Distinguish Dementia With Lewy Bodies Research Articles

Optimizing cCOG, a Web-based tool, to detect dementia with Lewy Bodies.

Distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) is challenging due to overlapping presentations. We adapted a Web-based test tool, cCOG, by adding a visuospatial task and a brief clinical survey and assessed its ability to differentiate between DLB and AD. We included 110 patients (n = 30 DLB, n = 32 AD dementia, and n = 48 controls with subjective cognitive decline (SCD)). Full cCOG comprises six cognitive subtasks and a survey addressing self-reported DLB core and autonomic features. First, we compared cCOG cognitive tasks to traditional neuropsychological tasks for all diagnostic groups and clinical questions to validated assessments of clinical features in DLB only. Then, we studied the performance of cCOG cognitive tasks and clinical questions, separately and combined, in differentiating diagnostic groups. cCOG cognitive tasks and clinical survey had moderate to strong correlations to standard neuropsychological testing (.61≤ r s ≤ .77) and to validated assessments of clinical features (.41≤ r s ≤ .65), except for fluctuations and REM-sleep behavior disorder (RBD) (r s = .32 and r s = .10). Full cCOG, including both cognitive tasks and brief survey had a diagnostic accuracy (acc) of 0.82 [95% CI 0.73-0.89], with good discrimination of DLB versus AD (acc 0.87 [0.76-0.95]) and DLB versus controls (acc 0.94 [0.86-0.98]). We illustrated that cCOG aids in distinguishing DLB and AD patients by using remote assessment of cognition and clinical features. Our findings pave the way to a funneled, harmonized diagnostic process among memory clinics and, eventually, a more timely and accurate diagnosis of DLB and AD.

Perception of fragmented letters differentiates pathologically confirmed dementia with Lewy bodies from Alzheimer’s disease

AbstractBackgroundThere is evidence that disproportionate impairment of visuoperceptual abilities can help distinguish Dementia with Lewy Bodies (DLB) from Alzheimer’s Disease (AD), but the reliability of this effect has not been established in patients with autopsy confirmed disease, and the impact of co‐occurring Lewy body and Alzheimer pathology has not been examined.MethodA relatively pure test of visuoperceptual ability, the Fragmented Letters Task of the Visual Object and Space Perception (VSOP) battery was administered to 19 patients with pathologically confirmed DLB (17 Neocortical, 2 Limbic) with various levels of concomitant AD and 23 patients with pathologically confirmed AD only. Groups were matched for a mild level of dementia (MMSE >15, AD mean=24.7+3.6 and DLB mean=25.7+3.4) and were compared to 45 healthy elderly controls. In the Fragmented Letters Task individuals must identify 20 letters that are visually degraded by 70%. Performances on more complex visuospatial (Block Design) and memory (California Verbal Learning Test; CVLT) tests were also compared.ResultDLB patients performed worse than AD patients (B=‐2.29±0.64, p = 6x10‐4) and controls (B=‐2.73±0.62, p=3.8x10‐5) on the Fragmented Letters Task even after adjustment for demographics, MMSE, and ability to identify intact letters. AD patients did not differ from controls (B=‐0.53±0.62, p=0.34). Results were similar when DLB with (n=8, B=‐2.31±0.81, p = 0.006) or without (n=11, B=‐2.15±0.77, p = 0.006) concomitant AD pathology (Braak stage < 4 vs. 5‐6) were separately compared to pure AD. ROC analyses to distinguish DLB from AD showed that the Fragmented Letter Test (AUC 0.86) outperformed Block Design (AUC 0.71) and CVLT Immediate Recall (AUC 0.48).ConclusionIn contrast to complex visuospatial and memory tasks, a relatively pure test of visuoperceptual ability, the Fragmented Letters Task, was uniquely impaired in DLB (vis a vis AD) and effective at distinguishing DLB from AD. Because impairment was not associated with concomitant AD pathology in DLB patients, and patients with AD were unimpaired, the deficit appears to be driven primarily by Lewy body pathology. Results suggest the quick and easily administered Fragmented Letters Task has excellent clinical utility for differentiating DLB from AD in mild to moderate stages of dementia.

Efficacy of Olfactory and Pareidolia Tests Compared With That of Indicative Biomarkers in Diagnosis of Dementia With Lewy Bodies.

Purpose: Although olfactory decline and visual hallucinations are useful in distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) in a clinical setting, neither is easy to evaluate objectively. The pareidolia test is used to assess susceptibility to visual hallucinations, while in Japan, the Odor Stick Identification Test for the Japanese (OSIT-J) is used to objectively quantify olfactory decline. The present study investigated the efficacy of these olfactory and pareidolia tests in differentiating AD from DLB. Their usefulness was then compared with that of the indicative biomarkers in neuroimaging for a clinical diagnosis of DLB listed in the Fourth Consensus Report of the Dementia with Lewy Bodies Consortium.Methods: A total of 24 probable DLB and 22 probable AD patients were enrolled. All underwent 4 diagnostic procedures: uptake of dopamine transporter in single photon emission computed tomography (DaT-SPECT) and meta-iodobenzylguanidine (MIBG) in myocardial scintigraphy, the pareidolia test, and OSIT-J. The sensitivity, specificity, and accuracy of these methods in differentiating DLB from AD were compared.Results: Sensitivity and specificity in differentiating DLB from AD were 86 and 100% by the heart-to-mediastinum ratio of MIBG uptake; 82 and 96% by the specific binding ratio on DaT-SPECT; 77 and 67% by the combination of OSIT-J and pareidolia test scores; 73 and 62% by the pareidolia test scores; and 77 and 58% by the OSIT-J scores, respectively.Conclusions: The present results suggest that the pareidolia and OSIT-J tests may be considered before resorting to nuclear neuroimaging in the diagnosis of DLB.

Neuropathological Changes in Dementia With Lewy Bodies and the Cingulate Island Sign.

The cingulate island sign (CIS) refers to the relative sparing of metabolism in the posterior cingulate cortex (PCC) and represents an important biomarker in distinguishing dementia with Lewy bodies (DLB) from Alzheimer disease (AD). The underlying basis of the CIS is unknown; therefore, our aim was to investigate which neurodegenerative changes underpin the formation of CIS. Using quantitative neuropathology, α-synuclein, phosphorylated Tau, and amyloid-β pathology was assessed in 12 DLB, 9 AD and 6 age-matched control patients in the anterior cingulate (ACC), midcingulate, PCC, precuneus/cuneus and parahippocampal gyrus. All participants had undergone 99mTc-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography imaging during life to define the presence or absence of CIS. In the DLB group, no significant correlations were observed between CIS ratios and neurodegenerative pathology in PCC. In DLB, however, the ACC showed lower HMPAO uptake, as well as significantly higher α-synuclein and amyloid-β burden compared with PCC, possibly underlying the relative preservation of perfusion in PCC when compared with ACC. Our findings suggest that neurodegenerative pathology does not directly correlate with the CIS in DLB, and other metabolic or pathological changes are therefore more likely to be relevant for the development of the CIS.

A proteomic signature for dementia with Lewy bodies

IntroductionWe sought to determine if a proteomic profile approach developed to detect Alzheimer's disease would distinguish patients with Lewy body disease from normal controls, and if it would distinguish dementia with Lewy bodies (DLB) from Parkinson's disease (PD). MethodsStored plasma samples were obtained from 145 patients (DLB n = 57, PD without dementia n = 32, normal controls n = 56) enrolled from patients seen in the Behavioral Neurology or Movement Disorders clinics at the Mayo Clinic, Florida. Proteomic assays were conducted and analyzed as per our previously published protocols. ResultsIn the first step, the proteomic profile distinguished the DLB-PD group from controls with a diagnostic accuracy of 0.97, sensitivity of 0.91, and specificity of 0.86. In the second step, the proteomic profile distinguished the DLB from PD groups with a diagnostic accuracy of 0.92, sensitivity of 0.94, and specificity of 0.88. DiscussionThese data provide evidence of the potential utility of a multitiered blood-based proteomic screening method for detecting DLB and distinguishing DLB from PD.

Cerebrospinal fluid from Dementia with Lewy body patients suppresses neuronal network activity

Cerebrospinal fluid from Dementia with Lewy body patients suppresses neuronal network activity

Specific Verbal Memory Measures May Distinguish Alzheimer's Disease from Dementia with Lewy Bodies.

Standard measures of commonly used memory tests may not be appropriate to distinguish different neurodegenerative diseases affecting memory. To study whether specific measures of verbal memory obtained with the Rey Auditory Verbal Learning test (RAVLT) could help distinguish dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). Twenty-nine DLB and 32 AD patients participated in the study and were followed longitudinally for 3 years until the diagnosis was confirmed according to standard clinical criteria. Twenty-eight healthy elderly subjects served as controls. The following verbal memory measures were evaluated: verbal learning (VL), verbal forgetting (VF), percentage of verbal forgetting (VF%), and serial position effects of the immediate recall performance. DLB and AD groups have comparable performances at the RAVLT immediate and delayed recall tasks. However, VL was higher in DLB than AD while VF% was greater in AD. With a VF% cut-off ≥75%, AD and DLB patients were differently distributed, with 58% of AD versus 21% of DLB above this cut-off. The recency effect was significant higher in AD than DLB. DLB patients had a better performance in VL than AD, but worse VF and recency effect. These specific measures of verbal memory could be used as cognitive markers in the differential diagnosis between these two conditions.

Diagnosis of dementia with Lewy bodies: can 123I-IMP and 123I-MIBG scintigraphy yield new core features?

Since the clinical symptoms of different types of dementia frequently overlap, especially in the earlier stages at onset, it is difficult to distinguish dementia with Lewy bodies (DLB) from other neurodegenerative dementias based on their clinical manifestations alone. Nuclear medicine imaging has been reported as a high-value index for the objective evaluation and diagnosis of DLB. The aim of this study was to evaluate whether nuclear medicine imaging findings may yield core features to be added to the diagnosis of DLB. We enrolled 332 patients with suspected DLB. All were evaluated by both 123I-metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy and 123I-labelled N-isopropyl-p-iodoamphetamine (123I-IMP). brain perfusion single-photon emission CT. The final clinical diagnosis indicated probable DLB in 92 patients (40 males, 52 females; mean age ± standard deviation, 77.4 ± 6.4 years; range, 56-89 years); 240 patients (98 males, 142 females; mean age, 75.5 ± 9.0 years; range, 70-87 years) were recorded as being without DLB. The accepted core features used for clinical evaluations were fluctuating cognition, visual hallucinations and Parkinsonism. The nuclear medicine evaluation indices were the severity score of cerebral blood flow on 123I-IMP scintigraphs of the posterior cingulate and praecuneus and a reduction in the blood flow in the occipital lobe. For 123I-MIBG evaluation, we recorded the early and delayed heart-to-mediastinum (H/M) ratios and the washout rate. Univariate and multivariate analyses of fluctuating cognition, visual hallucinations, Parkinsonism and early H/M ratio in patients with probable and without DLB revealed significant differences. Parameters based on 123I-IMP studies did not show any significant differences by multivariate analysis. The area under the curve for the early H/M ratio was 0.918; for fluctuating cognition, visual hallucinations and Parkinsonism, it was 0.693, 0.760 and 0.611, respectively, by receiver-operating characteristic analysis. The early H/M ratio of <2.0 on 123I-MIBG scintigraphs was of the highest diagnostic accuracy. The sensitivity, specificity and accuracy for the diagnosis of probable DLB were 82.4%, 96.3% and 92.5%, respectively. The early H/M ratio obtained by 123I-MIBG myocardial scintigraphy can serve as a reliable diagnostic index for the core clinical features of DLB. It can be used for the early diagnosis and treatment of DLB. Advances in knowledge: 123I-MIBG myocardial scintigraphy performed at the initial clinical examination can facilitate the early identification or exclusion of DLB and the early H/M ratio may be a diagnostic biomarker for DLB.

Clinical and Cognitive Phenotype of Mild Cognitive Impairment Evolving to Dementia with Lewy Bodies

Objective: The aim of this study was to determine which characteristics could better distinguish dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) at the mild cognitive impairment (MCI) stage, with particular emphasis on visual space and object perception abilities. Methods: Fifty-three patients with mild cognitive deficits that were eventually diagnosed with probable DLB (MCI-DLB: n = 25) and AD (MCI-AD: n = 28) at a 3-year follow-up were retrospectively studied. At the first visit, the patients underwent cognitive assessment including the Qualitative Scoring Mini Mental State Examination Pentagon Test and the Visual Object and Space Perception Battery. The Neuropsychiatric Inventory Questionnaire, Unified Parkinson's Disease Rating Scale (UPDRS) and questionnaires for cognitive fluctuations and sleep disorders were also administered. Results: The best clinical predictor of DLB was the presence of soft extrapyramidal signs (mean UPDRS score: 4.04 ± 5.9) detected in 72% of patients, followed by REM sleep behavior disorder (60%) and fluctuations (60%). Wrong performances in the pentagon's number of angles were obtained in 44% of DLB and 3.7% of AD patients and correlated with speed of visual attention. Executive functions, visual attention and visuospatial abilities were worse in DLB, while verbal episodic memory impairment was greater in AD. Deficits in the visual-perceptual domain were present in both MCI-DLB and AD. Conclusions: Poor performance in the pentagon's number of angles is specific of DLB and correlates with speed of visual attention. The dorsal visual stream seems specifically more impaired in MCI-DLB with respect to the ventral visual stream, the latter being involved in both DLB and AD. These cognitive features, associated with subtle extrapyramidal signs, should alert clinicians to a diagnostic hypothesis of DLB.

Addition of MHPG to Alzheimer's disease biomarkers improves differentiation of dementia with Lewy bodies from Alzheimer's disease but not other dementias

BackgroundOverlapping clinical features make it difficult to distinguish dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) and other dementia types. In this study we aimed to determine whether the combination of cerebrospinal fluid (CSF) biomarkers, amyloid-β42 (Aβ42), total tau protein (t-tau), and phosphorylated tau protein (p-tau), in combination with 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), could be useful in discriminating DLB from vascular dementia (VaD) and frontotemporal dementia (FTD), as we previously demonstrated for differentiation of DLB from AD. MethodsWe retrospectively analyzed concentrations of MHPG, Aβ42, t-tau, and p-tau in CSF in patients with DLB, AD, VaD, and FTD. Using previously developed multivariate logistic regression models we assessed the diagnostic value of these CSF parameters. ResultsThe currently used combination of Aβ42, t-tau, and p-tau yielded a sensitivity of 61.9% and a specificity of 91.7% for the discrimination between DLB and AD, but could not discriminate between DLB and VaD or FTD. The addition of MHPG to Aβ42, t-tau, and p-tau improves the discrimination of DLB from AD, yielding a sensitivity of 65.1% and specificity of 100%, but could not distinguish DLB from other forms of dementia. ConclusionsOur results confirm in a separate patient cohort that addition of MHPG to Aβ42, t-tau, and p-tau improves the discrimination of DLB from AD but not the differentiation of DLB from VaD or FTD.

Multivariate Spatial Covariance Analysis of 99MTc-Exametazime SPECT Images in Dementia with Lewy Bodies and Alzheimer'S Disease: Utility in Differential Diagnosis

We examined (99m)Tc-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 (F(1,64)=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 (F(1,61)=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.

Dementia With Lewy Bodies

The purpose of this review is to aid primary care providers in distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease and from Parkinson's disease with dementia. Differentiating these entities has important treatment implications. A PubMed search was undertaken using the keywords Lewy body dementia, dementia with Lewy bodies, and Lewy body disease. There were no date restrictions. Only articles in the English language were reviewed. References of selected articles were reviewed for additional sources. Initially, 2,967 articles were retrieved. All 3 authors participated in data selection and extraction. Articles were further selected for content specific to epidemiology, clinical presentation, diagnostic studies, treatment, and prognosis. For articles with repetitive information, the most current article was used. This resulted in a total of 62 articles included in the review. Dementia with Lewy bodies is the second leading cause of dementia after Alzheimer's disease. The core symptoms of DLB, including cognitive fluctuations, visual hallucinations, and parkinsonism, may not always be present as a triad, and clinicians may be unaware of associated symptoms. Thus, this diagnosis is frequently missed by primary care providers. Often, DLB is misdiagnosed as Alzheimer's disease, Parkinson's disease, or a primary psychiatric illness. Treatments for DLB include cholinesterase inhibitors and N-methyl-D-aspartate antagonists. Antipsychotics should be avoided or used with caution. Dementia with Lewy bodies is an often missed diagnosis. Symptoms are often attributed to other disorders. A high clinical suspicion is helpful in accurate diagnosis, and presence of any of the core symptoms should initiate clinical suspicion of DLB. Distinguishing DLB from other disorders has important treatment implications.

In Vivo Assessment of Vesicular Monoamine Transporter Type 2 in Dementia With Lewy Bodies and Alzheimer Disease

To assess the diagnostic potential of imaging striatal monoaminergic terminal integrity with the vesicular monoamine transporter type 2 (VMAT2) radioligand (18)F 9-fluropropyl-(+)-dihydrotetrabenazine ([(18)F]AV-133) and positron emission tomography to distinguish dementia with Lewy bodies (DLB) from Alzheimer disease (AD). Nine patients with DLB, 10 patients with AD, 20 patients with Parkinson disease (PD), and 10 healthy age-matched control subjects underwent [(18)F]AV-133 positron emission tomography studies. VMAT2 density was calculated through normalized tissue uptake value ratios at 120 to 140 minutes postinjection using the primary visual cortex as the reference region. Comparison of the tissue ratio for [(18)F]AV-133 between the different clinical diagnostic groups. Lower VMAT2 densities were observed in patients with DLB when compared with patients with AD especially in the posterior putamen (caudate: mean [SD], 1.24 [0.6] vs 2.83 [0.9]; P < .001; effect size = 2.1; anterior putamen: mean [SD], 0.90 [0.5] vs 3.01 [0.9]; P < .001; effect size = 2.9; posterior putamen: mean [SD], 0.62 [0.5] vs 2.87 [0.8]; P < .001; effect size = 3.4). Compared with healthy controls, [(18)F]AV-133 tissue ratios were significantly lower by 88% and 74% in the posterior putamen, 74% and 65% in the anterior putamen, and 53% and 51% in the caudate nucleus of patients with PD and DLB, respectively. In contrast to patients with PD and DLB, no reductions were observed in patients with AD. [(18)F]AV-133 allows assessment of nigrostriatal degeneration in Lewy body diseases. [(18)F]AV-133 can robustly detect reductions of dopaminergic nigrostriatal afferents in patients with DLB and assist in the differential diagnosis from AD.

Personality traits distinguishing dementia with Lewy bodies from Alzheimer disease

To identify personality traits that distinguish dementia with Lewy bodies (DLB) from Alzheimer disease (AD). We examined 290 participants enrolled in a longitudinal study (nondemented control = 34, DLB = 128, AD = 128) followed to autopsy. As part of the annual interview with the collateral source, the clinician asked about specific changes in personality, interests, and drives based on items from the Blessed Dementia Scale (BDS). Statistical analysis was performed using chi(2) and Fisher exact tests. Factor analysis was performed to determine underlying structure and receiver operating characteristic curves assessed the ability for each of three derived factors to discriminate DLB from AD. The sample was evaluated for a mean of 4.8 visits (range 1 to 14) with a mean age of 77.6 +/- 9.9 years. The participants' cognitive status ranged from nondemented (Clinical Dementia Rating [CDR] 0) through all stages of dementia (CDR > or = 0.5). Personality traits that distinguished DLB included diminished emotional responsiveness (p = 0.004), relinquishing hobbies (p = 0.01), growing apathy (p = 0.03), and purposeless hyperactivity (p = 0.003). Factor analyses of the BDS revealed a PASSIVE factor (diminished emotional responsiveness, relinquished hobbies, growing apathy, and purposeless hyperactivity) explaining 10.4% of variance and that DLB was more likely to manifest these personality traits than AD (p = 0.001). The PASSIVE factor discriminated DLB from AD (area under the curve = 0.61, 95% CI: 0.54 to 0.68, p = 0.006). Any change in personality is associated with the presence of visual hallucinations. Our results suggest that incorporating a brief, simple inventory of personality traits may improve the identification of individuals with dementia with Lewy bodies.

Diagnostic markers for diagnosing dementia with Lewy bodies: CSF and MIBG cardiac scintigraphy study

Objective This study examined the diagnostic value of cerebrospinal fluid (CSF) markers and iodine-123 metaiodobenzylguanidine ( 123I-MIBG) cardiac scintigraphy in distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). Methods CSF levels of amyloid β1-42 (Aβ42) and 181-Thr phosphorylated tau (p-tau) were measured using enzyme linked immunosorbent assay (ELISA) kits. 123I-MIBG cardiac scintigraphy was performed in patients with AD and DLB, and control (CTL) subjects. Results Increased CSF levels of p-tau in AD were found compared to DLB patients and CTL subjects ( P < 0.01), but there was no significant difference in CSF levels of Aβ42 between AD and DLB patients. The early and delayed heart to mediastinum (H/M) ratios of 123I-MIBG cardiac scintigraphy were significantly decreased in patients with DLB compared to AD patients and CTL subjects ( P < 0.01). The receiver operating characteristic (ROC) analysis revealed that the diagnostic value of 123I-MIBG cardiac scintigraphy was superior to that of CSF markers. Conclusions 123I-MIBG cardiac scintigraphy may be useful for discriminating between DLB and AD.

DLB fluctuations

To determine whether certain aspects of fluctuations reliably distinguish dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) and normal aging. Participants included 200 community-dwelling cognitively normal elderly persons, 70 DLB patients, and 70 AD patients with collateral informants. A 19-item questionnaire was administered to the informants that queried about symptoms of fluctuations and delirium. Fluctuations occur infrequently in nondemented elderly persons aged 58 to 98 years. In contrast, four characteristics of fluctuations were found to significantly differentiate AD from DLB. These composite features include daytime drowsiness and lethargy, daytime sleep of 2 or more hours, staring into space for long periods, and episodes of disorganized speech. The presence of three or four features of this composite occurred in 63% of DLB patients compared with 12% of AD patients and 0.5% of normal elderly persons. Informant endorsement of three or four of these items yielded a positive predictive value of 83% for the clinical diagnosis of DLB against an alternate diagnosis of AD. Endorsement of fewer than three items had a negative predictive value of 70% for the absence of a clinical diagnosis of DLB in favor of AD. The authors present evidence of test-retest reliability, convergent validity, and empirical verification with a separate cross-validation sample. Fluctuations were not associated with any particular combination of hallucinations, parkinsonism, or REM sleep behavior disorder. Based on informant report, disturbed arousal and disorganized speech are specific aspects of fluctuations in dementia with Lewy bodies that reliably distinguish dementia with Lewy bodies from Alzheimer's disease and normal aging.

Alzheimer's disease versus dementia with Lewy bodies: cerebral metabolic distinction with autopsy confirmation.

Seeking antemortem markers to distinguish Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), we examined brain glucose metabolism of DLB and AD. Eleven DLB patients (7 Lewy body variant of AD [LBVAD] and 4 pure diffuse Lewy body disease [DLBD]) who had antemortem position emission tomography imaging and autopsy confirmation were compared to 10 autopsy-confirmed pure AD patients. In addition, 53 patients with clinically-diagnosed probable AD, 13 of whom later fulfilled clinical diagnoses of DLB, were examined. Autopsy-confirmed AD and DLB patients showed significant metabolic reductions involving parietotemporal association, posterior cingulate, and frontal association cortices. Only DLB patients showed significant metabolic reductions in the occipital cortex, particularly in the primary visual cortex (LBVAD -23% and DLBD -29% vs AD -8%), which distinguished DLB versus AD with 90% sensitivity and 80% specificity. Multivariate analysis revealed that occipital metabolic changes in DLB were independent from those in the adjacent parietotemporal cortices. Analysis of clinically diagnosed probable AD patients showed a significantly higher frequency of primary visual metabolic reduction among patients who fulfilled later dinical criteria for DLB. In these patients, occipital hypometabolism preceded some clinical features of DLB. Occipital hypometabolism is a potential antemortem marker to distinguish DLB versus AD.