In a mixed memory clinical population this study aimed to uncover the prevalence of CIS, the diagnostic accuracy for DLB, and the relationship between CIS and disease severity. METHODS: CIS on [18F]FDG-PET was retrospectively assessed with the visual CIS rating scale (CISRs) in 1000 patients with a syndrome diagnosis of mild cognitive impairment (MCI) or dementia with no restrictions in etiological diagnosis. RESULTS: In this cohort 24.3 % had a CISRs score ≥1 and 3.5 % had a CISRs score = 4. The prevalence of a CISRs score ≥1 was highest in DLB (74.0 %, n = 57). A CISRs score ≥1 was present in at least 9 % in other diagnostic groups. The prevalence of CIS across disease severities showed no statistically significant difference (p = 0.23). To differentiate DLB from non-DLB the optimal cut-off was a CISRs score ≥1 (balanced accuracy = 77.1 %) in MCI/mild dementia and a CISRs score ≥2 (balanced accuracy = 80.6 %) in moderate/severe dementia. The positive predictive value of a CISRs score = 4 for DLB was 57.7 % in MCI/mild dementia and 33.3 % in moderate/severe dementia. CONCLUSION: The CISRs is useful in differentiating DLB from other etiologies in a mixed memory clinical population. Balanced accuracy and positive predictive value may vary across disease severities in the population studied.

Mapping morbidity 10 years prior to a diagnosis of young onset Alzheimer's disease.

INTRODUCTION: Early symptoms in young onset Alzheimer's disease (YOAD) may be misinterpreted, causing delayed diagnosis. This population-based study aimed to map morbidity prior to YOAD diagnosis. METHODS: In a register-based incidence density matched nested case-control study, we examined hospital-diagnosed morbidity for people diagnosed with YOAD in Danish memory clinics during 2016-2020 compared to controls in a 10-year period. Conditional logistic regression produced incidence rate ratios (IRRs). RESULTS: The study included 1745 cases and 5235 controls. YOAD patients had a higher morbidity burden in the year immediately before dementia diagnosis, for certain disorders up to 10 years before. This was especially evident for psychiatric morbidity with the highest increased IRRs throughout the entire period and IRR 1.43 (95% confidence interval 1.14-1.79) in the 5-10-years before dementia diagnosis. DISCUSSION: YOAD patients display a different pattern of morbidity up to 10 years prior to diagnosis. Awareness of specific alterations in morbidity may improve efforts toward a timely diagnosis. HIGHLIGHTS: Retrospective, nested case-control study of young onset Alzheimer's disease (YOAD). YOAD cases had a higher morbidity burden than controls. YOAD cases had a higher psychiatric morbidity burden up to 10 years before diagnosis. Altered morbidity patterns could serve as an early warning sign of YOAD.

Diagnostic accuracy of BASIC-Q for detection of cognitive impairment in a primary care setting - a cross-validation study.

OBJECTIVES: This study aims to evaluate the diagnostic accuracy and reliability of a new, brief questionnaire, 'Brief Assessment of Impaired Cognition- Questionnaire' (BASIC-Q) for detection of cognitive impairment, primarily developed for use in primary care. BASIC-Q has three components: Self-report, Informant report, and Orientation. Self-report and Orientation are completed by the individual and Informant report is answered by a close relative. METHODS: We included 275 participants ≥ 70 years, without a prior diagnosis of dementia, and with a close relative who agreed to participate as an informant. Participants were included prospectively in 14 general practices in urban and rural Denmark using a convenience sampling method. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the informant-completed Functional Activities Questionnaire (FAQ) and reported memory concern were used as a reference standard for the classification of the participants' cognitive function. RESULTS: BASIC-Q demonstrated a fair to good diagnostic accuracy to differentiate between people with cognitive impairment and normal cognition with an area under the ROC curve (AUC) of 0.84 (95% CI 0.79-0.89) and a sensitivity and specificity of 0.80 (95% CI 0.72-0.87) and 0.71 (95% CI 0.63-0.78). A prorated BASIC-Q score derived from BASIC-Q without Informant report had significantly lower classification accuracy than the full BASIC-Q. The test-retest reliability of BASIC-Q was good with an intraclass correlation coefficient of 0.84. CONCLUSION: BASIC-Q is a brief, easy-to-use questionnaire for identification of cognitive impairment in older adults. It demonstrated fair to good classification accuracy in a general practice setting and can be a useful case-finding tool when suspecting dementia in primary health care.

Proton pump inhibitors and dementia: A nationwide population-based study.

INTRODUCTION: Proton pump inhibitors (PPIs) may increase dementia risk. However, it is currently unknown whether timing of exposure or age at dementia diagnosis influence the risk. METHODS: We assessed associations between cumulative PPI use and dementia at different ages in a nationwide Danish cohort of 1,983,785 individuals aged 60 to 75 years between 2000 and 2018. RESULTS: During follow-up, there were 99,384 all-cause dementia incidences. Incidence rate ratio (IRR) of dementia with PPI ever-use compared with never-use was 1.36 (95% CI, 1.29 to 1.43) for age 60 to 69 years at diagnosis, 1.12 (1.09 to 1.15) for 70 to 79 years, 1.06 (1.03 to 1.09) for 80 to 89 years, and 1.03 (0.91 to 1.17) for 90+ years. Longer treatment duration yielded increasing IRRs. For cases below 90 years, increased dementia rate was observed regardless of treatment initiation up to >15 years before diagnosis. DISCUSSION: Regardless of timing of treatment initiation, PPI use was associated with increased dementia rate before age 90 years. Dementia rates increased with younger age at diagnosis. HIGHLIGHTS: After following 1,983,785 individuals for a median of 10 years, 99,384 developed dementia PPIs were used by 21.2% of cases and 18.9% of controls PPI use was associated with increased dementia rate regardless of time of treatment onset Magnitude of associations increased with younger age at diagnosis PPI use was not associated with dementia occurring after age 90 years.

Test-retest reliability and short-term variability of quantitative light reflex pupillometry in a mixed memory clinic cohort.

BACKGROUND: Quantitative light reflex pupillometry (qLRP) may be a promising digital biomarker in neurodegenerative diseases such as Alzheimer's disease (AD), as neuropathological changes have been found in the midbrain structures governing the light reflex. Studies investigating test-retest reliability and short-term, intra-subject variability of qLRP in these patient groups are missing. Our objective was therefore to investigate the test-retest reliability and short-term, intra-subject variability of qLRP in a memory clinic setting, where patients with neurodegenerative disease are frequently evaluated. METHODS: Test-retest reliability study. We recruited patients from a tertiary memory clinic and qLRP was carried out at a baseline visit and then repeated on day 3-14 and on day 21-35 using a hand-held pupillometer. We evaluated the test-retest reliability of qLRP by calculating intraclass correlation coefficients (ICCs) and intra-subject, short-term variability by fitting linear mixed models. We compared ICCs for subgroups based on age, sex, disease severity (MCI vs. mild dementia), AD diagnosis, and amount of neurodegeneration (cerebrospinal fluid-total tau levels). RESULTS: In total, 40 patients (mean age 72 years, 15 female, 22 with mild dementia) were included in the study. We found good-excellent reliability (ICC range 0.86-0.93) for most qLRP parameters. qLRP parameters exhibited limited intra-subject variability and we found no large sources of variability when examining subgroups. CONCLUSION: qLRP was found to have acceptable test-retest reliability and the study results pave the way for research using longitudinal or cross-sectional measurements to assess the construct in identifying and prognosticating neurodegenerative diseases.

Neurofilament light chain levels in serum among a large mixed memory clinic cohort: Confounders and diagnostic usefulness.

INTRODUCTION: Early and accurate diagnosis of neurocognitive disorders including neurodegenerative dementia remains challenging. This study explores the impact of biological factors on serum neurofilament light chain (NfL) levels and clinical usefulness for the detection of neurocognitive disorders in a mixed memory clinic. METHODS: Serum samples and clinical data were obtained from 1188 patients who underwent diagnostic investigations for memory complaints between January 2018 and September 2019. Serum NfL was measured using single molecule array technology. RESULTS: NfL exhibited a moderate association with age, estimated glomerular filtration rate (eGFR), and Fazekas score. NfL was able to differentiate between patients with neurocognitive disorders and those without with a sensitivity and specificity of 80%. NfL could, however, not distinguish between different dementia etiologies. DISCUSSION: Serum NfL could aid early diagnostic triage by identifying patients requiring further diagnostic procedures and therefore aid in a more focused use of health-care resources.

The copenhagen cross-linguistic naming test (C-CLNT): Development and validation in a multicultural memory clinic population.

OBJECTIVE: Despite recent advances in cross-cultural neuropsychological test development, suitable tests for cross-linguistic assessment of language functions are not widely available. The aims of this study were to develop and validate a brief naming test, the Copenhagen Cross-Linguistic Naming Test (C-CLNT), for the assessment of culturally, linguistically, and educationally diverse older adult populations in Europe. METHOD: The C-CLNT was based on a set of standardized color drawings. Items for the C-CLNT were selected by considering name agreement and frequency across five European and two non-European languages. Ambiguities in some of the selected items and scoring criteria were resolved after pilot testing in 10 memory clinic patients. The final 30-item C-CLNT was validated by verifying its psychometric properties in 24 controls and 162 diverse memory clinic patients with affective disorder, mild cognitive impairment, and with dementia. RESULTS: The C-CLNT had acceptable scale reliability (coefficient alpha = .67) and good construct validity, with moderate to strong correlations with traditional language tests (r = .42- .75). Diagnostic accuracy for dementia was good and significantly better than that of the Boston Naming Test (areas under the curve of .80 vs .64, p < .001), but was poor for mild cognitive impairment. Only 3% of the variance in C-CLNT test scores was explained by immigrant background, while 6% was explained by age and years of education. In comparison, these proportions were 34 and 22% for the BNT. CONCLUSIONS: The C-CLNT has promising clinical utility for cross-linguistic assessment of naming impairment in culturally, linguistically, and educationally diverse older adults.

Healthcare utilization prior to a diagnosis of young-onset Alzheimer's disease: a nationwide nested case-control study.

OBJECTIVE: Our aim was to identify changes in healthcare utilization prior to a young-onset Alzheimer's disease diagnosis. METHODS: In a retrospective incidence density matched nested case-control study using national health registers, we examined healthcare utilization for those diagnosed with young-onset Alzheimer's disease in Danish memory clinics during 2016-2018 compared with age- and sex-matched controls. Negative binomial regression analysis produced contact rate ratios. RESULTS: The study included 1082 young-onset Alzheimer's disease patients and 3246 controls. In the year preceding diagnosis, we found increased contact rate ratios for all types of contacts except physiotherapy. Contact rate ratios for contacts with a general practitioner were significantly increased also > 1-5 and > 5-10 years before diagnosis. The highest contact rate ratios were for psychiatric emergency contacts (8.69, 95% CI 4.29-17.62) ≤ 1 year before diagnosis. INTERPRETATION: Results demonstrate that young-onset Alzheimer's disease patients have increased healthcare utilization from 5 to 10 years prior to diagnosis. Awareness of specific alterations in health-seeking behaviour may help healthcare professionals provide timely diagnoses.

Hospital-Diagnosed Infections, Autoimmune Diseases, and Subsequent Dementia Incidence.

Importance: Systemic inflammation has been suggested to explain reported associations between infections and dementia. Associations between autoimmune diseases and dementia also suggest a role for peripheral systemic inflammation. Objective: To investigate the associations of infections and autoimmune diseases with subsequent dementia incidence and to explore potential shared signals presented by the immune system in the 2 conditions. Design, Setting, and Participants: This nationwide, population-based, registry-based cohort study was conducted between 1978 and 2018 (40-year study period). All Danish residents born 1928 to 1953, alive and in Denmark on January 1, 1978, and at age 65 years were included. Persons with prior registered dementia and those with HIV infections were excluded. Data were analyzed between May 2022 and January 2023. Exposures: Hospital-diagnosed infections and autoimmune diseases. Main Outcomes and Measures: All-cause dementia, defined as the date of a first registered dementia diagnosis after age 65 years in the registries. Poisson regression with person-years at risk as an offset variable was used to analyze time to first dementia diagnosis. Results: A total of 1 493 896 individuals (763 987 women [51%]) were followed for 14 093 303 person-years (677 147 [45%] with infections, 127 721 [9%] with autoimmune diseases, and 75 543 [5%] with dementia). Among individuals with infections, 343 504 (51%) were men, whereas among those with autoimmune diseases, 77 466 (61%) were women. The dementia incidence rate ratio (IRR) following any infection was 1.49 (95% CI, 1.47-1.52) and increased along with increasing numbers of infections in a dose-dependent manner. Dementia rates were increased for all infection sites in the short term, but not always in the long term. The dementia IRR following any autoimmune disease was 1.04 (95% CI, 1.01-1.06), but no dose-dependent increase was observed, and only a few autoimmune conditions showed increased IRRs for dementia. Conclusions and Relevance: These findings may point toward a role for infection-specific processes in the development of dementia, rather than general systemic inflammation, as previously hypothesized. Assessing these 2 conditions in a single setting may allow for additional insights into their roles in dementia and for hypotheses on possible underlying mechanisms.

Prediction of shunt response in idiopathic normal pressure hydrocephalus by combined lumbar infusion test and preoperative imaging scoring.

BACKGROUND AND PURPOSE: Idiopathic normal pressure hydrocephalus (iNPH) is a potentially treatable disorder, but prognostic tests or biomarkers are lacking. The aim was to study the predictive power of clinical, neuroimaging and lumbar infusion test parameters (resistance to outflow Rout , cardiac-related pulse amplitude PA and the PA to intracranial pressure ICP ratio). METHODS: In all, 127 patients diagnosed with iNPH who had a lumbar infusion test, a subsequent ventriculo-peritoneal shunt operation and at least 2 months of postoperative follow-up were retrospectively included. Preoperative magnetic resonance images were visually scored for NPH features using the iNPH Radscale. Preoperative and postoperative assessment was performed using cognitive testing, as well as gait and incontinence scales. RESULTS: At follow-up (7.4 months, range 2-20 months), an overall positive response was seen in 82% of the patients. Gait was more severely impaired at baseline in responders compared to non-responders. The iNPH Radscale score was borderline significantly higher in responders compared with non-responders, whereas no significant differences in infusion test parameters were seen between responders and non-responders. Infusion test parameters performed modestly with high positive (75%-92%) but low negative (17%-23%) predictive values. Although not significant, PA and PA/ICP seemed to perform better than Rout , and the odds ratio for shunt response seemed to increase in patients with higher PA/ICP, especially in patients with lower iNPH Radscale scores. CONCLUSION: Although only indicative, lumbar infusion test results increased the likelihood of a positive shunt outcome. Pulse amplitude measures showed promising results that should be further explored in prospective studies.

Subclinical Epileptiform Activity in Dementia with Lewy Bodies.

BACKGROUND: Patients with dementia with Lewy bodies (DLB) have a higher probability of seizures than in normal aging and in other types of neurodegenerative disorders. Depositions of α-synuclein, a pathological hallmark of DLB, can induce network excitability, which can escalate into seizure activity. Indicator of seizures are epileptiform discharges as observed using electroencephalography (EEG). However, no studies have so far investigated the occurrence of interictal epileptiform discharges (IED) in patients with DLB. OBJECTIVES: To investigate if IED as measured with ear-EEG occurs with a higher frequency in patients with DLB compared to healthy controls (HC). METHODS: In this longitudinal observational exploratory study, 10 patients with DLB and 15 HC were included in the analysis. Patients with DLB underwent up to three ear-EEG recordings, each lasting up to 2 days, over a period of 6 months. RESULTS: At baseline, IED were detected in 80% of patients with DLB and in 46.7% of HC. The spike frequency (spikes or sharp waves/24 hours) was significantly higher in patients with DLB as compared to HC with a risk ratio of 2.52 (CI, 1.42-4.61; P-value = 0.001). Most IED occurred at night. CONCLUSIONS: Long-term outpatient ear-EEG monitoring detects IED in most patients with DLB with an increased spike frequency compared to HC. This study extends the spectrum of neurodegenerative disorders in which epileptiform discharges occurs at an elevated frequency. It is possible that epileptiform discharges are, therefore, a consequence of neurodegeneration. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Plasma glucose is not associated with performance on standard cognitive screening tests in a mixed memory clinic cohort-An observational cross-sectional study.

BACKGROUND: It has been shown under experimental conditions that cognitive performance, especially working memory, is impaired in patients with type I and type II diabetes mellitus during hyperglycemic and hypoglycemic conditions, perhaps due to altered cerebral glucose metabolism. It is not known if patients with neurodegenerative diseases, who also exhibit pathological cerebral glucose metabolism, are affected in a similar manner by their plasma glucose levels. OBJECTIVE: We aimed to test if performance on two cognitive screening tests was associated with plasma glucose levels in a memory clinic cohort. METHODS: We included patients from the Copenhagen Memory Clinic Cohort with an available Mini Mental-State Examination (MMSE) test score and a plasma glucose measurement performed in conjunction with cognitive testing. We built linear regression models with MMSE and Addenbrooke's Cognitive Examination (ACE) test scores as the outcome and plasma glucose as the explaining variable and adjusted models for age, sex, and diabetes (plasma glucose measurement >11.1 mmol/L). We explored non-linear relationships by adding quadratic terms and by fitting a cubic spline regression model. RESULTS: In total, 2714 patients had an available MMSE score and a plasma glucose measurement. MMSE and ACE total scores were not associated with plasma glucose in a linear or non-linear fashion when we adjusted for age, sex, and diabetes. CONCLUSION: Plasma glucose levels, predominantly within normal ranges, were not associated with performance on routinely applied cognitive tests and do not need to be taken into consideration when interpreting test results from memory clinic patients.

Clinical validation of the cingulate island sign visual rating scale in dementia with Lewy bodies.

INTRODUCTION: The cingulate island sign (CIS) is a metabolic pattern on [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) associated with dementia with Lewy bodies (DLB). The aim of this study was to validate the visual CIS rating scale (CISRs) for the diagnosis of DLB and to explore the clinical correlates. METHODS: This single-center study included 166 DLB patients and 161 patients with Alzheimer's disease (AD). The CIS on [18F]FDG-PET scans was rated using the CISRs independently by three blinded raters. RESULTS: The optimal cut-off to differentiate DLB from AD was a CISRs score ≥ 1 (sensitivity = 66%, specificity = 84%) whereas a CISRs score ≥ 2 (sensitivity = 58%, specificity = 92%) was optimal to differentiate amyloid positive DLB (n = 43 (82.7%)) and AD. To identify DLB with abnormal (n = 53 (72.6%)) versus normal (n = 20 (27.4%)) dopamine transporter imaging, a CISRs cut-off of 4 had a specificity of 95%. DLB with a CISRs score of 4 performed significantly better in tests on free verbal recall and picture based cued recall, but worse on processing speed compared to DLB with a CISRs score of 0. CONCLUSION: This study confirms the CISRs as a valid marker for the diagnosis of DLB with a high specificity and a lower, but acceptable, sensitivity. Concomitant AD pathology does not influence diagnostic accuracy of the CISRs. In DLB patients, presence of CIS is associated with relative preserved memory function and impaired processing speed.