Hippocampal and insula volume in mild cognitive impairment with Lewy bodies

IntroductionDiagnostic criteria for prodromal dementia with Lewy bodies have recently been published. These include the use of imaging biomarkers to distinguish mild cognitive impairment with Lewy bodies (MCI-LB) from MCI due to other causes. Two potential biomarkers listed, though not formally included in the diagnostic criteria, due to insufficient evidence, are relatively preserved hippocampi, and atrophy of the insula cortex on structural brain imaging.MethodsIn this report, we sought to investigate these imaging biomarkers in 105 research subjects, including well characterised groups of patients with MCI-LB (n = 38), MCI with no core features of Lewy body disease (MCI-AD; n = 36) and healthy controls (N = 31). Hippocampal and insula volumes were determined from T1 weighted structural MRI scans, using grey matter segmentation performed with SPM software.ResultsAdjusting for age, sex and intracranial volume, there were no differences in hippocampal or insula volume between MCI-AD and MCI-LB, although in both conditions volumes were significantly reduced relative to controls.ConclusionOur results do not support the use of either hippocampal or insula volume to identify prodromal dementia with Lewy bodies.     

Visuoperceptual impairment in dementia with Lewy bodies

BACKGROUND: In dementia with Lewy bodies (DLB), vision-related cognitive and behavioral symptoms are common, and involvement of the occipital visual cortices has been demonstrated in functional neuroimaging studies. OBJECTIVES: To delineate visuoperceptual disturbance in patients with DLB in comparison with that in patients with Alzheimer disease and to explore the relationship between visuoperceptual disturbance and the vision-related cognitive and behavioral symptoms. DESIGN: Case-control study. SETTING: Research-oriented hospital. PATIENTS: Twenty-four patients with probable DLB (based on criteria of the Consortium on DLB International Workshop) and 48 patients with probable Alzheimer disease (based on criteria of the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association) who were matched to those with DLB 2:1 by age, sex, education, and Mini-Mental State Examination score. MAIN OUTCOME MEASURES: Four test items to examine visuoperceptual functions, including the object size discrimination, form discrimination, overlapping figure identification, and visual counting tasks. RESULTS: Compared with patients with probable Alzheimer disease, patients with probable DLB scored significantly lower on all the visuoperceptive tasks (P<.04 to P<.001). In the DLB group, patients with visual hallucinations (n = 18) scored significantly lower on the overlapping figure identification (P = .01) than those without them (n = 6), and patients with television misidentifications (n = 5) scored significantly lower on the size discrimination (P<.001), form discrimination (P = .01), and visual counting (P = .007) than those without them (n = 19). CONCLUSIONS: Visual perception is defective in probable DLB. The defective visual perception plays a role in development of visual hallucinations, delusional misidentifications, visual agnosias, and visuoconstructive disability charcteristic of DLB.     

Predictors of progression in patients with AD and Lewy bodies

OBJECTIVE: To examine the differences in the pattern of progression between AD and AD with Lewy bodies (AD+LB). METHODS: The authors examined predictors of functional and cognitive disability, institutionalization, and death, as well as time to the development of psychosis (e.g., delusions, hallucinations), extrapyramidal signs (EPS), diurnal hypersomnia, and depression in 185 patients with definite AD and 60 with autopsy-confirmed AD+LB. In addition, they analyzed a selected group of patients who did not have comorbid systemic or CNS disease that may have affected progression of the disease (AD = 98 versus AD+LB = 44). The mean follow-up was 58.91 +/- 35.2 months. RESULTS: All cases: Patients with AD+LB had faster time to the development of EPS and diurnal hypersomnia, but not to the development of psychosis or depression. The rate of cognitive and functional decline, time to institutionalization, and physical survival was not different between AD+LB and AD. Selected cases: Patients with AD+LB developed earlier EPS and diurnal hypersomnia than AD patients, and there was a trend to develop earlier major depression, but no differences were noted in time to psychosis. Patients with AD+LB had a faster time to institutionalization than those with AD. The rate of cognitive and functional decline and physical survival was not different between AD+LB and AD in these selected cases. CONCLUSION: Patients with AD+LB can develop EPS and diurnal hypersomnia earlier and have faster time to institutionalization than those with AD alone, but cognitive and functional decline and physical survival are similar between these two entities.     

Validity of clinical criteria for the diagnosis of dementia with Lewy bodies

OBJECTIVE: To assess the clinical validity of clinical diagnostic criteria for dementia with Lewy bodies (DLB). METHODS: We assessed the sensitivity, specificity, and positive and negative predictive values of the clinical criteria of the Consortium on dementia with Lewy Bodies (CDLB) in 18 patients with autopsy-proven DLB and in 76 patients with dementia not associated with Lewy bodies, using postmortem diagnosis as a gold standard. RESULTS: CDLB criteria had either high sensitivity or high specificity, but no set of criteria simultaneously provided both high sensitivity and high specificity. Clinical criteria had higher predictive validity in patients with pure DLB than in patients with DLB and AD. Seventy-eight percent of patients with pure DLB had two or more major criteria, compared with 44% of patients with DLB and AD (p<0.02). If the nine patients with DLB and AD were excluded from the DLB group, the CDLB criteria for probable DLB had sensitivity of 78% and specificity of 85%. CDLB criteria for probable DLB (two or more major criteria) distinguished DLB from AD with a sensitivity of 78% and a specificity of 64%. CONCLUSIONS: The proposed CDLB criteria have high negative predictive value and thus do well at excluding patients with DLB. Positive predictive value of 75% can be achieved by a combination of any three major or minor criteria, providing the analysis is confined to patients with mild to moderate dementia. Criteria were most accurate if confined to patients with pure DLB who had mild to moderate dementia.     

The progression of cognitive impairment in dementia with Lewy bodies, vascular dementia and Alzheimer's disease

BACKGROUND: Little is known about the rate of progression or associations of cognitive impairment in dementia with Lewy bodies (DLB), or the associations of accelerated decline. METHOD: Dementia patients from a case register were evaluated at baseline and 1 year follow-up using the Cambridge Assessment for Mental Disorders in the Elderly, section B (CAMCOG) and the Mini-Mental State Examination (MMSE) to determine the rate of cognitive decline. Operationalized clinical diagnoses were applied (NINCDS ADRDA for Alzheimer's disease (AD), NINCDS AIRENS for vascular dementia (VaD) and consensus criteria for DLB). RESULTS: One hundred and ninety-three patients completed annual MMSE schedules (AD, 101; DLB, 64; VaD, 38), of whom 154 completed the CAMCOG. The magnitude of cognitive decline (MMSE, 4-5 points; CAMCOG, 12-14 points) was similar in each of the dementias. The strongest predictor of accelerated cognitive decline in DLB was the apolipoprotein E4 allele (17.5 vs 8.3 points decline on the CAMCOG). CONCLUSION: Over 1 year, DLB, VaD and AD patients had similar rates of cognitive decline overall. Apolipoprotein E4 may be an important predictor of more rapid decline in DLB.     

Definition and diagnosis of dementia with Lewy bodies

Significant advances have been made in neuropathologic identification procedures for dementia with Lewy bodies (DLB), but difficulties remain in clinical diagnosis. Consensus criteria state that the core features of DLB are fluctuating cognition with pronounced variation in attention and alertness, recurrent visual hallucinations and spontaneous motor features of parkinsonism. At least two of these features must be present for the diagnosis of probable DLB. Assessments of the validity of the consensus criteria against autopsy generally indicate high specificity but varying sensitivity. More detailed assessments of core diagnostic features or better operationalization, particularly of fluctuating cognition, may help improve the diagnostic guidelines. Greater utilization of some features described as supporting the diagnosis (such as auditory hallucinations) and the potential inclusion of additional symptoms (such as REM sleep behavioral disorder) also may be useful. In addition, the potential role of more detailed neuropsychology and neuroimaging in the diagnostic process needs to be evaluated, although it is important that changes to the diagnostic criteria are based on empirical evidence. Other key issues pertain to the classification of DLB patients with concurrent Alzheimer's disease and the differentiation of DLB and Parkinson's disease dementia based on less than a 1-year history of parkinsonism preceding the dementia.     

Mitochondrial DNA haplogroups and susceptibility to AD and dementia with Lewy bodies

ARTICLE ABSTRACT: The authors analyzed the relationship between nuclear genetic risk factors (apolipoprotein E genotype) and mitochondrial DNA (mtDNA) sequence variants in pathologically proved cases of AD (n = 185), dementia with Lewy bodies (DLB; n = 84), and control subjects (n = 179). Specific European mtDNA haplogroups and the A4336G mutation were not associated with an increased risk of AD. mtDNA haplogroup H was overrepresented in the DLB patients when compared with control subjects. Additional studies are needed to clarify the significance of the association.     

Simplified neuropathological diagnosis of dementia with Lewy bodies

Pathological criteria have recently been developed to differentiate those cases where Lewy bodies contribute to the dementing process. We applied consensus criteria to 20 cases with a pathological diagnosis of Alzheimer's disease (all demented) and/or Parkinson's disease (three without dementia) and eight controls. In addition, we applied the criteria to the different cortical layers to determine whether the site of the semiquantification affected the diagnosis. In the parietal lobe, few Lewy bodies were observed, and this region could be excluded. Rare Lewy bodies present in the frontal association cortex in a number of Parkinson's disease cases resulted in their classification as limbic or transitional cases with Lewy bodies. Exclusion of this non-limbic association cortex resulted in many of these cases with rare cortical Lewy bodies being re-classified as having brain stem predominant Lewy bodies, thus improving the diagnostic accuracy of the criteria. Most of these cases were non-demented. No other case was re-classified by excluding these cortical regions from the analysis. Few Lewy bodies were present in cortical layers I and II, and these layers could be excluded from the semiquantitative procedure without change to the overall classification of cases. The occasional presence of possible Lewy bodies in cases with Alzheimer's disease and controls incorrectly classified these cases as having brain stem predominant Lewy body disease, although these cases had no brain stem Lewy bodies. These modifications to the consensus criteria for assessing Lewy body disease (i.e. exclude parietal and frontal lobe, cortical layers I and II, and cases without brain stem Lewy bodies), provide significant time and cost savings for neuropathologists and researchers using this criteria to diagnose and study dementia with Lewy bodies.     

Three years survival in patients with a clinical diagnosis of dementia with Lewy bodies

The majority of information available on the prognosis of dementia with Lewy bodies (DLB) is based on retrospective data from autopsy series, which are subject to selection bias due to the specific reasons patients are referred for post-mortem studies. The earlier studies comparing DLB patients with patients with Alzheimer's disease (AD) suggest that the mean duration of illness is shorter in DLB patients than in patients with AD. However, more recent studies have not observed significant differences between DLB and AD in age of onset, age at death or duration of illness. We report a 3 year follow-up of a cohort of 114 consecutive patients with dementia, referred to an old age psychiatric service and diagnosed using ICD 10 criteria and the McKeith and Byrne DLB criteria. The case notes of all patients were reviewed to determine the date of onset of symptoms and the date of first presentation to the psychiatric services. Information about outcome was gathered from case notes, hospital files and general practitioner (GP) records. Of the original sample of 114 patients, 106 could be traced. Sixty-four had died and 42 were still alive at the time of the follow-up. Thirty-two patients had originally been assigned the diagnosis of DLB, 43 the diagnosis of AD, 31 vascular dementia and other diagnoses. There were no differences between the AD and DLB group in age at onset, age at death or survival. We have not found any evidence that the prognosis of clinically diagnosed DLB patients is worse than that of patients with a clinical diagnosis of AD.     

Butyrylcholinesterase and progression of cognitive deficits in dementia with Lewy bodies

Butyrylcholinesterase is implicated in the pathology of AD. Selective inhibitors increase acetylcholine and improve cognitive function in animal models. In dementia with Lewy bodies, cholinergic activities are more affected than in AD. The authors report a highly significant association between temporal cortex butyrylcholinesterase activity and the rate of cognitive decline in a prospectively studied, autopsy-confirmed dementia with Lewy bodies series.     

Regional cerebral blood flow difference between dementia with Lewy bodies and AD.

The authors studied 14 patients with dementia with Lewy bodies (DLB), 14 patients with AD, and 14 healthy control subjects with N-isopropyl-p-[123I]iodoamphetamine SPECT. Comparison with the statistical parametric mappings revealed that relative cerebral blood flow was lower in the occipital lobes and higher in the right medial temporal lobe in the DLB group than in the AD group. Decreased occipital perfusion and relatively well preserved medial temporal perfusion are features that distinguish DLB from AD.     

Occipital hypoperfusion on SPECT in dementia with Lewy bodies but not AD

OBJECTIVE: To compare regional cerebral blood flow (rCBF) changes using 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) SPECT in subjects with dementia with Lewy bodies (DLB) and AD and in normal age-matched control subjects; to examine the utility of SPECT changes in the differential diagnosis of AD and DLB. METHOD: Whole-brain SPECT scans were acquired using a single-headed rotating gamma camera (IGE CamStar XR/T) in elderly subjects with consensus criteria DLB (n = 23; mean age = 79.4 years), National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association AD (n = 50; 81.9 years), and normal control subjects (n = 20; 78.1 years) after injection with 500 MBq of 99mTc-HMPAO. Region-of-interest analysis was performed using a SPECT template registered in Talairach space, with rCBF normalized to cerebellum. RESULTS: Both DLB and AD subjects had significantly reduced rCBF in parietal and temporal regions compared with the control subjects. The AD group also showed a significant reduction in rCBF in the frontal and medial temporal regions and the DLB in the occipital areas compared with control subjects. AD and DLB groups differed only in occipital perfusion (p < 0.01). SPECT measures (occipital and medial temporal) correctly classified 69% of all subjects, with a 65% sensitivity and 87% specificity for DLB against AD and control subjects. CONCLUSION: Temporoparietal hypoperfusion on SPECT is common to both AD and DLB. Occipital hypoperfusion is more frequently seen in DLB. Although not diagnostically specific in individual cases, occipital hypoperfusion on SPECT should raise suspicion that DLB may be the cause of dementia, prompting careful search for other features of the disorder.     

Early detection of dementia with Lewy bodies in patients with amnestic mild cognitive impairment using 123I-MIBG cardiac scintigraphy

Increasing clinical attention has been focused on cardiac sympathetic denervation for the differential diagnosis of dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) with the development of [123I] metaiodobenzylguanidine (MIBG) scintigraphy. Decreased MIBG uptake, which reflects cardiac sympathetic denervation, has been detected in DLB, but not in AD. However, the time course of detected cardiac sympathetic degeneration is poorly understood in DLB. Herein, the authors report two patients with a clinical diagnosis of amnestic mild cognitive impairment (MCI) who had cardiac sympathetic denervation, detected by cardiac (123)I-MIBG scintigraphy, without the core clinical features of DLB. One amnestic MCI patient had nocturnal dream enactment behavior, consistent with clinically probable REM sleep behavior disorder (RBD), and converted to probable DLB with the development of recurrent visual hallucination and spontaneous parkinsonism two years after MCI is diagnosed. The other amnestic MCI patient exhibited occipital metabolic reduction on [18F]-fluoro-d-glucose (FDG) positron emission tomography (PET) scan, which is the preferentially affected region in DLB patients, although she had no core or suggestive clinical features of DLB. Both patients had abnormal findings on electrocardiogram at annual health checkups despite having no cardiac-related symptoms. Detailed clinical examinations, including angiography and echocardiogram, revealed no overt etiology, supporting the idea that cardiac sympathetic denervation is due to underlying Lewy body disease. The clinical courses of these patients suggest that (123)I-MIBG cardiac scintigraphy is useful for the detection of DLB in the predementia phase, even before core clinical features appear.     

Clinical symptoms in mild cognitive impairment with Lewy bodies: Frequency,time of onset,and discriminant ability

Background and purpose

Mild cognitive impairment with Lewy bodies (MCI-LB) is associated with a range of cognitive, motor, neuropsychiatric, sleep, autonomic, and visual symptoms. We investigated the cumulative frequency of symptoms in a longitudinal cohort of MCI-LB compared with MCI due to Alzheimer disease (MCI-AD) and analysed the ability of a previously described 10-point symptom scale to differentiate MCI-LB and MCI-AD, in an independent cohort.

Methods

Participants with probable MCI-LB (n = 70), MCI-AD (n = 51), and controls (n = 34) had a detailed clinical assessment and annual follow-up (mean duration = 1.7 years). The presence of a range of symptoms was ascertained using a modified version of the Lewy Body Disease Association Comprehensive LBD Symptom Checklist at baseline assessment and then annually.

Results

MCI-LB participants experienced a greater mean number of symptoms (24.2, SD = 7.6) compared with MCI-AD (11.3, SD = 7.4) and controls (4.2, SD = 3.1; p < 0.001 for all comparisons). A range of cognitive, parkinsonian, neuropsychiatric, sleep, and autonomic symptoms were significantly more common in MCI-LB than MCI-AD, although when present, the time of onset was similar between the two groups. A previously defined 10-point symptom scale demonstrated very good discrimination between MCI-LB and MCI-AD (area under the receiver operating characteristic curve = 0.91, 95% confidence interval = 0.84–0.98), replicating our previous finding in a new cohort.

Conclusions

MCI-LB is associated with the frequent presence of a particular profile of symptoms compared to MCI-AD. Clinicians should look for evidence of these symptoms in MCI and be aware of the potential for treatment. The presence of these symptoms may help to discriminate MCI-LB from MCI-AD.