Detection in life of confirmed Alzheimer's disease using a simple measurement of medial temporal lobe atrophy by computed tomography

Perspectives on pain in Down syndrome

Down syndrome (DS) or trisomy 21 is a genetic condition often accompanied by chronic pain caused by congenital abnormalities and/or conditions, such as osteoarthritis, recurrent infections, and leukemia. Although DS patients are more susceptible to chronic pain as compared to the general population, the pain experience in these individuals may vary, attributed to the heterogenous structural and functional differences in the central nervous system, which might result in abnormal pain sensory information transduction, transmission, modulation, and perception. We tried to elaborate on some key questions and possible explanations in this review. Further clarification of the mechanisms underlying such abnormal conditions induced by the structural and functional differences is needed to help pain management in DS patients.

The impact of depression on language function in individuals with Alzheimer's disease: a pre/post-treatment design

BACKGROUND

It is uncertain whether depression might affect cognitive function in Alzheimer's disease (AD). Most of studies on the effect of depression treatment on cognitive function in AD were briefly evaluated by Mini-Mental State Examination (MMSE). MMSE is poor sensitive to detect cognitive change. This study examined the cognitive response to depression treatment in AD via multi-domain assessment. In addition, we explored whether effect of depression treatment in AD is different those of late-life depression (LLD).

METHODS

This study include AD patients with depression (AD + D) and without depression (AD - D), LLD patients (LLD), and healthy controls (HC). The patients were treated according to their diagnosis for 16 weeks: acetylcholinesterase inhibitors (AChEIs) and selective serotonin reuptake inhibitors (SSRIs) for AD + D, AChEIs for AD - D, and SSRIs for LLD. The cognitive changes from pre- to post-treatment were compared between AD + D and AD - D or LLD and HC. An independent sample t test was performed to compare the degree of change between the groups. Paired t tests were used to determine cognitive function changes in each depression treatment responder group.

RESULTS

At baseline, AD + D had more impairment in language function compared to AD - D, and LLD had greater deficit in executive function than HC. After depression treatment, more impaired cognitive domains at baseline were improved in AD + D and LLD, respectively. Moreover, AD + D showed an improvement in the global cognitive function (MMSE).

CONCLUSIONS

Results indicated that language function was influenced by depression in AD, which is first evidence for specific cognitive domain related to depression in AD. Our finding indicates that depression could negatively impact cognitive function, and depression treatment may have beneficial cognitive effect in both AD and LLD. This study suggests the importance of early detection and treatment of depression in AD and LLD. Trial registration Clinical Research Information Service, CRIS, ID#: KCT0004041, Registered 5 June 2019, retrospectively registered after first patient enrollment date (4 March 2014) https://cris.nih.go.kr/cris/search/detailSearch.do?seq=14140&status=5&seq_group=14140&search_page=M .

Hippocampal calcification and its effects on cognitive function and symptoms in dementia

BACKGROUND

Hippocampal calcification (HC), highly prevalent in older people, has not attracted attention until recently. Despite its potential effects on cognition and behaviour, and its possible impact on the diagnosis and severity of dementia, it has not been investigated. This study aimed to evaluate the prevalence of HC and its influence on cognition and behavioural symptoms in patients with dementia.

METHODS

Data from consecutive patients who visited a medical centre for dementia, for the first time between April 2016 and September 2018, were extracted and analysed. These data included the patients' demographics, the presence of HC and hippocampal thickness as measured on computed tomography, the diagnosis of dementia and its type, cognitive function measured using the Mini-Mental State Examination and the Clock Drawing Test, and the chief complaints or symptoms prompting the visit.

RESULTS

A high incidence of HC (85/267 patients) was observed. There was no significant difference in the ages of patients with and without HC. Patients with HC had higher cognitive function than those without HC at their first visit. This result was contrary to our expectations as it was not explained by the chief complaints recorded at the first visit.

CONCLUSIONS

Our study showed a high prevalence of HC in older patients with dementia. Patients with HC had better cognitive function than did those without HC during their first hospital visit. This study suggests that HC may not affect the cognitive functions related to dementia. However, further research is needed to evaluate the long-term consequences of dementia with HC.

European Stroke Organisation and European Academy of Neurology joint guidelines on post-stroke cognitive impairment

BACKGROUND AND PURPOSE

The optimal management of post-stroke cognitive impairment (PSCI) remains controversial. These joint European Stroke Organisation (ESO) and European Academy of Neurology (EAN) guidelines provide evidence-based recommendations to assist clinicians in decision making regarding prevention, diagnosis, treatment and prognosis.

METHODS

Guidelines were developed according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews, assessed the quality of the available evidence, and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations.

RESULTS

There was limited randomized controlled trial (RCT) evidence regarding single or multicomponent interventions to prevent post-stroke cognitive decline. Lifestyle interventions and treating vascular risk factors have many health benefits, but a cognitive effect is not proven. We found no evidence regarding routine cognitive screening following stroke, but recognize the importance of targeted cognitive assessment. We describe the accuracy of various cognitive screening tests, but found no clearly superior approach to testing. There was insufficient evidence to make a recommendation for use of cholinesterase inhibitors, memantine nootropics or cognitive rehabilitation. There was limited evidence on the use of prediction tools for post-stroke cognition. The association between PSCI and acute structural brain imaging features was unclear, although the presence of substantial white matter hyperintensities of presumed vascular origin on brain magnetic resonance imaging may help predict cognitive outcomes.

CONCLUSIONS

These guidelines highlight fundamental areas where robust evidence is lacking. Further definitive RCTs are needed, and we suggest priority areas for future research.

European Stroke Organisation and European Academy of Neurology joint guidelines on post-stroke cognitive impairment

The optimal management of post-stroke cognitive impairment remains controversial. These joint European Stroke Organisation (ESO) and European Academy of Neurology (EAN) guidelines provide evidence-based recommendations to assist clinicians in decision making around prevention, diagnosis, treatment and prognosis. These guidelines were developed according to ESO standard operating procedure and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and, where possible, meta-analyses of the literature, assessed the quality of the available evidence and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations based on the GRADE approach. There was limited randomised controlled trial evidence regarding single or multicomponent interventions to prevent post-stroke cognitive decline. Interventions to improve lifestyle and treat vascular risk factors may have many health benefits but a beneficial effect on cognition is not proven. We found no evidence around routine cognitive screening following stroke but recognise the importance of targeted cognitive assessment. We described the accuracy of various cognitive screening tests but found no clearly superior approach to testing. There was insufficient evidence to make a recommendation for use of cholinesterase inhibitors, memantine nootropics or cognitive rehabilitation. There was limited evidence on the use of prediction tools for post-stroke cognitive syndromes (cognitive impairment, dementia and delirium). The association between post-stroke cognitive impairment and most acute structural brain imaging features was unclear, although the presence of substantial white matter hyperintensities of presumed vascular origin on acute MRI brain may help predict cognitive outcomes. These guidelines have highlighted fundamental areas where robust evidence is lacking. Further, definitive randomised controlled trials are needed, and we suggest priority areas for future research.

In vivo hippocampal 31P NMR metabolites in Alzheimer's disease and ageing

Memory loss is the most common early symptom of Alzheimer's disease (AD). For this study, we chose the hippocampi as regions of interest. The hippocampus, which is closely associated with memory processing, is known to be vulnerable to damage in the early stage of AD. We considered both inter-group (patients vs controls) and intra-group (right vs left hippocampus) comparisons. We examined seven patients meeting the DSM-III-R criteria of senile dementia and the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association (NINCDS — ADRDA) criteria of probable AD, and II aged controls. This study focused on the measurement of phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy metabolites in each hippocampus. We found significant differences in phosphorus metabolites for both intra-group comparison (pH shifted towards relative alkalosis in the left hippocampus of patients) and inter-group consideration (reduced phosphodiesters [Pde]and elevated gamma adenosine triphosphate (ATP) in the right hippocampus, higher inorganic phosphate (pHi) in the left hippocampus for patients as compared to controls). We suggest energy failure and membrane functional breakdown in patients compared to aged controls.

The role of brain structural magnetic resonance imaging in the assessment of hippocampal subfields in Alzheimer’s disease

Background

Volumetric MR neuroimaging can visualize the pattern of hippocampal subfield atrophic changes in AD. This can be used as a biomarker in early diagnosis of AD and allow early treatment to improve memory, behavioral symptoms, and delay the cognitive deterioration. The aim of this work is to assess the role of the volumetric study of different hippocampal subfields as a post-processing technique of structural MR imaging in patients with Alzheimer’s disease of different severity of cognitive functions. The regional ethics committee approved the study and written informed consent was obtained from all participants. In the duration from 2016 to 2018, a cross-sectional study was conducted on 30 patients (17 males and 13 females) and 15 healthy elderly controls (9 males and 6 females) referred to the Radiodiagnosis Department from the Neuropsychiatry Department. Patients were diagnosed with AD by clinical examination and using the Mini Mental State Examination (MMSE) and the Clinical Dementia Rating scale (CDR) as a measure of general cognitive performance.

Results

CA1 and subiculum subfields were significantly reduced in size in patients with Alzheimer’s disease in relation to the age-matched control group (P < 0.05). This finding was positively correlated with the MMSE score and negatively correlated with CDR clinical tests. No significant atrophy was found among other hippocampal subfields in the patients’ group.

Conclusion

This study proposed a new approach to detect atrophy in hippocampal subfields, using MR volumetric study of high-resolution T1 images, that can be used as a biomarker in the diagnosis of AD patients and differentiating them from elderly control subjects which is important in early diagnosis of AD and hence the proper treatment to improve the prognosis of the cognitive function.

The Role of Nutrition in Cognitive Function and Brain Ageing in the Elderly

PURPOSE OF REVIEW

The purposes of this review were to examine literature published over the last 5 years and to evaluate the role of nutrition in cognitive function and brain ageing, focussing on the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets.

RECENT FINDINGS

Results suggest that higher adherence to a healthy dietary pattern is associated with preservation of brain structure and function as well as slower cognitive decline, with the MIND diet substantially slowing cognitive decline, over and above the MeDi and DASH diets. Whilst results to-date suggest adherence to a healthy diet, such as the MeDi, DASH, or MIND, is an important modifiable risk factor in the quest to develop strategies aimed at increasing likelihood of healthy brain ageing, further work is required to develop dietary guidelines with the greatest potential benefit for public health; a research topic of increasing importance as the world's population ages.

Neuroimmune nexus of depression and dementia: Shared mechanisms and therapeutic targets

Dysfunctional immune activity is a physiological component of both Alzheimer's disease (AD) and major depressive disorder (MDD). The extent to which altered immune activity influences the development of their respective cognitive symptoms and neuropathologies remains under investigation. It is evident, however, that immune activity affects neuronal function and circuit integrity. In both disorders, alterations are present in similar immune networks and neuroendocrine signalling pathways, immune responses persist in overlapping neuroanatomical locations, and morphological and structural irregularities are noted in similar domains. Epidemiological studies have also linked the two disorders, and their genetic and environmental risk factors intersect along immune-activating pathways and can be synonymous with one another. While each of these disorders individually contains a large degree of heterogeneity, their shared immunological components may link distinct phenotypes within each disorder. This review will therefore highlight the shared immune pathways of AD and MDD, their overlapping neuroanatomical features, and previously applied, as well as novel, approaches to pharmacologically manipulate immune pathways, in each neurological condition. LINKED ARTICLES: This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc.

Raman Spectrometric Detection Methods for Early and Non-Invasive Diagnosis of Alzheimer's Disease

The continuous increasing rate of patients suffering of Alzheimer's disease (AD) worldwide requires the adoption of novel techniques for non-invasive early diagnosis and monitoring of the disease. Here we review the various Raman spectroscopic techniques, including Fourier Transform-Raman spectroscopy, surface-enhanced Raman scattering spectroscopy, coherent anti-Stokes Raman scattering spectroscopy, and confocal Raman microspectroscopy, that could be used for the diagnosis of AD. These techniques have shown the potential to detect AD biomarkers, such as the amyloid-β peptide and the tau protein, or the neurotransmitters involved in the disease (e.g., Glutamate and γ-Aminobutyric acid), or the typical structural alterations in specific brain areas. The possibility to detect the specific biomarkers in liquid biopsies and to obtain high resolution 3D microscope images of the affected area make the Raman spectroscopy a valuable ally in the early diagnosis and monitoring of AD.

A novel method of quantifying brain atrophy associated with age-related hearing loss

A growing body of evidence has shown that a relationship between age-related hearing loss and structural brain changes exists. However, a method to measure brain atrophy associated with hearing loss from a single MRI study (i.e. without an interval study) that produces an independently interpretable output does not. Such a method would be beneficial for studying patterns of structural brain changes on a large scale. Here, we introduce our method for this.

Audiometric evaluations and mini-mental state exams were obtained in 34 subjects over the age of 80 who have had brain MRIs in the past 6 years. CSF and parenchymal brain volumes (whole brain and by lobe) were obtained through a novel, fully automated algorithm. Atrophy was calculated by taking the ratio of CSF to parenchyma. High frequency hearing loss was associated with disproportional temporal lobe atrophy relative to whole brain atrophy independent of age (r = 0.471, p = 0.005). Mental state was associated with frontoparietal atrophy but not to temporal lobe atrophy, which is consistent with known results. Our method demonstrates that hearing loss is associated with temporal lobe atrophy and generalized whole brain atrophy. Our algorithm is efficient, fully automated, and able to detect significant associations in a small cohort.

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A novel, fully automated method measuring brain atrophy using CSF to brain parenchymal volume ratios is introduced.

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Brain atrophy is obtained from a single MRI study and unlike brain volume, is interpretable without relative comparison.

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Age-related hearing loss is significantly associated with both temporal lobe and generalized whole brain atrophy.

Dementia: What is it All About?

Dementia is an increasingly frequent clinical syndrome that is characterised by deficits in multiple cognitive domains, changes in behaviour and functional deterioration. Alzheimer's disease, together with vascular dementia, account for 2/3 of all cases of dementia. Other less frequent causes of dementia include dementia with Lewy bodies and frontotemporal dementia. This paper reviews the clinical, pathophysiological and neuroimaging aspects of these four prevalent causes of dementia.

Using neuroimaging to inform clinical practice for the diagnosis and treatment of mild cognitive impairment

Advances in structural and functional neuroimaging techniques have unquestionably improved understanding of the development and progression of Alzheimer disease (AD), with evidence supporting regional (and network) change that underlies cognitive decline across the "healthy" aging/mild cognitive impairment (MCI)/AD spectrum. This review focuses on visual rating scales and volumetric analyses that could be easily integrated into clinical practice, followed by a review of functional neuroimaging findings suggesting that widespread cerebral dysfunction underlies the learning and memory deficits in MCI. Evidence of preserved neuroplasticity in this population and that cognitive rehabilitation techniques may capitalize on this plasticity to improve cognition in those with MCI is also discussed.

Neuroimaging in dementia

Over the last few years, advances in neuroimaging have generated biomarkers, which increase diagnostic certainty, provide valuable information about prognosis, and suggest a particular pathology underlying the clinical dementia syndrome. We aim to review the evidence for use of already established imaging modalities, along with selected techniques that have a great potential to guide clinical decisions in the future. We discuss structural, functional and molecular imaging, focusing on the most common dementias: Alzheimer's disease, fronto-temporal dementia, dementia with Lewy bodies and vascular dementia. Finally, we stress the importance of conducting research using representative cohorts and in a naturalistic set up, in order to build a strong evidence base for translating imaging methods for a National Health Service. If we assess a broad range of patients referred to memory clinic with a variety of imaging modalities, we will make a step towards accumulating robust evidence and ultimately closing the gap between the dramatic advances in neurosciences and meaningful clinical applications for the maximum benefit of our patients.

Diagnostic imaging devices in Alzheimer’s disease

This review discusses current imaging devices in the diagnosis of Alzheimer's disease, their neurobiological correlates and future perspectives in the development of these techniques. The challenge of diagnostic devices is to achieve high accuracy in early, preferably preclinical disease stages at the individual patient level. This is of utmost importance for the development of disease-modifying strategies and monitoring their efficacy. In order to achieve this goal, larger validation trials with prospective designs in unselected and mixed patient populations are needed. A combination of imaging methods of different modalities, both structural and functional, will probably provide optimal diagnostic sensitivity in early cases and specificity towards other dementia syndromes, as well as give in vivo insight into the distribution of disease pathology and residual brain capacity for coping with cognitive decline.

Prestroke dementia: characteristics and clinical features in consecutive series of patients

BACKGROUND/AIM

The prestroke level of cognitive function should be taken into account in order to predict the impact of stroke on the subsequent risk of dementia. The aim of the present study was to investigate the presence and correlates of prestroke dementia (PSD) as well as to identify its clinical features.

METHODS

Premorbid clinical and cognitive features of 158 consecutively recruited patients with a diagnosis of acute cerebrovascular pathology were assessed by interviewing the caregivers using multidimensional assessment. Patients were divided into two groups (PSD group and prestroke nondemented group). Baseline cognitive, functional and behavioral variables and neuroradiological hallmarks (medial temporal lobe atrophy, MTLA) were compared between these two groups.

RESULTS

In a logistic regression model, older age (OR 1.05), female gender (OR 2.3), Neuropsychiatric Inventory total score (OR 1.1) and MTLA (OR 1.2) were the variables independently associated with PSD.

CONCLUSIONS

These findings support the hypothesis that cognitive impairment in patients with stroke may not only be a direct consequence of the acute cerebrovascular event but also a consequence of underlying neurodegenerative pathology.

Inflammatory proteins in plasma are associated with severity of Alzheimer's disease

Markers of Alzheimer’s disease (AD) are being widely sought with a number of studies suggesting blood measures of inflammatory proteins as putative biomarkers. Here we report findings from a panel of 27 cytokines and related proteins in over 350 subjects with AD, subjects with Mild Cognitive Impairment (MCI) and elderly normal controls where we also have measures of longitudinal change in cognition and baseline neuroimaging measures of atrophy. In this study, we identify five inflammatory proteins associated with evidence of atrophy on MR imaging data particularly in whole brain, ventricular and entorhinal cortex measures. In addition, we observed six analytes that showed significant change (over a period of one year) in people with fast cognitive decline compared to those with intermediate and slow decline. One of these (IL-10) was also associated with brain atrophy in AD. In conclusion, IL-10 was associated with both clinical and imaging evidence of severity of disease and might therefore have potential to act as biomarker of disease progression.

Temporal order memory assessed during spatiotemporal navigation as a behavioral cognitive marker for differential Alzheimer's disease diagnosis

Episodic memory impairment is a hallmark for early diagnosis of Alzheimer's disease. Most actual tests used to diagnose Alzheimer's disease do not assess the spatiotemporal properties of episodic memory and lead to false-positive or -negative diagnosis. We used a newly developed, nonverbal navigation test for Human, based on the objective experimental testing of a spatiotemporal experience, to differentially Alzheimer's disease at the mild stage (N = 16 patients) from frontotemporal lobar degeneration (N = 11 patients) and normal aging (N = 24 subjects). Comparing navigation parameters and standard neuropsychological tests, temporal order memory appeared to have the highest predictive power for mild Alzheimer's disease diagnosis versus frontotemporal lobar degeneration and normal aging. This test was also nonredundant with classical neuropsychological tests. As a conclusion, our results suggest that temporal order memory tested in a spatial navigation task may provide a selective behavioral marker of Alzheimer's disease.

[Comparison of quantitative image indexes of brain MRI between differentiates idiopathic normal pressure hydrocephalus and Alzheimer disease, predict positive response of the CSF drainage in possible idiopathic normal pressure hydrocephalus]

AIM

The clinical guidelines for idiopathic normal pressure hydrocephalus (iNPH) in Japan recommend cerebrospinal fluid (CSF) drainage. The positive response rate of the diagnostic CSF drainage is not very high because brain MRI findings of Alzheimer disease (AD) are similar to those of iNPH. Therefore, we sought to determine simple, quantitative indexes of head MRI to differentiate iNPH from AD and to predict positive response of the CSF drainage in possible iNPH.

METHODS

Eighteen patients with the clinical criteria of possible iNPH who had undergone diagnostic CSF drainage were evaluated. Nineteen patients with the clinical criteria of probable AD were used as controls. VSRAD, Evans index, and previously reported indicators were measured on brain MRI in all patients. These parameters were compared between AD and iNPH, and between iNPH responders and non-responders.

RESULTS

VSRAD, Evans index, bifrontal index, width and height of the temporal horn, and the maximum height of the Sylvian fissure were higher in iNPH than AD. The cutoff value of the bifrontal index, width and height of the temporal horn, and maximum height of the Sylvian fissure were 0.31, 6.0 mm, 3.13 mm, and 7.6 mm, respectively. The minimum thickness of the medial temporal lobe was higher in the CSF drainage responders than the non-responders. The cutoff value of the minimum thickness of the medial temporal lobe was 11.0 mm.

CONCLUSIONS

Our results suggest that simple image indexes of brain MRI could distinguish iNPH from AD and predict positive response to CSF drainage in iNPH.

The use of CT in dementia

Neuroimaging has become part of the required investigations when assessing a patient with dementia. In this brief paper, we summarize the role of computed tomography (CT) in the routine work-up in dementia and provide some information about the role of the CT scan in the field of dementia research. Although CT is far less sensitive than magnetic resonance imaging (MRI) in detecting changes associated with cognitive impairment, it may still have a role in this regard. This role is mainly that of detecting secondary, sometimes treatable causes of cognitive impairment, such as intracranial masses. In this sense, CT should be seen as a first-line tool. Possible advantages of CT are lower cost; shorter acquisition time, making it more adaptable to patients with poor compliance; and the possibility that it can be performed in patients with metal devices, such as a pacemaker. The role of CT in the field of dementia research is very restricted in comparison to that of MRI, and is limited to the structural assessment of vascular lesions, and to a lesser extent, to that of degenerative changes, particularly when using specific slicing.

Hippocampal atrophy in subcortical vascular dementia

BACKGROUND AND PURPOSE

New research criteria for subcortical vascular dementia (SVaD) have been suggested to define a more homogeneous subgroup of vascular dementia. Hippocampal (Hc) atrophy is a hallmark of Alzheimer's disease (AD), but it also occurs in other dementia disorders including vascular dementias. So far, it is unknown to which extent Hc atrophy is present in SVaD.

METHODS

From a larger consecutive referral population in a memory clinic, 11 patients fulfilling the research criteria for SVaD were carefully matched with comparison groups of healthy controls and patients with AD. To estimate the extent of Hc atrophy in SVaD, both Hc volumetry and visual rating of medial temporal lobe atrophy (MTA) were applied.

RESULTS

In SVaD, significant Hc atrophy occurred. The extent was intermediate between controls and patients with AD both on Hc volumetry and visual MTA ratings. At the same level of global cognition, Hc volumes were reduced by 11.6% in SVaD and 16.6% in AD, relative to controls.

CONCLUSIONS

Patient groups with AD and SVaD as identified by current research criteria appear to overlap considerably with regard to the feature of Hc atrophy. While contamination with AD is a likely cause, other mechanisms of Hc atrophy in SVaD also deserve consideration. The findings have implications for the design of future clinical trials of SVaD.

Retrospective evaluation of revised criteria for the diagnosis of Alzheimer's disease using a cohort with post-mortem diagnosis

OBJECTIVE

The criteria currently used to diagnose Alzheimer's disease (AD) require the presence of dementia, i.e. cognitive impairment sufficient to affect normal social and/or occupational function. Dubois et al. (Dubois et al., 2007) have recently proposed a set of revised criteria that may aid the diagnosis of the earlier stages of AD, and do not require the presence of dementia. We aimed to evaluate the new predementia-AD criteria through their retrospective application to the OPTIMA cohort with post-mortem (PM) confirmed diagnoses.

METHODS

The criteria were evaluated for sensitivity and specificity using cognitive, neuroimaging and cerebrospinal fluid data and clinical information for exclusion criteria. Limitations in choice of cognitive test, use of CT scans rather than MRI and missing CSFs affected the outcomes. Analyses were carried out for the whole cohort (n = 243) and on a mild-stage subgroup (n = 99) defined by MMSE ≥ 21.

RESULTS

Of the four options for fulfilling the revised-criteria, the best results for the whole cohort were achieved using memory and CSF data with exclusion criteria applied (.68 sensitivity and .93 specificity). The pattern was similar for the mild cohort, but with lower sensitivity. Specificities of 1.0 were reached with supportive criteria, CSF and CSF plus MTL.

CONCLUSIONS

The revised-criteria, when applied to our cohort, offer good specificity and reasonable sensitivity when compared with the gold standard of PM diagnosis. The criteria were not more effective for early stage dementia.

Neuroimaging Studies in Alzheimer's Disease

Alzheimer's Disease (AD) is a progressive neurodegenerative disease associated with memory loss and gradual behavioral, functional and cognitive impairment. Conventional imaging studies, such as magnetic resonance or computed tomography have played a secondary role in AD diagnosis: While other causes of memory loss and cognitive deficit can be evaluated by these imaging methods, AD structural changes are not detected until very late in the course of the disease. Recent and more precise techniques have been developed to detect subtle changes not visualized with those imaging methods. This article presents a review of the neuroimaging techniques used as a diagnostic aid for AD.

The ART of loss: Abeta imaging in the evaluation of Alzheimer's disease and other dementias

Molecular neuroimaging based on annihilation radiation tomographic (ART) techniques such as positron emission tomography (PET), in conjunction with related biomarkers in plasma and cerebrospinal fluid (CSF), are proving valuable in the early and differential diagnosis of Alzheimer's disease (AD). With the advent of new therapeutic strategies aimed at reducing beta-amyloid (Abeta) burden in the brain to potentially prevent or delay functional and irreversible cognitive loss, there is increased interest in developing agents that allow assessment of Abeta burden in vivo. Abeta burden as assessed by molecular imaging matches histopathological reports of Abeta plaque distribution in aging and dementia and appears more accurate than FDG for the diagnosis of AD. Abeta imaging is also a very powerful tool in the differential diagnosis of AD from fronto-temporal dementia (FTD). Although Abeta burden as assessed by PET does not correlate with measures of cognitive decline in AD, it does correlate with memory impairment and rate of memory decline in mild cognitive impairment (MCI) and healthy older subjects. Approximately 30% of asymptomatic controls present cortical (11)C-PiB retention. These observations suggest that Abeta deposition is not part of normal ageing, supporting the hypothesis that Abeta deposition occurs well before the onset of symptoms and is likely to represent preclinical AD. Further longitudinal observations are required to confirm this hypothesis and to better elucidate the role of Abeta deposition in the course of Alzheimer's disease.

Role of imaging techniques in the diagnosis of dementia

Dementia is a common and growing problem, affecting 5% of the over 65 s and 20% of the over 80s. The recent availability of new treatments for dementia, as well as the importance of subtype-specific management, has renewed interest in the use of brain imaging techniques that can assist in the accurate recognition of Alzheimer's disease (AD), dementia with Lewy bodies (DLB), vascular dementia (VaD) and frontotemporal dementia (FTD). Structural imaging, historically used to exclude an intracerebral lesion as a cause for dementia, is increasingly playing a role in "ruling in" diagnoses, with atrophy of the hippocampus and entorhinal cortex an early and sensitive marker for AD, and cortical and subcortical infarcts and white matter lesions characteristic of VaD. Regionally distinct patterns of hypoperfusion on single-photon emission computed tomography (SPECT) or hypometabolism on positron emission tomography (PET) can help differentiate FTD, AD and VaD, and dopaminergic loss in the basal ganglia can differentiate DLB from AD. Newer techniques show great promise to detect specific neuroreceptor changes as well as pathological underpinnings of dementia, such as amyloid and tau pathology.

Regional atrophy of the corpus callosum in dementia

The regional distribution of degeneration of the corpus callosum (CC) in dementia is not yet clear. This study compared regional CC size in participants (n = 179) from the Cache County Memory and Aging Study. Participants represented a range of cognitive function: Alzheimer's disease (AD), vascular dementia (VaD), mild ambiguous (MA-cognitive problems, but not severe enough for diagnosis of dementia), and healthy older adults. CC outlines obtained from midsagittal magnetic resonance images were divided into 99 equally spaced widths. Factor analysis of these callosal widths identified 10 callosal regions. Multivariate analysis of variance revealed significant group differences for anterior and posterior callosal regions. Post-hoc pairwise comparisons of CC regions in patient groups as compared to the control group (controlling for age) revealed trends toward smaller anterior and posterior regions, but not all were statistically significant. As compared to controls, significantly smaller anterior and posterior CC regions were found in the AD group; significantly smaller anterior CC regions in the VaD group; but no significant CC regional differences in the MA group. Findings suggest that dementia-related CC atrophy occurs primarily in the anterior and posterior portions.

Is there any role for computed tomography measurements of medial temporal lobe atrophy in dementia? A review of the literature and case series from a memory clinic

Neuroimaging in dementia has focused on documenting any burden of vascular disease or excluding any reversible intracranial pathology. We review the use of computed tomography to examine for medial temporal lobe atrophy in dementia and compare this with a case series of such measurements from our memory clinic. Measures of medial temporal lobe atrophy were used to separate patients with Alzheimer's disease from those with normal cognition, mood disorders or other forms of early dementia.

Profile of cognitive impairment in dementia associated with Parkinson's disease compared with Alzheimer's disease

OBJECTIVE

To compare the profile of cognitive impairment in Alzheimer's disease (AD) with dementia associated with Parkinson's disease (PDD).

METHODS

Neuropsychological assessment was performed in 488 patients with PDD and 488 patients with AD using the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog). Logistic regression analysis was used to investigate whether the diagnosis could be accurately predicted from the cognitive profile. Additionally, the cognitive profiles were compared with a normative group using standardised effect sizes (Cohen's d).

RESULTS

Diagnosis was predicted from the cognitive profile, with an overall accuracy of 74.7%. Poor performance of the AD patients on the orientation test in ADAS-cog best discriminated between the groups, followed by poor performance of the PDD patients on the attentional task in MMSE. Both groups showed memory impairment, AD patients performing worse than PDD patients.

CONCLUSION

The cognitive profile in PDD differs significantly from that in AD. Performance on tests of orientation and attention are best in differentiating the groups.

Medial Temporal Lobe Atrophy, Apolipoprotein Genotype, and Plasma Homocysteine in Sri Lankan Patients with Alzheimer's Disease

The authors studied the association of Alzheimer's disease (AD) with total plasma homocysteine (tHcy) and apolipoprotein E (apoE) genotype, and the usefulness of measuring medial temporal lobe thickness (MTL) thickness for the diagnosis of AD in Sri Lankan patients. Using criteria of the NINCDS-ADRDA, 23 AD patients and 21 controls were recruited. All underwent MTL-oriented computed tomographic (CT) scans, measurement of plasma tHcy, and apoE genotyping. Mean plasma tHcy was significantly higher in AD patients than controls (p=.001). This association was independent of age, sex, body mass index (BMI), serum folate and vitamin B12, and serum creatinine. The frequency of apoE4 allele was significantly higher (p=.003) in AD patients, and the adjusted odds ratio of AD for the presence of one or more apoE4 alleles compared with none was 10.39 (95% CI 1.77-61.10; p=.010). The mean minimum MTL thickness was significantly higher in control subjects compared to that of AD patients (p<.001). This first report of apoE4, plasma tHcy, MTL thickness, and AD from Sri Lanka shows that high plasma tHcy, the presence of apoE4 allele, and MTL atrophy are associated with AD.

Does the Hippocampal Atrophy Correlate With the Cortical Theta Power in Elderly Subjects With a Range of Cognitive Impairment?

A previous study with a small sample (N = 39) showed a significant correlation between the cortical theta activity and the hippocampal volume in different stages of cognitive impairment in aged subjects. The recent study was aimed to replicate these results in a much bigger sample. The authors examined a sample of 121 right-handed subjects. The sample consisted of 37 healthy controls, 40 patients with questionable dementia, and 44 patients with mild dementia assessed by Clinical Dementia Rating. All subjects underwent EEG and brain MRI. Mean spectral power was calculated, and volume of hippocampal segments was measured. EEG theta power of the left and right hemisphere correlated significantly with the hippocampal volume on the left and right side in different stages of cognitive impairment. An increase of theta power was associated with decreased hippocampal volume. No other significant correlations were found for alpha or beta band power. No correlation was found between cortical theta and global brain volume. There seems to be a direct relationship between neuronal loss of the hippocampus and changed cortical theta activity for different stages of cognitive impairment in aged subjects.

Susceptibility groups for Alzheimer's disease (OPTIMA cohort): Integration of gene variants and biochemical factors

Information on gene variants and blood levels (APOE, BCHE-K, TF-C2, HFE-D, HFE-Y, ACE I/D, AR1; homocysteine, folate and vitamin B(12)) is available for participants in the Oxford Project to Investigate Memory and Ageing (OPTIMA) cohort (n=575). This information identified four risk sets for Alzheimer's disease (AD) using grade of membership analysis (GoM). Graded membership scores that relate individuals to each set are automatically generated. Sets I and III had low intrinsic risk. Set II had high intrinsic risk associated with multiple gene variants, e.g., APOE44/34. Set IV also had high intrinsic risk demonstrating low folate and B(12) levels. Membership in the high intrinsic risk sets was summed, coded as either close versus not close (>or=0.80 versus <0.80) and input into logistic models to predict relative risk: close resemblance multiplied risk 80-fold for possible AD before age 65 and 55-fold for probable or definite AD at ages 65-74. These findings implicate both biochemical and genetic factors in the risk for AD and further support dietary supplementation with folate and vitamin B(12) as a potential means to delay the onset of AD and/or its rate of progression.

La lunga attesa: towards a molecular approach to neuroimaging and therapeutics in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by the gradual onset of dementia. The pathological hallmarks of the disease are Aβ amyloid plaques, neurofibrillary tangles (NFT), synaptic loss and reactive gliosis. Current diagnosis of AD is made by clinical, neuropsychologic, and neuroimaging assessments. Routine structural neuroimaging evaluation with computed tomography (CT) and magnetic resonance imaging (MRI) is based on non-specific features such as atrophy, a late feature in the progression of the disease, hence the crucial importance of developing new approaches for early and specific recognition at the prodromal stages of AD. Functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), positron emission tomography (PET) and single photon emission computed tomography (SPECT), possibly in conjuction with other related Aβ biomarkers in plasma and CSF, could prove to be valuable in the differential diagnosis of AD, as well as in assessing prognosis. With the advent of new therapeutic strategies aimed at reducing the Aβ amyloid burden in the brain, there is increasing interest in the development of MRI contrast agents and PET and SPECT radioligands that will permit the assessment of Aβ amyloid burden in vivo. - ma dov'è / la lenta processione di stagioni / che fu un'alba infinita e senza strade, / dov'è la lunga attesa e qual è il nome / del vuoto che ci invade. - Eugenio Montale.

Molecular mechanisms for Alzheimer's disease: implications for neuroimaging and therapeutics

Alzheimer's disease is a progressive neurodegenerative disorder characterised by the gradual onset of dementia. The pathological hallmarks of the disease are beta-amyloid (Abeta) plaques, neurofibrillary tangles, synaptic loss and reactive gliosis. The current therapeutic effort is directed towards developing drugs that reduce Abeta burden or toxicity by inhibiting secretase cleavage, Abeta aggregation, Abeta toxicity, Abeta metal interactions or by promoting Abeta clearance. A number of clinical trials are currently in progress based on these different therapeutic strategies and they should indicate which, if any, of these approaches will be efficacious. Current diagnosis of Alzheimer's disease is made by clinical, neuropsychologic and neuroimaging assessments. Routine structural neuroimaging evaluation with computed tomography and magnetic resonance imaging is based on non-specific features such as atrophy, a late feature in the progression of the disease, hence the crucial importance of developing new approaches for early and specific recognition at the prodromal stages of Alzheimer's disease. Functional neuroimaging techniques such as functional magnetic resonance imaging, magnetic resonance spectroscopy, positron emission tomography and single photon emission computed tomography, possibly in conjunction with other related Abeta biomarkers in plasma and CSF, could prove to be valuable in the differential diagnosis of Alzheimer's disease, as well as in assessing prognosis. With the advent of new therapeutic strategies there is increasing interest in the development of magnetic resonance imaging contrast agents and positron emission tomography and single photon emission computed tomography radioligands that will permit the assessment of Abeta burden in vivo.

Association of minimal thickness of the medial temporal lobe with hippocampal volume, maximal and minimal hippocampal length: volumetric approach with horizontal magnetic resonance imaging scans for evaluation of a diagnostic marker for neuroimaging of Alzheimer's disease

A 3-D volumetric study of the medial temporal lobe (MTL) was performed to evaluate how a minimum thickness of the MTL (mtMTL), a visually estimated measure, is associated with other MTL measures, maximal and minimal hippocampal length (max-HL, min-HL) and hippocampal volume, all measured with a 3-D device, Neurolucida, in 33 patients with Alzheimer's disease (AD), seven patients with mild cognitive impairment (MCI), and 20 age-matched controls. Cognitive impairment was evaluated with Mini-Mental State examination (MMSE). The T1-weighted horizontal magnetic resonance imaging (MRI) scans with slices 5 mm thick were analyzed with Neurolucida and the mtMTL was measured with visual estimation. The MTL was divided into the amygdala and hippocampus. Max-HL on both sides was longer in controls than in AD and MCI, whereas min-HL and mtMTL were longer in controls than in AD, and no difference was observed between MCI and controls. Similarly hippocampal volume was larger in controls than in AD, and no differences were seen within the MCI and controls. No difference in amygdala and midbrain volumes was observed among AD, MCI and controls. Correlation of MMSE score with min-HL and mtMTL was higher than that with max-HL. Although hippocampal and MTL measures examined here failed to show significant difference between AD and MCI, max-HL could be a diagnostic neuroimaging sign of AD. The high correlation of MMSE with mtMTL as well as with min-HL compared with that with max-HL, also will support neuroimaging diagnosis of AD.

The role of quantitative structural imaging in the early diagnosis of Alzheimer's disease

The goal of this article is to review the role of structural neuroimaging in the diagnosis of Alzheimer's disease (AD). We present relevant neuroanatomy, highlight progress in the domain of AD imaging, and review the clinical characteristics of the prodromal phase of AD. We describe the history of the diagnostic issue by examining at cross-section and longitudinally the differences between patients who have AD and normal controls. We also present how subsequent works applied these characteristic traits to the early detection of the prodromal disease and to prediction of future decline. The article delineates the differences between subjects who have mild cognitive impairment and AD, which illustrate the spreading of the pathology with disease progression. The last section describes problems encountered in the differential diagnosis.

Imaginem oblivionis: the prospects of neuroimaging for early detection of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by the gradual onset of dementia. The pathological hallmarks of the disease are A beta amyloid plaques, neurofibrillary tangles, and reactive gliosis. Current diagnosis of AD is made by clinical, neuropsychologic, and neuroimaging assessments. Routine structural neuroimaging evaluation is based on non-specific features such as atrophy, a late feature in the progression of the disease, hence the crucial importance of developing new approaches for early and specific recognition at the prodromal stages of AD. Functional neuroimaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) could prove to be valuable in the differential diagnosis of AD, as well as in assessing prognosis. With the advent of new therapeutic strategies aimed at reducing the A beta amyloid burden in the brain, there is increasing interest in the development of PET and SPECT radioligands that will permit the assessment of A beta amyloid burden in vivo. From this, the prospect of specific preclinical diagnosis arises, possibly in conjunction with other related A beta biomarkers in plasma and CSF.

Pathological aging of the brain: an overview

The number of elderly people is increasing rapidly and, therefore, an increase in neurodegenerative and cerebrovascular disorders causing dementia is expected. Alzheimer disease (AD) is the most common cause of dementia. Vascular dementia, dementia with Lewy bodies, and frontotemporal dementia are the most frequent causes after AD, but a large proportion of patients have a combination of degenerative and vascular brain pathology. Characteristic magnetic resonance (MR) imaging findings can contribute to the identification of different diseases causing dementia. The MR imaging protocol should include axial T2-weighted images (T2-WI), axial fluid-attenuated inversion recovery (FLAIR) or proton density-weighted images, and axial gradient-echo T2*-weighted images, for the detection of cerebrovascular pathology. Structural neuroimaging in dementia is focused on detection of brain atrophy, especially in the medial temporal lobe, for which coronal high resolution T1-weighted images perpendicular to the long axis of the temporal lobe are extremely important. Single photon emission computed tomography and positron emission tomography may have added value in the diagnosis of dementia and may become more important in the future, due to the development of radioligands for in vivo detection of AD pathology. New functional MR techniques and serial volumetric imaging studies to identify subtle brain abnormalities may also provide surrogate markers for pathologic processes that occur in diseases causing dementia and, in conjunction with clinical evaluation, may enable a more rigorous and early diagnosis, approaching the accuracy of neuropathology.

Arterial stiffness is an independent risk factor for cognitive impairment in the elderly: a pilot study

BACKGROUND

Loss of cognitive function is a common condition in the elderly population. Cognitive impairment is defined as the transitional stage of cognitive decline, between normal aging and early dementia. We tested whether arterial stiffness, evaluated as pulse wave velocity (PWV), is associated with cognitive impairment in older subjects, and whether PWV is increased at a comparable extent in older subjects with cortical or subcortical cerebral lesions when compared with age-matched controls referred for memory deficits.

SUBJECTS AND METHODS

Eighty-four subjects (78 +/- 5 years, 30 men and 54 women) referred for memory deficit with no history of stroke or atrial fibrillation were studied. Carotid-femoral PWV was determined non-invasively with Complior. The Mini Mental State Examination was assessed as a measure of global cognitive function. The sum of the score on the Activities of Daily Living and Instrumental Activities of Daily Living scales was used as a measure of personal independency. Based upon brain imaging, subjects were classified as referred for memory deficits with normal brain imaging, or control, with subcortical microvascular lesions or with cortical atrophy.

RESULTS

PWV, normalized for mean blood pressure, was inversely correlated with the Mini Mental State Examination (r = -0.26, P < 0.05), even after controlling for education, prevalent cardiovascular (CV) disease, CV risk factors, and medication use (beta coefficient = -0.28, P < 0.01). PWV was also inversely correlated with personal independency (r = -0.36, P < 0.01; beta coefficient = -0.38, P < 0.01, after multiple adjustment). In the presence of no significant differences in age, education, traditional CV risk factor levels, carotid plaques, or prevalence of CV disease, higher PWV values were more frequent in subjects with cortical atrophy than in patients with subcortical microvascular lesions or controls (P < 0.05).

CONCLUSIONS

PWV was associated with cognitive impairment and with a greater personal dependency, independently of major modifiable CV risk factors.

Rate of progression of cognitive decline in Alzheimer's disease: effect of butyrylcholinesterase K gene variation

OBJECTIVE

To determine whether individuals with Alzheimer's disease (AD) and the K variant allele of butyrylcholinesterase have a slower rate of cognitive decline than those without the K variant allele of butyrylcholinesterase.

METHOD

The cognitive status of 339 community based subjects with AD was assessed with the Mini Mental State Examination at baseline and yearly over a three year follow up period. The rates of cognitive decline of subjects with and without the K variant allele were compared.

RESULT

Presence of the K allele was associated with a slower average rate of cognitive decline in subjects with severe AD.

CONCLUSIONS

This finding is consistent with the suggestion that the K variant of butyrylcholinesterase has an important role in disease progression in AD, and this may have implications for treatment.

Predicting the outcome of cholinesterase inhibitor treatment in Alzheimer's disease

OBJECTIVE

To investigate the possibility that response to cholinesterase inhibitor therapy could be predicted by easily measurable variables that are known to change as a result of treatment (such as the Mini Mental State Examination), measures of function (such as the instrumental activities of daily living and the social behaviour subscales of the Nurse's Observation Scale for Geriatric Patients), and measures of attention (such as the Digit Symbol Substitution Test; DSST), or that might influence response through structural (for example, age, cerebrovascular disease, medial temporal lobe (MTL) atrophy, hypertension) or chemical (for example, smoking) mechanisms.

METHOD

This was a cohort study of 160 consecutive outpatients with probable Alzheimer's disease who commenced cholinesterase inhibitor treatment over a 3 year period in a semi-rural area of Scotland.

RESULTS

The overall response rate was 42.1%. Stratification of response between good and poor responders was possible using baseline DSST and a measure of MTL thickness using CT. Among the patients, 60.4% of those above the cut off point for both DSST and MTL thickness (29/48 subjects) were classified as good responders, compared with 6.3% of subjects below the cut off point for both (1/16 subjects). Subjects above the cut off point for both measures were more likely to be classified as good responders than subjects with only one or no values above the respective cut off points (chi(2) = 10.61, df = 1, p = 0.001)

CONCLUSIONS

The DSST and a measure of MTL thickness derived from CT scanning may be useful in improving the prediction of response to cholinesterase inhibitors in subjects with AD. Subjects with low DSST scores and more severe MTL atrophy are unlikely to respond to treatment. These preliminary data justify a prospective trial of the usefulness of our suggested predictive measures.

In vivo proton magnetic resonance spectroscopy of the temporal lobe in Alzheimer's disease

PURPOSE

Prior proton magnetic resonance spectroscopy (MRS) studies have consistently reported decreased brain n-acetyl aspartate (NAA) levels and increased myo-inositol (mI) levels in subjects with Alzheimer's disease (AD) relative to healthy comparison subjects. These studies have usually been conducted in small and homogeneous populations of patients with established Alzheimer's disease. Few studies have tested the usefulness of this finding in a general population seeking evaluation for memory loss and other cognitive declines. We designed a study to evaluate the significance of single-voxel proton MRS findings in these patients with memory loss and other cognitive declines. GENERAL METHOD: Thirty-five subjects with a primary complaint of memory loss and other cognitive declines were consecutively referred over a period of 13 months to a specialty clinic. Patients with a diagnosis of mild to moderate probable Alzheimer's disease (N = 22), non-Alzheimer's dementia (depression, multiinfarct dementia, Parkinson's Disease, Korsakoff's Psychosis, and bipolar disorder; N = 13), and healthy comparison subjects (N = 18) were examined with respect to possible differences in metabolites using proton MRS in a 3.4-ml anterior temporal lobe voxel.

FINDINGS

The Alzheimer's disease group had 10.7% lower NAA/creatine (Cr) ratios relative to the healthy comparison group and 9.4% lower NAA/creatine relative to the non-Alzheimer's dementia group (15.0% lower NAA/creatine relative to the depression subgroup of the non-Alzheimer's dementia group). There were no significant differences in choline (Cho) or myo-inositol ratios among the groups. There were significant correlations between NAA/creatine ratios and mini-mental status exam (MMSE) scores in subjects with Alzheimer's disease (t = 2.41, p = 0.032) but not in subjects with non-Alzheimer's dementia or in its depression subgroup.

CONCLUSIONS

This study found a reduction in the neuronal marker NAA in the anterior temporal lobe of patients diagnosed with probable Alzheimer's disease, using a short add-on proton MRS exam. This change was not observed in patients whose memory loss and other cognitive declines were not attributed to Alzheimer's disease, suggesting that it may aid in the diagnosis or detection of Alzheimer's disease.