Accuracy of clinical diagnosis in primary degenerative dementia: correlation with neuropathological findings

Nanoneuromedicines for Neurodegenerative Diseases

Introduction:

Neurodegenerative disease is a collective term for a number of diseases that affect the neurons in the human brain. The location of the neuronal loss in the brain leads to the specified disease based on the progression of the clinical symptoms. No drugs are available for complete cure of these diseases. Most of the drugs only slow down the progression of neuronal damage. The combination of drugs with nanotechnology gave a new promising hope for the treatment of neurological disorders. Nanomedicines are extremely useful for safe, effective, target oriented and sustained delivery. Due to their size in nanometer, they possess distinct and improved properties in comparison to their bulk counterpart. The utility of nanomedicines in neurological disorders including neurodegenerative diseases constitutes nanoneuromedicines.

Conclusion:

In this article, a comprehensive overview of the application of nanoneuromedicines in neurodegenerative diseases such as Alzheimer’s Disease (AD), Parkinson’s Disease (PD) and Amyotrophic Lateral Sclerosis (ALS) is provided.

Progression of Alzheimer-Type Dementia in Institutionalized Patients: A Cross-Sectional Study

A gradual deterioration of mental and physical condition is one of the main clinical signs of dementia of the Alzheimer type (DA T). To describe this deterioration, we evaluated 88 institutionalized patients with DA T and plotted their current status on a number of different clinical parameters as a function of time from the estimated onset of dementia. Ratings of speech, cooperation, social contact, and communication were in the very low range in patients with duration of DA T of three years or longer, while the rating of mood was similar regardless of duration of DA T. Half of the patients were unable to dress themselvesfive years after onset of symptoms and unable to sleep regularly six years after onset. By seven years 50% had developed rigidity on passive movement, and by eight years half were unable to feed themselves and to walk without assistance. By nine to ten years, 50% had developed contractures of the limbs and were mute, and by twelve years, half of those who survived had lost eye contact with caregivers.

Clinicopathologic study of Alzheimer's disease: Alzheimer mimics

A definite diagnosis of Alzheimer's disease (AD) can only be made at autopsy. Even at expert research centers, diagnostic accuracy is relatively low. We conducted this study to examine the accuracy of clinical diagnosis of AD and present a list of clinical and neuropsychological findings that could render the clinical diagnosis difficult. Using the National Alzheimer's Coordinating Center database, the records of 533 patients who had been diagnosed clinically with AD, and later underwent autopsy, were reviewed retrospectively. Since the pathologic results of 119 subjects did not meet the criteria for definite AD, we labeled them as Alzheimer "mimics". The neuropathological diagnoses of Alzheimer mimics consisted of dementia with Lewy bodies (n = 35, 29%), insufficient AD (n = 22, 18%), vascular disease (n = 15, 13%), frontotemporal lobar degeneration (n = 14, 12%), and hippocampal sclerosis (n = 10, 8%). History of pacemaker insertion (10.92% versus 4.11%, p = 0.005), congestive heart failure (13.45% versus 6.04%, p = 0.007), hypertension (56.30% versus 47.83%, p = 0.037), and resting tremor (14.29% versus 10.87%, p = 0.170) was more prevalent in Alzheimer mimics. Clinical Dementia Rating score and frequency of Neuropsychiatric Inventory Questionnaire items reflecting delusions, agitation, depression, and motor disturbance were more severe in confirmed AD. In addition to Mini-Mental State Examination (16.97 ± 8.29 versus 12.74 ± 15.26, p < 0.001), Logical Memory, Animal Fluency, Boston Naming Test, and Digit Span scores showed more severe impairment in confirmed AD. Continuing systematic comparisons of the current criteria for the clinical and pathological dementia diagnoses are essential to clinical practice and research, and may also lead to further improvement of the diagnostic procedure.

Patterns of cortical thinning in Alzheimer's disease and frontotemporal dementia

In vivo measurement of cortical thickness is a sensitive representation of pathology in neurodegenerative disorders which primarily target the gray mantle. In this study we used magnetic resonance images to describe the patterns of cortical thinning in 11 frontotemporal dementia (FTD), 38 Alzheimer's disease (AD) and 34 healthy elderly (H(E)) subjects. AD and FTD displayed significant thinning of the cortical mantle compared to the H(E) group, but with distinctive distributions. AD subjects had significantly thinner cortex in all lobes whereas FTD compared to H(E) showed significant differences only in specific regions of frontal and temporal lobes. When compared to AD, the FTD subjects had a trend of thinner cortex in the anterior cingulate region and in selective regions of anterior frontal and temporal regions. In conclusion, the cortical thinning in dementia when compared to H(E), is disease specific whereby FTD subjects display a pattern distinct than that seen in Alzheimer's disease.

The validity of clinical diagnoses of dementia in a group of consecutively autopsied memory clinic patients

BACKGROUND

Epidemiological studies show that up to 10% of individuals aged 65 years and older suffer from dementia, most commonly from dementia of the Alzheimer Type (DAT) (1). Clinicopathological studies are critical to our understanding of this disease and improving the accuracy of clinical diagnoses.

OBJECTIVES

Our objectives were to examine the validity of clinical diagnoses of DAT, to determine the prevalence of different forms of dementia in this sample, and to investigate the relationship between age at death and polymorbidity.

SUBJECTS AND METHOD

Clinical data were available from 221 patients who had been examined at the Basel Memory Clinic between 1986 and 1996. From this population, 34% (75 patients) were autopsied in the Department of Pathology, University Hospital Basel, and neuropathological examinations were additionally performed on 62 (83%) of these patients. Clinical and neuropathological data were retrospectively compared.

RESULTS

67.8% of the neuropathologically examined patients received a definitive diagnosis of AD (Alzheimer's disease), vascular dementia (VaD) or mixed dementia (AD and VaD). AD alone or with other histopathological hallmarks of dementia was the most prevalent neuropathological diagnosis (63%). VaD was deemed the only cause of dementia in only 4.8% of patients. The sensitivity for DAT was 75.9%, the specificity 60.6%. Increasing age was associated with an increasing number of clinical and neuropathological diagnoses.

CONCLUSION

The sensitivity and specificity of the clinical diagnoses of DAT found in our study are similar to previous reports (2-5). Older patients had more etiologies of their dementia than younger patients. This study reaffirms the need for internationally accepted criteria for clinical and neuropathological diagnoses, as well as further clinical-neuropathological investigations to further refine the clinical diagnostic process.

Reappraisal of a consecutive autopsy series of patients with primary degenerative dementia: Lewy-related pathology

Dementia with Lewy bodies (DLB) is a common but underdiagnosed dementing disorder. Its criteria were defined in 1996, and revised in 2005. DLB is characterised neuropathologically by widely distributed cortical Lewy bodies (LBs), usually associated with Alzheimer-type pathology. We have re-evaluated the neuropathology of 55 autopsied patients with clinically diagnosed primary degenerative dementia to determine the frequency of DLB in this cohort, which was originally examined when neither the entity of DLB nor its diagnostic criteria had been defined. We also evaluated how discovery of a new entity affects previous diagnoses. Of the 55 brains, 16 (29%) contained LBs. All 16 originally had a neuropathological diagnosis of Alzheimer's disease (AD). 11 (20%) fulfilled the neuropathological criteria for DLB. Three patients had AD with LBs in the brain stem only, and two patients had LBs in the limbic cortex only. Because the criteria and reliable markers for DLB were not available at the time of the autopsies, the diagnosis of DLB had not been possible. The common co-occurrence of AD-type pathology in DLB makes the clinical diagnosis of DLB problematic even today. This study also raises the question of the relative significances of Lewy-related and AD-type pathologies to the development of dementia.

Hippocampal sclerosis dementia with tauopathy

In some elderly individuals with dementia, hippocampal sclerosis (HS) is the only remarkable autopsy finding. The cause of HS in this setting is puzzling, since known causes of HS such as seizures or global hypoxic-ischemic episodes are rarely present. We here describe a series of HS cases that have a widespread neuronal and/or glial tauopathy. Of 14 consecutive cases of HS, 12 had been clinically diagnosed with dementia and/or Alzheimer's disease (AD) while 2 were non-demented; 7 cases had also been clinically diagnosed with parkinsonism. In addition to HS, 6 cases also met pathologic diagnostic criteria for AD. Gallyas silver staining and immunohistochemistry with the AT8 antibody revealed a glial and/or neuronal tauopathy in 12 of 14 cases, with frequent positive neurons and/or glial cells in the neocortex, basal ganglia, thalamus and/or limbic regions; in addition, 8 of the 14 cases had argyrophilic grains. Screening for known tau mutations was negative in all cases. Western blots of sarkosyl-insoluble tau protein showed a mixture of 3- and 4-repeat forms. The results suggest that most cases of HS dementia are sporadic multisystem tauopathies; we suggest the term "hippocampal sclerosis dementia with tauopathy" (HSDT) for these.

Mixed dementia: epidemiology, diagnosis, and treatment

Alzheimer's disease (AD) and vascular dementia (VaD) are the most frequent causes of dementia in older people. Although AD can be diagnosed with a considerable degree of accuracy, the distinction between isolated AD, VaD, and mixed dementia (MD), where both pathologies coexist in the same patient, remains a controversial issue and one of the most difficult diagnostic challenges. Although MD represents a very frequent pathology, especially in older people, as reported in neuropathological studies, the respective importance of degenerative and vascular lesions, their interaction in the genesis of dementia, and the mere existence of MD are still debated. Accurate diagnosis of MD is of crucial significance for epidemiological purposes and for preventive and therapeutic strategies. Until recently, pharmacological studies have generally focused on pure disease, AD or VaD, and have provided little information on the best therapeutic approach to MD. This article provides an overview of MD in older people. A retrospective review of the recent literature on prevalence, incidence, course, risk factors, diagnosis, and treatment of MD was performed. The article also emphasizes the need for further studies, including neuropsychological and functional evaluations, and neuroimaging and clinicopathological correlations to develop a better understanding of MD, which appears to be one of the most common forms of dementia.

Cerebrospinal fluid carnitine levels in patients with Alzheimer's disease

We assessed free carnitine (FC) and acylcarnitine esters (AC) in both cerebrospinal fluid (CSF) and plasma from 24 patients with diagnostic criteria for Alzheimer's disease (AD), and from 28 healthy matched-controls. We found no significant correlation between FC and AC levels in CSF. FC and AC levels in CSF did not differ significantly between AD patients and controls, but plasma FC levels were significantly lower in AD patients. CSF and plasma FC and AC levels did not correlate with age, age at onset of AD, duration of AD, and scores of the Minimental State Examination of Folstein. Although these results suggest that CSF carnitine levels are apparently unrelated with the risk for AD, the trend of the FC/AC ratio to be higher in AD patients might suggest the possibility of a lower carnitine acetyltransferase activity in AD, as previously reported in some brain areas.

Cerebrospinal fluid levels of alpha-tocopherol (vitamin E) in Alzheimer's disease

We compared CSF and serum levels, and the CST/serum ratio of alpha-tocopherol (vitamin E), measured by HPLC, in 44 apparently well-nourished patients with Alzheimer's disease (AD) and 37 matched controls. CSF and serum vitamin E levels were correlated, both in AD patients and in controls. The mean CSF and serum vitamin E levels were significantly lower in AD patients, and the CSF/serum ratio of AD patients did not differ significantly between the 2 study groups. CSF vitamin E levels did not correlate with age, age at onset, duration of the disease and score of the Minimental State Examination in the AD group. Weight and body mass index were significantly lower in AD patients than in controls. These results suggest that low CSF and serum vitamin E concentrations in AD patients could be related with a deficiency of dietary intake of vitamin E.

Fallacies in the pathological confirmation of the diagnosis of Alzheimer's disease

OBJECTIVE

Necropsy confirmed clinical diagnostic accuracy for Alzheimer's disease is claimed to exceed 90%. This figure contains two fallacies; it includes cases in which Alzheimer's disease exists with other diseases affecting cognition and the studies that report these figures excluded cases without necropsy (verification bias). The effect of these errors is estimated.

METHODS

Data were taken from the University of Western Ontario Dementia Study, a registry of dementia cases with clinical and psychometric follow up to necropsy based in a university memory disorders clinic with secondary and tertiary referrals. Data were available on 307 patients; 200 (65%) had clinically diagnosed Alzheimer's disease, 12 (4%) vascular dementia, 47 (15%) mixed dementia, and 48 (16%) had other diagnoses. One hundred and ninety two of 307 cases (63%) died and 122 of 192 fatalities (64%) had necropsies. The pathological material was interpreted in two ways, allowing and disallowing coexistent disease in making a diagnosis of Alzheimer's disease. In cases without necropsy, progressive cognitive loss was used as a marker for degenerative dementia. The outcome measures of interest were the positive predictive value of a clinical diagnosis of Alzheimer's disease allowing and disallowing coexistent diseases and with and without correction for cases that were not necropsied.

RESULTS

The clinical diagnoses differed significantly between the population who died and those who did not. In cases without necropsy, 22% had no dementia on follow up, concentrated in early cases and men, showing considerable scope for verification bias. The positive predictive value of a diagnosis of Alzheimer's disease was 81% including coexistent diseases, falling to 44% when limited to pure cases. Combined, these factors reduce the positive predictive value to 38% for pure Alzheimer's disease.

CONCLUSIONS

Correction for dual pathology and verification bias halves the positive predictive value of the clinical diagnosis of Alzheimer's disease. Data derived from necropsy studies cannot be extrapolated to the whole population. This has important implications including uncertainty about diagnosis and prognosis and a dilution effect in therapeutic trials in Alzheimer's disease.

Reversal of cognitive impairment in an elderly parkinsonian patient by transcranial application of picotesla electromagnetic fields

A 74 year old retired building inspector with a 15 year history of Parkinson's disease (PD) presented with severe resting tremor in the right hand, generalized bradykinesia, difficulties with the initiation of gait with freezing, mental depression and generalized cognitive impairment despite being fully medicated. Testing of constructional abilities employing various drawing tasks demonstrated drawing impairment compatible with severe left hemispheric dysfunction. After receiving two successive transcranial applications, each of 20 minutes duration, with AC pulsed electromagnetic fields (EMFs) of 7.5 picotesla flux density and frequencies of 5Hz and 7Hz respectively, his tremor remitted and there was dramatic improvement in his drawing performance. Additional striking improvements in his drawing performance occurred over the following two days after he continued to receive daily treatments with EMFs. The patient's drawings were subjected to a Reliability Test in which 10 raters reported 100% correct assessment of pre- and post drawings with all possible comparisons (mean 2 = 5.0; p < .05). This case demonstrates in PD rapid reversal of drawing impairment related to left hemispheric dysfunction by brief transcranial applications of AC pulsed picotesla flux density EMFs and suggests that cognitive deficits associated with Parkinsonism, which usually are progressive and unaffected by dopamine replacement therapy, may be partly reversed by administration of these EMFs. Treatment with picotesla EMFs reflects a "cutting edge" approach to the management of cognitive impairment in Parkinsonism.

The role of the electroencephalogram in the diagnosis of dementia of the Alzheimer type: an attempt at technology assessment

In a first attempt at technology assessment of the electroencephalogram (EEG) in the diagnosis of patients with Alzheimer's disease (AD), three conclusions were reached: notwithstanding the well defined clinical criteria, there remains a need for a laboratory technique to confirm the diagnosis since a 100% accuracy cannot be obtained by clinical methods only; although the EEG has a high sensitivity in separating AD patients from normal controls, the sensitivity of the EEG is at present not satisfactory when studying populations with a low prevalence of AD patients; the sensitivity of the EEG is higher or equal to the best other laboratory techniques (magnetic resonance imaging [MRI], computerized tomography [CT], SPECT, PET) available at the moment. Since the EEG and MRI can be helpful in different aspects of the differential diagnosis it is argued that all AD patients should be studied at least once by EEG as well as by MRI.

Respiratory chain enzyme activities in isolated mitochondria of lymphocytes from patients with Alzheimer's disease

We studied respiratory chain enzyme activities in lymphocyte mitochondria from 33 patients with Alzheimer's disease (AD) and from 30 age- and sex-matched healthy controls. The respiratory chain enzyme activities did not differ significantly between patients and controls. No patient showed any value for respiratory chain enzyme levels below normal range. Values for activities of complexes in the AD group did not correlate with age at onset or duration of the disease. Our finding of normal mitochondrial function in lymphocyte mitochondria suggests that this tissue cannot be used to demonstrate the involvement of oxidative phosphorylation in AD and, thus, to develop a diagnostic test for AD.

Sensitivity, specificity, and positive predictive value of technetium 99-HMPAO SPECT in discriminating Alzheimer's disease from other dementias

Investigators have reported high sensitivity and specificity values for single photon emission computerized tomography (SPECT) when distinguishing Alzheimer's disease (AD) patients from normal elderly controls or from selected patient groups. The role of SPECT in identifying AD among unselected patients with memory complaints requires investigation. We examined 139 consecutive patients with 99Tc-HMPAO SPECT. NINCDS-ADRDA diagnoses were determined blind to SPECT results, and scans were read and classified by visual inspection blind to clinical diagnoses. Bilateral temporoparietal hypoperfusion (TP) occurred in 75% of probable, 65% of possible, and 45% of unlikely AD patients, yielding a sensitivity of 75% and a specificity of 52% when comparing probable AD versus unlikely AD groups. A positive predictive value of 78% was obtained based on a 69% prevalence of AD in our total clinic population. Patients with false-positive results included a variety of dementing illnesses; all patients with bilateral hypoperfusion had dementia. A pattern of TP on SPECT scans is seen in most patients with AD, but could be found in other dementias as well and cannot be regarded as specific to AD. Reduced TP perfusion discriminated between demented and nondemented individuals. Further strategies for SPECT interpretation that improve diagnostic specificity should be sought.

Specific tau variants in the brains of patients with myotonic dystrophy

The mutation causing myotonic dystrophy (DM) is an unstable CTG trinucleotide repeat in a gene encoding for a protein with putative serine-threonine kinase activity. Several studies have reported the appearance of abnormally frequent neurofibrillary tangles (NFTs) in the cortex of patients with DM. Using immunologic probes against normal and pathologic hyperphosphorylated tau proteins, the basic components of NFTs, we performed a biochemical and immunohistochemical study of the brains of two DM cases. We compared the tau profiles with those found in Alzheimer's disease (AD) using mono- and two-dimensional immunoblotting. Patients were aged 53 and 61 years at death. In both cases, we observed few perikaryal and axonal inclusions in the hippocampus as well as the entorhinal and inferior temporal cortices. As in AD brain homogenates, pathologic tau proteins, named tau 55, 64, and 69, were exclusively immunodetected in the DM cases in the hippocampus, the entorhinal cortex, and in most of the temporal areas. Amounts of pathologic tau proteins were higher in the more severely affected case, but lower than in AD brain homogenates. Pathologic tau proteins were less acidic in DM than in AD. We found a very low amount of the tau 69 isoform in DM extracts, and in most of the cortical areas, tau 55 was overexpressed compared with AD homogenates. A link between the increase of kinase activity and the presence of pathologic tau proteins is discussed.

Diagnostic accuracy of Alzheimer's disease: a neuropathological study

This prospective study focused on the accuracy of diagnosis of Alzheimer's disease (AD). We recruited 100 dementia patients and 20 controls who underwent a systematic evaluation. The clinical diagnosis of probable AD or possible AD according to the NINCDS-ADRDA criteria was assigned in 69% of the patients, 21% had vascular dementia (VaD) (DSM-III-R) and 8% had mixed AD-VaD; only 2 patients (2%) had the Lewy body variant of AD (AD-LB). During a 3-year period 57 patients died, 53 of them (93%) being autopsied. Neuropathological examination according to the CERAD criteria showed definite AD in 27 out of 28 (96%) patients diagnosed as probable AD. In the possible AD group, the diagnostic accuracy was also high, 86% showed at least some degree of AD pathological alterations. The neocortical senile plaque scores correlated significantly with tangle scores in patients with AD pathology, and there was a significant negative correlation between age of onset and neocortical tangle scores. The concordance between the clinical diagnosis and pathological findings was clearly lower in VaD than in AD. In the clinical VaD group, 8 of 10 patients had at least some degree of AD changes together with vascular changes and only 2 of 10 patients had pure VaD. This study confirms the high accuracy of the NINCDS-ADRDA criteria for diagnosing AD. In contrast, uncertainty in the clinical diagnosis of VaD should be taken into account, for example, in drug trials with VaD patients.

Regional cerebral glucose metabolism and postmortem pathology in Alzheimer's disease

In four patients with an antemortem diagnosis of probable Alzheimer's disease (AD) regional cerebral glucose metabolism (rCMRGl) was studied prospectively by positron emission tomography (PET) and compared with postmortem semiquantitative neuropathology. The interval between the last PET study and autopsy was 1.3 +/- 0.8 years. In comparison with age-matched controls, the AD patients showed predominant temporoparietal hypometabolism spreading to other cortical and subcortical regions during serial PET scans. All patients had neuropathological findings typical for AD. There was a significant relationship between rCMRGl and density of senile plaques (SP) in one patient (tau b = -0.86, P < 0.05). SP were distributed quite homogeneously in all regions examined. Neurofibrillary tangles (NFT) were concentrated focally in the hippocampus-amygdala-entorhinal complex. In the context of widespread developing cortical hypometabolism, the predilection of NFT for involvement in limbic areas suggests a disruption of projection neurons as the pathogenetic process of cortical dysfunction.

Cognitive deficits in non-Alzheimer's degenerative diseases

Although observed in various brain disorders, dementia is particularly frequent in neurodegenerative diseases. Alzheimer's disease is characterized by the association of progressive amnesia with either instrumental (aphasia, apraxia, agnosia) or behavioral (apathy, indifference, anosognosia) disorders, depending upon the location of the underlying neuronal lesions. By contrast, memory, linguistic, praxic, visuo-spatial or comportemental impairments are dissociated in more focal "lobar" atrophies, while planning and retrieval deficits predominate in movement disorders with dementia. Alzheimer's and non-Alzheimer's neurodegenerative diseases can therefore be distinguished insofar as the severity and location of the associated neuronal lesions differ. Dementia may be observed in various brain diseases, either vascular, metabolic, demyelinating, traumatic, infectious, inflammatory, neoplastic or hydrocephalus (Chui, 1989). It is particularly frequent in neurodegenerative diseases. The recent clinical description of focal lobar atrophies (Weintraub and Mesulam, 1993) and the analysis of cognitive impairment observed in diseases with movement disorders (Cummings and Benson, 1984) have changed the conception of dementia, that may no more be defined as a global deterioration of higher cortical functions. The relative specificity of the cognitive picture of each disease depends on the location of the underlying neuronal lesions. Together with other tools, such as the neurological examination or the functional imagery, the neuropsychological exam may contribute to characterize the clinical picture of a patient with non-Alzheimer's degenerative disease and therefore to determine a clinical diagnosis, that remains probable till the neuropathological confrontation.

Clinico-pathological correlation in dementias

The object of this study is to investigate whether or not there are clinical signs and symptoms in patients with dementia that, by themselves or jointly, can be associated with the pathological diagnosis of Alzheimer's disease. Twelve patients with dementia were studied, in whom the clinical diagnosis of Alzheimer's disease was made according to established criteria. A sample of leptomeninges, cortex and subcortical white matter was obtained from each patient and was processed for light and electron microscopy. In the cases in whom neuritic plaques and neurofibrilary tangles were present, pathological changes were quantified. The diagnosis of Alzheimer's disease was confirmed in 5 cases, whereas in 3 patients spongiform encephalopathy was present. In the remaining patients, the number of neuritic plaques was within normal limits for the age of the subjects. Comparison of the data in Alzheimer (n = 5) and non-Alzheimer (n = 7) groups showed an increased, statistically significant incidence of acalculia, abnormalities of judgment, impairment of abstraction and primitive reflexes in the former. Although good fitting models were obtained, none achieved perfect discrimination. The model that included alterations of judgment and acalculia gave the best fit.

SPECT perfusion imaging in the diagnosis of dementia

Single-photon emission computed tomography (SPECT) imaging has provided the practicing clinician with a method of studying brain function in patients with dementia. A large and growing number of papers report the experiences of a number of laboratories in the use of this technique in the evaluation of demented patients. Studies from several laboratories comparing patients with Alzheimer's disease to control subjects report sensitivity and specificity of SPECT perfusion imaging to be in the 80% vicinity. In addition, a number of studies suggest that the dementias that show the greatest similarities in perfusion patterns to Alzheimer's disease are multi-infarct dementia and dementia associated with Parkinson's disease. Although considerable data exists to guide the physician, a rigorous scientific approach to studying patients in a prospective, unselected clinical sample, with autopsy confirmation of the diagnosis, is needed to define clearly the utility of the technique in diagnosing dementias.

Volumes of hippocampus, amygdala and frontal lobes in the MRI-based diagnosis of early Alzheimer's disease: correlation with memory functions

We studied the usefulness of measuring volumes of the hippocampus, amygdala and frontal lobes with coronal magnetic resonance imaging (MRI) scans in the diagnosis of early Alzheimer's disease (AD). We examined 32 patients diagnosed according to the NINCDS-ADRDA criteria of probable AD and 16 age-matched healthy cognitively normal controls. The AD patients had mild dementia with a mean score of 22.8 in the Mini-Mental Status Examination (MMSE). We used a 1.5 T magnetic resonance imager and normalized the volumes for brain area. The AD patients had significantly smaller volumes of the right and the left hippocampus (-38%) (ANOVA, p < 0.0001) and the left frontal lobe (-16%, p < 0.05) compared to controls. The reductions in volumes of the right frontal lobe (-13%), the right amygdala (-14%) or the left amygdala (-18%) were not statistically significant. In the discriminant function analysis which included the volumes of the hippocampus, amygdala, and the frontal lobes and age, the volumes of the left and right hippocampus, the left and right frontal lobe, and the right amygdala entered the model and we could correctly classify 92% of the subjects into AD and control groups (Chi-square 42.6, df 5, p < 0.001). By using the volumes of the hippocampus, the frontal lobes or the amygdala on their alone, the correct classification was achieved in 88%, 65% and 58% of the subjects, respectively. In addition, in AD patients the volumes of the left hippocampus correlated significantly with the MMSE score and with immediate and delayed verbal memory; the smaller the volume the more impaired was their performance. Our data indicate that measurements of volumes of the hippocampus might be useful in diagnosis of early AD.

Progression and outcome of patients in a Canadian dementia clinic

Five hundred and fifty-three patients were referred to a Canadian dementia clinic for standardized evaluation. The majority (83.5%) had a dementia with Alzheimer's disease (AD) accounting for 89% of dementias. Patients with probable AD who were followed for five years had variable rates of progression, increased mortality (37.1%, 2.5 times the expected rate) and a high rate of institutionalization (79%). Simple demographic (age) and social factors (marital status) were strong predictors for institutionalization. It was extremely difficult at presentation to predict the rate of progression. The prevalence of AD in autopsied cases was 62.5%. Clinic patients were younger, had milder dementias, and were more likely to have AD than patients identified in the course of a contemporaneous population-based dementia prevalence study.

Prevalence of associated diseases in different types of dementia among elderly institutionalized patients: analysis of 3447 records

OBJECTIVE

To determine the prevalence of dementia in a population of hospitalized or institutionalized elderly patients, and that of associated diseases according to dementia type.

DESIGN

Retrospective analysis of a database of diagnostic codes.

SUBJECTS

All patients admitted to 1 of the 4 geriatric units participating in the study at the Charles Foix Hospital between 1980 and 1989.

MEASUREMENTS

All diagnoses mentioned in the discharge summary that could cause or contribute to hospitalization were recorded for each patient. A final list of 54 different diagnoses could be recorded for each patient. Dementia was subdivided into 3 subtypes: Alzheimer dementia (DAT), vascular dementia (VD), and other types of dementia (unclassifiable dementia).

MAIN RESULTS

The study involved 3447 patients aged 81.0 +/- 8.3 years, of whom 27.7% were men. Dementia was the most frequent disease in this population (34.3%); Alzheimer disease was responsible for 15%, vascular dementia for 9.5%, and other types for 9.8%. The average number of associated diseases was 3.23 +/- 2.10 in the Alzheimer dementia group, 4.73 +/- 2.38 in the vascular dementia group, and 3.96 +/- 2.26 in the nondemented group. Parkinson disease was present in 15.5% of patients with unclassifiable dementia, compared with 7.6% in the nondemented group (P < 0.001). There were significantly more diseases commonly seen in bedridden patients in the group of patients with both other types of dementia and Parkinson disease than in the group of other types of dementia patients without Parkinson disease (P < 0.01).

CONCLUSION

Dementia was the most common disease observed in our elderly institutionalized population. Alzheimer patients had significantly fewer associated diseases than nondemented patients, whereas the reverse was found in the vascular dementia group. The co-existence of Parkinson disease and dementia in our population was associated with the poorest health status, as these patients were more likely to present simultaneously such conditions as pressure sores, incontinence, dehydration, or iatrogenesis.

A chronic physiological rat model of dementia

We have developed an aging rat model that mimics specific pathology reported in dementia, particularly Alzheimer's disease (AD). The model involves subjecting rats to chronic cerebrovascular insufficiency (CVI) for 1-9 weeks. Gross and sensory-motor function remains normal but spatial memory acquisition and retention are impaired after 1 week and worsens progressively with time. In vivo [31P]NMR spectroscopy evaluation in CVI animals showed membrane phospholipid synthesis increase in the hippocampal-cortex region of affected animals which increases with time. Post-mortem examination revealed that CA1 neurons can express selective damage 1 week after CVI and the number of CA1 neurons thus affected increases in proportion with time. MOreover, there is progressive increase in GFAP hypertrophy and hyperplasia in the hippocampal region during the 9-week observation period. Reduction of microtubule-associated protein 2 and pre-terminal noradrenergic varicosities in the hippocampus-cortex is seen after 9 weeks but not 1 week of CVI. All the above changes have been reported in AD-affected brains. The present CVI model appears as a useful screen in investigating potential therapy for AD as well as increasing understanding of this disorder.

Alzheimer's disease: improvement of visual memory and visuoconstructive performance by treatment with picotesla range magnetic fields

Impairments in visual memory and visuoconstructive functions commonly occur in patients with Alzheimer's disease (AD). Recently, I reported that external application of electromagnetic fields (EMF) of extremely low intensity (in the picotesla range) and of low frequency (in the range of 5Hz-8Hz) improved visual memory and visuoperceptive functions in patients with Parkinson's disease. Since a subgroup of Parkinsonian patients, specifically those with dementia, have coexisting pathological and clinical features of AD, I investigated in two AD patients the effects of these extremely weak EMF on visual memory and visuoconstructive performance. The Rey-Osterrieth Complex Figure Test as well as sequential drawings from memory of a house, a bicycle, and a man were employed to evaluate the effects of EMF on visual memory and visuoconstructive functions, respectively. In both patients treatment with EMF resulted in a dramatic improvement in visual memory and enhancement of visuoconstructive performance which was associated clinically with improvement in other cognitive functions such as short term memory, calculations, spatial orientation, judgement and reasoning as well as level of energy, social interactions, and mood. The report demonstrates, for the first time, that specific cognitive symptoms of AD are improved by treatment with EMF of a specific intensity and frequency. The rapid improvement in cognitive functions in response to EMF suggests that some of the mental deficits of AD are reversible being caused by a functional (i.e., synaptic transmission) rather than a structural (i.e., neuritic plaques) disruption of neuronal communication in the central nervous system.

Neurofilament profile in olfactory mucosa of patients with a clinical diagnosis of Alzheimer's disease

In an attempt to find a reliable peripheral marker of Alzheimer's disease (AD), pieces of olfactory mucosa were removed by biopsy from 11 patients with probable AD and from eight control patients. The samples were analysed immunocytochemically using monoclonal and polyclonal antibodies. The olfactory and peripheral neurons of the olfactory mucosa in both AD and control patients typically exhibited immunoreactivity to neurofilament (NF) triplet proteins, including both phosphorylated and non-phosphorylated epitopes, as well as to synaptophysin, but lacked reactivity to other intermediate filament proteins, microtubule-associated protein 2 and tau. Our results do not support the recent findings suggesting the lack of NF proteins in olfactory neurons or the preferential phosphorylated status of NF proteins in olfactory neurons solely in AD.

Alzheimer's disease: the problem of incorrect clinical diagnosis

We reviewed the medical records of eight patients clinically diagnosed with Alzheimer's disease who were found on autopsy to have neuropathologic findings inconsistent with Alzheimer's disease. The clinical criteria for the diagnosis of probable Alzheimer's disease from the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS/ADRDA) were retrospectively applied to these patients. The patients presented with clinical features atypical for Alzheimer's disease early in the course of the disease, including focal neurologic findings, gait abnormalities, motor speech abnormalities, and extrapyramidal features. Attention to these clinical red flags may decrease the likelihood of misdiagnosis of Alzheimer's disease in a patient with a non-Alzheimer's disease cause of dementia.

Delusions in Alzheimer's disease and multi-infarct dementia

Neuropsychiatric symptoms such as delusions and misidentifications have been reported in dementia ranging from 10% to 73% in Alzheimer's disease (AD) patients and up to 40% in multi-infarct dementia (MID) patients. The aim of this study was to investigate in 61 AD and 31 MID patients both the frequency and the content of delusions during the course of illness and to evaluate the relationship between these and both functional and mental decline. The results indicated that delusion experiences had occurred in 45% of AD patients and in 38% of MID patients, occurring most frequently during the first year of illness. Patients who experienced psychiatric symptoms showed higher mini mental state examination scores and were less impaired in functional disability measures. With regard to the content, no significant differences were observed between AD and MID patients; 53% of psychotic symptoms were found to be paranoid delusions while 47% were misidentification delusions.

Oxidative polymorphism of debrisoquine is not related to the risk of Alzheimer's disease

Oxidative polymorphism of debrisoquine has been studied in patients suffering from many spontaneous disorders which show genetic and/or environmental factors in their pathogenesis. To elucidate whether any relationship exists between this genetic polymorphism and the risk of developing Alzheimer disease (AD) we determined the oxidative phenotype and metabolic ratio (MR) of debrisoquine (DBQ) in 47 patients with AD or senile dementia of Alzheimer type (SDAT) and 837 healthy controls. The patients were free of drugs during at least the previous 30 days; all the controls were free of drugs. Three patients (6.38%) and 42 controls (5.02%) were classified as poor metabolizers (PM) of DBQ (non-significant difference). The distribution of MR values in the AD/SDAT patients showed non-significant differences when compared with controls. There was no relation between oxidative polymorphism of DBQ and age at onset of the disease. These results suggest that DBQ oxidative genetic polymorphism cannot be considered as a risk factor for developing AD-SDAT.

Blinking in patients with memory disorders during short term memory tasks

The occurrence of blinking during short term memory tasks was analyzed for 32 subjects divided into three groups: 12 memory impaired patients, 10 elderly normals (age-matched to the patients), and 10 young normals. The subjects were participating in a study of brain evoked potentials accompanying memory activities. They were instructed not to blink during the performance of the memory tasks for reasons related to the quality of the recorded potentials. In this context, the withholding of blinking can be considered a secondary task. Blinking during the short term memory tasks was inversely related to performance accuracy (r = -.57). Age, mini-mental score and reaction time were also significantly related to the frequency of blinking. Dividing the memory patients into two groups according to the incidence of blinking, ("high-blinking" and "low-blinking"), revealed a significant difference in overall task accuracy with the high-blinking group performing more poorly than the low-blinking group.

Clinicopathological studies of the dementias from an epidemiological viewpoint

Studies which examine patients with and without dementia during life and then examine brain tissue after death are extremely difficult to conduct. There are now several such studies published, representing a major contribution to the understanding of the pathologies of the dementias. These studies were not designed to represent population samples and, from an epidemiological viewpoint, they are flawed because none are population-based and none represent the full range of function observed during life. It is therefore important to examine the available studies for their contributions and biases.

Cortical biopsy in Alzheimer's disease: Diagnostic accuracy and neurochemical, neuropathological, and cognitive correlations

Neurochemical assessments were performed on biopsy samples taken from the right frontal lobe of patients diagnosed with Alzheimer's disease (AD), before the implantation of a ventricular catheter and pump assembly for the infusion of bethanechol chloride as an experimental therapy. The pathologically diagnosed patients with AD (n = 35; mean age, 67 +/- 1.5 yr) were compared with a group of samples from normal age-equivalent autopsied controls (n = 22; mean age, 68 +/- 2 yr) and autopsied AD brains (n = 11; mean age, 73 +/- 2 yr). Samples were assayed for choline acetyltransferase (ChAT), acetylcholinesterase, binding to [3H]quinuclidinyl benzilate as an index of total muscarinic cholinergic binding, and [3H]pirenzepine binding as an index of M1 cholinergic receptor subtype binding. Mean levels of ChAT activity were decreased in the biopsied patients to 36% of age-matched autopsied controls. The loss of ChAT activity correlated significantly with the Mini-Mental State Examination, an index of global cognitive function. Mean ChAT activity in autopsied AD cortex was further decreased compared with controls, indicating continuous decline through the course of the disease. Acetylcholinesterase followed a similar, less dramatic decline. No differences were found in [3H]quinuclidinyl benzilate binding or [3H]pirenzepine binding between biopsied and autopsied controls. Neuritic plaque counts did not correlate with either the Mini-Mental State Examination or ChAT activity in the biopsy specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Toward a definite diagnosis of Alzheimer's disease

There is a significant, and growing, number of patients who suffer from dementia of the Alzheimer's type (DAT). However, due to clinical variability and symptom overlap, and despite millions of dollars spent in diagnostic work-ups, the diagnosis of DAT remains one of exclusion or by neuropathologic study (usually postmortem). This report evaluates two promising methods, the newly refined clinical criteria sets (e.g., NINCDS-ADRDA) and single-photon emission computed tomography (SPECT), on their capacity for definite, accurate, and early diagnosis of DAT patients. We found that clinical diagnosis of DAT can achieve a weighted average for sensitivity of 72%, specificity of 86%, and diagnostic confidence of 72%; however, when NINCDS-ADRDA criteria are used, these results improve to 88%, 91%, and 92%, respectively. SPECT scans could differentiate DAT patients from normals with 86% sensitivity, 96% specificity, and 98% diagnostic confidence. Comparable figures for DAT versus multi-infarct dementia (MID) are 82%, 81%, and 86%, respectively. We conclude that, although a definite clinical diagnosis of DAT is still elusive and more research is needed, the use of either NINCDS-ADRDA criteria or SPECT scans may enhance diagnostic accuracy.

Alzheimer's disease

Alzheimer's disease is one of the most severe and most common chronic diseases of older persons. Because occurrence of the disease is strongly related to age, its public health impact is likely to continue to increase as the population ages. As with many other diseases, a diagnosis of Alzheimer's disease is made through a combination of clinical history, physical, and neurologic examination, and laboratory evaluation. Because the dominant feature of this disease is its effect on cognition, its diagnosis requires careful evaluation of cognitive function usually with formal neuropsychological performance testing. Clinical evaluation of persons for Alzheimer's disease has four objectives: (1) to determine as accurately as possible if the person has dementia; (2) if dementia is present, to determine whether its presentation and course are consistent with a diagnosis of Alzheimer's disease; (3) to assess evidence for any alternate diagnoses, especially if the presentation and course are atypical for Alzheimer's disease; and (4) to evaluate evidence of other, coexisting, diseases that may contribute to the dementia, with strong emphasis on conditions that might respond to treatment. There is no reliable antemortem diagnostic test for Alzheimer's disease; the main purpose of laboratory testing is to identify other conditions that might cause or exacerbate dementia. Pathologically, Alzheimer's disease is characterized by the presence of two lesions on microscopic examination of the brain: neuritic plaques and neurofibrillary tangles. Both lesions can be seen in the brains of older persons without dementia. However, they are found in greater numbers in the neocortex and hippocampus with Alzheimer's disease. Caring for patients with Alzheimer's disease is demanding and requires compassion and skills that go beyond the choices among sophisticated and effective therapies that characterize much of modern medical practice. The current lack of effective pharmacotherapy for cognitive dysfunction in Alzheimer's disease should not obscure that there are many areas in which intervention can improve quality of life for both the patient and the caregiver. Achieving success in these areas typically requires that the physician work effectively with providers of many other medical and nonmedical services. Community resources, advocacy, behavior management, and experimental therapies and procedures, should be discussed with the family of each patient. In addition, persons with mild disease should be promptly informed of their diagnosis in order to obtain their wishes regarding life prolonging measures and extended care options.

Commingling analysis of memory performance in offspring of Alzheimer patients

Dementia of the Alzheimer type (DAT) is a neurodegenerative disorder which afflicts approximately 3% of the population. Genetic influences are indicated from twin and family studies although genetic heterogeneity has been suggested from both pedigree analyses and linkage investigations. Autosomal dominant inheritance with age-dependent penetrance has been suggested in at least some families with DAT. In the present investigation, we examine memory and nonmemory task performance in 106 asymptomatic offspring (mean age 40.6 years) of 54 DAT probands. Intraclass sibling correlations revealed little evidence of sibling similarity for performance on three memory tasks which have been reported to be relatively sensitive to the memory losses accompanying DAT. Subsequent investigations of the distributions of the cognitive task scores in the offspring revealed evidence for a commingling of two distributions for the three memory tasks but not for the nonmemory measures. These findings are consistent with a hypothesis that these distributions reflect genotypic subgroups, carriers, and noncarriers, of a presumed DAT gene.

Medical disorders in Alzheimer's disease and vascular dementia

The clinical and postmortem findings of 29 patients with Alzheimer's disease were evaluated and compared to the findings of 19 patients with vascular dementia. The patients with Alzheimer's disease had received treatment for an average of 2.0 internal medical disorders, the patients with vascular dementia for 2.1 disorders. The average number of medical diseases found at postmortem was 3.7 in the group with Alzheimer's dementia and 4.1 in vascular dementia. Apart from a marginally increased rate of peripheral occlusive artery disease in vascular dementia, the proportions of the most common disorders of the cardiovascular, genitourinary, gastrointestinal and endocrinological disorders and the most common causes of death did not differ significantly between these groups. Therefore patients with Alzheimer's disease should receive the same internal medical attention as patients with vascular dementia.

Platelet membrane fluidity in Alzheimer's disease and multi-infarct dementia: a spin label study

The membrane fluidity of platelets isolated from 15 patients with probable Alzheimer's disease (AD), 11 patients with probable multi-infarct dementia (MID), and 7 neurologically healthy controls was studied by electron spin resonance (ESR) spectroscopy employing spin label techniques. Spin label I(12,3) probed the shallow site (hydrophilic region) and spin label I(5, 10) the deeper site (hydrophobic region) of the platelet membrane. With both probes, a significant increase in membrane fluidity was observed in patients with AD and MID, as compared to age-matched controls. However, there were no significant differences in fluidity between AD and MID patients. Our results suggest an increased platelet membrane fluidity in dementias, but the change seems not to be specific to AD.