Neuropathology of Alzheimer's disease and other dementias

Feeding and hydration issues for older adults with dementia

All cultures dictate the need to feed the hungry and create rituals for almost every life passage around the consumption of food and beverage. Yet, in old age and among those who cannot advocate for themselves, mealtime is medicalized and demoted to an insignificant event without dignity or regard for individualized needs. Attention must be paid to not only what people eat, but how they eat, and how they are supported in that process. Kayser-Jones summarized the extensive findings of several ethnographic studies in nursing homes by noting the multi-factorial issues involved in delivering excellent care to all residents, especially those lacking an advocate. Her findings exposed how lack of staff education, inadequate staffing and supervision, disregard for personal and cultural preferences, lack of assessment for comorbid health problems, intake of food and fluids, dysphagia, and oral health problems all contributed to malnutrition and dehydration among the residents studied. This seminal set of studies, along with Dr. Kayser-Jones' testimony in US Congressional hearings directly affected the design of federal regulatory protocols to address malnutrition and dehydration. In an attempt to increase the number of staff available to assist at meals, the Centers for Medicare and Medicaid issued a change in regulations on Sept. 26, 2003, allowing reimbursement for staff trained for a total of 8 hours to act as feeding assistants. This change is intended to, "provide more residents with help in eating and drinking and reduce the incidence of unplanned weight loss and dehydration". Although seen as answering some of the staffing ratio issues at meal times,this rule change has been criticized for not addressing the complexities of resident needs at meal times. Although offering food and fluid is time-consuming and requires special knowledge of physiological changes and empathy for persons whose behavior might be objectionable at times, it may be one of the few times during the day that the individual with dementia receives normalized social interaction. Thus, as in the care of all vulnerable persons with dementia, whether at home or in an institution, perhaps the greatest challenge and need is for nurses and other caregivers to provide a social environment that promotes individual dignity and comfort.

Single-channel quantitative multiplex reverse transcriptase-polymerase chain reaction for large numbers of gene products differentiates nondemented from neuropathological Alzheimer's disease

Effective approaches using array technologies are critical to understand the molecular bases of human diseases. The results obtained using such procedures require analysis and validation procedures that are still under development. In the context of Alzheimer's disease, in which the identification of molecular mechanisms of underlying pathologies is vital, we describe a robust assay that is the first real-time reverse transcriptase-polymerase chain reaction-based high-throughput approach that can simultaneously quantitate the expression of a large number of genes at the copy number level from a minute amount of starting material. Using this approach within the human brain, we were able to quantitate as many as 19 genes at a time with only one type of fluorescent probe. The number of genes included can be considerably increased. Examples of consistent changes in Alzheimer's disease within these 19 candidate genes included reductions in targets related to the dendritic and synaptic apparatus. These changes were specific to Alzheimer's disease when compared with Parkinson's disease cases. We also present comparison data with microarray analysis from the same brain region and the same patients. The high sensitivity and reproducibility of this technology coupled with appropriate multivariate analysis is proposed here to form a biotechnology platform that can be widely used for diagnostic purposes as well as basic research.

Inflammatory blockade restores adult hippocampal neurogenesis

Cranial radiation therapy causes a progressive decline in cognitive function that is linked to impaired neurogenesis. Chronic inflammation accompanies radiation injury, suggesting that inflammatory processes may contribute to neural stem cell dysfunction. Here, we show that neuroinflammation alone inhibits neurogenesis and that inflammatory blockade with indomethacin, a common nonsteroidal anti-inflammatory drug, restores neurogenesis after endotoxin-induced inflammation and augments neurogenesis after cranial irradiation.

Epidemiology of neurodegeneration

Alzheimer's disease, Parkinson's disease, and motor neuron disease share a propensity to occur with increasing age and as either a sporadic or a familial disorder. A number of behavioral and environmental risk factors have been proposed for each disorder, but most associations lack consistency and specificity. Over the last decade the remarkable frequency of these disorders has become apparent, and the identification of mutations in genes has provided the means to understand their pathogenesis. Better and more accurate means to characterize and diagnose these diseases has greatly facilitated analytic epidemiology. The analysis of behavioral and genetic factors that may lower disease risk has led to clinical trials that are either in progress or being planned with the aim of preventing these disorders.

Pain processing in dementia and its relation to neuropathology

Most clinical studies of pain in dementia have focused on assessment procedures that are sensitive to pain in "demented" or "cognitively impaired" elderly patients. The neuropathology of dementia has not played a major part in pain assessment. In this review, the neuropathological effects of dementia on the medial and the lateral pain systems are discussed. We focus on Alzheimer's disease (AD), vascular dementia, and frontotemporal dementia. Lewy-body disease and Creutzfeldt-Jakob disease are briefly reviewed. The results of the studies reviewed show that, although the subtypes of dementia show common neuropathological features (such as atrophy and white-matter lesions), the degree by which they occur and affect pain-related areas determine the pattern of changes in pain experience. More specifically, in AD and even more so in frontotemporal dementia, a decrease in the motivational and affective components of pain is generally present whereas vascular dementia might be characterised by an increase in affective pain experience. Future studies should combine data from experimental pain studies and neuropathological information for pain assessment in dementia.

Defining diffuse Lewy body disease. Tetrad of symptoms distinguishes illness from other dementias

It is an ageless principle in medicine that physicians cannot diagnose and treat an illness they do not recognize. In the past two decades, we have come to recognize the classic clinical picture of diffuse Lewy body disease. Once primary care physicians understand this challenging disorder, they are in an ideal position to identify and manage it. As with many dementing illnesses and other medical conditions, diffuse Lewy body disease is not curable, but much can be done to improve the quality of life of patients and their family.

Clinical manifestations of Parkinson's disease and parkinsonism

The most common disorder in a patient presenting to a movement disorder clinic will be parkinsonism. The challenge is to provide the patient with the most accurate diagnosis and prognosis possible. The assumption at the time of initial presentation of the clinical diagnosis of Parkinson's disease is often wrong (20-25%). Waiting to see the pattern of progression, and response to medication provides invaluable additional information. This manuscript summarizes the clinical manifestations of Parkinson's disease and the main akinetic-rigid syndromes (progressive supranuclear palsy, multiple system atrophy, cortical-basal ganglionic degeneration, and dementia with Lewy bodies) that make up the differential diagnosis.

Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT): Clinical Applications

Positron emission tomography and single-photon emission computed tomography are nuclear imaging modalities that excel in depicting the biological function of tissue. Unlike structural imaging methods, they provide functional diagnostic information about brain neoplasms, stroke, neurodegenerative disorders, epilepsy, cortical visual loss, and migraine.

Pain assessment in patients with possible vascular dementia

PREVIOUS studies comparing Alzheimer's disease (AD) patients with the normal elderly suggest that AD patients experience less pain. In the present study, pain reporting in 20 patients with possible vascular dementia (VaD) was compared to 20 nondemented elderly who had comparable pain conditions. It was hypothesized that, due to de-afferentiation, the possible VaD patients would experience more pain than the cognitively intact elderly. Pain assessment was conducted using three visual analogue scales, (1) the Coloured Analogue Scale (CAS) for Pain Intensity, (2) the CAS for Pain Affect, and (3) the Faces Pain Scale (FPS); a verbal pain questionnaire, Number of Words Chosen--Affective (NWC-A) of the McGill Pain Questionnaire; and an observation scale, the Checklist of Nonverbal Pain Indicators (CNPI). Results showed a significant increase in the scores on the CAS for Pain Affect and the FPS in the demented patients compared to the control group. There was a tendency for an increase in scores on the CNPI in the VaD group. These results suggest that patients with possible VaD suffer more pain than healthy elderly without cognitive impairment.

The pathology of ischemic-vascular dementia: an update

In Western memory clinic-based series, ischemic-vascular dementia (IVD) is seen in 8-10% of cognitively impaired elderly subjects. Its prevalence in autopsy series ranges from 0.03% to 58% with reasonable values of 4-10%, while in Japan, IVD is seen in 22-35% and mixed-type dementia (MTD) (Alzheimer disease/AD+IVD) in 6-11%. In a large Viennese autopsy series, "pure" IVD was observed in 9.4% of demented elderly and in 2.9% of those clinically diagnosed as possible/probable AD MTD was observed in 3.1% and 1.3% respectively. The major morphological types of IVD are multi-infarct encephalopathy (MIE), small vessel infarct type-strategic infarct dementia (SID), subcortical arteriosclerotic leukoencephalopathy (Binswanger), multilacunar state, mixed cortico-subcortical type, granular cortical atrophy, and post-ischemic encephalopathy. In contrast to previous suggestions that IVD is mainly the result of large hemispheral infarcts or losses of over 100 ml of brain tissue, recent data indicate that cognitive decline is commonly associated with widespread small ischemic or vascular lesions (microinfarcts, lacunes) throughout the brain with predominant involvement of the basal ganglia, white matter, and hippocampus. The lesion pattern of "pure" IVD, which is related to arteriolosclerosis and hypertensive microangiopathy, differs from that in mixed-type dementia, more often showing large infarcts. Although recent studies suggest that concomitant small cerebral infarcts do not significantly influence the overall rate of cognitive decline in AD patients or may be important for mental decline in early AD, both mild AD pathology and microvascular cerebral lesions appear to be common and may interact in "unmasking" or promoting dementia.

Cerebrovascular pathology and dementia in autopsied Honolulu-Asia Aging Study participants

Clinicopathologic data from 285 autopsies were analyzed. The decedents were long-standing participants in the Honolulu-Asia Aging Study, a prospective epidemiologic investigation of stroke, neurodegenerative diseases, and aging. We assessed the prevalence at death of four primary neuropathologic processes using specific microscopic lesions as indicators. An algorithm was developed to assign each decedent to one of six subsets, corresponding to pathologic dominance by microvascular lesions (14% of decedents), Alzheimer lesions (12%), hippocampal sclerosis (5%), cortical Lewy bodies (5%), codominance by two or more primary processes (9%), or without a dominant pathologic process recognized (55%). Definite or probable dementia had been identified in 118 of the decedents. The proportions of men in each subset identified as demented were (in the same order) 57%, 53%, 79%, 57%, 76%, and 25%. In this autopsied panel of older Japanese-American men, the importance of microvascular lesions as a likely explanation for dementia was nearly equal to that of Alzheimer lesions. The cerebrovascular lesion type most essentially and inclusively related to dementia was multiple microinfarction.

Vascular basis of Alzheimer's pathogenesis

Considerable evidence now indicates that Alzheimer's disease (AD) is primarily a vascular disorder. This conclusion is supported by the following evidence: (1) epidemiologic studies linking vascular risk factors to cerebrovascular pathology that can set in motion metabolic, neurodegenerative, and cognitive changes in Alzheimer brains; (2) evidence that AD and vascular dementia (VaD) share many similar risk factors; (3) evidence that pharmacotherapy that improves cerebrovascular insufficiency also improves AD symptoms; (4) evidence that preclinical detection of potential AD is possible from direct or indirect regional cerebral perfusion measurements; (5) evidence of overlapping clinical symptoms in AD and VaD; (6) evidence of parallel cerebrovascular and neurodegenerative pathology in AD and VaD; (7) evidence that cerebral hypoperfusion can trigger hypometabolic, cognitive, and degenerative changes; and (8) evidence that AD clinical symptoms arise from cerebromicrovascular pathology. The collective data presented in this review strongly indicate that the present classification of AD is incorrect and should be changed to that of a vascular disorder. Such a change in classification would accelerate the development of better treatment targets, patient management, diagnosis, and prevention of this disorder by focusing on the root of the problem. In addition, a theoretical capsule summary is presented detailing how AD may develop from chronic cerebral hypoperfusion and the role of critically attained threshold of cerebral hypoperfusion (CATCH) and of vascular nitric oxide derived from endothelial nitric oxide synthase in triggering the cataclysmic cerebromicrovascular pathology.

Where does parkinson disease pathology begin in the brain?

The substantia nigra is not the induction site in the brain of the neurodegenerative process underlying Parkinson disease (PD). Instead, the results of this semi-quantitative study of 30 autopsy cases with incidental Lewy body pathology indicate that PD in the brain commences with the formation of the very first immunoreactive Lewy neurites and Lewy bodies in non-catecholaminergic neurons of the dorsal glossopharyngeus-vagus complex, in projection neurons of the intermediate reticular zone, and in specific nerve cell types of the gain setting system (coeruleus-subcoeruleus complex, caudal raphe nuclei, gigantocellular reticular nucleus), olfactory bulb, olfactory tract, and/or anterior olfactory nucleus in the absence of nigral involvement. The topographical parcellation of the nuclear grays described here is based upon known architectonic analyses of the human brainstem and takes into consideration the pigmentation properties of a few highly susceptible nerve cell types involved in PD. In this sample and in all 58 age- and gender-matched controls, Lewy bodies and Lewy neurites do not occur in any of the known prosencephalic predilection sites (i.e. hippocampal formation, temporal mesocortex, proneocortical cingulate areas, amygdala, basal nucleus of Meynert, interstitial nucleus of the diagonal band of Broca, hypothalamic tuberomamillary nucleus).

Alzheimer disease as a vascular disorder: nosological evidence

BACKGROUND

The main stumbling block in the clinical management and in the search for a cure of Alzheimer disease (AD) is that the cause of this disorder has remained uncertain until now.

SUMMARY OF REVIEW

Evidence that sporadic (nongenetic) AD is primarily a vascular rather than a neurodegenerative disorder is reviewed. This conclusion is based on the following evidence: (1) epidemiological studies showing that practically all risk factors for AD reported thus far have a vascular component that reduces cerebral perfusion; (2) risk factor association between AD and vascular dementia (VaD); (3) improvement of cerebral perfusion obtained from most pharmacotherapy used to reduce the symptoms or progression of AD; (4) detection of regional cerebral hypoperfusion with the use of neuroimaging techniques to preclinically identify AD candidates; (5) presence of regional brain microvascular abnormalities before cognitive and neurodegenerative changes; (6) common overlap of clinical AD and VaD cognitive symptoms; (7) similarity of cerebrovascular lesions present in most AD and VaD patients; (8) presence of cerebral hypoperfusion preceding hypometabolism, cognitive decline, and neurodegeneration in AD; and (9) confirmation of the heterogeneous and multifactorial nature of AD, likely resulting from the diverse presence of vascular risk factors or indicators of vascular disease.

CONCLUSIONS

Since the value of scientific evidence generally revolves around probability and chance, it is concluded that the data presented here pose a powerful argument in support of the proposal that AD should be classified as a vascular disorder. According to elementary statistics, the probability or chance that all these findings are due to an indirect pathological effect or to coincidental circumstances related to the disease process of AD seems highly unlikely. The collective data presented in this review strongly support the concept that sporadic AD is a vascular disorder. It is recommended that current clinical management of patients, treatment targets, research designs, and disease prevention efforts need to be critically reassessed and placed in perspective in light of these important findings.

Current awareness in geriatric psychiatry. Bibliography

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley &amp: Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of geriatric psychiatry. Each bibliography is divided into 9 sections: 1 Books, Reviews &amp: Symposia; 2 General; 3 Assessment; 4 Epidemiology; 5 Therapy; 6 Care; 7 Dementia; 8 Depression; 9 Psychology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted