Nature and extent of person recognition impairments associated with Capgras syndrome in Lewy body dementia

Patients with Capgras syndrome (CS) adopt the delusional belief that persons well-known to them have been replaced by an imposter. Several current theoretical models of CS attribute such misidentification problems to deficits in covert recognition processes related to the generation of appropriate affective autonomic signals. These models assume intact overt recognition processes for the imposter and, more broadly, for other individuals. As such, it has been suggested that CS could reflect the "mirror-image" of prosopagnosia. The purpose of the current study was to determine whether overt person recognition abilities are indeed always spared in CS. Furthermore, we examined whether CS might be associated with any impairments in overt affective judgments of facial expressions. We pursued these goals by studying a patient with Dementia with Lewy bodies (DLB) who showed clear signs of CS, and by comparing him to another patient with DLB who did not experience CS, as well as to a group of healthy control participants. Clinical magnetic resonance imaging scans revealed medial prefrontal cortex (mPFC) atrophy that appeared to be uniquely associated with the presence CS. We assessed overt person recognition with three fame recognition tasks, using faces, voices, and names as cues. We also included measures of confidence and probed pertinent semantic knowledge. In addition, participants rated the intensity of fearful facial expressions. We found that CS was associated with overt person recognition deficits when probed with faces and voices, but not with names. Critically, these deficits were not present in the DLB patient without CS. In addition, CS was associated with impairments in overt judgments of affect intensity. Taken together, our findings cast doubt on the traditional view that CS is the mirror-image of prosopagnosia and that it spares overt recognition abilities. These findings can still be accommodated by models of CS that emphasize deficits in autonomic responding, to the extent that the potential role of interoceptive awareness in overt judgments is taken into account.

Non-Alzheimer's disease-related memory impairment and dementia

Although Alzheimer's disease (AD) is a common cause of memory impairment and dementia in the elderly disturbed memory function is a widespread subjective and/or objective symptom in a variety of medical conditions. The early detection and correct distinction of AD from non-AD memory impairment is critically important to detect possibly treatable and reversible underlying causes. In the context of clinical research, it is crucial to correctly distinguish between AD or non-AD memory impairment in order to build homogenous study populations for the assessment of new therapeutic possibilities. The distinction of AD from non-AD memory impairment may be difficult, especially in mildly affected patients, due to an overlap of clinical symptoms and biomarker alterations between AD and certain non-AD conditions. This review aims to describe recent aspects of the differential diagnosis of AD and non-AD related memory impairment and how these may be considered in the presence of memory deficits.

Neuroimaging in dementia

Over the last few years, advances in neuroimaging have generated biomarkers, which increase diagnostic certainty, provide valuable information about prognosis, and suggest a particular pathology underlying the clinical dementia syndrome. We aim to review the evidence for use of already established imaging modalities, along with selected techniques that have a great potential to guide clinical decisions in the future. We discuss structural, functional and molecular imaging, focusing on the most common dementias: Alzheimer's disease, fronto-temporal dementia, dementia with Lewy bodies and vascular dementia. Finally, we stress the importance of conducting research using representative cohorts and in a naturalistic set up, in order to build a strong evidence base for translating imaging methods for a National Health Service. If we assess a broad range of patients referred to memory clinic with a variety of imaging modalities, we will make a step towards accumulating robust evidence and ultimately closing the gap between the dramatic advances in neurosciences and meaningful clinical applications for the maximum benefit of our patients.

Art and the brain: a view from dementia

OBJECTIVE

Art making encompasses a range of perceptual and cognitive functions involving widely distributed brain systems. The dementias impact on these systems in different ways, raising the possibility that each dementia has a unique artistic signature.

DESIGN

Here we use a review of the visual art of 14 artists with dementia (five Alzheimer's disease, seven fronto-temporal dementia and two dementia with Lewy bodies) to further our understanding of the neurobiological constituents of art production and higher artistic function.

RESULTS

Artists with Alzheimer's disease had prominent changes in spatial aspects of their art and attributes of colour and contrast. These qualities were preserved in the art of fronto-temporal dementia, which was characterised by perseverative themes and a shift towards realistic representation. The art of dementia with Lewy Bodies was characterised by simple, bizarre content.

CONCLUSIONS

The limitations of using visual aspects of individual artworks to infer the impact of dementia on art production are discussed with the need for a wider perspective encompassing changes in cognition, emotion, creativity and artistic personality. A novel classificatory scheme is presented to help characterise neural mechanisms of higher artistic functions in future studies.

Inter-Species Glia Differences: Implications for Successful Translation of Transgenic Rodent Alzheimer's Disease Model Treatment Using Bexarotene

Despite a multitude of efficacious treatments for the cognitive symptoms and pathology in transgenic mouse models of Alzheimer's disease (AD), success in human trials has been elusive. Rodent-human brain dissimilarities may help explain failures of past human trials and improve outcomes of future ones. This review highlights the essential role of the human brain's exceptional myelination in achieving and maintaining optimal brain functions, as well as underlying its vulnerability to age-related myelin breakdown and the degenerative brain diseases that process can trigger. This alternative myelin-centered perspective is used herein to help explain key disconnects in the existing treatment literature by focusing on recent reports on brain effects of bexarotene, the only marketed retinoid X receptor (RXR) agonist. The myelin perspective exposes significant yet underexplored opportunities for novel treatment and prevention interventions that have the potential to considerably reduce the tremendous burden of degenerative brain diseases.

Determination of the biodistribution and dosimetry of ¹²³I-FP-CIT in male patients with suspected Parkinsonism or Lewy body dementia using planar and combined planar and SPECT/CT imaging

In this study, (123)I-FP-CIT biodistribution and dosimetry was determined in 10 adult male patients using planar gamma camera imaging alone or in combination with single photon emission computed tomography /X-ray computed tomography (SPECT/CT) imaging. Dosimetric assessment using planar plus SPECT/CT imaging resulted in significantly different estimates of organ-absorbed doses compared to estimates based on planar imaging alone. We conclude that the use of complementary SPECT/CT measurements in biodistribution studies is valuable for determining the organ doses more accurately.

A predictive model of neurodegeneration in idiopathic REM-sleep behavior disorder

OBJECTIVE

To investigate whether Parkinson's disease (PD) and dementia are competing risks in subjects with idiopathic rapid-eye-movement sleep behavior disorder (RBD).

METHODS

The number of incidental PD cases observed in 11 longitudinal RBD studies was compared with the corresponding expected number as estimated by a simple mathematical model based on population parameters for PD age-of-onset.

RESULTS

The expected number of incidental PD cases exceeded observed PD cases (p-value < 0.001) but was in agreement with the sum of observed PD cases and observed mild cognitive impairment/dementia cases (p-value = 0.34). Sensitivity analyses confirmed the results.

CONCLUSION

In the RBD population, PD and dementia cases are competing risks, suggesting that alpha-synuclein pathology occurs simultaneously in substantia nigra and neocortex. This observation has implications for the design and analysis of trials of neuroprotection.

Nigrostriatal dopamine terminal imaging with dopamine transporter SPECT: an update

This article gives an update on nigrostriatal dopamine terminal imaging, with emphasis on SPECT performed with the presynaptic dopamine transporter (DAT) ligand (123)I-FP-CIT. The paper covers the rational use of this technique in the diagnostic work-up of patients with known or suspected parkinsonian syndromes. In detail, it addresses the impact of the method for the proof or exclusion of neurodegenerative parkinsonism, for its early and preclinical diagnosis, and for the evaluation of disease progression. The importance of normal DAT binding for differentiating symptomatic parkinsonism and relevant tremor syndromes from neurodegeneration is highlighted. Particularly emphasized is the role of DAT SPECT for diagnosing Lewy body dementia and its separation from Alzheimer dementia. Finally, some remarks deal with the economic aspects of the use of these imaging techniques in the clinical setting.

Assessing mild cognitive impairment with amyloid and dopamine terminal molecular imaging

We evaluated PET-based classification of neurodegenerative pathology in mild cognitive impairment (MCI).

METHODS

Our study was a cross-sectional and prospective evaluation of a cohort of 27 MCI subjects drawn from a university-based cognitive disorders clinic. We compared expert clinical consensus classification of MCI at entry and possible dementia at follow-up with molecular imaging-based classification using (11)C-dihydotetrabenazine PET measurement of striatal dopamine terminal integrity and (11)C-Pittsburgh compound B ((11)C-PiB) PET measurement of cerebral amyloid burden.

RESULTS

Eleven subjects were initially classified clinically as amnestic MCI, 7 as multidomain MCI, and 9 as nonamnestic MCI. At a mean follow-up of 3 y, 18 subjects converted to dementia. PET imaging evidence of significant cerebral amyloid deposition or nigrostriatal denervation was a strong predictor of conversion to dementia. There was only moderate concordance between expert clinical classifications and PET-based classifications of dementia subtypes.

CONCLUSION

Combined PET molecular imaging of cerebral amyloid burden and striatal dopamine terminal integrity may be useful for identifying subjects at high risk for progression to dementia and in defining neurochemically differentiated subsets of MCI subjects.

Persistence of cholinesterase inhibitor treatment in dementia: insights from a naturalistic study

BACKGROUND

Cholinesterase inhibitors (ChEI) are widely used in dementia, but there is a lack of practice guidelines in case of intolerance or absence of perceived effect.

METHODS

Two hundred and forty patients (mean age 77 years, SD 6.3, 66% female) with Alzheimer's disease or Lewy body dementia were prescribed a ChEI and evaluated annually under conditions of standard practice. Of these, 152 patients maintained, 36 switched, and 52 abandoned ChEI treatment.

RESULTS

Less behavioural disturbance and less cognitive deterioration were observed, respectively, at the 3- and 4-year follow-up assessments in the patients who maintained the first prescribed ChEI (p < 0.05). Cognitive benefits were reinforced in the patients who experienced some adverse event, but no benefits were observed when the patient or caregiver did not perceive an effect.

CONCLUSIONS

Maintenance of the first prescribed ChEI was supported when some benefit was perceived by the patient or caregiver, even in cases of nonserious adverse events.

[Parkinsonian disorders: from clinical manifestations to diagnostic classification]

Parkinsonism may include atypical clinical manifestations, which are warning signs for the clinicians and motivate further investigations to identify an etiology other than idiopathic Parkinson's disease. The dismemberment of pathological entities, the advances of morphological and functional imaging of the brain, and new insights into molecular biology have successively led to more precise clinical phenotype and mechanisms. Except for etiologies with specific treatment, such as Wilson's disease or Parkinsonism secondary to a lesion of basal ganglia, or the discontinuation of a culprit drug, the treatment of Parkinsonian syndrome is mainly based on a multidisciplinary approach, involving occupational therapist, physiotherapist, speech therapist, psychologist and social worker. L-Dopa may be tried but it is less effective in atypical Parkinsonian syndrome than in Parkinson's disease. Formal diagnosis, only achievable post-mortem, is not available during the lifetime of the patient. Although some additional tests provide undeniable assistance, the clinical approach remains an essential and critical step to avoid costly and unnecessary investigations.

White matter hyperintensities in mild lewy body dementia

Background

The objective of this study was to explore the load of white matter hyperintensities (WMH) in patients with Lewy body dementia (LBD) and compare to Alzheimer's disease (AD) and normal controls (NC).

Methods

Diagnosis of LBD and AD was made according to consensus criteria and cognitive tests were administered. MRI scans for 77 (61 AD and 16 LBD) patients and 37 healthy elderly control subjects were available for analysis. We segmented WMH from FLAIR images using an automatic thresholding technique and calculated the volume of WMH in several regions of the brain, using non-parametric tests to compare groups. Multivariate regression was applied.

Results

There were no significant differences in WMH between AD and LBD. We found a significant correlation between total and frontal WMH and Mini-Mental State Examination (MMSE) and verbal fluency scores in the AD group, but not in the LBD group.

Conclusion

The WMH load in LBD was similar to that of AD. A correlation between WMH load and cognition was found in the AD group, but not in the LBD group, suggesting that vascular disease contributes to cognitive impairment in AD but not LBD.

Clinicopathological correlates of lewy body disease: fundamental issues

Lewy body pathology (LBP) is the pathological hallmark of Lewy body diseases, such as Parkinson's disease and Lewy body dementia. Recent studies have shed new light on the role of LBP, the interactions of LBP with concomitant pathologies, and the propagation of LBP from the olfactory bulb and enteric nervous system to the central nervous system. The intrinsic difficulty with identifying clinicopathological correlates could be overcome by improving our understanding of the pathological evolution of LBP.

Dementia with Parkinson disease: Clinical diagnosis, neuropsychological aspects and treatment

Dementia with Parkinson's disease represents a controversial issue in the complex group of alpha-synucleinopathies. The author acknowledges the concept of a "continuum" between Parkinson disease's (PD), Lewy body dementia (LBD), and dementia in Parkinson's disease (PDD). However, the practicing neurologist needs to identify the phenotypic signs of each dementia. The treatment and prognosis are different in spite of the overlaps between them. The main aim of this review was to characterize the clinical diagnoses of dementia associated with Parkinson's disease (PDD). Secondarily, the review discussed some epidemiological and neuropsychological issues. Selection of articles was not systematic and reflects the author's opinion, where the main text selected was the recommendations from the Movement Disorder Society Task Force for PDD diagnosis. The Pub Med, OVID, and Proquest data bases were used for the search.

Normal pressure hydrocephalus co-existing with a second dementia disorder

An 87-year-old woman had both Lewy body dementia and normal pressure hydrocephalus simultaneously. One should not automatically exclude the possibility of normal pressure hydrocephalus simply because another neurodegenerative disorder is present, especially if the second disorder masks typical symptoms of normal pressure hydrocephalus. Better identification of dual diagnosis patients could lead to improvements in gait and incontinence following ventriculoperitoneal or lumboperitoneal shunting, even if the natural history of the other neurodegenerative disease remains unchanged.