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1.  Alzheimer and Vascular Neuropathological Changes Associated with Different Cognitive States in a Non-Demented Sample 
The state between aging with no cognitive impairment and dementia has become a major focus for intervention. The neuropathological and neurobiological correlates of this intermediate state are therefore of considerable interest, particularly from population representative samples. Here we investigate the neuropathological profile associated with different cognitive ability levels measured using strata defined by Mini Mental State Examination (MMSE) scores. One hundred and fifty one individuals were stratified into three cognitive groups including: non-, mildly, and moderately impaired at death. Alzheimer’s disease, atrophy, and vascular pathologies were investigated. Mild impairment was associated with an increased risk of vascular pathologies including small vessel disease and lacunes. In contrast, the moderately impaired group showed a more extensive pattern of pathology, including tangles and neuritic plaques (entorhinal/hippocampus), atrophy (cortical and hippocampal), and vascular disease (small vessel disease, lacunes, and infarcts). In a population-based sample of older people, MMSE score defined strata are associated with multiple pathologies. The profile of AD and vascular changes becomes more complex with increased cognitive impairment and these changes are likely to constitute a major substrate for age associated cognitive impairment. The results highlight the need for rigorous investigation of both neurodegenerative and vascular risks factors in old age.
PMCID: PMC3975483  PMID: 22233761
Aging; Alzheimer’s disease; cognitive impairment; neuropathology; vascular pathology
2.  Multivariate spatial covariance analysis of 99mTc-exametazime SPECT images in dementia with Lewy bodies and Alzheimer's disease: utility in differential diagnosis 
We examined 99mTc-exametazime brain blood flow single-photon emission computed tomography (SPECT) images using a spatial covariance analysis (SCA) approach to assess its diagnostic value in distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). Voxel SCA was simultaneously applied to a set of preprocessed images (AD, n=40; DLB, n=26), generating a series of eigenimages representing common intercorrelated voxels in AD and DLB. Linear regression derived a spatial covariance pattern (SCP) that discriminated DLB from AD. To investigate the diagnostic value of the model SCP, the SCP was validated by applying it to a second, independent, AD and DLB cohort (AD, n=34; DLB, n=29). Mean SCP expressions differed between AD and DLB (F1,64=36.2, P<0.001) with good diagnostic accuracy (receiver operating characteristic (ROC) curve area 0.87, sensitivity 81%, specificity 88%). Forward application of the model SCP to the independent cohort revealed similar differences between groups (F1,61=38.4, P<0.001), also with good diagnostic accuracy (ROC 0.86, sensitivity 80%, specificity 80%). Multivariate analysis of blood flow SPECT data appears to be robust and shows good diagnostic accuracy in two independent cohorts for distinguishing DLB from AD.
PMCID: PMC3618400  PMID: 23361395
Alzheimer's disease; differential diagnosis; dementia with Lewy bodies; perfusion; spatial covariance; SPECT
3.  A Multicenter Study of Glucocerebrosidase Mutations in Dementia With Lewy Bodies 
JAMA neurology  2013;70(6):10.1001/jamaneurol.2013.1925.
While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders.
To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB).
We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity.
Eleven centers from sites around the world performing genotyping.
Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity.
Main Outcome Measures
Frequency of GBA1 mutations in cases and controls.
We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78–14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53–15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P<.001), with higher disease severity scores.
Conclusions and Relevance
Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.
PMCID: PMC3841974  PMID: 23588557
4.  Covariant perfusion patterns provide clues to the origin of cognitive fluctuations and attentional dysfunction in Dementia with Lewy bodies 
International Psychogeriatrics / Ipa  2013;25(12):1917-1928.
Fluctuating cognition (FC), particularly in attention, is a core and defining symptom in dementia with Lewy bodies (DLB) but is seen much less frequently in Alzheimer's dementia (AD). However, its neurobiological origin is poorly understood. The aim of our study was therefore to characterize perfusion patterns in DLB patients that are associated with the severity and frequency of FC as measured both clinically and using objective neuropsychological assessments.
Spatial covariance analyses were applied to data derived from single photon emission computed tomography (SPECT) HMPAO brain imaging in 19 DLB and 23 AD patients. Patients underwent clinical assessment of their FC and cognitive function as well as objective testing of their attention.
Covariant perfusion principal components (PCs) were not associated with either FC or cognitive or attentional measures in AD. However, in DLB patients, the second PC (defined as DLB-cognitive motor pattern, DLB-PCI2) which was characterized by bilateral relative increases in cerebellum, basal ganglia, and supplementary motor areas and widespread bilateral decreases in parietal regions, positively correlated with poorer cognitive function, increased FC and worse attentional function measured both clinically and neurophysiologically (p < 0.05) as well as with the severity of bradykinesia (p = 0.04).
FC in DLB appears distinct from those seen in AD, and likely to be driven by internal neurobiological perturbations in brain circuitry as evidenced using spatial covariance analyses of cerebral perfusion. FC and certain aspects of attentional dysfunction in DLB may, in part, depend upon both distributed motor and non-motor networks.
PMCID: PMC3819183  PMID: 24148774
attention; Alzheimer’s disease; single photon emission computed tomography; SPECT; imaging
5.  Cholinesterase inhibitor use does not significantly influence the ability of 123I‐FP‐CIT imaging to distinguish Alzheimer's disease from dementia with Lewy bodies 
123I‐labelled 2β‐carbomethoxy‐3β‐(4‐iodophenyl)‐N‐(3‐fluoropropyl) nortropane (123I‐FP‐CIT) imaging is a diagnostic tool to help differentiate dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). However, in animals, cholinesterase inhibitors (ChEi) have been reported to reduce radioligand binding to the striatal dopamine transporter. As ChEi are frequently used in people with dementia, it is important to determine whether their use affects 123I‐FP‐CIT uptake in the striatum.
To clarify whether chronic ChEi therapy modulates striatal dopamine transporter binding measured by 123I‐FP‐CIT in patients with AD, DLB and Parkinson's disease with dementia (PDD).
Cross sectional study in 99 patients with AD (nine on ChEi, 25 not on ChEi), DLB (nine on ChEi, 19 not on ChEi) and PDD (six on ChEi, 31 not on ChEi) comparing 123I‐FP‐CIT striatal binding (caudate, anterior and posterior putamen) in patients receiving compared with those not receiving ChEi, correcting for key clinical variables including diagnosis, age, sex, Mini‐Mental State Examination score, severity of parkinsonism and concurrent antidepressant use.
As previously described, 123I‐FP‐CIT striatal uptake was lower in DLB and PDD subjects compared with those with AD. Median duration of ChEi use was 180 days. 123I‐FP‐CIT uptake was not significantly reduced in subjects receiving ChEi compared those not receiving ChEi (mean percentage reduction: AD 4.3%; DLB 0.7%; PDD 6.1%; p = 0.40). ChEi use did not differentially affect striatal 123FP‐CIT uptake between patient groups (p = 0.83).
Use of ChEi does not significantly influence the ability of 123I‐FP‐CIT imaging to distinguish AD from DLB.
PMCID: PMC2117542  PMID: 17299017
6.  Diagnosing Mild Cognitive Impairment (MCI) in clinical trials: a systematic review 
BMJ Open  2013;3(2):e001909.
To describe how criteria for amnestic Mild Cognitive Impairment (aMCI) have been operationalised in randomised controlled clinical trials (RCTs).
Systematic review.
Information sources
EMBASE, PubMed and PSYCHInfo were searched from their inception to February 2012. Electronic clinical trial registries were also searched (February 2012).
Study selection
RCTs were included where participant selection was made using Petersen et al-defined aMCI. There was no restriction on intervention type or the outcome tested.
Data extraction
For each trial, we extracted information on study design, demographics, exclusion criteria and the operationalisation strategy for the five aMCI diagnostic criteria including: (1) memory complaint, (2) normal general cognitive function, (3) memory impairment, (4) no functional impairment and (5) no dementia.
223 articles and 278 registered trials were reviewed, of which 22 met inclusion criteria. Various methods were applied for operationalising aMCI criteria resulting in variability in participant selection. Memory complaint and assessment of general cognitive function were the most consistently measured criteria. There was large heterogeneity in the neuropsychological methods used to determine memory impairment. It was not possible to assess the impact of these differences on case selection accuracy for dementia prediction. Further limitations include selective and unclear reporting of how each of the criteria was measured.
The results highlight the urgent need for a standardised approach to map aMCI. Lack of uniformity in clinical diagnosis, however, is not exclusively a problem for MCI but also for other clinical states such as dementia including Alzheimer's disease, Lewy Body, frontotemporal or vascular dementia. Defining a uniform approach to MCI classification, or indeed for any classification concept within the field of dementia, should be a priority if further trials are to be undertaken in the older aged population based on these concepts.
PMCID: PMC3586181  PMID: 23386579
Mental Health; Neurology
7.  Supporting clinical research in the NHS in England: the National Institute for Health Research Dementias and Neurodegenerative Diseases Research Network 
Clinical research is best done when aligned with clinical care - that is, when the patient can be identified, recruited and, in many instances, researched in parallel with the delivery of clinical service. However, to achieve this effectively requires identification of the additional cost to the National Health Service clinical support services and the development of an appropriately skilled workforce. The National Institute for Health Research (NIHR) Cancer Research Network demonstrated the value of dedicated research support in terms of the number of patients recruited into clinical trials. Building on this model, the NIHR in England funded the Dementias and Neurodegenerative Diseases Research Network (DeNDRoN). DeNDRoN is now in its sixth year and has established a geographically widespread network of research support staff and research leadership managed by a central coordinating centre. Success can already be measured by a significant increase in the number of patients entering studies and the speed with which both commercial and noncommercial studies are completed. There are also early indications that the network will result in improved patient outcomes.
PMCID: PMC3506937  PMID: 22769969
8.  Visual cortex in dementia with Lewy bodies: magnetic resonance imaging study 
The British Journal of Psychiatry  2012;200(6):491-498.
Visual hallucinations and visuoperceptual deficits are common in dementia with Lewy bodies, suggesting that cortical visual function may be abnormal.
To investigate: (1) cortical visual function using functional magnetic resonance imaging (fMRI); and (2) the nature and severity of perfusion deficits in visual areas using arterial spin labelling (ASL)-MRI.
In total, 17 participants with dementia with Lewy bodies (DLB group) and 19 similarly aged controls were presented with simple visual stimuli (checkerboard, moving dots, and objects) during fMRI and subsequently underwent ASL-MRI (DLB group n = 15, control group n = 19).
Functional activations were evident in visual areas in both the DLB and control groups in response to checkerboard and objects stimuli but reduced visual area V5/MT (middle temporal) activation occurred in the DLB group in response to motion stimuli. Posterior cortical perfusion deficits occurred in the DLB group, particularly in higher visual areas.
Higher visual areas, particularly occipito-parietal, appear abnormal in dementia with Lewy bodies, while there is a preservation of function in lower visual areas (V1 and V2/3).
PMCID: PMC3365275  PMID: 22500014
9.  Visual hallucinations in dementia with Lewy bodies: transcranial magnetic stimulation study 
The British Journal of Psychiatry  2011;199(6):492-500.
The aetiology of visual hallucinations is poorly understood in dementia with Lewy bodies. Pathological alterations in visual cortical excitability may be one contributory mechanism.
To determine visual cortical excitability in people with dementia with Lewy bodies compared with aged-matched controls and also the relationship between visual cortical excitability and visual hallucinations in dementia with Lewy bodies.
Visual cortical excitability was determined by using transcranial magnetic stimulation (TMS) applied to the occiput to elicit phosphenes (transient subjective visual responses) in 21 patients with dementia with Lewy bodies and 19 age-matched controls.
Phosphene parameters were similar between both groups. However, in the patients with dementia with Lewy bodies, TMS measures of visual cortical excitability correlated strongly with the severity of visual hallucinations (P = 0.005). Six patients with dementia with Lewy bodies experienced visual hallucination-like phosphenes (for example, seeing people or figures on stimulation) compared with none of the controls (P = 0.02).
Increased visual cortical excitability in dementia with Lewy bodies does not appear to explain visual hallucinations but it may be a marker for their severity.
PMCID: PMC3227808  PMID: 22016436
10.  Multifactorial intervention after a fall in older people with cognitive impairment and dementia presenting to the accident and emergency department: randomised controlled trial 
BMJ : British Medical Journal  2003;326(7380):73.
To determine the effectiveness of multifactorial intervention after a fall in older patients with cognitive impairment and dementia attending the accident and emergency department.
Randomised controlled trial.
274 cognitively impaired older people (aged 65 or over) presenting to the accident and emergency department after a fall: 130 were randomised to assessment and intervention and 144 were randomised to assessment followed by conventional care (control group).
Two accident and emergency departments, Newcastle upon Tyne.
Main outcome measures
Primary outcome was number of participants who fell in year after intervention. Secondary outcomes were number of falls (corrected for diary returns), time to first fall, injury rates, fall related attendances at accident and emergency department, fall related hospital admissions, and mortality.
Intention to treat analysis showed no significant difference between intervention and control groups in proportion of patients who fell during 1 year's follow up (74% (96/130) and 80% (115/144), relative risk ratio 0.92, 95% confidence interval 0.81 to 1.05). No significant differences were found between groups for secondary outcome measures.
Multifactorial intervention was not effective in preventing falls in older people with cognitive impairment and dementia presenting to the accident and emergency department after a fall.
What is already known on this topicMultifactorial intervention prevents falls in cognitively normal older people living in the community and in those who present to the accident and emergency department after a fallFall prevention strategies have not been tested by controlled trials in patients with cognitive impairment and dementia who fallWhat this study addsNo benefit was shown from multifactorial assessment and intervention after a fall in patients with cognitive impairment and dementia presenting to the accident and emergency departmentThe intervention was less effective in these patients than in cognitively normal older people
PMCID: PMC139930  PMID: 12521968
11.  Glucocerebrosidase Mutations alter the endoplasmic reticulum and lysosomes in Lewy body disease 
Journal of Neurochemistry  2012;123(2):298-309.
Lewy body disease (LBD) development is enhanced by mutations in the GBA gene coding for glucocerebrosidase (GCase). The mechanism of this association is thought to involve an abnormal lysosomal system and we therefore sought to evaluate if lysosomal changes contribute to the pathogenesis of idiopathic LBD. Analysis of post-mortem frontal cortex tissue from 7 GBA mutation carriers with LBD, 5 GBA mutation carriers with no signs of neurological disease and human neural stem cells exposed to a GCase inhibitor was used to determine how GBA mutation contributes to LBD. GBA mutation carriers demonstrated a significantly reduced level of GCase protein and enzyme activity and retention of glucocerebrosidase isoforms within the endoplasmic reticulum (ER). This was associated with enhanced expression of the lysosomal markers LAMP1 and LAMP2, though the expression of ATP13A2 and Cathepsin D was reduced, along with the decreased activity of Cathepsin D. The ER unfolded protein response (UPR) regulator BiP/GRP78 was reduced by GBA mutation and this was a general phenomenon in LBD. Despite elevation of GRP94 in LBD, individuals with GBA mutations showed reduced GRP94 expression, suggesting an inadequate UPR. Finally, human neural stem cell cultures showed that inhibition of GCase causes acute reduction of BiP, indicating that the UPR is affected by reduced glucocerebrosidase activity. The results indicate that mutation in GBA leads to additional lysosomal abnormalities, enhanced by an impaired UPR, potentially causing α-synuclein accumulation.
PMCID: PMC3494984  PMID: 22803570
dementia with Lewy bodies; endoplasmic reticulum; glucocerebrosidase; Lewy body disease; lysosome; Parkinson’s disease

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