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1.  MRS in Early and Presymptomatic Carriers of a Novel Octapeptide Repeat Insertion in the Prion Protein Gene 
To evaluate the proton MR spectroscopy (1H MRS) changes in carriers of a novel octapeptide repeat insertion in the Prion Protein Gene (PRNP) and family history of frontotemporal dementia with ataxia. Four at-risk mutation carriers and 13 controls were compared using single voxel, short TE, 1H MRS from the posterior cingulate gyrus. The mutation carriers had an increased choline/creatine, p=0.003 and increased myoinositol/creatine ratio, p=0.003. 1H MRS identified differences in markers of glial activity and choline metabolism in pre- and early symptomatic carriers of a novel PRNP gene octapeptide insertion. These findings expand the possible diagnostic utility of 1H MRS in familial prion disorders.
doi:10.1111/j.1552-6569.2012.00717.x
PMCID: PMC3480551  PMID: 22612156
MRS; MRI; familial prion disorders; frontotemporal dementia
2.  Age and APOE genotype influence rate of cognitive decline in non-demented elderly 
Neuropsychology  2013;27(4):10.1037/a0032707.
Objective
This study examined the impact of age and apolipoprotein E (APOE) genotype on the rate of cognitive decline in non-demented elderly participants in a simulated Alzheimer’s disease (AD) primary prevention treatment trial carried out by the Alzheimer’s Disease Cooperative Study.
Method
Cognitive tests were administered at baseline and at four subsequent annual evaluations to 417 non-demented participants (172 men, 245 women) between the ages of 74 and 93 (mean=79.13 ± 3.34). APOE genotyping was available for 286 of the participants.
Results
Four-year decline was evident on measures of orientation, memory, executive function and language. Faster decline was evident in APOE ε4+ (a genetic risk factor for AD; n=73) than ε4− participants (n=213), even after controlling for education, gender, ethnicity, and baseline functional and cognitive abilities. This discrepancy increased with increasing age indicating an age X genotype interaction.
Conclusions
These results are consistent with population-based studies, and extend the findings to a carefully-screened sample that meets inclusion and exclusion criteria for an AD primary prevention trial. The interaction between age and APOE genotype on rate of decline suggests that preclinical disease may be over represented in olderε4+ individuals. Thus, APOE genotype and age should be considered in the design of AD primary prevention treatment trials.
doi:10.1037/a0032707
PMCID: PMC3831285  PMID: 23876113
Cognitive decline; Apolipoprotein E; Aging
3.  The Alien Limb Phenomenon 
Journal of neurology  2013;260(7):1880-1888.
Background
Alien limb phenomenon refers to involuntary motor activity of a limb in conjunction with the feeling of estrangement from that limb. Alien limb serves as a diagnostic feature of corticobasal syndrome.
Objective
Our objective was to determine the differential diagnoses of alien limb and to determine the features in a large group of patients with the alien limb with different underlying etiologies.
Methods
We searched the Mayo Clinic Medical Records Linkage system to identify patients with the diagnosis of alien limb seen between January 1, 1996, and July 11, 2011.
Results
One hundred fifty patients with alien limb were identified. Twenty two were followed in the Alzheimer’s Disease Research Center. Etiologies of alien limb included corticobasal syndrome (n=108), stroke (n=14), Creutzfeldt Jacob disease (n=9), Hereditary diffuse leukoencephalopathy with spheroids (n=5), tumor (n=4), progressive multifocal leukoencephalopathy(n=2), demyelinating disease (n=2), progressive dementia not otherwise specified (n=2), posterior reversible encephalopathy syndrome (n=1), corpus callosotomy (n=1), intracerebral hemorrhage (n=1) and thalamic dementia (n=1). Ten of fourteen cerebrovascular cases were right hemisphere in origin. All cases involved the parietal lobe. Of the 44 patients with corticobasal syndrome from the Alzheimer’s Disease Research Center cohort, 22 had alien limb, and 73% had the alien limb affecting the left extremities. Left sided corticobasal syndrome was significantly associated with the presence of alien limb (p=0.004).
Conclusions
These findings support the notion that the alien limb phenomenon is partially related to damage underlying the parietal cortex, especially the right parietal, disconnecting it from other cortical areas.
doi:10.1007/s00415-013-6898-y
PMCID: PMC3914666  PMID: 23572346
Alien limb; corticobasal syndrome
4.  Association of Mediterranean diet with Mild Cognitive Impairment and Alzheimer’s disease: A Systematic Review and Meta-Analysis 
Background/Objective
To conduct a systematic review of all studies to determine whether there is an association between the Mediterranean diet (MeDi) and cognitive impairment.
Methods
We conducted a comprehensive search of the major databases and hand-searched proceedings of major neurology, psychiatry, and dementia conferences through November 2012. Prospective cohort studies examining the MeDi with longitudinal follow-up of at least 1 year and reporting cognitive outcomes (mild cognitive impairment [MCI] or Alzheimer’s disease [AD]) were included. The effect size was estimated as hazard-ratio (HR) with 95% confidence intervals (CIs) using the random-effects model. Heterogeneity was assessed using Cochran’s Q-test and I2-statistic.
Results
Out of the 664 studies screened, five studies met eligibility criteria. Higher adherence to the MeDi was associated with reduced risk of MCI and AD. The subjects in the highest MeDi tertile had 33% less risk (adjusted HR=0.67; 95% CI, 0.55–0.81; P<0.0001) of cognitive impairment (MCI or AD) as compared to the lowest MeDi score tertile. Among cognitively normal individuals, higher adherence to the MeDi was associated with a reduced risk of MCI (HR=0.73; 95% CI, 0.56–0.96; P=0.02) and AD (HR=0.64; 95% CI, 0.46–0.89; P=0.007). There was no significant heterogeneity in the analyses.
Conclusions
While the overall number of studies is small, pooled results suggest that a higher adherence to the MeDi is associated with a reduced risk of developing MCI and AD, and a reduced risk of progressing from MCI to AD. Further prospective-cohort studies with longer follow-up and randomized controlled trials are warranted to consolidate the evidence.
doi:10.3233/JAD-130830
PMCID: PMC3946820  PMID: 24164735
Mediterranean diet; MCI; Mild Cognitive Impairment; Alzheimer’s disease; systematic review; meta-analysis
5.  Evaluation of Memory Impairment in Aging Adult Survivors of Childhood Acute Lymphoblastic Leukemia Treated With Cranial Radiotherapy 
Background
Cranial radiotherapy (CRT) is a known risk factor for neurocognitive impairment in survivors of childhood cancer and may increase risk for mild cognitive impairment and dementia in adulthood.
Methods
We performed a cross-sectional evaluation of survivors of childhood acute lymphoblastic leukemia (ALL) treated with 18 Gy (n = 127) or 24 Gy (n = 138) CRT. Impairment (age-adjusted score >1 standard deviation below expected mean, two-sided exact binomial test) on the Wechsler Memory Scale IV (WMS-IV) was measured. A subset of survivors (n = 85) completed structural and functional neuroimaging.
Results
Survivors who received 24 Gy, but not 18 Gy, CRT had impairment in immediate (impairment rate = 33.8%, 95% confidence interval [CI] = 25.9% to 42.4%; P < .001) and delayed memory (impairment rate = 30.2%, 95% CI = 22.6% to 38.6%; P < .001). The mean score for long-term narrative memory among survivors who received 24 Gy CRT was equivalent to that for individuals older than 69 years. Impaired immediate memory was associated with smaller right (P = .02) and left (P = .008) temporal lobe volumes, and impaired delayed memory was associated with thinner parietal and frontal cortices. Lower hippocampal volumes and increased functional magnetic resonance imaging activation were observed with memory impairment. Reduced cognitive status (Brief Cognitive Status Exam from the WMS-IV) was identified after 24 Gy (18.5%, 95% CI = 12.4% to 26.1%; P < .001), but not 18 Gy (8.7%, 95% CI = 4.4% to 15.0%; P = .11), CRT, suggesting a dose–response effect. Employment rates were equivalent (63.8% for 24 Gy CRT and 63.0% for 18 Gy CRT).
Conclusions
Adult survivors who received 24 Gy CRT had reduced cognitive status and memory, with reduced integrity in neuroanatomical regions essential in memory formation, consistent with early onset mild cognitive impairment.
doi:10.1093/jnci/djt089
PMCID: PMC3687368  PMID: 23584394
6.  Assessment of cognition in mild cognitive impairment: A comparative study 
The demand for rapidly administered, sensitive, and reliable cognitive assessments that are specifically designed for identifying individuals in the earliest stages of cognitive decline (and to measure subtle change over time) has escalated as the emphasis in Alzheimer’s disease clinical research has shifted from clinical diagnosis and treatment toward the goal of developing presymptomatic neuroprotective therapies. To meet these changing clinical requirements, cognitive measures or tailored batteries of tests must be validated and determined to be fit-for-use for the discrimination between cognitively healthy individuals and persons who are experiencing very subtle cognitive changes that likely signal the emergence of early mild cognitive impairment. We sought to collect and review data systematically from a wide variety of (mostly computer-administered) cognitive measures, all of which are currently marketed or distributed with the claims that these instruments are sensitive and reliable for the early identification of disease or, if untested for this purpose, are promising tools based on other variables. The survey responses for 16 measures/batteries are presented in brief in this review; full survey responses and summary tables are archived and publicly available on the Campaign to Prevent Alzheimer’s Disease by 2020 Web site (http://pad2020.org). A decision tree diagram highlighting critical decision points for selecting measures to meet varying clinical trials requirements has also been provided. Ultimately, the survey questionnaire, framework, and decision guidelines provided in this review should remain as useful aids for the evaluation of any new or updated sets of instruments in the years to come.
doi:10.1016/j.jalz.2011.03.009
PMCID: PMC4042858  PMID: 21575877
Cognition; Neuropsychological assessment; Alzheimer’s disease; Mild cognitive impairment; Clinical trials
7.  A Prospective Study of Chronic Obstructive Pulmonary Disease and Risk of Mild Cognitive Impairment 
JAMA neurology  2014;71(5):581-588.
BACKGROUND
Previous studies suggest cross-sectional associations between a diagnosis of chronic obstructive pulmonary disease (COPD) and mild cognitive impairment (MCI). However, few studies have assessed whether COPD, a potentially modifiable factor, is associated with an increased risk of MCI and if the relation is specific to type of MCI.
OBJECTIVE
To investigate whether a diagnosis of COPD, and COPD duration, is associated with an increased risk of incident MCI, and MCI subtypes (amnestic MCI (a-MCI) and non-amnestic MCI (na-MCI)).
DESIGN
Mayo Clinic Study on Aging, a prospective population-based cohort study.
SETTING
Olmsted County, Minnesota.
PARTICIPANTS
The study included 1425 cognitively normal individuals aged 70–89 years, who were randomly selected from Olmsted County, MN, on October 1, 2004, using the medical records linkage system.
METHODS
At baseline and every 15 months thereafter, participants were assessed with a nurse interview, neurological examination, and neuropsychological testing. A diagnosis of COPD was confirmed via medical record chart review. A baseline diagnosis of COPD and disease duration were examined as risk factors for MCI and MCI-subtypes using Cox proportional hazards models and adjusting for demographic variables and medical comorbidities, using age as the time scale.
MAIN OUTCOME MEASURES
Incident MCI, amnestic MCI, non-amnestic MCI
RESULTS
Of 1425 cognitively normal subjects at baseline, 370 developed incident MCI. The median duration of follow-up was 5.1 years (Interquartile Range [IQR], 3.8–5.4 years). COPD significantly increased the risk of na-MCI by 83% (HR 1.83; 95% CI, 1.04–3.23), but not any MCI or a-MCI in multivariate analyses. There was a dose-response relationship such that individuals with COPD duration of 5 years or longer at baseline had the greatest risk of both MCI (HR 1.58, 95% CI:1.04, 2.40) and na-MCI (HR 2.58, 95% CI:1.32–5.06).
CONCLUSIONS AND RELEVANCE
COPD was associated with an increased risk of MCI, particularly na-MCI. There was a dose-response relationship between COPD duration and risk of MCI. These findings highlight the importance of COPD as a risk factor for MCI and may provide a substrate for early intervention to prevent or delay the onset and progression of MCI, particularly na-MCI.
doi:10.1001/jamaneurol.2014.94
PMCID: PMC4020948  PMID: 24637951
8.  Brain regional correlation of amyloid-β with synapses and apolipoprotein E in non-demented individuals: potential mechanisms underlying regional vulnerability to amyloid-β accumulation 
Acta neuropathologica  2013;125(4):535-547.
To reveal the underlying mechanisms responsible for the regional vulnerability to amyloid-β (Aβ) accumulation prior to the development of Alzheimer’s disease, we studied distribution of Aβ, apolipoprotein E (apoE), synaptic markers, and other molecules involved in Aβ metabolism in multiple brain areas of non-demented individuals. Twelve brain regions including neocortical, limbic, and subcortical areas were dissected from brains of non-demented individuals and extracted according to increasing insolubility by a sequential three-step method. The levels of Aβ40, Aβ42, apoE, APP, APP-CTFβ, BACE1, presenilin-1, neprilysin, insulysin, LRP1, LDLR, synaptophysin, PSD95, GFAP, and lactate were determined by ELISAs or enzymatic assays. The regional distribution of apoE showed moderate-to-strong inverse correlation with levels of Aβ, especially insoluble Aβ40. On the other hand, the regional distributions of synaptic markers, particularly PSD95, showed moderate-to-strong positive correlation with levels of Aβ, especially soluble Aβ40. The regional correlations between Aβ and LRP1, GFAP, or lactate were mild-to-moderate. Moderate-to-strong positive regional correlations were observed between apoE and GFAP or lactate and between PSD95 and LRP1. No significant regional correlations were detected between Aβ and APP, APP-CTFβ, BACE1, or presenilin-1, those involved in Aβ production. There were no significant negative regional correlations between Aβ and two major Aβ degrading enzymes, neprilysin and insulysin. These regional correlations remained consistent regardless of the degree of Aβ accumulation. The regional vulnerability to Aβ accumulation may be due to a net balance between two competing processes: (1) synapses involved in promoting the initial Aβ accumulation and (2) astrocyte-derived apoE involved in preventing Aβ accumulation.
doi:10.1007/s00401-013-1086-9
PMCID: PMC3612369  PMID: 23371365
Alzheimer’s disease; Amyloid-β; Regional vulnerability; Apolipoprotein E; Synapses
9.  Brain Injury Biomarkers Are Not Dependent on β-amyloid in Normal Elderly 
Annals of neurology  2013;73(4):472-480.
Background
The new criteria for preclinical Alzheimer’s Disease (AD) proposed 3 stages: abnormal levels of β-amyloid (stage 1); stage 1 plus evidence of brain injury (stage 2); and stage 2 plus subtle cognitive changes (stage 3). However, a large group of subjects with normal β-amyloid biomarkers have evidence of brain injury; we labeled them as “suspected non-Alzheimer pathway” (sNAP) group. The characteristics of the sNAP group are poorly understood.
Methods
Using the preclinical AD classification, 430 cognitively normal subjects from the Mayo Clinic Study of Aging who underwent brain MR, 18fluorodeoxyglucose (FDG) and Pittsburgh compound B (PiB) positron emission tomography (PET) were evaluated with FDG PET regional volumetrics, MR regional brain volumetrics, white matter hyperintensity (WMH) volume and number of infarcts. We examined cross-sectional associations across AD preclinical stages, those with all biomarkers normal, and the sNAP group.
Results
The sNAP group had a lower proportion (14%) with APOE ε4 genotype than the preclinical AD stages 2 + 3. The sNAP group did not show any group differences compared to stages 2 + 3 of the preclinical AD group on measures of FDG PET regional hypometabolism, MR regional brain volume loss, cerebrovascular imaging lesions, vascular risk factors, imaging changes associated with α-synucleinopathy or physical findings of parkinsonism.
Conclusions
Cognitively normal persons with brain injury biomarker abnormalities, with or without abnormal levels of β-amyloid, were indistinguishable on a variety of imaging markers, clinical features and risk factors. The initial appearance of brain injury biomarkers that occurs in cognitively normal persons with preclinical AD may not depend on β-amyloidosis.
doi:10.1002/ana.23816
PMCID: PMC3660408  PMID: 23424032
Alzheimer’s disease; PET imaging; MR imaging; Epidemiology
10.  Ventricular atrophy and its clinical correlates in the imaging cohort from the ADCS MCI Donepezil/Vitamin E study 
We analyzed the baseline and 3-year T1-weighted magnetic resonance imaging data of 110 amnestic mild cognitive impairment (MCI) participants with minimal hippocampal atrophy at baseline from the Alzheimer’s Disease Cooperative Study group (ADCS) MCI Donepezil/Vitamin E trial. 46 subjects converted to AD (MCIc) while 64 remained stable (MCInc). We used the radial distance technique to examine the differences in lateral ventricle shape and size between MCIc and MCInc and the associations between ventricular enlargement and cognitive decline.
MCIc group had significantly larger frontal and right body/occipital horns relative to MCInc at baseline and significantly larger bilateral frontal, body/occipital and left temporal horns at follow-up. Global cognitive decline measured with ADAScog and MMSE and decline in activities of daily living (ADL) were associated with posterior lateral ventricle enlargement. Decline in ADAScog and ADL were associated with left temporal and decline in MMSE with right temporal horn enlargement. After correction for baseline hippocampal volume decline in ADL showed a significant association with right frontal horn enlargement. Executive decline was associated with right frontal and left temporal horn enlargement.
doi:10.1097/WAD.0b013e3182677b3d
PMCID: PMC3662002  PMID: 23694947
Alzheimer’s disease; AD; mild cognitive impairment; MCI; imaging; MRI; brain atrophy; ventricular enlargement
11.  Cardiac Disease Increases Risk of Non-amnestic Mild Cognitive Impairment: Stronger impact in women 
JAMA neurology  2013;70(3):374-382.
Objective
Non-amnestic mild cognitive impairment (naMCI), a putative precursor of vascular and other non-Alzheimer’s disease dementias, is hypothesized to have a vascular etiology. We investigated the association of cardiac disease with amnestic (aMCI) and non-amnestic (naMCI) MCI.
Design
A prospective, population-based, cohort study with a median 4.0 years of follow-up.
Setting
Olmsted County, Minnesota.
Participants
Participants were evaluated at baseline and every 15 months using the Clinical Dementia Rating scale, a neurological evaluation, and neuropsychological testing. A diagnosis of normal cognition, MCI, or dementia was made by consensus. Cardiac disease at baseline was assessed from the participant’s medical records.
Main outcome measures
Incident MCI, aMCI, naMCI.
Results
Among 1,450 subjects free of MCI or dementia at baseline, 366 developed MCI. Cardiac disease was associated with an increased risk of naMCI (hazard ratio [HR] 95% confidence interval; 1.77 [1.16–2.72]). However, the association varied by sex (P for interaction = .02). Cardiac disease was associated with an increased risk of naMCI (HR, 3.07 [1.58–5.99]) in women, but not in men (HR, 1.16 [0.68–1.99]. Cardiac disease was not associated with any MCI or aMCI.
Conclusion
Cardiac disease is an independent risk factor for naMCI, within sex comparisons showed a stronger association in women. Prevention and management of cardiac disease and vascular risk factors may reduce the risk of naMCI.
doi:10.1001/jamaneurol.2013.607
PMCID: PMC3734560  PMID: 23358884
12.  What is the quality of life in the oldest old? 
International psychogeriatrics / IPA  2011;23(6):1003-1010.
Background
Maintaining and improving quality of life has become a major focus in geriatric medicine, but the oldest old have received limited attention in clinical investigations. We aimed to investigate the relationship between self-perceived and caregiver-perceived quality of life (QOL), cognitive functioning, and depressive symptoms in the oldest old.
Methods
This IRB-approved prospective study recruited community dwellers aged 90–99 years old. Collected data included neurological evaluation, DSM III-R criteria for dementia, Mini-Mental State Examination (MMSE), Dementia Rating Scale (DRS), Geriatric Depression Scale (GDS), Record of Independent Living (ROIL), and QOL assessment using the Linear Analogue Self Assessment (LASA).
Results
Data on 144 subjects (56 cognitively normal (normal), 13 mild cognitive impairment (MCI), 41 dementia (DEM), 34 dementia with stroke and parkinsonism (DEMSP)) over a three-year period were analyzed. Mean ages ranged from 93 to 94 years, and the majority were female with at least high school education. Overall functional ability was higher in groups without dementia (p < 0.0001). All subjects reported high overall QOL (range 6.76–8.3 out of 10), regardless of cognitive functioning. However, caregivers perceived the subjects’ overall QOL to be lower with increasing severity of cognitive impairment (p < 0.0001). Lower GDS scores correlate with higher self-perceived overall QOL (ρ = −0.38, p < 0.0001).
Conclusions
In our community sample of the oldest old, there was a fairly high level of overall QOL, whether or not cognitive impairment exists. Individuals perceive their QOL better than caregivers do, and the difference in subjects’ and caregivers’ perception is more pronounced for the groups with dementia. QOL is more strongly correlated with depressive symptoms than with dementia severity.
doi:10.1017/S1041610210002462
PMCID: PMC3924179  PMID: 21281556
geriatric; well being; cognition; depression; dementia; stroke; parkinsonism; MCI
13.  Occupational differences between Alzheimer’s and aphasic dementias: implication for teachers 
We aimed to determine if there is an association between teaching and the development of progressive speech and language disorders (SLDs). Occupation was compared between 100 patients with a progressive SLD, 404 Alzheimer’s dementia patients, and the 2008 US census. In SLDs the most common occupation was teacher (22%), versus 8% in Alzheimer’s dementia. The odds ratio of being a teacher in SLDs compared to Alzheimer’s dementia was 3.4 (95% CI=1.87, 6.17). No differences were observed in the frequency of other occupations. The frequency of teachers was higher in SLDs compared to the US census; odds ratio of 6.9 (95% CI=4.3, 11.1). Farming, forestry and fishing occupations were more frequent in SLDs compared to the US census. We identified an association between progressive SLDs and the occupation of teaching. Since teaching is a communication demanding occupation, teachers may be more sensitive to the development of speech and language impairments.
doi:10.1177/1533317513494455
PMCID: PMC3920458  PMID: 23838322
Alzheimer’s; dementia; aphasia; teacher; occupation
14.  Frontal asymmetry in behavioral variant FTD: clinicoimaging & pathogenetic correlates 
Neurobiology of aging  2012;34(2):636-639.
We aimed to assess associations between clinical, imaging, pathological and genetic features and frontal lobe asymmetry in behavioral variant frontotemporal dementia (bvFTD). Volumes of the left and right dorsolateral, medial and orbital frontal lobes were measured in 80 bvFTD subjects and subjects were classified into three groups according to the degree of asymmetry (asymmetric left, asymmetric right, symmetric) using cluster analysis. The majority of subjects were symmetric (65%), with 20% asymmetric left and 15% asymmetric right. There were no clinical differences across groups, although there was a trend for greater behavioral dyscontrol in right asymmetric compared to left asymmetric subjects. More widespread atrophy involving the parietal lobe was observed in the symmetric group. Genetic features differed across groups with symmetric frontal lobes associated with C9ORF72 and tau mutations, while asymmetric frontal lobes were associated with progranulin mutations. These findings therefore suggest that neuroanatomical patterns of frontal lobe atrophy in bvFTD are influenced by specific gene mutations.
doi:10.1016/j.neurobiolaging.2012.03.009
PMCID: PMC3404265  PMID: 22502999
Frontotemporal dementia; frontal lobes; MRI; asymmetry; microtubule associated protein tau; progranulin; C9ORF72; pathology
15.  Corticospinal tract degeneration associated with TDP-43 type C pathology and semantic dementia 
Brain  2013;136(2):455-470.
Four subtypes of frontotemporal lobar degeneration with TDP-43 immunoreactive inclusions have been described (types A–D). Of these four subtypes, motor neuron disease is more commonly associated with type B pathology, but has also been reported with type A pathology. We have noted, however, the unusual occurrence of cases of type C pathology having corticospinal tract degeneration. We aimed to assess the severity of corticospinal tract degeneration in a large cohort of cases with type C (n = 31). Pathological analysis included semi-quantitation of myelin loss of fibres of the corticospinal tract and associated macrophage burden, as well as axonal loss, at the level of the medullary pyramids. We also assessed for motor cortex degeneration and fibre loss of the medial lemniscus/olivocerebellar tract. All cases were subdivided into three groups based on the degree of corticospinal tract degeneration: (i) no corticospinal tract degeneration; (ii) equivocal corticospinal tract degeneration; and (iii) moderate to very severe corticospinal tract degeneration. Clinical, genetic, pathological and imaging comparisons were performed across groups. Eight cases had no corticospinal tract degeneration, and 14 cases had equivocal to mild corticospinal tract degeneration. Nine cases, however, had moderate to very severe corticospinal tract degeneration with myelin and axonal loss. In these nine cases, there was degeneration of the motor cortex without lower motor neuron degeneration or involvement of other brainstem tracts. These cases most commonly presented as semantic dementia, and they had longer disease duration (mean: 15.3 years) compared with the other two groups (10.8 and 9.9 years; P = 0.03). After adjusting for disease duration, severity of corticospinal tract degeneration remained significantly different across groups. Only one case, without corticospinal tract degeneration, was found to have a hexanucleotide repeat expansion in the C9ORF72 gene. All three groups were associated with anterior temporal lobe atrophy on MRI; however, the cases with moderate to severe corticospinal tract degeneration showed right-sided temporal lobe asymmetry and greater involvement of the right temporal lobe and superior motor cortices than the other groups. In contrast, the cases with no or equivocal corticospinal tract degeneration were more likely to show left-sided temporal lobe asymmetry. For comparison, the corticospinal tract was assessed in 86 type A and B cases, and only two cases showed evidence of corticospinal tract degeneration without lower motor neuron degeneration. These findings confirm that there exists a unique association between frontotemporal lobar degeneration with type C pathology and corticospinal tract degeneration, with this entity showing a predilection to involve the right temporal lobe.
doi:10.1093/brain/aws324
PMCID: PMC3572926  PMID: 23358603
TDP-43 type C; corticospinal tract; MRI; semantic dementia; right temporal lobe
16.  Update on hypothetical model of Alzheimer’s disease biomarkers 
Lancet neurology  2013;12(2):207-216.
In 2010, the authors published a hypothetical model of the major biomarkers of Alzheimer’s disease (AD). The model was received with interest because we described the temporal evolution of AD biomarkers in relation to each other and to the onset and progression of clinical symptoms. In the interim, evidence has accumulated that supports the major assumptions of this model. Evidence has also appeared that challenges some of the assumptions underlying our original model. Recent evidence has allowed us to modify our original model. Refinements include indexing subjects by time rather than clinical symptom severity; incorporating inter-subject variability in cognitive response to the progression of AD pathophysiology; modifications of the specific temporal ordering of some biomarkers; and, recognition that the two major proteinopathies underlying AD biomarker changes, Aβ and tau, may be initiated independently in late onset AD where we hypothesize that an incident Aβopathy can accelerate an antecedent tauopathy.
doi:10.1016/S1474-4422(12)70291-0
PMCID: PMC3622225  PMID: 23332364
17.  Caloric Intake, Aging, and Mild Cognitive Impairment: A Population-Based Study 
In a population-based case-control study, we examined whether moderate and high caloric intakes are differentially associated with the odds of having mild cognitive impairment (MCI). The sample was derived from the Mayo Clinic Study of Aging in Olmsted County, Minnesota. Non-demented study participants aged 70–92 years (1,072 cognitively normal persons and 161 subjects with MCI) reported their caloric consumption within 1 year of the date of interview by completing a Food Frequency Questionnaire. An expert consensus panel classified each subject as either cognitively normal or having MCI based on published criteria. We conducted multivariable logistic regression analyses to compute odds ratios (OR) and 95% confidence intervals (95% CI) after adjusting for age, sex, education, depression, medical comorbidity, and body mass index. We also conducted stratified analyses by apolipoprotein E ε4 genotype status. Analyses were conducted in tertiles of caloric intake: 600 to <1,526 kcals per day (reference group); 1,526 to 2,143 kcals per day (moderate caloric intake group); and >2,143 kcals per day (high caloric intake group). In the primary analysis, there was no significant difference between the moderate caloric intake group and the reference group (OR 0.87, 95% CI 0.53–1.42, p = 0.57). However, high caloric intake was associated with a nearly two-fold increased odds of having MCI (OR 1.96, 95% CI 1.26–3.06, p = 0.003) as compared to the reference group. Therefore, high caloric intake was associated with MCI but not moderate caloric intake. This association is not necessarily a cause-effect relationship.
doi:10.3233/JAD-121270
PMCID: PMC3578975  PMID: 23234878
aging; APOE ε4 genotype; caloric intake; mild cognitive impairment; population-based
18.  Polysomnographic Findings in Dementia With Lewy Bodies 
The neurologist  2013;19(1):1-6.
Introduction
The clinical features of dementia with Lewy bodies (DLB) during wakefulness are well known. Other than REM sleep behavior disorder (RBD), only limited data exists on other sleep disturbances and disorders in DLB. We sought to characterize the polysomnographic (PSG) findings in a series of DLB patients with sleep-related complaints.
Methods
Retrospective study of patients with DLB who underwent clinical PSG at Mayo Clinic Rochester or Mayo Clinic Jacksonville over an almost 11 year span for evaluation of dream enactment behavior, excessive nocturnal movements, sleep apnea, hypersomnolence, or insomnia. The following variables were analyzed: respiratory disturbance index (RDI) in disordered breathing events/hour, periodic limb movement arousal index (PLMAI), arousals for no apparent reason (AFNAR), total arousal index (TAI), presence of REM sleep without atonia (RSWA), and percent sleep efficiency (SE).
Results
Data on 78 patients (71M, 7F) were analyzed. The mean age was 71 ± 8 years. Seventy-five (96%) patients had histories of recurrent dream enactment during sleep with 83% showing confirmation of RSWA +/- dream enactment during PSG. Mean RDI = 11.9 ± 5.8, PLMAI = 5.9 ± 8.5, AFNARI = 10.7 ± 12.0, and TAI = 26.6 ± 17.4. SE was <80% in 72% of the sample, <70% in 49%, and <60% in 24%. In patients who did not show evidence of significant disordered breathing (23 with RDI<5), 62% of arousals were AFNARs. In those patients who had significant disordered breathing (55 with RDI ≥ 5), 36% of arousals were AFNARs. Six patients underwent evaluations with PSG plus MSLT. Two patients had mean initial sleep latencies less than five minutes, and both had RDI<5. No patient had any sleep onset rapid eye movement periods. Nineteen patients have undergone neuropathologic examination, and 18 have had limbic- or neocortical-predominant Lewy body pathology. One had progressive supranuclear palsy, but no REM sleep was recorded in prior PSG.
Conclusions
In patients with DLB and sleep-related complaints, several sleep disturbances in addition to RBD are frequently present. In this sample, about three quarters had a significant number of arousals not accounted for by a movement or breathing disturbance, and the primary sleep disorders do not appear to entirely account for the poor sleep efficiency in DLB, especially in those without a significant breathing disorder. Further studies are warranted to better understand the relationship between disturbed sleep, arousal and DLB; such characterization may provide insights into potential avenues of treatment of symptoms which could impact quality of life.
doi:10.1097/NRL.0b013e31827c6bdd
PMCID: PMC3587292  PMID: 23269098
Sleep disorders; REM sleep behavior disorder; dementia with Lewy bodies; synucleinopathy
19.  Limb Immobilization and Corticobasal Syndrome 
Parkinsonism & related disorders  2012;18(10):1097-1099.
Background
Recently, we evaluated two patients with corticobasal syndrome (CBS) who reported symptom onset after limb immobilization. Our objective was to investigate the association between trauma, immobilization and CBS.
Methods
The charts of forty-four consecutive CBS patients seen in the Mayo Clinic Alzheimer Disease Research Center were reviewed with attention to trauma and limb immobilization.
Results
10 CBS patients (23%) had immobilization or trauma on the most affected limb preceding the onset or acceleration of symptoms. The median age at onset was 61. Six patients manifested their first symptoms after immobilization from surgery or fracture with one after leg trauma. Four patients had pre-existing symptoms of limb dysfunction but significantly worsened after immobilization or surgery.
Conclusions
23 percent of patients had immobilization or trauma of the affected limb. This might have implications for management of CBS, for avoiding injury, limiting immobilization and increasing movement in the affected limb.
doi:10.1016/j.parkreldis.2012.05.025
PMCID: PMC3461122  PMID: 22721974
Corticobasal syndrome; plasticity; immobilization
20.  Genome-wide pathway analysis of memory impairment in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort implicates gene candidates, canonical pathways, and networks 
Brain imaging and behavior  2012;6(4):634-648.
Memory deficits are prominent features of mild cognitive impairment (MCI) and Alzheimer’s disease (AD). The genetic architecture underlying these memory deficits likely involves the combined effects of multiple genetic variants operative within numerous biological pathways. In order to identify functional pathways associated with memory impairment, we performed a pathway enrichment analysis on genome-wide association data from 742 Alzheimer’s Disease Neuroimaging Initiative (ADNI) participants. A composite measure of memory was generated as the phenotype for this analysis by applying modern psychometric theory to item-level data from the ADNI neuropsychological test battery. Using the GSA-SNP software tool, we identified 27 canonical, expertly-curated pathways with enrichment (FDR-corrected p-value < 0.05) against this composite memory score. Processes classically understood to be involved in memory consolidation, such as neurotransmitter receptor-mediated calcium signaling and long-term potentiation, were highly represented among the enriched pathways. In addition, pathways related to cell adhesion, neuronal differentiation and guided outgrowth, and glucose- and inflammation-related signaling were also enriched. Among genes that were highly-represented in these enriched pathways, we found indications of coordinated relationships, including one large gene set that is subject to regulation by the SP1 transcription factor, and another set that displays co-localized expression in normal brain tissue along with known AD risk genes. These results 1) demonstrate that psychometrically-derived composite memory scores are an effective phenotype for genetic investigations of memory impairment and 2) highlight the promise of pathway analysis in elucidating key mechanistic targets for future studies and for therapeutic interventions.
doi:10.1007/s11682-012-9196-x
PMCID: PMC3713637  PMID: 22865056
memory; psychometrics; Alzheimer’s disease; mild cognitive impairment; pathway analysis; genome-wide association study
21.  Effect of Lifestyle Activities on AD Biomarkers and Cognition 
Annals of neurology  2012;72(5):730-738.
Objectives
To investigate the effect of intellectual and physical activity on biomarkers of Alzheimer’s disease (AD) pathophysiology and cognition in a non-demented elderly population. The biomarkers evaluated were brain Aβ-amyloid load via PIB-PET, neuronal dysfunction via FDG-PET and neurodegeneration via Structural-MRI.
Methods
We studied 515 non-demented (428 cognitively normal and 87 MCI) participants in the population based Mayo Clinic Study of Aging who completed a 3T MRI, PET scans, APOE genotype, had lifestyle activity measures and cognition data available. The imaging measures computed were global PiB-PET uptake; global FDG-PET and MRI based hippocampal volume. We consolidated activity variables into lifetime intellectual, current intellectual and current physical activities. We used a global cognitive Z-score as a measure of cognition. We applied two independent methods – partial correlation analysis adjusted for age and gender and path analysis using structural equations to evaluate the associations between lifestyle activities, imaging biomarkers and global cognition.
Results
None of the lifestyle variables correlated with the biomarkers and the path associations between lifestyle variables and biomarkers were not significant (p>0.05). On the other hand, all the biomarkers were correlated with global cognitive Z-score (p<0.05) and the path associations between (lifetime and current) intellectual activities and global Z-score were significant (p<0.01).
Interpretation
Intellectual and physical activity lifestyle factors were not associated with AD biomarkers but intellectual lifestyle factors explained variability in the cognitive performance in this non-demented population. This study provides evidence that lifestyle activities may delay the onset of dementia but do not significantly influence the expression of AD pathophysiology.
doi:10.1002/ana.23665
PMCID: PMC3539211  PMID: 23280791
Alzheimer’s disease; Imaging biomarkers; Lifestyle Activities
22.  ApoE and Quality of Life in Nonagenarians 
Objectives
ApoE ε4 is associated with adverse health conditions that negatively impact the quality of life (QOL). The relationship between ApoE ε4 and QOL has not been explored in the oldest old. Our study aimed to examine ApoE in the oldest old, and explore its association with QOL.
Design
Cross-sectional cohort study.
Setting
A medium sized community in Olmsted County, Minnesota, USA.
Participants
90–99 year old individuals living independently or in long term care environments.
Measurements
We collected demographic information and measured cognitive function (Short Test of Mental Status [STMS], Mini-Mental State Examination [MMSE], Mattis Dementia Rating Scale [DRS]), QOL (Linear Analogue Self Assessment [LASA]) and ApoE distribution. Subjects were classified as cognitively normal, mild cognitive impairment (MCI), dementia (DEM), or dementia with stroke and/or parkinsonism (DEMSP). Regression model was used to assess the predictors of QOL.
Results
121 subjects (45 cognitively normal, 13 MCI, 34 DEM, 29 DEMSP) aged 90–99,106 (87.6 %) females, were included. Frequency of ApoE ε3 allele was highest [194 (80.2%): ε2/3 18, ε3/3 77, ε3/4 22] followed by ApoE ε4 [25 (10.3%): ε2/4 3, ε3/4 22] and ApoE ε2 [23 (9.5%; ε2/2 1, ε2/3 18, ε2/4 3]. None of the subjects carried ApoE ε4/4 genotype. QOL was similar between ApoE ε4 carrier and non-carriers. Physical well-being, emotional well-being, intellectual well-being, social connectedness and coping ability were positively associated with QOL, whereas male gender, DEMSP, pain frequency and pain severity were negatively associated.
Conclusions
The most common ApoE in the oldest old was ε3/3 genotype and ε3 allele. No association was found between ApoE ε4 and QOL. However, those with high physical, emotional and intellectual well being, social connectedness and coping ability had the highest overall QOL.
doi:10.1016/j.jamda.2012.06.012
PMCID: PMC3461124  PMID: 22863665
Well being; oldest old; apolipoprotein E
23.  Neuroimaging correlates of pathologically-defined atypical Alzheimer’s disease 
Lancet neurology  2012;11(10):868-877.
Background
Atypical variants of Alzheimer’s disease (AD) have been pathologically defined based on the distribution of neurofibrillary tangles; hippocampal sparing (HpSp) AD shows minimal involvement of the hippocampus and limbic predominant (LP) AD shows neurofibrillary tangles restricted to the medial temporal lobe. We aimed to determine whether MRI patterns of atrophy differ across HpSp AD, LP AD and typical AD, and whether imaging could be a useful predictor of pathological subtype during life.
Methods
In this case-control study, we identified 177 patients who had been prospectively followed in the Mayo Clinic Alzheimer’s Disease Research Center, were demented during life, had AD pathology at autopsy (Braak stage ≥ IV, intermediate-high probability AD) and an antemortem MRI. Cases were assigned to one of three pathological subtypes (HpSp n=19, typical n=125, or LP AD n=33) based on neurofibrillary tangle counts and their ratio in association cortices to hippocampus, without reference to neuronal loss. Voxel-based morphometry and atlas-based parcellation were used to compare patterns of grey matter loss across groups, and to controls.
Findings
The severity of medial temporal and cortical grey matter atrophy differed across subtypes. The most severe medial temporal atrophy was observed in LP AD, followed by typical AD, and then HpSp AD. Conversely, the most severe cortical atrophy was observed in HpSp AD, followed by typical AD, and then LP AD. A ratio of hippocampal-to-cortical volume provided the best discrimination across all three AD subtypes. The majority of typical AD (98/125;78%) and LP AD (31/33;94%) subjects, but only 8/19 (42%) of the HpSp AD subjects, presented with a dominant amnestic syndrome.
Interpretation
Patterns of atrophy on MRI differ across the pathological subtypes of AD, suggesting that MR regional volumetrics reliably track the distribution of neurofibrillary tangle pathology and can predict pathological subtype during life.
Funding
US National Institutes of Health (National Institute on Aging)
doi:10.1016/S1474-4422(12)70200-4
PMCID: PMC3490201  PMID: 22951070
24.  Amyloid Deposition, Hypometabolism, and Longitudinal Cognitive Decline 
Annals of neurology  2012;72(4):578-586.
Objective
Using data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) population, we examined (1) cross-sectional relationships between amyloid deposition, hypometabolism, and cognition, and (2) associations between amyloid and hypometabolism measurements and longitudinal cognitive measurements.
Methods
We examined associations between mean cortical florbetapir uptake, mean 18F-fluorodeoxyglucose–positron emission tomography (FDG-PET) within a set of predefined regions, and Alzhiemer’s Disease Assessment Scale (ADAS-cog) performance in 426 ADNI participants (126 normal, 162 early mild cognitive impairment [EMCI], 85 late MCI [LMCI], 53 Alzheimer disease [AD] patients). For a subset of these (76 normal, 81 LMCI) we determined whether florbetapir and FDG-PET were associated with retrospective decline in longitudinal ADAS-cog measurements.
Results
Twenty-nine percent of normal subjects, 43% of EMCI patients, 62% of LMCI patients, and 77% of AD patients were categorized as florbetapir positive. Florbetapir was negatively associated with concurrent FDG and ADAS-cog in both MCI groups. In longitudinal analyses, florbetapir-positive subjects in both normal and LMCI groups had greater ongoing ADAS-cog decline than those who were florbetapir negative. However, in normal subjects, florbetapir positivity was associated with greater ADAS-cog decline than FDG, whereas in LMCI, FDG positivity was associated with greater decline than florbetapir.
Interpretation
Although both hypometabolism and β-amyloid (Aβ) deposition are detectable in normal subjects and all diagnostic groups, Aβ showed greater associations with cognitive decline in normal participants. In view of the minimal cognitive deterioration overall in this group, this suggests that amyloid deposition has an early and subclinical impact on cognition that precedes metabolic changes. At moderate and later stages of disease (LMCI/AD), hypometabolism becomes more pronounced and more closely linked to ongoing cognitive decline.
doi:10.1002/ana.23650
PMCID: PMC3786871  PMID: 23109153
25.  Vascular Contributions to Cognitive Impairment and Dementia 
Background and Purpose
This scientific statement provides an overview of the evidence on vascular contributions to cognitive impairment and dementia. Vascular contributions to cognitive impairment and dementia of later life are common. Definitions of vascular cognitive impairment (VCI), neuropathology, basic science and pathophysiological aspects, role of neuroimaging and vascular and other associated risk factors, and potential opportunities for prevention and treatment are reviewed. This statement serves as an overall guide for practitioners to gain a better understanding of VCI and dementia, prevention, and treatment.
Methods
Writing group members were nominated by the writing group co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council Scientific Statement Oversight Committee, the Council on Epidemiology and Prevention, and the Manuscript Oversight Committee. The writing group used systematic literature reviews (primarily covering publications from 1990 to May 1, 2010), previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. After peer review by the American Heart Association, as well as review by the Stroke Council leadership, Council on Epidemiology and Prevention Council, and Scientific Statements Oversight Committee, the statement was approved by the American Heart Association Science Advisory and Coordinating Committee.
Results
The construct of VCI has been introduced to capture the entire spectrum of cognitive disorders associated with all forms of cerebral vascular brain injury—not solely stroke—ranging from mild cognitive impairment through fully developed dementia. Dysfunction of the neurovascular unit and mechanisms regulating cerebral blood flow are likely to be important components of the pathophysiological processes underlying VCI. Cerebral amyloid angiopathy is emerging as an important marker of risk for Alzheimer disease, microinfarction, microhemorrhage and macrohemorrhage of the brain, and VCI. The neuropathology of cognitive impairment in later life is often a mixture of Alzheimer disease and microvascular brain damage, which may overlap and synergize to heighten the risk of cognitive impairment. In this regard, magnetic resonance imaging and other neuroimaging techniques play an important role in the definition and detection of VCI and provide evidence that subcortical forms of VCI with white matter hyperintensities and small deep infarcts are common. In many cases, risk markers for VCI are the same as traditional risk factors for stroke. These risks may include but are not limited to atrial fibrillation, hypertension, diabetes mellitus, and hypercholesterolemia. Furthermore, these same vascular risk factors may be risk markers for Alzheimer disease. Carotid intimal-medial thickness and arterial stiffness are emerging as markers of arterial aging and may serve as risk markers for VCI. Currently, no specific treatments for VCI have been approved by the US Food and Drug Administration. However, detection and control of the traditional risk factors for stroke and cardiovascular disease may be effective in the prevention of VCI, even in older people.
Conclusions
Vascular contributions to cognitive impairment and dementia are important. Understanding of VCI has evolved substantially in recent years, based on preclinical, neuropathologic, neuroimaging, physiological, and epidemiological studies. Transdisciplinary, translational, and transactional approaches are recommended to further our understanding of this entity and to better characterize its neuropsychological profile. There is a need for prospective, quantitative, clinical-pathological-neuroimaging studies to improve knowledge of the pathological basis of neuroimaging change and the complex interplay between vascular and Alzheimer disease pathologies in the evolution of clinical VCI and Alzheimer disease. Long-term vascular risk marker interventional studies beginning as early as midlife may be required to prevent or postpone the onset of VCI and Alzheimer disease. Studies of intensive reduction of vascular risk factors in high-risk groups are another important avenue of research.
doi:10.1161/STR.0b013e3182299496
PMCID: PMC3778669  PMID: 21778438
AHA Scientific Statements; vascular dementia; Alzheimer disease; risk factors; prevention; treatment

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