Search tips
Search criteria

Results 1-25 (160)

Clipboard (0)

Select a Filter Below

more »
more »
Year of Publication
more »
1.  Subtle gait changes in patients with REM Behavior Disorder 
Many people with REM sleep behavior disorder have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. As gait disorders are common in the synucleinopathies, early abnormalities in gait in those with REM sleep behavior disorder could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment.
We identified 42 probable REM sleep behavior disorder subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence and stride dynamics with an automated gait analysis system.
Cases and controls were similar in age (79.9 ± 4.7 & 80.1 ± 4.7, p= 0.74), UPDRS score (3.3 ± 5.5 & 1.9 ± 4.1, p=0.21) and Mini-Mental State Examination scores (27.2 ± 1.9 & 27.7 ± 1.6, p=0.10). A diagnosis of probable REM sleep behavior disorder was associated with decreased velocity (−7.9 cm/sec, 95%CI −13.8 to −2.0, p<0.01), cadence (−4.4 steps/min, 95%CI −7.6 to −1.3, p<0.01), and significantly increased double limb support variability (30%, 95%CI 6 – 60, p=0.01), greater stride time variability (29%, 95%CI 2 – 63, p=0.03) and swing time variability (46%, 95%CI 15 – 84, p<0.01).
Probable REM sleep behavior disorder is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable REM sleep behavior disorder supplemented by gait analysis may help as a screening tool for disorders of α-synuclein.
PMCID: PMC3952497  PMID: 24130124
REM Sleep Behavior Disorder; gait; gait variability
2.  Treatment Outcomes in REM Sleep Behavior Disorder 
Sleep medicine  2013;14(3):237-242.
REM sleep behavior disorder (RBD) is usually characterized by potentially injurious dream enactment behaviors (DEB). RBD treatment aims to reduce DEBs and prevent injury, but outcomes require further elucidation. We surveyed RBD patients to describe longitudinal treatment outcomes with melatonin and clonazepam.
We surveyed and reviewed records of consecutive RBD patients seen at Mayo Clinic between 2008–2010 to describe RBD-related injury frequency/severity as well as RBD Visual Analog Scale (VAS) ratings, medication dosage, and side effects. Statistical analyses were performed with appropriate non-parametric matched pairs tests before and after treatment, and with comparative group analyses for continuous and categorical variables between treatment groups. The primary outcome variables were RBD VAS ratings and injury frequency.
Forty-five (84.9%) of 53 respondent surveys were analyzed. Mean age was 65.8 years and 35 (77.8%) patients were men. Neurodegenerative disorders were seen in 24 (53%) patients, and 25 (56%) received antidepressants. Twenty-five patients received melatonin, 18 received clonazepam, and 2 received both as initial treatment. Before treatment, 27 patients (60%) reported an RBD associated injury. Median dosages were melatonin 6 mg and clonazepam 0.5 mg. RBD VAS ratings were significantly improved following both treatments (pm=.0001, pc=.0005). Melatonin-treated patients reported significantly reduced injuries (pm=.001, pc=.06) and fewer adverse effects (p=0.07). Mean durations of treatment were no different between groups (for clonazepam 53.9 +/− 29.5 months, and for melatonin 27.4 +/− 24 months, p=0.13) and there were no differences in treatment retention, with 28% of melatonin and 22% of clonazepam-treated patients discontinuing treatment (p=0.43).
Melatonin and clonazepam were each reported to reduce RBD behaviors and injuries and appeared comparably effective in our naturalistic practice experience. Melatonin-treated patients reported less frequent adverse effects than those treated with clonazepam. More effective treatments that would eliminate injury potential and evidence-based treatment outcomes from prospective clinical trials for RBD are needed.
PMCID: PMC3617579  PMID: 23352028
REM sleep behavior disorder; parasomnia; melatonin; clonazepam; treatment; side effects; tolerability; retention; injury; falls; synucleinopathy
3.  Polysomnographic Findings in Dementia With Lewy Bodies 
The neurologist  2013;19(1):1-6.
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.
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).
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.
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.
PMCID: PMC3587292  PMID: 23269098
Sleep disorders; REM sleep behavior disorder; dementia with Lewy bodies; synucleinopathy
4.  Age-at-Onset in Late Onset Alzheimer Disease is Modified by Multiple Genetic Loci 
JAMA neurology  2014;71(11):1394-1404.
As APOE locus variants contribute to both risk of late-onset Alzheimer disease and differences in age-at-onset, it is important to know if other established late-onset Alzheimer disease risk loci also affect age-at-onset in cases.
To investigate the effects of known Alzheimer disease risk loci in modifying age-at-onset, and to estimate their cumulative effect on age-at-onset variation, using data from genome-wide association studies in the Alzheimer’s Disease Genetics Consortium (ADGC).
Design, Setting and Participants
The ADGC comprises 14 case-control, prospective, and family-based datasets with data on 9,162 Caucasian participants with Alzheimer’s occurring after age 60 who also had complete age-at-onset information, gathered between 1989 and 2011 at multiple sites by participating studies. Data on genotyped or imputed single nucleotide polymorphisms (SNPs) most significantly associated with risk at ten confirmed LOAD loci were examined in linear modeling of AAO, and individual dataset results were combined using a random effects, inverse variance-weighted meta-analysis approach to determine if they contribute to variation in age-at-onset. Aggregate effects of all risk loci on AAO were examined in a burden analysis using genotype scores weighted by risk effect sizes.
Main Outcomes and Measures
Age at disease onset abstracted from medical records among participants with late-onset Alzheimer disease diagnosed per standard criteria.
Analysis confirmed association of APOE with age-at-onset (rs6857, P=3.30×10−96), with associations in CR1 (rs6701713, P=7.17×10−4), BIN1 (rs7561528, P=4.78×10−4), and PICALM (rs561655, P=2.23×10−3) reaching statistical significance (P<0.005). Risk alleles individually reduced age-at-onset by 3-6 months. Burden analyses demonstrated that APOE contributes to 3.9% of variation in age-at-onset (R2=0.220) over baseline (R2=0.189) whereas the other nine loci together contribute to 1.1% of variation (R2=0.198).
Conclusions and Relevance
We confirmed association of APOE variants with age-at-onset among late-onset Alzheimer disease cases and observed novel associations with age-at-onset in CR1, BIN1, and PICALM. In contrast to earlier hypothetical modeling, we show that the combined effects of Alzheimer disease risk variants on age-at-onset are on the scale of, but do not exceed, the APOE effect. While the aggregate effects of risk loci on age-at-onset may be significant, additional genetic contributions to age-at-onset are individually likely to be small.
PMCID: PMC4314944  PMID: 25199842
Alzheimer Disease; Alzheimer Disease Genetics; Alzheimer’s Disease - Pathophysiology; Genetics of Alzheimer Disease; Aging
5.  Hypothyroidism and Risk of Mild Cognitive Impairment in Elderly Persons - A Population Based Study 
JAMA neurology  2014;71(2):201-207.
Association of clinical and subclinical hypothyroidism with mild cognitive impairment (MCI) is not established.
To evaluate the association of clinical and subclinical hypothyroidism with MCI in a large population based cohort.
A cross-sectional, population-based study.
Olmsted County, Minnesota.
Randomly selected participants were aged 70 to 89 years on October 1, 2004, and were without documented prevalent dementia. A total of 2,050 participants were evaluated and underwent in-person interview, neurological evaluation and neuropsychological testing to assess performance in memory, attention/executive function, visuospatial, and language domains. Subjects were diagnosed by consensus as cognitively normal, MCI or dementia according to published criteria. Clinical and subclinical hypothyroidism was ascertained from a medical records-linkage system.
Association of clinical and subclinical hypothyroidism with MCI.
Among 1904 eligible participants, the frequency of MCI was 16% in 1450 subjects with normal thyroid function, 17% in 313 subjects with clinical hypothyroidism, and 18% in 141 subjects with subclinical hypothyroidism. After adjusting for covariates (age, gender, education, education years, sex, ApoE ε 4, depression, diabetes, hypertension, stroke, BMI and coronary artery disease) we found no significant association between clinical or subclinial hypothyroidism and MCI [OR 0.99 (95% CI 0.66–1.48) and OR 0.88 (95% CI 0.38–2.03) respectively]. No effect of gender interaction was seen on these effects. In stratified analysis, the odds of MCI with clinical and subclinical hypothyroidisn among males was 1.02 (95%CI, 0.57–1.82) and 1.29 (95%CI 0.68–2.44), among females was 1.04 (95% 0.66–1.66) and 0.86 (95% CI 0.37–2.02) respectively.
In this population based cohort of eldery, neither clinical nor subclinical hypothyrpodism was associated with MCI. Our findings need to be validated in a separate settings using the published criteria for MCI and also confirmed in a longitudinal study.
PMCID: PMC4136444  PMID: 24378475
6.  Higher risk of progression to dementia in mild cognitive impairment cases who revert to normal 
Neurology  2014;82(4):317-325.
To estimate rates of progression from mild cognitive impairment (MCI) to dementia and of reversion from MCI to being cognitively normal (CN) in a population-based cohort.
Participants (n = 534, aged 70 years and older) enrolled in the prospective Mayo Clinic Study of Aging were evaluated at baseline and every 15 months to identify incident MCI or dementia.
Over a median follow-up of 5.1 years, 153 of 534 participants (28.7%) with prevalent or incident MCI progressed to dementia (71.3 per 1,000 person-years). The cumulative incidence of dementia was 5.4% at 1 year, 16.1% at 2, 23.4% at 3, 31.1% at 4, and 42.5% at 5 years. The risk of dementia was elevated in MCI cases (hazard ratio [HR] 23.2, p < 0.001) compared with CN subjects. Thirty-eight percent (n = 201) of MCI participants reverted to CN (175.0/1,000 person-years), but 65% subsequently developed MCI or dementia; the HR was 6.6 (p < 0.001) compared with CN subjects. The risk of reversion was reduced in subjects with an APOE ε4 allele (HR 0.53, p < 0.001), higher Clinical Dementia Rating Scale–Sum of Boxes (HR 0.56, p < 0.001), and poorer cognitive function (HR 0.56, p < 0.001). The risk was also reduced in subjects with amnestic MCI (HR 0.70, p = 0.02) and multidomain MCI (HR 0.61, p = 0.003).
MCI cases, including those who revert to CN, have a high risk of progressing to dementia. This suggests that diagnosis of MCI at any time has prognostic value.
PMCID: PMC3929198  PMID: 24353333
7.  Association of diabetes with amnestic and nonamnestic mild cognitive impairment 
Type 2 diabetes may increase the risk of amnestic mild cognitive impairment (aMCI) through Alzheimer's disease (AD)-related and vascular pathology and may also increase the risk of nonamnestic MCI (naMCI) through vascular disease mechanisms. We examined the association of type 2 diabetes with mild cognitive impairment (MCI) and MCI subtype (aMCI and naMCI) overall and by sex.
Participants were Olmsted County, Minnesota residents (70 years and older) enrolled in a prospective, population-based study. At baseline and every 15 months thereafter, participants were evaluated using the Clinical Dementia Rating scale, a neurological evaluation, and neuropsychological testing for a diagnosis of normal cognition, MCI, and dementia by a consensus panel. Type 2 diabetes was ascertained from the medical records of participants at baseline.
Over a median 4.0 years of follow-up, 348 of 1450 subjects developed MCI. Type 2 diabetes was associated (hazard ratio [95% confidence interval]) with MCI (1.39 [1.08–1.79]), aMCI (1.58 [1.17–2.15]; multiple domain: 1.58 [1.01–2.47]; single domain: 1.49 [1.09–2.05]), and the hazard ratio for naMCI was elevated (1.37 [0.84–2.24]). Diabetes was strongly associated with multiple-domain aMCI in men (2.42 [1.31–4.48]) and an elevated risk of multiple domain naMCI in men (2.11 [0.70–6.33]), and with single domain naMCI in women (2.32 [1.04–5.20]).
Diabetes was associated with an increased risk of MCI in elderly persons. The association of diabetes with MCI may vary with subtype, number of domains, and sex. Prevention and control of diabetes may reduce the risk of MCI and Alzheimer's disease.
PMCID: PMC3830601  PMID: 23562428
Mild cognitive impairment; Risk factors; Type 2 diabetes; Incidence; Cohort studies; Population-based studies; Sex differences; Diabetic retinopathy; Diabetic neuropathy
8.  Characterization of a Family With c9FTD/ALS Associated With the GGGGCC Repeat Expansion in C9ORF72 
Archives of neurology  2012;69(9):1164-1169.
The hexanucleotide repeat in the chromosome 9 open reading frame 72 (C9ORF72) gene was recently discovered as the pathogenic mechanism underlying many families with frontotemporal dementia (FTD) and/or amyotrophic lateral sclerosis (ALS) linked to chromosome 9 (c9FTD/ALS). We report the clinical, neuropsychological, and neuroimaging findings of a family with the C9ORF72 mutation and clinical diagnoses bridging the FTD, parkinsonism and ALS spectrum.
To characterize the antemortem characteristics of a family with c9FTD/ALS associated with the GGGGCC repeat expansion in C9ORF72
Clinical series.
Tertiary care academic medical center.
The members of the family affected by the mutation with features of FTD and/or ALS.
Main Outcome Measures
Clinical, neuropsychological, and neuroimaging assessments.
All three examined subjects had the hexanucleotide expansion detected in C9ORF72. All had personality/behavioral changes early in the course of the disease. One case had levodopa-unresponsive parkinsonism, and one had ALS. MRI showed symmetric bilateral frontal, temporal, insular and cingulate atrophy.
This report highlights the clinical and neuroimaging characteristics of a family with c9FTD/ALS. Further studies are needed to better understand the phenotypical variability and the clinico-neuroimaging-neuropathologic correlations.
PMCID: PMC3625860  PMID: 22637471
9.  Abnormal daytime sleepiness in dementia with Lewy bodies compared to Alzheimer’s disease using the Multiple Sleep Latency Test 
Excessive daytime sleepiness is a commonly reported problem in dementia with Lewy bodies (DLB). We examined the relationship between nighttime sleep continuity and the propensity to fall asleep during the day in clinically probable DLB compared to Alzheimer’s disease (AD) dementia.
A full-night polysomnography was carried out in 61 participants with DLB and 26 with AD dementia. Among this group, 32 participants with DLB and 18 with AD dementia underwent a daytime Multiple Sleep Latency Test (MSLT). Neuropathologic examinations of 20 participants with DLB were carried out.
Although nighttime sleep efficiency did not differentiate diagnostic groups, the mean MSLT initial sleep latency was significantly shorter in participants with DLB than in those with AD dementia (mean 6.4 ± 5 minutes vs 11 ± 5 minutes, P <0.01). In the DLB group, 81% fell asleep within 10 minutes compared to 39% of the AD dementia group (P <0.01), and 56% in the DLB group fell asleep within 5 minutes compared to 17% in the AD dementia group (P <0.01). Daytime sleepiness in AD dementia was associated with greater dementia severity, but mean MSLT latency in DLB was not related to dementia severity, sleep efficiency the night before, or to visual hallucinations, fluctuations, parkinsonism or rapid eye movement sleep behavior disorder. These data suggest that abnormal daytime sleepiness is a unique feature of DLB that does not depend on nighttime sleep fragmentation or the presence of the four cardinal DLB features. Of the 20 DLB participants who underwent autopsy, those with transitional Lewy body disease (brainstem and limbic) did not differ from those with added cortical pathology (diffuse Lewy body disease) in dementia severity, DLB core features or sleep variables.
Daytime sleepiness is more likely to occur in persons with DLB than in those with AD dementia. Daytime sleepiness in DLB may be attributed to disrupted brainstem and limbic sleep–wake physiology, and further work is needed to better understand the underlying mechanisms.
PMCID: PMC4266572  PMID: 25512763
10.  Probable REM Sleep Behavior Disorder Increases Risk for Mild Cognitive Impairment and Parkinson’s Disease: A Population-Based Study 
Annals of Neurology  2012;71(1):49-56.
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.
PMCID: PMC3270692  PMID: 22275251
sleep disorders; parasomnias; dementia; Alzheimer’s disease; dementia with Lewy bodies; parkinsonism; synuclein
11.  Nonamnestic mild cognitive impairment progresses to dementia with Lewy bodies 
Neurology  2013;81(23):2032-2038.
To determine the rate of progression of mild cognitive impairment (MCI) to dementia with Lewy bodies (DLB).
We followed 337 patients with MCI in the Mayo Alzheimer's Disease Research Center (range 2–12 years). Competing risks survival models were used to examine the rates of progression to clinically probable DLB and Alzheimer disease (AD). A subset of patients underwent neuropathologic examination.
In this clinical cohort, 116 remained as MCI, while 49 progressed to probable DLB, 162 progressed to clinically probable AD, and 10 progressed to other dementias. Among nonamnestic MCI, progression rate to probable DLB was 20 events per 100 person-years and to probable AD was 1.6 per 100 person-years. Among amnestic MCI, progression rate to probable AD was 17 events per 100 person-years, and to DLB was 1.5 events per 100 person-years. In 88% of those who developed probable DLB, the baseline MCI diagnosis included attention and/or visuospatial deficits. Those who developed probable DLB were more likely to have baseline daytime sleepiness and subtle parkinsonism. In 99% of the clinically probable AD group, the baseline MCI diagnosis included memory impairment. Neuropathologic confirmation was obtained in 24 of 30 of those with clinically probable AD, and in 14 of 18 of those with clinically probable DLB.
In a clinical sample, patients with nonamnestic MCI were more likely to develop DLB, and those with amnestic MCI were more likely to develop probable AD.
PMCID: PMC3854825  PMID: 24212390
12.  Treatment of Dementia with Lewy Bodies 
PMCID: PMC3913181  PMID: 24222315
Dementia with Lewy bodies; Treatment; Cholinesterase inhibitors; Parkinson's disease dementia; Antipsychotic; Dysautonomia; REM sleep behavior disorder
13.  MRI and pathology of REM sleep behavior disorder in dementia with Lewy bodies 
Neurology  2013;81(19):1681-1689.
To determine structural MRI and digital microscopic characteristics of REM sleep behavior disorder in individuals with low-, intermediate-, and high-likelihood dementia with Lewy bodies (DLB) at autopsy.
Patients with autopsy-confirmed low-, intermediate-, and high-likelihood DLB, according to the probability statement recommended by the third report of the DLB Consortium, and antemortem MRI, were identified (n = 75). The clinical history was assessed for presence (n = 35) and absence (n = 40) of probable REM sleep behavior disorder (pRBD), and patients' antemortem MRIs were compared using voxel-based morphometry. Pathologic burdens of phospho-tau, β-amyloid, and α-synuclein were measured in regions associated with early neuropathologic involvement, the hippocampus and amygdala.
pRBD was present in 21 patients (60%) with high-likelihood, 12 patients (34%) with intermediate-likelihood, and 2 patients (6%) with low-likelihood DLB. Patients with pRBD were younger, more likely to be male (p ≤ 0.001), and had a more frequent neuropathologic diagnosis of diffuse (neocortical) Lewy body disease. In the hippocampus and amygdala, phospho-tau and β-amyloid burden were lower in patients with pRBD compared with those without pRBD (p < 0.01). α-Synuclein burden did not differ in the hippocampus, but trended in the amygdala. Patients without pRBD had greater atrophy of temporoparietal cortices, hippocampus, and amygdala (p < 0.001) than those with pRBD; atrophy of the hippocampus (p = 0.005) and amygdala (p = 0.02) were associated with greater phospho-tau burdens in these regions.
Presence of pRBD is associated with a higher likelihood of DLB and less severe Alzheimer-related pathology in the medial temporal lobes, whereas absence of pRBD is characterized by Alzheimer-like atrophy patterns on MRI and increased phospho-tau burden.
PMCID: PMC3812105  PMID: 24107861
14.  Diabetes and Elevated HbA1c levels are Associated with Brain Hypometabolism but not Amyloid Accumulation 
Dysfunctional insulin signaling may affect brain metabolism or amyloid deposition. We investigated the associations of type 2 diabetes with amyloid accumulation measured using 11C-Pittsburgh Compound B (PiB) and brain hypometabolism measured using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET).
We studied a sample of non-demented participants from the population-based Mayo Clinic Study of Aging. All subjects underwent MRI, amyloid PET and FDG PET. Alzheimer’s disease (AD) signature and region of interest (ROI) measures for PiB retention ratio and FDG ratio were measured. Diabetes was assessed from the Rochester Epidemiology Project medical records-linkage system.
Among 749 participants (median age 79.0 years; 56.5% male, 81.0% cognitively normal; 20.6% diabetics), FDG hypometabolism (FDG ratio < 1.31) in the AD signature meta-ROI was more common in diabetics (48.1%) than in non-diabetics (28.9%; p <0.001). The median FDG ratio was lower in diabetics vs. non-diabetics in the AD signature meta-ROI (1.32 vs. 1.40, p < 0.001), and in the angular (1.40 vs. 1.48, p < 0.001) and posterior cingulate gyri ROIs (1.63 vs. 1.72, p < 0.001). The odds ratio (OR [95% confidence interval]) for abnormal AD signature FDG hypometabolism was elevated (OR, 2.28 [1.56, 3.33]) in diabetics vs. non-diabetics after adjustment for age, sex, and education, and after additional adjustment for Apolipoprotein ε4 allele, glycemic level, and cognitive status (OR, 1.69 [1.10, 2.60]). However, AD signature PiB retention ratio was similar in diabetics vs. non-diabetics (OR, 1.03 [0.71, 1.51]; p = 0.87). In post-hoc analyses in non-diabetics, a 1% increase in HBA1c was associated with greater AD signature hypometabolism in cognitively normal subjects (OR, 1.93 [1.03, 3.62; p = 0.04]) and in the total cohort (OR 1.59 [0.92, 2.75; p = 0.10).
Diabetes and poor glycemic control in non-diabetics may enhance glucose hypometabolism in AD signature regions. These factors should be investigated in longitudinal studies for their role in detecting onset of symptoms in AD.
PMCID: PMC4011952  PMID: 24652830
Diabetes; cerebral glucose metabolism; FDG- and PiB-PET imaging; hemoglobin A1c; amyloid accumulation
15.  Practice effects and longitudinal cognitive change in normal aging vs. incident mild cognitive impairment and dementia in the Mayo Clinic Study of Aging 
The Clinical neuropsychologist  2013;27(8):10.1080/13854046.2013.836567.
The objective of this study was to examine practice effects and longitudinal cognitive change in a population based cohort classified as clinically normal at their initial evaluation. We examined 1390 individuals with a median age of 78.1 years and re-evaluated them up to four times at approximate 15 month intervals, with an average follow-up time of five years. Of the 1390 participants, 947 (69%) individuals remained cognitively normal, 397 (29%) progressed to mild cognitive impairment (MCI), and 46 (3%) to dementia. The stable normal group showed an initial practice effect in all domains which was sustained in memory and visuospatial reasoning. There was only a slight decline in attention and language after visit 3. We combined individuals with incident MCI and dementia to form one group representing those who declined. The incident MCI/dementia group showed an unexpected practice effect in memory from baseline to visit 2, with a significant decline thereafter. This group did not demonstrate practice effects in any other domain and showed a downward trajectory in all domains at each evaluation. Modeling cognitive change in an epidemiologic sample may serve as a useful benchmark for evaluating cognitive change in future intervention studies.
PMCID: PMC3869900  PMID: 24041121
Cognition; memory; practice effects; mild cognitive impairment; Alzheimer’s disease
16.  Incidence of Dementia with Lewy Bodies and Parkinson’s Disease Dementia 
JAMA neurology  2013;70(11):1396-1402.
Epidemiologic data on dementia with Lewy bodies (LBD) and Parkinson’s disease dementia (PDD) remain limited in the US and worldwide. These data are essential to guide research and clinical or public health interventions.
To investigate the incidence of DLB among residents of Olmsted County, MN, and compare it to the incidence of PDD.
The medical records-linkage system of the Rochester Epidemiology Project was used to identify all persons who developed parkinsonism and, in particular, DLB or PDD from 1991 through 2005 (15 years). A movement disorders specialist reviewed the complete medical records of each suspected patient to confirm the diagnosis.
Olmsted County, MN, from 1991 through 2005 (15 years).
Main Outcome Measure
Incidence of DLB and PDD.
All the residents of Olmsted County, MN who gave authorization for medical record research.
Among 542 incident cases of parkinsonism, 64 had DLB and 46 had PDD. The incidence rate of DLB was 3.5 per 100,000 person-years overall, and it increased steeply with age. Similarly, the incidence of PDD was 2.5 overall and also increased steeply with age. The incidence rate of DLB and PDD combined was 5.9. Patients with DLB were younger at onset of symptoms than patients with PDD and had more hallucinations and cognitive fluctuations. Men had a higher incidence of DLB than women across the age spectrum. The pathology was consistent with the clinical diagnosis in 24 of 31 patients who underwent autopsy (77.4%).
The overall incidence rate of DLB is lower than the rate for Parkinson’s disease. DLB risk increases steeply with age and is markedly higher in men. This men-to-women difference may suggest different etiologic mechanisms.
PMCID: PMC4181848  PMID: 24042491
17.  Chiari 1 Malformation Presenting as Central Sleep Apnea during Pregnancy: A Case Report, Treatment Considerations, and Review of the Literature 
Purpose: Chiari malformation (CM) type-1 frequently causes obstructive or central sleep-disordered breathing (SDB) in both adults and children, although SDB is relatively rare as a presenting manifestation in the absence of other neurological symptoms. The definitive treatment of symptomatic CM is surgical decompression. We report a case that is, to our knowledge, a novel manifestation of central sleep apnea (CSA) due to CM type-1 with severe exacerbation and initial clinical presentation during pregnancy.
Methods: Case report from tertiary care comprehensive sleep medicine center with literature review of SDB manifestations associated with CM type-1. PubMed search was conducted between January 1982 and October 2013.
Results: We report a 25-year-old woman with severe CSA initially presenting during her first pregnancy that eventually proved to be caused by CM type-1. The patient was successfully treated preoperatively by adaptive servoventilation (ASV), with effective resolution of SDB following surgical decompression, and without recurrence in a subsequent pregnancy. Our literature review found that 58% of CM patients with SDB had OSA alone, 28% had CSA alone, 8 (10%) had mixed OSA/CSA, and 6 (8%) had hypoventilation. Of CM patients presenting with SDB, 50% had OSA, 42% had CSA, 8% had mixed OSA/CSA, and 10.4% had hypoventilation. We speculate that CSA may develop in CM patients in whom brainstem compression results in excessive central chemoreflex sensitivity with consequent hypocapnic CSA.
Conclusion: Chiari malformation type-1 may present with a diversity of SDB manifestations, and timely recognition and surgical referral are necessary to prevent further neurological deficits. ASV therapy can effectively manage CSA caused by CM type-1, which may initially present during pregnancy.
PMCID: PMC4208407  PMID: 25386156
Chiari malformation; central sleep apnea; pregnancy; presentation; adaptive servoventilation
18.  Validation of the Mayo Sleep Questionnaire to Screen for REM Sleep Behavior Disorder in an Aging and Dementia Cohort 
Sleep medicine  2011;12(5):445-453.
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.
PMCID: PMC3083495  PMID: 21349763
sleep disorders; parasomnias; dementia; Alzheimer’s disease; dementia with Lewy bodies; parkinsonism
19.  Clinical Characterization of a Kindred with a Novel Twelve Octapeptide Repeat Insertion in the Prion Protein Gene 
Archives of Neurology  2011;68(9):1165-1170.
To report the clinical, electroencephalographic, and neuroradiologic findings in a kindred with a novel insertion in the prion protein gene (PRNP).
Clinical description of a kindred.
Mayo Clinic Alzheimer’s Disease Research Center (Rochester).
Two pathologically-confirmed cases and their relatives.
Main outcome measures
Clinical features, electroencephalographic patterns, magnetic resonance imaging abnormalities, genetic analyses and neuropathological features.
The proband presented with clinical and neuroimaging features of atypical frontotemporal dementia (FTD) and ataxia. Generalized tonic-clonic seizures developed later in her course, and electroencephalography revealed spike and wave discharges but no periodic sharp wave complexes. Her affected sister and father also exhibited FTD-like features, and both experienced generalized tonic-clonic seizures and gait ataxia late in their course. Genetic analyses in the proband identified a novel defect in PRNP with one mutated allele carrying a 288 base pair insertion (BPI) consisting of 12 octapeptide repeats. Neuropathologic examination of the sister and proband revealed PrP-positive plaques and widespread tau-positive tangles.
This kindred has a unique combination of clinical and neuropathologic features associated with the largest BPI identified to date in PRNP, and underscores the need to consider familial prion disease in the differential diagnosis of a familial FTD-like syndrome.
PMCID: PMC3326586  PMID: 21911696
frontotemporal dementia; FTD; nonfluent aphasia; Gerstmann–Straüssler–Scheinker syndrome (GSS); Creutzfeldt-Jakob disease (CJD); prion; PRNP
20.  Characterization of frontotemporal dementia and/or amyotrophic lateral sclerosis associated with the GGGGCC repeat expansion in C9ORF72 
Brain  2012;135(3):765-783.
Numerous kindreds with familial frontotemporal dementia and/or amyotrophic lateral sclerosis have been linked to chromosome 9, and an expansion of the GGGGCC hexanucleotide repeat in the non-coding region of chromosome 9 open reading frame 72 has recently been identified as the pathogenic mechanism. We describe the key characteristics in the probands and their affected relatives who have been evaluated at Mayo Clinic Rochester or Mayo Clinic Florida in whom the hexanucleotide repeat expansion were found. Forty-three probands and 10 of their affected relatives with DNA available (total 53 subjects) were shown to carry the hexanucleotide repeat expansion. Thirty-six (84%) of the 43 probands had a familial disorder, whereas seven (16%) appeared to be sporadic. Among examined subjects from the 43 families (n = 63), the age of onset ranged from 33 to 72 years (median 52 years) and survival ranged from 1 to 17 years, with the age of onset <40 years in six (10%) and >60 in 19 (30%). Clinical diagnoses among examined subjects included behavioural variant frontotemporal dementia with or without parkinsonism (n = 30), amyotrophic lateral sclerosis (n = 18), frontotemporal dementia/amyotrophic lateral sclerosis with or without parkinsonism (n = 12), and other various syndromes (n = 3). Parkinsonism was present in 35% of examined subjects, all of whom had behavioural variant frontotemporal dementia or frontotemporal dementia/amyotrophic lateral sclerosis as the dominant clinical phenotype. No subject with a diagnosis of primary progressive aphasia was identified with this mutation. Incomplete penetrance was suggested in two kindreds, and the youngest generation had significantly earlier age of onset (>10 years) compared with the next oldest generation in 11 kindreds. Neuropsychological testing showed a profile of slowed processing speed, complex attention/executive dysfunction, and impairment in rapid word retrieval. Neuroimaging studies showed bilateral frontal abnormalities most consistently, with more variable degrees of parietal with or without temporal changes; no case had strikingly focal or asymmetric findings. Neuropathological examination of 14 patients revealed a range of transactive response DNA binding protein molecular weight 43 pathology (10 type A and four type B), as well as ubiquitin-positive cerebellar granular neuron inclusions in all but one case. Motor neuron degeneration was detected in nine patients, including five patients without ante-mortem signs of motor neuron disease. While variability exists, most cases with this mutation have a characteristic spectrum of demographic, clinical, neuropsychological, neuroimaging and especially neuropathological findings.
PMCID: PMC3286335  PMID: 22366793
frontotemporal dementia; amyotrophic lateral sclerosis; motor neuron disease; TDP-43; neurogenetics; chromosome 9
21.  Midbrain atrophy is not a biomarker of PSP pathology 
Midbrain atrophy is a characteristic feature of progressive supranuclear palsy (PSP), although it is unclear whether it is associated with the PSP syndrome (PSPS) or PSP pathology. We aimed to determine whether midbrain atrophy is a useful biomarker of PSP pathology, or whether it is only associated with typical PSPS.
We identified all autopsy-confirmed subjects with the PSP clinical phenotype (i.e. PSPS) or PSP pathology and a volumetric MRI. Of 24 subjects with PSP pathology, 11 had a clinical diagnosis of PSPS (PSP-PSPS), and 13 had a non-PSPS clinical diagnosis (PSP-other). Three subjects had PSPS and corticobasal degeneration pathology (CBD-PSPS). Healthy control and disease control groups (i.e. a group without PSPS or PSP pathology) and a group with CBD pathology and corticobasal syndrome (CBD-CBS) were selected. Midbrain area was measured in all subjects.
Midbrain area was reduced in each group with clinical PSPS (with and without PSP pathology). The group with PSP pathology and non-PSPS clinical syndromes did not show reduced midbrain area. Midbrain area was smaller in the subjects with PSPS compared to those without PSPS (p<0.0001), with an area under the receiver-operator-curve of 0.99 (0.88,0.99). A midbrain area cut-point of 92 mm2 provided optimum sensitivity (93%) and specificity (89%) for differentiation.
Midbrain atrophy is associated with the clinical presentation of PSPS, but not with the pathological diagnosis of PSP in the absence of the PSPS clinical syndrome. This finding has important implications for the utility of midbrain measurements as diagnostic biomarkers for PSP pathology.
PMCID: PMC3773014  PMID: 23746093
Progressive supranuclear palsy; tau; neuropathology; MRI; midbrain
22.  Associations of repeat sizes with clinical and pathological characteristics in C9ORF72 expansion carriers (Xpansize-72): a cross-sectional cohort study 
Lancet neurology  2013;12(10):10.1016/S1474-4422(13)70210-2.
Hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9ORF72) are currently the major genetic cause of frontotemporal dementia (FTD) and motor neuron disease (MND). Presently, it is unknown whether expansion size affects disease severity or phenotypes.
We performed a cross-sectional Southern blot characterization study (Xpansize-72) in a cohort of subjects obtained at the Mayo Clinic and Banner Sun Health Research Institute. All subjects carried GGGGCC repeat expansions in C9ORF72, and high quality DNA was available from the frontal cortex, cerebellum and/or blood. Southern blotting techniques and densitometry were employed to estimate the repeat size of the most abundant expansion species. Comparisons of repeat sizes between tissues were made using Wilcoxon rank sum and Wilcoxon signed rank tests, and between disease subgroups using Kruskal-Wallis rank sum tests. The association of repeat size with age at onset and age at collection was evaluated using a Spearman’s test of correlation; whereas the association between repeat size and survival after disease onset was examined using Cox proportional hazards regression models.
Our cohort consisted of 84 C9ORF72 expansion carriers, including FTD patients (n=35), FTD/MND patients (n=16), MND patients (n=30), and unaffected subjects (n=3). We focused our analysis on three major tissue subgroups: frontal cortex (41 subjects [21 FTD, 11 FTD/MND, 9 MND]), cerebellum (40 subjects [20 FTD, 12 FTD/MND, 8 MND]), and blood (50 subjects [15 FTD, 9 FTD/MND, 23 MND, 3 unaffected expansion carriers]). Repeat lengths in the cerebellum were significantly smaller (median 12·3 kb [~1667 repeat units], IQR 11·1–14·3) than in the frontal cortex (median 33·8 kb [~5250 repeat units], IQR 23·5–44·9, p<0·0001), or in blood (median 18·6 kb [~2717 repeat units], IQR 13·9–28·1, p=0·0002). Within these tissues, there was no significant difference in repeat length between disease subgroups (cerebellum p=0·96, frontal cortex p=0·27, blood p=0·10). In the frontal cortex of FTD patients, repeat length correlated with age at onset (r=0·63, p=0·003) and age at collection (r=0·58, p=0·006); this correlation was not detected in the cerebellum or blood. Finally, only in the cerebellum, survival after disease onset was poorer in patients from our overall cohort with repeat lengths greater than 1467 repeat units (25th percentile, HR 3·27, 95% CI 1·34–7·95, p=0·009): the median survival was 4·8 years (IQR 3·0–7·4) in the group with longer expansions versus 7·4 years (IQR 6·3–10·9) in the group with smaller expansions.
Substantial variation in repeat size is observed between cerebellum, frontal cortex, and blood; relatively long repeat sizes in the cerebellum confer an important survival disadvantage. Our findings indicate that expansion size does affect disease severity, which could be relevant for genetic counseling.
PMCID: PMC3879782  PMID: 24011653
23.  Genetic modifiers in carriers of repeat expansions in the C9ORF72 gene 
Hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9ORF72) are causative for frontotemporal dementia (FTD) and motor neuron disease (MND). Substantial phenotypic heterogeneity has been described in patients with these expansions. We set out to identify genetic modifiers of disease risk, age at onset, and survival after onset that may contribute to this clinical variability.
We examined a cohort of 330 C9ORF72 expansion carriers and 374 controls. In these individuals, we assessed variants previously implicated in FTD and/or MND; 36 variants were included in our analysis. After adjustment for multiple testing, our analysis revealed three variants significantly associated with age at onset (rs7018487 [UBAP1; p-value = 0.003], rs6052771 [PRNP; p-value = 0.003], and rs7403881 [MT-Ie; p-value = 0.003]), and six variants significantly associated with survival after onset (rs5848 [GRN; p-value = 0.001], rs7403881 [MT-Ie; p-value = 0.001], rs13268953 [ELP3; p-value = 0.003], the epsilon 4 allele [APOE; p-value = 0.004], rs12608932 [UNC13A; p-value = 0.003], and rs1800435 [ALAD; p-value = 0.003]).
Variants identified through this study were previously reported to be involved in FTD and/or MND, but we are the first to describe their effects as potential disease modifiers in the presence of a clear pathogenic mutation (i.e. C9ORF72 repeat expansion). Although validation of our findings is necessary, these variants highlight the importance of protein degradation, antioxidant defense and RNA-processing pathways, and additionally, they are promising targets for the development of therapeutic strategies and prognostic tests.
Electronic supplementary material
The online version of this article (doi:10.1186/1750-1326-9-38) contains supplementary material, which is available to authorized users.
PMCID: PMC4190282  PMID: 25239657
C9ORF72; Frontotemporal dementia; Motor neuron disease; Genetic modifier; Repeat expansion
24.  Greatest rapid eye movement sleep atonia loss in men and older age 
To determine quantitative REM sleep muscle tone in men and women without REM sleep behavior disorder, we quantitatively analyzed REM sleep phasic and tonic muscle activity, phasic muscle burst duration, and automated REM atonia index in submentalis and anterior tibialis muscles in 25 men and 25 women without REM sleep behavior disorder. Men showed significantly higher anterior tibialis phasic muscle activity. Higher phasic muscle activity was independently associated with male sex and older age in multivariate analysis. Men and the elderly may be biologically predisposed to altered REM sleep muscle atonia control, and/or some may have occult neurodegenerative disease, possibly underlying the predominance of older men with REM sleep behavior disorder.
PMCID: PMC4241799  PMID: 25493286
25.  Prominent Phenotypic Variability Associated with Mutations in Progranulin 
Neurobiology of aging  2007;30(5):739-751.
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.
PMCID: PMC3164546  PMID: 17949857
Frontotemporal dementia; FTDP-17; Progranulin; PGRN; MRI

Results 1-25 (160)