Mild cognitive impairment--beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive Impairment

The First Key Symposium was held in Stockholm, Sweden, 2-5 September 2003. The aim of the symposium was to integrate clinical and epidemiological perspectives on the topic of Mild Cognitive Impairment (MCI). A multidisciplinary, international group of experts discussed the current status and future directions of MCI, with regard to clinical presentation, cognitive and functional assessment, and the role of neuroimaging, biomarkers and genetics. Agreement on new perspectives, as well as recommendations for management and future research were discussed by the international working group. The specific recommendations for the general MCI criteria include the following: (i) the person is neither normal nor demented; (ii) there is evidence of cognitive deterioration shown by either objectively measured decline over time and/or subjective report of decline by self and/or informant in conjunction with objective cognitive deficits; and (iii) activities of daily living are preserved and complex instrumental functions are either intact or minimally impaired.

Current concepts in mild cognitive impairment

The field of aging and dementia is focusing on the characterization of the earliest stages of cognitive impairment. Recent research has identified a transitional state between the cognitive changes of normal aging and Alzheimer's disease (AD), known as mild cognitive impairment (MCI). Mild cognitive impairment refers to the clinical condition between normal aging and AD in which persons experience memory loss to a greater extent than one would expect for age, yet they do not meet currently accepted criteria for clinically probable AD. When these persons are observed longitudinally, they progress to clinically probable AD at a considerably accelerated rate compared with healthy age-matched individuals. Consequently, this condition has been recognized as suitable for possible therapeutic intervention, and several multicenter international treatment trials are under way. Because this is a topic of intense interest, a group of experts on aging and MCI from around the world in the fields of neurology, psychiatry, geriatrics, neuropsychology, neuroimaging, neuropathology, clinical trials, and ethics was convened to summarize the current state of the field of MCI. Participants reviewed the world scientific literature on aging and MCI and summarized the various topics with respect to available evidence on MCI. Diagnostic criteria and clinical outcomes of these subjects are available in the literature. Mild cognitive impairment is believed to be a high-risk condition for the development of clinically probable AD. Heterogeneity in the use of the term was recognized, and subclassifications were suggested. While no treatments are recommended for MCI currently, clinical trials regarding potential therapies are under way. Recommendations concerning ethical issues in the diagnosis and the management of subjects with MCI were made.

A pathogenic mutation for probable Alzheimer's disease in the APP gene at the N-terminus of beta-amyloid

Mutations at codon 717 in exon 17 of the beta-amyloid precursor protein (APP) gene have previously been shown to segregate with early onset Alzheimer's disease in some families. We have identified a double mutation at codons 670 and 671 (APP 770 transcript) in exon 16 which co-segregates with the disease in two large (probably related) early-onset Alzheimer's disease families from Sweden. Two base pair transversions (G to T, A to C) from the normal sequence predict Lys to Asn and Met to Leu amino acid substitutions at codons 670 and 671 of the APP transcript. This mutation occurs at the amino terminal of beta-amyloid and may be pathogenic because it occurs at or close to the endosomal/lysosomal cleavage site of the molecule. Thus, pathogenic mutations in APP frame the beta-amyloid sequence.

Influence of social network on occurrence of dementia: a community-based longitudinal study

BACKGROUND

Few data are available on the effect of social ties on dementia development. This study explored whether single social network components and different degrees of the social connections affect dementia incidence.

METHODS

A community-based cohort of 1203 non-demented people, living at home in the Kungsholmen district of Stockholm, Sweden, and who had good cognition, was followed for an average period of 3 years. On the basis of medical and psychological data, 176 patients were diagnosed with dementia according to the criteria of the third edition revision of the Diagnostic and Statistical Manual of Mental Disorders. Information on social network was obtained by personal interview by trained nurses at baseline. The covariates included in the analysis were age, sex, education, cognitive and functional status, depressive symptoms, and vascular diseases.

FINDINGS

Those individuals living alone, and those without any close social ties, both had an adjusted relative risk for developing dementia of 1.5 (95% CI 1.0-2.1 and 1.0-2.4, respectively). Compared with married people living with someone, single people and those living alone had an adjusted relative risk of 1.9 (95% CI 1.2-3.1). Infrequent contacts with network resources did not increase the risk of the disease if such contacts were experienced as satisfying. When all components were combined in an index, a poor or limited social network increased the risk of dementia by 60% (95% CI 1.2-2.1), and a significant gradient was found for the four degrees of social connections (p=0.0009).

INTERPRETATION

An extensive social network seems to protect against dementia. Confirmation of this finding and further investigation to clarify the mechanisms are worthwhile due to the implications for prevention.

A 1-year, randomized, placebo-controlled study of donepezil in patients with mild to moderate AD

OBJECTIVE

To evaluate the long-term clinical efficacy and safety of donepezil versus placebo over 1 year in patients with mild to moderate AD.

METHODS

Patients (n = 286; mean age, 72.5 years) with possible or probable AD from five Northern European countries were randomized to receive either donepezil (n = 142; 5 mg/day for 28 days, followed by 10 mg/day) or placebo (n = 144) for 1 year.

RESULTS

The study was completed by 66.9% of the donepezil- and 67.4% of the placebo-treated patients. The benefit of donepezil over placebo was demonstrated by the Gottfries-Bråne-Steen (a global assessment for rating dementia symptoms) total score at weeks 24, 36, and 52 (p < 0.05) and at the study end point (week 52, last observation carried forward; p = 0.054). Advantages of donepezil over placebo were also observed in cognition and activities of daily living (ADL) assessed by the Mini-Mental State Examination at weeks 24, 36, and 52, and the end point (p < 0.02) and by the Progressive Deterioration Scale at week 52 and the end point (p < 0.05). Adverse events (AE) were recorded for 81.7% of donepezil- and 75.7% of placebo-treated patients, with 7% of donepezil- and 6.3% of placebo-treated patients discontinuing because of AE. Treatment response to donepezil was not predicted by APOE genotype or sex in this population.

CONCLUSION

As the first 1-year, multinational, double-blinded, placebo-controlled study of a cholinesterase inhibitor in AD, these data support donepezil as a well tolerated and effective long-term treatment for patients with AD, with benefits over placebo on global assessment, cognition, and ADL.

Cerebrospinal fluid beta-amyloid(1-42) in Alzheimer disease: differences between early- and late-onset Alzheimer disease and stability during the course of disease

OBJECTIVES

To study the diagnostic potential of the 42 amino acid form of beta-amyloid (beta-amyloid(1-42)) in cerebrospinal fluid (CSF) as a biochemical marker for Alzheimer disease (AD), the intra-individual biological variation of CSF-beta-amyloid(1-42) level in patients with AD, and the possible effects of differential binding between beta-amyloid and apolipoprotein E isoforms on CSF-beta-amyloid(1-42) levels.

DESIGN

A 20-month prospective follow-up study.

SETTING

Community population-based sample of consecutive patients with AD referred to the Piteå River Valley Hospital, Piteå, Sweden.

PATIENTS

Fifty-three patients with AD (mean +/- SD age, 71.4 +/- 7.4 years) diagnosed according to the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association criteria and 21 healthy, age-matched (mean +/- SD age, 68.8 +/- 8.0 years) control subjects.

MAIN OUTCOME MEASURES

Cerebrospinal fluid beta-amyloid(1-42) level--analyzed using enzyme-linked immunosorbent assay--and severity of dementia--analyzed using the Mini-Mental State Examination.

RESULTS

Mean +/- SD levels of CSF-beta-amyloid(1-42) were decreased (P<.001) in patients with AD (709 +/- 304 pg/mL) compared with controls (1678 +/- 436 pg/mL). Most patients with AD (49 [92%] of 53 patients) had reduced levels (<1130 pg/mL). A highly significant correlation (r = 0.90; P<.001) between baseline and 1-year follow-up CSF-beta-amyloid(1-42) levels was found. There were no significant correlations between CSF-beta-amyloid(1-42) level and duration (r = -0.16) or severity (r = -0.02) of dementia. Low levels were also found in patients with mild dementia (Mini-Mental State Examination score, >25).

CONCLUSIONS

The sensitivity of CSF-beta-amyloid(1-42) level as a diagnostic marker for AD is high. The intra-individual biological variation in CSF-beta-amyloid(1-42) level is low. Low CSF-beta-amyloid(1-42) levels are also found in the earlier stages of dementia in patients with AD. These findings suggest that CSF-beta-amyloid(1-42) analyses may be of value in the clinical diagnosis of AD, especially in the early course of the disease, when drug therapy may have the greatest potential of being effective but clinical diagnosis is particularly difficult.

Evaluation of CSF-tau and CSF-Abeta42 as diagnostic markers for Alzheimer disease in clinical practice

OBJECTIVE

To evaluate the diagnostic potential of cerebrospinal fluid (CSF) levels of tau and beta-amyloid protein ending at amino acid 42 (Abeta42) as biomarkers for Alzheimer disease (AD) in clinical practice.

DESIGN

A 1-year prospective study.

SETTING

Community population-based sample of all consecutive patients admitted for investigation of cognitive symptoms to the Piteå River Valley Hospital, Piteå, Sweden.

PATIENTS

A total of 241 patients with probable AD (n = 105), possible AD (n = 58), vascular dementia (n = 23), mild cognitive impairment (n = 20), Lewy body dementia (n = 9), other neurological disorders (n = 3), and psychiatric disorders (n = 5) and nondemented individuals (n = 18).

MAIN OUTCOME MEASURES

Cerebrospinal fluid tau and CSF-Abeta42 were assayed each week as routine clinical neurochemical analyses. Sensitivity and specificity were defined using the regression line from 100 control subjects from a multicenter study. Positive and negative predictive values were calculated for different prevalence rates of AD.

RESULTS

We found increased CSF-tau and decreased CSF-Abeta42 levels in probable and possible AD. Sensitivity was 94% for probable AD, 88% for possible AD, and 75% for mild cognitive impairment, whereas specificity was 100% for psychiatric disorders and 89% for nondemented. Specificity was lower in Lewy body dementia (67%) mainly because of low CSF-Abeta42 levels and in vascular dementia (48%) mainly because of high CSF-tau levels. Sensitivity for CSF-tau and CSF-Abeta42 increased in patients with AD possessing the ApoE epsilon4 allele, approaching 100%. At a prevalence of AD of 45%, the positive predictive value was 90% and the negative predictive value was 95%.

CONCLUSIONS

Cerebrospinal fluid tau and CSF-Abeta42 have so far been studied in research settings, under conditions providing data on the optimal performance. We examined a prospective patient sample, with assays run in clinical routine, giving figures closer to the true performance of CSF-tau and CSF-Abeta42. The predictive value for AD was greater than 90%. Therefore, these biomarkers may have a role in the clinical workup of patients with cognitive impairment, especially to differentiate early AD from normal aging and psychiatric disorders.

Diabetes, Alzheimer disease, and vascular dementia: a population-based neuropathologic study

OBJECTIVE

To investigate the relation of diabetes to dementia, Alzheimer disease (AD), and vascular dementia (VaD), through analyses of incidence, mortality, and neuropathologic outcomes in a prospective population-based study of the oldest old.

METHODS

The Vantaa 85+ study included 553 residents living in the city of Vantaa, Finland, and aged ≥85 years on April 1, 1991. Survivors were reexamined in 1994, 1996, 1999, and 2001. Autopsies were performed in 291 persons who died during the follow-up (48% of total population). Diabetes was assessed according to self-report, medical record of physician-diagnosed diabetes, or use of antidiabetic medication. Macroscopic infarcts were identified from 1-cm coronal slices of cerebral hemispheres, 5-mm transverse brainstem slices, and sagittal cerebellum slices. Methenamine silver staining was used for β-amyloid, methenamine silver-Bodian staining for neurofibrillary tangles, and modified Bielschowsky method for neuritic plaques. Cox proportional hazards and multiple logistic regression models were used to analyze the association of diabetes with dementia and neuropathology, respectively.

RESULTS

Diabetes at baseline doubled the incidence of dementia, AD, and VaD, and increased mortality. Individuals with diabetes were less likely to have β-amyloid (hazard ratio [HR] [95% confidence interval (CI)] was 0.48 [0.23-0.98]) and tangles (HR [95% CI] 0.72 [0.39-1.33]) but more likely to have cerebral infarcts (HR [95% CI] 1.88 [1.06-3.34]) after all adjustments.

CONCLUSION

Elderly patients with diabetes develop more extensive vascular pathology, which alone or together with AD-type pathology (particularly in APOE ε4 carriers) results in increased dementia risk.

Very old women at highest risk of dementia and Alzheimer's disease: incidence data from the Kungsholmen Project, Stockholm

OBJECTIVE

To determine the incidence of different types of dementia in the very old, and to explore the relation with age and gender.

DESIGN

A dementia-free cohort was followed for an average of three years in Stockholm, Sweden. At the end of the follow-up, the subjects were interviewed by nurses, clinically examined by physicians, and cognitively assessed by psychologists. Deceased cohort members were studied using death certificates, hospital clinical records, and discharge diagnoses. Dementia diagnoses were made according to the DSM-III-R criteria independently by two physicians.

PARTICIPANTS

The cohort consisted of 1,473 subjects (75+ years old), of which 987 were clinically examined at follow-up, 314 died before the examination, and 172 refused to participate.

RESULTS

During the follow-up, 148 subjects developed dementia. In the age-group 75 to 79, the incidence rates for dementia were 19.6 for women and 12.4 for men per 1,000 person-years, whereas for 90+ year-old subjects the corresponding figures were 86.7 and 15.0 per 1,000 person-years. A similar pattern of distribution by age and gender was seen for Alzheimer's disease. In each age stratum, the incidence rates of dementia and Alzheimer's disease were higher for women than for men. The age-adjusted odds ratio for women was 1.9 for dementia and 3.1 for Alzheimer's disease.

CONCLUSIONS

(1) The incidence of dementia increases with age, even in the oldest age groups; (2) women have a higher risk of developing dementia than men, especially at very old ages; (3) this pattern is mainly due to the age and gender distribution of Alzheimer's disease, rather than vascular dementia.

Distribution of different fiber types in human skeletal muscles: effects of aging studied in whole muscle cross sections

The effects of aging on the total number and size of fibers, and the proportion and distribution of type 1 (slow twitch) and type 2 (fast twitch) fibers were studied in cross sections (15 mu thick) of autopsied whole m. vastus lateralis from two age groups. Each group consisted of six, previously physically healthy males (mean age 72 +/- 1 years and 30 +/- 6 years, respectively). The size of the muscles of the older individuals was 18% smaller (P less than 0.01) and the total number of fibers was 25% lower (P less than 0.01) than those of the young individuals (mean number 364,000 +/- 50,000 vs 478,000 +/- 56,000). There was, however, no significant difference in the mean fiber size (indirectly determined) or the proportion of the two fiber types, though a preferential reduction in type 2 fiber number in the aged individuals was seen. The relative occurrence of the fiber types at various depths in the aged muscles was found to be more even than in muscles from the young individuals. The results suggest that the aging atrophy in m. vastus lateralis, at least up to the age of 70, is primarily the result of a loss of fibers.

Volume and number of neurons of the human hippocampal formation in normal aging and Alzheimer's disease

In order to observe changes owing to aging and Alzheimer's disease (AD) in the volumes of subdivisions of the hippocampus and the number of neurons of the hippocampal formation, 18 normal brains from subjects who died of nonneurological causes and had no history of long-term illness or dementia (ten of these brains comprised the aged control group) and 13 AD brains were analyzed. An optimized design for sampling, measuring volume by using the Cavalieri principle, and counting the number of neurons by using the optical disector was implemented on 50 microns-thick cresyl-violet sections. The mean total volume of the principal subdivisions of the hippocampal formation (fascia dentata, hilus, CA3-2, CA1, and subiculum) showed a negative correlation with age in normal subjects (r = -0.56, 2P < 0.05), and a 32% mean reduction in the AD group compared with controls (P < 0.001). This finding supports the measurement of the coronal cross-sectional area and the volume of the hippocampal formation in the clinical diagnosis of AD. There was an inverse relationship between the age of normal subjects and the number of neurons in CA1 (r = -0.84, 2P < 0.0001) and subiculum (r = -0.49, 2P < 0.05) but not in other subdivisions. Pronounced AD-related reductions in neuron number were found only in the subiculum and the fascia dentata. Compared with controls, both losses represented 23% of neurons (P < 0.05). These results 1) confirm that AD is a qualitatively different process from normal aging and 2) reveal the regional selectivity of neuron loss within the hippocampal formation in aging and AD, which may be relevant to understanding the mechanisms involved in the neuron loss associated with the two processes.

Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline

The aim of this international guideline on dementia was to present a peer-reviewed evidence-based statement for the guidance of practice for clinical neurologists, geriatricians, psychiatrists, and other specialist physicians responsible for the care of patients with dementia. It covers major aspects of diagnostic evaluation and treatment, with particular emphasis on the type of patient often referred to the specialist physician. The main focus is Alzheimer's disease, but many of the recommendations apply to dementia disorders in general. The task force working group considered and classified evidence from original research reports, meta-analysis, and systematic reviews, published before January 2006. The evidence was classified and consensus recommendations graded according to the EFNS guidance. Where there was a lack of evidence, but clear consensus, good practice points were provided. The recommendations for clinical diagnosis, blood tests, neuroimaging, electroencephalography (EEG), cerebrospinal fluid (CSF) analysis, genetic testing, tissue biopsy, disclosure of diagnosis, treatment of Alzheimer's disease, and counselling and support for caregivers were all revised when compared with the previous EFNS guideline. New recommendations were added for the treatment of vascular dementia, Parkinson's disease dementia, and dementia with Lewy bodies, for monitoring treatment, for treatment of behavioural and psychological symptoms in dementia, and for legal issues. The specialist physician plays an important role together with primary care physicians in the multidisciplinary dementia teams, which have been established throughout Europe. This guideline may contribute to the definition of the role of the specialist physician in providing dementia health care.

Defective brain microtubule assembly in Alzheimer's disease

Brains obtained within 2-4 hours post mortem and histopathologically confirmed for Alzheimer's disease and non-Alzheimer brains from age-matched controls were examined for in-vitro assembly of microtubules and neurofilaments. Microtubule assembly was observed only in control but not in Alzheimer brains, and neurofilaments were obtained from both types of brain. The microtubule-associated protein tau, which stimulates assembly of microtubules from tubulin, was abnormally phosphorylated in Alzheimer but not in control brain microtubule preparations. Alzheimer brains did not show the presence of any inhibitor of microtubule assembly or any abnormality of tubulin. DEAE-dextran, a polycation which mimics tau in stimulating microtubule assembly, induced the assembly of microtubules in Alzheimer brain. Tubulin from both normal and Alzheimer brains was labelled on western blots by a monoclonal antibody to the tyrosinylated carboxy-terminal epitope of alpha tubulin. These studies suggest that in Alzheimer's disease tubulin can be assembled into brain microtubules, but the process is defective, probably because of abnormal phosphorylation of tau. This post-translational alteration of tau might be the cause of the neurofibrillary abnormality in Alzheimer's disease.

Distribution of active glycogen synthase kinase 3beta (GSK-3beta) in brains staged for Alzheimer disease neurofibrillary changes

Accumulation of paired helical filaments (PHFs) in neurofibrillary tangles, neuropil threads, and dystrophic neurites is one of the major neuropathological hallmarks of Alzheimer disease (AD). The principal protein subunit of PHFs is the abnormally hyperphosphorylated tau. Glycogen synthase kinase 3beta (GSK-3beta) is one of the candidate kinases involved in PHF-tau formation. To play a role in PHF-tau formation, it would be expected that GSK-3beta is active in tangle bearing neurons. In the present study, we investigated the regional and intracellular distributions of active and inactive forms of GSK-3beta in brains staged for neurofibrillary changes. We found that neurons with tangle-like inclusions positive for active, but not inactive, GSK-3beta appear initially in the Pre-alpha layer of the entorhinal cortex and extend to other brain regions, coincident with the sequence of the development of neurofibrillary changes. Active, but not inactive, GSK-3beta was found to initially accumulate in the cytoplasm of pretangle neurons. These data provide direct in situ evidence that is consistent with the involvement of GSK-3beta in PHF-tau formation.

Relative abundance of Alzheimer A beta amyloid peptide variants in Alzheimer disease and normal aging

The Alzheimer A beta amyloid peptide (A beta) is the principal proteinaceous component of amyloid associated with Alzheimer disease (AD). We have determined the relative abundance of A beta structural variants present in amyloid from brains of 10 individuals with sporadic AD, 2 individuals with familial AD carrying specific mutations in the Alzheimer amyloid precursor protein gene, and 5 nondemented elderly controls. A procedure of isolation based on the extreme insolubility of A beta amyloid was used. The purified, nondigested A beta was analyzed by N-terminal sequencing and electrospray-ionization mass spectrometry. Three principal A beta variants were detected--A beta-(1-40), A beta-(1-42), and A beta-(11-42)--in all brains analyzed. The predominant variant in sporadic AD was A beta-(1-40), whereas the principal A beta variant in nondemented elderly controls was A beta-(1-42). The ratio A beta-(1-40)/A beta-(1-42) differed by 10-fold between brains from nondemented controls and those with sporadic AD.

Intracerebroventricular infusion of nerve growth factor in three patients with Alzheimer's disease

Nerve growth factor (NGF) is important for the survival and maintenance of central cholinergic neurons, a signalling system impaired in Alzheimer's disease. We have treated 3 patients with Alzheimer's disease with a total of 6.6 mg NGF administered continuously into the lateral cerebral ventricle for 3 months in the first 2 patients and a total of 0.55 mg for 3 shorter periods in the third patient. The patients were extensively evaluated with clinical, neuropsychological, neurophysiological and neuroradiological techniques. Three months after the NGF treatment ended, a significant increase in nicotine binding was found in several brain areas in the first 2 patients and in the hippocampus in the third patient as studied by positron emission tomography. A clear cognitive amelioration could not be demonstrated, although a few neuropsychology tests showed slight improvements. The amount of slow-wave cortical activity as studied by electroencephalography was reduced in the first 2 patients. Two negative side effects occurred with NGF treatment: first, a dull, constant back pain was observed in all 3 patients, which in 1 patient was aggravated by axial loading resulting in sharp, shooting pain of short duration. When stopping the NGF infusion, the pain disappeared within a couple of days. Reducing the dose of NGF lessened the pain. Secondly, a marked weight reduction during the infusion with a clear weight gain after ending the infusion was seen in the first 2 patients. We conclude from this limited trial that, while long-term intracerebroventricular NGF administration may cause certain potentially beneficial effects, the intraventricular route of administration is also associated with negative side effects that appear to outweigh the positive effects of the present protocol. Alternative routes of administration, and/or lower doses of NGF, perhaps combined with low doses of other neurotrophic factors, may shift this balance in favor of positive effects.

Quantitative electroencephalography in mild cognitive impairment: longitudinal changes and possible prediction of Alzheimer's disease

The present study evaluated the clinical course of patients with mild cognitive impairment (MCI), the pattern of electroencephalography (EEG) changes following cognitive deterioration, as well as the potential of neurophysiological measures in predicting dementia. Twenty-seven subjects with MCI were followed for a mean follow up period of 21 months. Fourteen subjects (52%) progressed (P MCI) to clinically manifest Alzheimer's disease (AD), and 13 (48%) remained stable (S MCI). The two MCI subgroups did not differ in baseline EEG measures between each other and the healthy controls (n = 16), but had significantly lower theta relative power at left temporal, temporo-occipital, centro-parietal, and right temporo-occipital derivation when compared to the reference AD group (n = 15). The P MCI baseline alpha band temporo-parietal coherence, alpha relative power values at left temporal and temporo-occipital derivations, theta relative power values at frontal derivations, and the mean frequency at centro-parietal and temporo-occipital derivations overlapped with those for AD and control groups. After the follow-up, the P MCI patients had significantly higher theta relative power and lower beta relative power and mean frequency at the temporal and temporo-occipital derivations. A logistic regression model of baseline EEG values adjusted for baseline Mini-Mental Test Examination showed that the important predictors were alpha and theta relative power and mean frequency from left temporo-occipital derivation (T5-O1), which classified 85% of MCI subjects correctly.

Changes in the brain catecholamines in patients with dementia of Alzheimer type

Brain monoamine concentrations were determined post mortem in 19 patients with dementia of Alzheimer type. Samples were taken from 10 parts of the brain and compared with an age-matched control group. There were lower mean concentrations of dopamine in the demented group of patients in seven regions of the brain, and two of these were at a significant level. There were also significantly lower concentrations of homovanillic acid in the nucleus caudatus and in the putamen. The means of the concentrations of noradrenaline were also lower, and in the putamen and the cortex gyrus frontalis significant differnces were observed. The 5-hydroxytryptamine concentrations were slightly lower in the demented group but the differences did not reach significance. The degree of intellectual deterioration was negatively correlated with the noradrenaline concentrations in the hypothalamus and the cortex gyrus cinguli.

Discrimination of Alzheimer's disease and mild cognitive impairment by equivalent EEG sources: a cross-sectional and longitudinal study

OBJECTIVES

The spatial aspects of brain electrical activity can be assessed by equivalent EEG frequency band generators. We aimed to describe alterations of these EEG generators in Alzheimer's disease (AD) and healthy aging and whether they could serve as predictive markers of AD in subjects at risk.

METHODS

The amplitude and 3-dimensional localization of equivalent EEG sources were evaluated using FFT dipole approximation in 38 mild AD patients, 31 subjects with mild cognitive impairment (MCI) and 24 healthy control subjects.

RESULTS

AD patients showed an increase of delta and theta global field power (GFP), which corresponds to the generalized EEG amplitude, as well as a reduction of alpha GFP when compared to the controls. A decrease of alpha and beta GFP was found in AD patients, as compared to the MCI subjects. With respect to topography in the antero-posterior direction, sources of alpha and beta activity shifted more anteriorly in AD patients compared to both the controls and MCI subjects. No significant difference was found between MCI and controls. Combined alpha and theta GFP were the best discriminating variables between AD patients and controls (84% correct classification) and AD and MCI subjects (78% correctly classified). MCI subjects were followed longitudinally (25 months on average) in order to compare differences in baseline EEG variables between MCI subjects who progressed to AD (PMCI) and those who remained stable (SMCI). Compared to SMCI, PMCI had decreased alpha GFP and a more anterior localization of sources of theta, alpha and beta frequency. In a linear discriminant analysis applied on baseline values of the two MCI subgroups, the best predictor of future development of AD was found to be antero-posterior localization of alpha frequency.

CONCLUSIONS

FFT dipole approximation and frequency analysis performed by conventional FFT showed comparable classification accuracy between the studied groups. We conclude that localization and amplitude of equivalent EEG sources could be promising markers of early AD.

Prevalence of Alzheimer's disease and other dementias in an elderly urban population: relationship with age, sex, and education

We studied the prevalence of different types of dementia in an elderly population in Stockholm, Sweden, in relation to age, sex, and education. The study confirmed Alzheimer's disease (AD) as the most frequent type of dementia and the positive association of dementias with age, even in the most advanced ages. In contrast to previously reported data, we found the same proportion of AD and vascular dementia in the different age strata, and no sex differences regarding the prevalence of different dementia types. Finally, less educated people had a higher prevalence of all dementias, due essentially to a higher prevalence of alcoholic dementia and unspecified type of dementia. The prevalence of AD was similar across different levels of education.

Memantine in severe dementia: results of the 9M-Best Study (Benefit and efficacy in severely demented patients during treatment with memantine)

OBJECTIVES

To assess clinical efficacy and safety of memantine--an uncompetitive N-methyl-D-aspartate (NMDA) antagonist--in moderately severe to severe primary dementia.

MATERIALS AND METHODS

Dementia was defined by DSM-III-R criteria and severity was assessed by the Global Deterioration Scale (stages 5-7) and the Mini-Mental State Examination (< 10 points). Primary endpoints were the Clinical Global Impression of Change (CGI-C) rated by the physician, and the Behavioural Rating Scale for Geriatric Patients (BGP), subscore 'care dependence', rated by the nursing staff. Secondary endpoints included the modified D-Scale (Arnold/Ferm).

RESULTS

The ITT sample comprised 166 patients and 151 patients were treated per protocol. At 12-week ITT endpoint analysis, 82 received memantine 10 mg per day, 84 placebo. Dementia was in 49% of the Alzheimer type and in 51% of the vascular type (CT, Hachinski score). A positive response in the CGI-C was seen in 73% versus 45% in favour of memantine (stratified Wilcoxon p < 0.001), independent of the etiology of dementia. The results in the BGP subscore 'care dependence' were 3.1 points improvement under memantine and 1.1 points under placebo (p = 0.016). A coincident response of the two independent target variables was observed in 61.3% (memantine) versus 31.6% (placebo). Secondary endpoint analysis of the D-Scale assessing basic ADL functions support the primary results. Regarding the safety profile, no significant differences between treatment groups were observed.

CONCLUSIONS

The results of this trial support the hypothesis that memantine treatment leads to functional improvement and reduces care dependence in severely demented patients.

Acute confusional states in elderly patients treated for femoral neck fracture

The aims of this study were to estimate the incidence of acute confusional state (ACS), its predisposing factors and consequences in 111 consecutive patients operated for fractured neck of the femur. The incidence of ACS was 61 percent and the predicting factors were old age and dementia. Drugs with anticholinergic effect, depression, and previous stroke were factors that seemed to be associated with the development of ACS. Ninety-two percent of the patients who had severe perioperative blood pressure drops developed ACS. The consequences of ACS were prolonged ward-stay at the orthopedic department, a greater need for long-term care after discharge, and poor walking ability at discharge and six months after surgery. The confused patients also had more complications, such as urinary problems, feeding problems and decubital ulcers, as compared with the nonconfused patients.

Increased expression of brain-derived neurotrophic factor mRNA in rat hippocampus is associated with improved spatial memory and enriched environment

Enriched environment has been shown to enhance learning and memory and to induce morphological changes in the hippocampus. We report that rats housed in an enriched environment showed improved performance in the Morris water maze and decreased spontaneous motor activity. Exposure to behavioural tests increased expression of the mRNA that encodes brain-derived neurotrophic factor in the hippocampus. This was not seen when rats subjected to impoverished housing were tested suggesting that environmental history of the animal is of importance to induce expression of brain-derived neurotrophic factor in the hippocampus that may promote neuronal changes related to learning and memory.

Influence of age and time interval between death and autopsy on dopamine and 3-methoxytyramine levels in human basal ganglia

The caudate nuclei and putamens of 30 human brains were analyzed for dopamine and its metabolite 3-methoxytyramine, most of which was presumably formed from dopamine postmortally. It was found that dopamine and the sum (dopamine + methoxytyramine) but not methoxytyramine declined with the time interval between death and autopsy as well as with age.

Predictors of progression from mild cognitive impairment to Alzheimer disease

OBJECTIVE

To determine the occurrence of neuropsychiatric symptomatology and the relation to future development of Alzheimer disease (AD) in persons with and without mild cognitive impairment (MCI).

METHOD

We followed 185 persons with no cognitive impairment and 47 with MCI (amnestic and multidomain), ages 75 to 95, from the population-based Kungsholmen Project, Stockholm, Sweden, for 3 years. Three types of neuropsychiatric symptoms were assessed at baseline: mood-related depressive symptoms, motivation-related depressive symptoms, and anxiety-related symptomatology. AD at 3-year follow-up was diagnosed according to Diagnostic and Statistical Manual for Mental Disorders-III-R criteria.

RESULTS

Psychiatric symptoms occurred more frequently in persons with MCI (36.2% mood, 36.2% motivation, and 46.8% anxiety symptoms) than in cognitively intact elderly individuals (18.4% mood, 13.0% motivation, and 24.9% anxiety). Of persons with both MCI and anxiety symptoms, 83.3% developed AD over follow-up vs 6.1% of cognitively intact persons and 40.9% persons who had MCI without anxiety. Among persons with MCI, the 3-year risk of progressing to AD almost doubled with each anxiety symptom (relative risk [RR] = 1.8 [1.2 to 2.7] per symptom). Conversely, among cognitively intact subjects, only symptoms of depressive mood were related to AD development (RR = 1.9 [1.0 to 3.6] per symptom).

CONCLUSIONS

The predictive validity of mild cognitive impairment (MCI) for identifying future Alzheimer disease (AD) cases is improved in the presence of anxiety symptoms. Mood-related depressive symptoms (dysphoria, suicidal ideation, etc.) in preclinical AD might be related to the neuropathologic mechanism, as they appear preclinically in persons both with and without MCI.