REM sleep behavior disorder (RBD) is associated with neurodegenerative disease and particularly with the synucleinopathies. Convenience samples involving subjects with idiopathic RBD have suggested an increased risk of incident mild cognitive impairment (MCI), dementia (usually dementia with Lewy bodies) or Parkinson’s disease (PD). There is no data on such risk in a population-based sample.
Cognitively normal subjects aged 70–89 in a population-based study of aging who screened positive for probable RBD using the Mayo Sleep Questionnaire were followed at 15 month intervals. In a Cox Proportional Hazards Model, we measured the risk of developing MCI, dementia, PD among the exposed (pRBD+) and unexposed (pRBD−) cohorts.
Forty-four subjects with pRBD+ at enrollment (median duration of pRBD features was 7.5 years), and 607 pRBD− subjects, were followed prospectively for a median of 3.8 years. Fourteen of the pRBD+ subjects developed MCI and one developed PD (15/44=34% developed MCI / PD); none developed dementia. After adjustment for age, sex, education, and medical comorbidity, pRBD+ subjects were at increased risk of MCI / PD [Hazard Ratio (HR) 2.2, 95% Confidence Interval (95%CI) 1.3 – 3.9; p=0.005]. Inclusion of subjects who withdrew from the study produced similar results, as did exclusion of subjects with medication-associated RBD. Duration of pRBD symptoms did not predict the development of MCI / PD (HR 1.05 per 10 years, 95%CI 0.84 – 1.3; p=0.68).
In this population-based cohort study, we observed that pRBD confers a 2.2-fold increased risk of developing MCI / PD over four years.
sleep disorders; parasomnias; dementia; Alzheimer’s disease; dementia with Lewy bodies; parkinsonism; synuclein
To validate a questionnaire focused on REM sleep behavior disorder (RBD) among participants in an aging and dementia cohort.
RBD is a parasomnia that can develop in otherwise neurologically-normal adults as well as in those with a neurodegenerative disease. Confirmation of RBD requires polysomnography (PSG). A simple screening measure for RBD would be desirable for clinical and research purposes.
We had previously developed the Mayo Sleep Questionnaire (MSQ), a 16 item measure, to screen for the presence of RBD and other sleep disorders. We assessed the validity of the MSQ by comparing the responses of patients’ bed partners with the findings on PSG. All subjects recruited in the Mayo Alzheimer’s Disease Research Center at Mayo Clinic Rochester and Mayo Clinic Jacksonville from 1/00 to 7/08 who had also undergone a PSG were the focus of this analysis.
The study sample was comprised of 176 subjects [150 male; median age 71 years (range 39–90)], with the following clinical diagnoses: normal (n=8), mild cognitive impairment (n=44), Alzheimer’s disease (n=23), dementia with Lewy bodies (n=74), as well as other dementia and/or parkinsonian syndromes (n=27). The core question on recurrent dream enactment behavior yielded a sensitivity (SN) of 98% and specificity (SP) of 74% for the diagnosis of RBD. The profile of responses on four additional subquestions on RBD and one on obstructive sleep apnea improved specificity.
These data suggest that among aged subjects with cognitive impairment and/or parkinsonism, the MSQ has adequate SN and SP for the diagnosis of RBD. The utility of this scale in other patient populations will require further study.
sleep disorders; parasomnias; dementia; Alzheimer’s disease; dementia with Lewy bodies; parkinsonism
Few studies have reported neuropsychiatric symptoms (NPS) in Primary Progressive Aphasia (PPA), a neurodegenerative disorder that primarily affects the left hemisphere. Depression is associated with left-sided stroke, but it remains unclear if depression and other NPS are also associated with PPA. The authors compared the frequency of NPS in 55 cases of PPA with 110 cognitively normal persons matched for age, sex and education. Depression, apathy, agitation, anxiety, appetite change, and irritability are associated with PPA. Hallucinations, delusion and night time behavior were not associated with PPA.
Behavioural variant frontotemporal dementia is characterized by a change in comportment. It is associated with considerable functional decline over the course of the illness albeit with sometimes dramatic variability among patients. It is unknown whether any baseline features, or combination of features, could predict rate of functional decline in behavioural variant frontotemporal dementia. The aim of this study was to investigate the effects of different baseline clinical, neuropsychological, neuropsychiatric, genetic and anatomic predictors on the rate of functional decline as measured by the Clinical Dementia Rating Sum of Boxes scale. We identified 86 subjects with behavioural variant frontotemporal dementia that had multiple serial Clinical Dementia Rating Sum of Boxes assessments (mean 4, range 2–18). Atlas-based parcellation was used to generate volumes for specific regions of interest at baseline. Volumes were utilized to classify subjects into different anatomical subtypes using the advanced statistical technique of cluster analysis and were assessed as predictor variables. Composite scores were generated for the neuropsychological domains of executive, language, memory and visuospatial function. Behaviours from the brief questionnaire form of the Neuropsychiatric Inventory were assessed. Linear mixed-effects regression modelling was used to determine which baseline features predict rate of future functional decline. Rates of functional decline differed across the anatomical subtypes of behavioural variant frontotemporal dementia, with faster rates observed in the frontal dominant and frontotemporal subtypes. In addition, subjects with poorer performance on neuropsychological tests of executive, language and visuospatial function, less disinhibition, agitation/aggression and night-time behaviours at presentation, and smaller medial, lateral and orbital frontal lobe volumes showed faster rates of decline. In many instances, the effect of the predictor variables observed across all subjects was also preserved within anatomical subtypes. Furthermore, some of the predictor variables improved our prediction of rate of functional decline after anatomical subtype was taken into account. In particular, age at onset was a highly significant predictor but only after adjusting for subtype. We also found that although some predictor variables, for example gender, Mini-Mental State Examination score, and apathy/indifference, did not affect the rate of functional decline; these variables were associated with the actual Clinical Dementia Rating Sum of Boxes score estimated for any given time-point. These findings suggest that in behavioural variant frontotemporal dementia, rate of functional decline is driven by the combination of anatomical pattern of atrophy, age at onset, and neuropsychiatric characteristics of the subject at baseline.
frontotemporal dementia; behaviour; functional decline; brain volumes; mixed effects models
Mutations in progranulin (PGRN) are associated with frontotemporal dementia with or without parkinsonism. We describe the prominent phenotypic variability within and among eight kindreds evaluated at Mayo Clinic Rochester and/or Mayo Clinic Jacksonville in whom mutations in PGRN were found. All available clinical, genetic, neuroimaging and neuropathologic data was reviewed. Age of onset ranged from 49 to 88 years and disease duration ranged from 1 to 14 years. Clinical diagnoses included frontotemporal dementia (FTD), primary progressive aphasia, FTD with parkinsonism, parkinsonism, corticobasal syndrome, Alzheimer’s disease, amnestic mild cognitive impairment, and others. One kindred exhibited maximal right cerebral hemispheric atrophy in all four affected individuals, while another had maximal left hemisphere involvement in all three of the affected. Neuropathologic examination of 13 subjects revealed frontotemporal lobar degeneration with ubiquitin-positive inclusions plus neuronal intranuclear inclusions in all cases. Age of onset, clinical phenotypes and MRI findings associated with most PGRN mutations varied significantly both within and among kindreds. Some kindreds with PGRN mutations exhibited lateralized topography of degeneration across all affected individuals.
Frontotemporal dementia; FTDP-17; Progranulin; PGRN; MRI
In the past 10 years, there has been a virtual explosion in the literature concerning the construct of mild cognitive impairment. The interest in this topic demonstrates the increasing emphasis on the identification of the earliest features of cognitive disorders such as Alzheimer’s disease and other dementias. Mild cognitive impairment represents the earliest clinical features of these conditions and, hence, has become a focus of clinical, epidemiological, neuroimaging, biomarker, neuropathological, disease mechanism and clinical trials research. This review summarizes the progress that has been made while also recognizing the challenges that remain.
Mild cognitive impairment; Alzheimer’s disease; Imaging; Cognitive decline
Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disorder that affects language. We applied a computerized information-theoretic technique to assess the type and severity of language-related FTLD symptoms. Audio-recorded samples of 48 FTLD patients from three participating medical centers were elicited using the Cookie Theft picture stimulus. The audio was transcribed and analyzed by calculating two measures: a perplexity index and an out-of-vocabulary (OOV) rate. The perplexity index represents the degree of deviation in word patterns used by FTLD patients compared to patterns of healthy adults. The OOV rate represents the proportion of words used by FTLD patients that were not used by the healthy speakers to describe the stimulus. In this clinically well-characterized cohort, the perplexity index and the OOV rate were sensitive to spontaneous language manifestations of semantic dementia and the distinction between semantic dementia and progressive logopenic aphasia variants of FTLD. Our study not only supports a novel technique for the characterization of language-related symptoms of FTLD in clinical trial settings, it also validates the basis for the clinical diagnosis of semantic dementia as a distinct syndrome.
frontotemporal lobar degeneration; semantic dementia; perplexity; entropy; statistical language modeling
To characterize a kindred with a familial neurodegenerative disorder associated with a mutation in progranulin (PGRN), emphasizing the unique clinical features in this kindred.
Clinical, radiologic, pathologic, and genetic characterization of a kindred with a familial neurodegenerative disorder.
Multispecialty group academic medical center.
Affected members of a kindred with dementia +/- parkinsonism associated with a unique mutation in PGRN.
Main Outcome Measure
Ten affected individuals were identified, among whom six presented with initial amnestic complaints resulting in initial diagnoses of AD or amnestic mild cognitive impairment (MCI). A minority of individuals presented with features characteristic of FTD. The ages of onset of generation II (mean 75.8 years, range 69-80 years) were far greater than those of generation III (mean 60.7 years, range 55-66 years). The pattern of cerebral atrophy varied widely among affected individuals. Neuropathology in six individuals showed frontotemporal lobar degeneration with ubiquitin positive neuronal cytoplasmic and intranuclear inclusions (FTLD-U + NII). PGRN analysis revealed a single base pair deletion in exon 2 (c.154delA), causing a frameshift (p.Thr52Hisfs×2) and therefore creation of a premature termination codon and likely null allele.
We describe a large kindred in which the majority of affected individuals had clinical presentations resembling AD or amnestic MCI in association with a mutation in PGRN and underlying FTLD-U + NII neuropathology. This is in distinct contrast to previously reported kindreds, where clinical presentations have typically been within the spectrum of FTLD. The basis for the large difference in age of onset between generations will require further study.
MRI; progranulin; frontotemporal dementia; PGRN
This study compares diagnostic accuracy of magnetic resonance (MR)-based hippocampal volumetry, single voxel (SV) 1H MR Spectroscopy (MRS) and MR diffusion weighted imaging (DWI) measurements in discriminating patients with amnestic mild cognitive impairment (MCI), Alzheimer’s disease (AD) and normally aging elderly. Sixty-one normally aging elderly, 24 MCI, and 22 AD patients underwent MR-based hippocampal volumetry, 1H MRS, and DWI. 1H MRS voxels were placed over both of the posterior cingulate gyri and N-acetyl aspartate (NAA) / creatine (Cr), myoinositol (MI) /Cr and NAA /MI ratios were obtained. Apparent diffusion coefficient (ADC) maps were derived from DWI and hippocampal borders were traced to measure hippocampal ADC. At 80% specificity, the most sensitive single measurement to discriminate MCI (79 %) and AD (86 %) from controls was hippocampal volumes. The most sensitive single measurement to discriminate AD from MCI was posterior cingulate gyrus NAA /Cr (67 %). At high specificity (>85 –90%) combinations of MR measures had superior diagnostic sensitivity compared to any single MR measurement for the AD vs. control and control vs. MCI comparisons. The MR measures that best discriminate more from less affected individuals along the cognitive continuum from normal to AD vary with disease severity. Selection of imaging measures used for clinical assessment or monitoring efficiency of therapeutic intervention should be tailored to the clinical stage of the disease.
Alzheimer’s disease; mild cognitive impairment; 1H MRS; diffusion weighted imaging; hippocampal volumetry; MRI
TAR DNA-binding protein 43 (TDP-43) is one of the major disease proteins in frontotemporal lobar degeneration with ubiquitin immunoreactivity. Approximately 1/4 of subjects with pathologically confirmed Alzheimer's disease (AD) have abnormal TDP-43 (abTDP-43) immunoreactivity. The aim of this study was to determine if subjects with pathologically confirmed AD and abTDP-43 immunoreactivity have distinct clinical, neuropsychological, imaging or pathological features compared to subjects with AD without abTDP-43 immunoreactivity.
Eighty-four subjects were identified that had a pathological diagnosis of AD, neuropsychometric testing, and volumetric MRI. Immunohistochemistry for TDP-43 was performed on sections of hippocampus and medial temporal lobe, and positive cases were classified into one of three types. Neuropsychometric data was collated and compared in subjects with and without abTDP-43 immunoreactivity. Voxel-based morphometry was used to assess patterns of gray matter atrophy in subjects with and without abTDP-43 immunoreactivity compared to age and gender matched controls.
Twenty-nine (34%) of the 84 AD subjects had abTDP-43 immunoreactivity. Those with abTDP-43 immunoreactivity were older at onset and death, and performed worse on the Clinical Dementia Rating scale, Mini-Mental State Examination and Boston Naming Test than subjects without abTDP-43 immunoreactivity. Subjects with and without abTDP-43 immunoreactivity had medial temporal and temporoparietal gray matter loss compared to controls; however, those with abTDP-43 immunoreactivity showed greater hippocampal atrophy. Multivariate logistic regression adjusting for age at death demonstrated that hippocampal sclerosis was the only pathological predictor of abTDP-43 immunoreactivity.
The presence of abTDP-43 immunoreactivity is associated with a modified AD clinicopathological and radiological phenotype.
This study tests if measures of hippocampal water diffusivity at baseline can predict future progression to Alzheimer’s Disease (AD) in amnestic mild cognitive impairment (aMCI). Higher baseline hippocampal diffusivity was associated with a greater hazard of progression to AD in aMCI (p=0.002). MR diffusion weighted imaging (DWI) may help identify patients with aMCI who will progress to AD as well or better than structural MRI measures of hippocampal atrophy.
To determine the 1H MR spectroscopic (MRS) findings and inter-group differences among common dementias: Alzheimer's disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration (FTLD).
We consecutively recruited 206 normal elderly, 121 patients with AD, 41 with FTLD, 20 with DLB, and 8 with VaD. We evaluated the 1H MRS metabolite ratio changes in common dementias with respect to normal, and also differences among the common dementias.
N-acetylaspartate/Creatine (NAA/Cr) was lower than normal in patients with AD, FTLD, and VaD. Myo-inositol (mI)/Cr was higher than normal in patients with AD and FTLD. Choline (Cho)/Cr was higher than normal in patients with, AD, FTLD, and DLB. There were no metabolite differences between patients with AD and FTLD, nor between patients with DLB and VaD. NAA /Cr was lower in patients with AD and FTLD than DLB. MI /Cr was higher in patients with AD and FTLD than VaD. MI /Cr was also higher in patients with FTLD than DLB.
NAA/Cr levels are decreased in dementias that are characterized by neuron loss such as AD, FTLD, and VaD. MI/Cr levels are elevated in dementias that are pathologically characterized by gliosis such as AD and FTLD. Cho/Cr levels are elevated in dementias that are characterized by a profound cholinergic deficit such as AD and DLB.
Magnetic Resonance (MR)- based volume measurements of atrophy are potential markers of disease progression in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). Longitudinal changes in 1H MR spectroscopy (1H MRS) metabolite markers have not been characterized in aMCI subjects. Our objective was to determine the longitudinal 1H MRS metabolite changes in patients with aMCI, and AD, and to compare 1H MRS metabolite ratios and ventricular volumes in tracking clinical disease progression in AD. The neuronal integrity marker N-acetylaspartate/Creatine ratio declined in aMCI and AD patients compared to cognitively normal elderly. The changein 1H MRS metabolite ratios correlated with clinical progression about as strongly as the rate of ventricular expansion, suggesting that 1H MRS metabolite ratios may be useful markers for the progression of AD. Choline/Creatine ratio declined in stable aMCI, compared to converter aMCI patients and cognitively normal elderly, which may be related to a compensatory mechanism in aMCI patients who did not to progress to AD.
1H MR spectroscopy; 1H MRS; imaging; Alzheimer’s disease; mild cognitive impairment; serial; longitudinal; N-acetylaspartate; choline
The aim of this study was to examine the associations of Apolipoprotein E (APOE) genotype, metabolic changes in the posterior cingulate detected by 1H magnetic resonance spectroscopy (MRS), and neuropsychologic measures of memory and cognition both in normally aging elderly, and in patients with mild cognitive impairment (MCI) and AD. We studied 67 controls, 18 MCI and 33 AD patients. We used the Dementia Rating Scale total score (DRSTOT) as a measure of general cognitive function and the total learning from the Auditory Verbal Learning Test (AVTOT) as a measure of memory performance. No differences were noted on 1H MRS metabolite ratios or cognitive measures across APOE genotype within control and patient groups.. In controls, age was a significant predictor of both cognitive test scores, and NAA/Cr was a univariate associate of DRSTOT. All three 1H MRS metabolite ratios, N-acetylaspartate (NAA)/Creatine (Cr), myoinositol (MI)/Cr, and NAA/MI, were univariate associates of AVTOT and DRSTOT scores in the combined MCI and AD group. In stepwise regression analyses in the combined patient group only NAA/MI entered the model. These data suggest NAA/Cr could be a modest predictor of general cognitive function in both healthy elderly and impaired patients, while MI/Cr is a more specific marker for neuropsychologic dysfunction associated with neurodegenerative disease. Among 1H MRS measurements, the NAA/MI ratio maybe the most efficient predictor of memory and cognitive function in patients with MCI and AD.
1HMRS; Cognition; Aging; Mild Cognitive Impairment; Alzheimer’s Disease
The risk for Alzheimer’s disease (AD) is influenced by both age and ApoE status. The present study addresses the associations of age and ApoE status on complex pathologic features in AD (n=81) including coexistent cerebrovascular disease (CVD), argyrophilic grain disease (AGD), and Lewy body disease (LBD). The frequency of coexistent cerebrovascular disease increased with increasing age. Age and ApoE status were differentially associated with atherosclerosis, lacunar infarctions, and microvascular pathology. Coexistent Lewy body pathology was negatively associated with age, dropping off abruptly after age 90. The presence of an ApoE ε4 allele was associated with an increased frequency of coexistent LBD. Logistic regression analyses demonstrated both dependent and independent effects of age and ApoE status on the presence of coexistent Lewy body pathology in AD. While the decreasing frequency of LBD in AD after age 90 could be partly accounted for by a lower probability of an ApoE ε4 allele, the independent association with age suggests either 1) a survival effect, 2) decreased incidence with advancing age, or 3) both.
Alzheimer’s disease; cerebrovascular disease; Lewy body disease; argyrophilic grains; age; apolipoprotein E
Little is known about the population-based prevalence of neuropsychiatric symptoms in mild cognitive impairment (MCI).
To estimate the prevalence of neuropsychiatric symptoms in MCI and normal cognitive aging in a defined population.
Cross-sectional study derived from an ongoing population-based prospective cohort study.
The Mayo Clinic Study of Aging.
We studied a random sample of 1969 non-demented participants out of the target population of 9965 elderly persons residing in Olmsted County on the prevalence date (October 1, 2004). Neuropsychiatric data were available on 319 of the 329 MCI subjects (97.0%) and on 1590 of the 1640 cognitively normal subjects (97.0%).
Neurological, cognitive, and neuropsychiatric data were gathered from the study participants. A classification of normal cognitive aging, MCI, and dementia was adjudicated by an expert consensus panel. Accordingly, 329 subjects were classified as having MCI and the remaining 1640 subjects were classified as cognitively normal.
Main Outcome Measure
The Neuropsychiatric Inventory Questionnaire (NPI-Q).
Multi-variable logistic regression analyses were conducted, after adjusting for age, sex, and education. By taking into consideration both the odds ratio and the frequency of a symptom, the most distinguishing features between the 2 groups were apathy (odds ratio [OR], 4.53; 95% confidence interval [95% CI], 3.11–6.60; P<.001), agitation (OR, 3.60; 95% CI, 2.18–5.92; P<.001), anxiety (OR, 3.00; 95% CI, 2.01–4.48; P<.001), irritability (OR, 2.99; 95% CI, 2.11–4.22; P<.001), and depression (OR, 2.78; 95% CI, 2.06–3.76; P<.001). Delusion had the highest OR (8.12; 95% CI, 2.92–22.60; P<.001); however, it was rare in both cognitively normal subjects (6/1590=0.4%) and MCI (11/319=3.4%). Thus, the population attributable risk for delusion was only 2.62% as compared to 14.60% for apathy.
Non-psychotic symptoms affected approximately 50% of subjects with MCI and 25% of cognitively normal subjects. By contrast, psychotic symptoms were rare.
To provide a clinical tool for calculating a patient's future risk for developing cognitive impairment based on age, family history, and AVLT retention.
1019 cognitively normal persons followed for an average of 5 years. 159 participants were eventually diagnosed with cognitive impairment.
Risk of developing cognitive impairment increases with age and family history, but decreases with better memory performance. A nomogram is provided for calculation of relative risk of developing cognitive impairment in combinations of age, family history, and memory performance.
These results enhance clinicians' ability to provide information to a patient about risk of cognitive impairment.
cognitive decline; dementia; risk; AVLT; family history
There is limited information on the validity of the pathological criteria of the Third Consortium on Dementia with Lewy bodies (CDLB) and none based upon prospectively diagnosed cases. In this study the core clinical features of dementia with Lewy bodies (DLB) and the suggestive clinical feature of rapid eye movement sleep behavior disorder were assessed using a battery of standardized clinical instruments in 76 patients with the clinical diagnosis of either DLB or Alzheimer disease. At autopsy, 29 patients had high-likelihood, 17 had intermediate-likelihood and 6 had low-likelihood DLB pathology. The frequency of core clinical features and the accuracy of the clinical diagnosis of probable DLB were significantly greater in high-likelihood than in low-likelihood cases. This is consistent with the concept that the DLB clinical syndrome is directly related to Lewy body pathology and inversely related to Alzheimer pathology. Thus, the Third CDLB neuropathological criteria scheme performed reasonably well and is useful for estimating the likelihood of the premortem DLB syndrome based upon postmortem findings. In view of differences in the frequency of clinically probable DLB in cases with Braak NFT stages V (90%) and VI (20%) and diffuse cortical Lewy bodies, a possible modification of the scheme considering cases with NFT stage VI to be low-likelihood DLB is suggested.
Alzheimer disease; α-synuclein; Clinicopathologic correlation; Diagnostic criteria; Dementia with Lewy bodies; Prospective study; REM behavior disorder
Although a majority of patients with amnestic mild cognitive impairment (aMCI) progress to Alzheimer disease, the natural history of nonamnestic MCI (naMCI) is less clear. Noninvasive imaging surrogates for underlying pathological findings in MCI would be clinically useful for identifying patients who may benefit from disease-specific treatments at the prodromal stage of dementia.
To determine the characteristic magnetic resonance imaging (MRI) and proton MR spectroscopy (1H MRS) profiles of MCI subtypes.
Community-based sample at a tertiary referral center.
Ninety-one patients with single-domain aMCI, 32 patients with multiple-domain aMCI, 20 patients with single- or multiple-domain naMCI, and 100 cognitively normal elderly subjects frequency-matched by age and sex.
Main Outcome Measures
Posterior cingulate gyrus 1H MRS metabolite ratios, hippocampal volumes, and cerebrovascular disease on MRI.
Patients with single-domain aMCI were characterized by small hippocampal volumes and elevated ratios of myo-inositol to creatine levels. Patients with naMCI on average had normal hippocampal volumes and 1H MRS metabolite ratios, but a greater proportion (3 of 20 patients [15%]) had cortical infarctions compared with patients with single-domain aMCI (6 of 91 [7%]). For characterization of MCI subtypes, 1H MRS and structural MRI findings were complementary.
The MRI and 1H MRS findings in singledomain aMCI are consistent with a pattern similar to that of Alzheimer disease. Absence of this pattern on average in patients with naMCI suggests that cerebrovascular disease and other neurodegenerative diseases may be contributing to the cognitive impairment in many individuals with naMCI.
We tested if rates of brain atrophy accelerate in individuals with amnestic mild cognitive impairment (aMCI) as they progress to typical late onset Alzheimer's Disease (AD). We included comparisons to aMCI subjects who did not progress (labeled aMCI-S) and also to cognitively normal elderly subjects (CN).
We studied 46 aMCI subjects who progressed to AD (labeled aMCI-P), 46 CN, and 23 aMCI-S. All subjects must have had three or more serial MRI scans. Rates of brain shrinkage and ventricular expansion were measured across all available serial MRI scans in each subject. Change in volumes relative to the point at which subjects progressed to a clinical diagnosis of AD (the index date) was modeled in aMCI-P. Change in volumes relative to age was modeled in all three clinical groups.
In aMCI-P the change in pre to post index rate (i.e. acceleration) of ventricular expansion was 1.7 cm3/yr, and acceleration in brain shrinkage was 5.3 cm3/yr. Brain volume declined and ventricular volume increased in all three groups with age. Volume changes decelerated with increasing age in aMCI-P, and to a lesser extent aMCI-S, but were linear in the matched CN. Among all aMCI subjects, rates of atrophy were greater in apolipoprotein E ε4 carriers than non-carriers.
Rates of atrophy accelerate as individuals progress from aMCI to typical late onset AD. Rates of atrophy are greater in younger than older aMCI-P and aMCI-S subjects. We did not find that atrophy rates varied with age in 70 – 90 year old CN subjects.
To test the hypothesis that magnetic resonance imaging (MRI)-based measurements of hippocampal volume were related to the risk of future conversion to Alzheimer's disease (AD) in elderly patients with a mild cognitive impairment (MCI)
Persons who develop AD pass through a transitional state which can be characterized as a MCI. However, in some patients MCI is a more benign condition which may not progress to AD or may do so slowly.
Eighty consecutive patients who met criteria for the diagnosis of MCI were recruited from the Mayo Clinic Alzheimer's Disease Center/Alzheimer's Disease Patient Registry.
At entry into the study each patient received a MRI examination of the head from which the volumes of both hippocampi were measured. Patients were then followed longitudinally with approximately annual clinical/cognitive assessments. The primary endpoint was the crossover of individual MCI patients to the clinical diagnosis of AD during longitudinal clinical followup.
Over the period of longitudinal observation, which averaged 32.6 months, 27 of the 80 MCI patients became demented. Hippocampal atrophy at baseline was associated with crossover from MCI to AD (relative risk, 0.69, p = 0.015). When hippocampal volume was entered into bivariate models with age, post menopausal estrogen replacement, standard neuropsychological tests, apolipoprotein E genotype, history of ischemic heart disease and hypertension the relative risks were not substantially different from that found univariately and the associations between hippocampal volume and crossover remained significant.
In elderly patients with MCI, hippocampal atrophy determined by premorbid MRI-based volume measurements is predictive of subsequent conversion to AD.
Dementia; Alzheimer's disease; Magnetic resonance imaging; brain; Quantitative MRI; Hippocampus; Volumetric MR
Although it is established that the apolipoprotein E (APOE) e4 allele increases the risk of Alzheimer’s disease (AD), epidemiological studies indicate that genetic risk decreases late in life. This raises the question of whether the effects of APOE on cognition which are seen in midlife arise from a cognitive phenotype of APOE or from the presence of early AD in some APOE-e4 carriers. We addressed this question by comparing the cognitive consequences of variation in the APOE gene between individuals over the age of 80 (old-old) and middle-aged and young-old individuals. A spatially cued discrimination paradigm – previously shown to be sensitive to AD and to APOE genotype – required a speeded categorization of a target letter following cues that were valid, invalid, or neutral in predicting target location. Results revealed greater costs of invalid cues in the APOE-e4 carriers of middle-aged and young-old, but not old-old, groups. The dissipation of the APOE effect in old-old individuals at lower risk of AD suggests that visuospatial attention impairments seen as early as midlife in APOE-e4 carriers may be a preclinical marker of AD.
attention; APOE; phenotype; old-old
Progressive supranuclear palsy; corticobasal degeneration; neuropsychology; pathology; atypical