Lewy body dementia

Nuclear factor kappa-B p50 and p65 subunits expression in dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia after Alzheimer's disease (AD). Parkinsonism in DLB is mainly caused by neuronal loss with Lewy bodies (LBs) in the substantia nigra, thereby inducing degeneration of the nigrostriatal dopaminergic pathway similar to that in Parkinson's disease (PD). To clarify the pathogenesis of DLB, it is important to investigate the mechanisms involved in the degenerative process of LB-bearing neurones. Several reports suggest a role for nuclear factor kappa-B (NFkappaB) in the manifestation of neurodegenerative conditions such as AD and PD. The aim of the present study was to investigate whether NFkappaB subunits are involved in the pathogenesis of neurodegeneration in DLB by measuring tyrosine hydroxylase (TH), NFkappaB p65 and p50 protein expression in frontal cortex and substantia nigra pars compacta of DLB and control human brains. An increase, although not statistically significant, in nigral TH expression in DLB cases was observed. There were no differences in the cortical and nigral expression levels of NFkappaB p65 subunit between control and DLB cases. Western blots of the frontal cortex showed no differences in the expression levels of NFkappaB p50 subunit. However, NFkappaB p50 levels were significantly decreased (P < 0.05) in the pars compacta of the substantia nigra in the DLB cases in comparison with controls. The decrease in the expression of the p50 subunit in the substantia nigra of DLB cases achieved in the present study may increase the vulnerability of the dopaminergic neurones to a possible neurotoxic effect of p65 subunit. Thus, normal levels of NFkappaB p65 might be toxic in neurones with a low expression of the NFkappaB p50 subunit.

Low alpha-synuclein 126 mRNA levels in dementia with Lewy bodies and Alzheimer disease

Alpha-synuclein, a main component of Lewy bodies in synucleinopathies and senile plaques in Alzheimer disease, is centrally involved in neurodegeneration. Three different isoforms (alpha-synuclein 112, 126, and 140) resulting from alternative splicing have been described so far. The present study explores alpha-synuclein 126 mRNA expression levels in the prefrontal cortex of six patients with dementia with Lewy bodies, eight patients with Lewy body variant of Alzheimer disease, eight patients with Alzheimer disease, and 10 controls. Relative alpha-synuclein 126 expression levels were determined by real-time polymerase chain reaction with competimer technology. Alpha-synuclein 126 mRNA expression was markedly decreased in the three dementias in comparison with controls, suggesting an important role of this alpha-synuclein isoform in the normal brain.

What best differentiates Lewy body from Alzheimer's disease in early-stage dementia?

To determine which clinical feature(s) [among visual hallucinations (VH), extrapyramidal signs (EPS) and visuospatial impairment] in the earliest stages of disease best predicted a diagnosis of dementia with Lewy bodies (DLB) at autopsy, first-visit data of 23 pathologically proven DLB and 94 Alzheimer's disease cases were compared. There were no group differences with regard to age, gender, education or global severity of dementia at presentation (mean Mini-Mental State Examination: 24.0 versus 25.0, mean Dementia Rating Scale: 123.6 versus 125.7). DLB patients at initial presentation displayed an increased frequency of VH (P = 0.001), but not EPS (P = 0.3), compared to Alzheimer's disease patients. However, only a minority of DLB cases had either VH (22%), EPS (26%) or both (13%). In contrast, although not a core feature, visuospatial/constructional impairment was observed in most of the DLB cases (74%). Among clinical variables, presence/recent history of VH was the most specific to DLB (99%), and visuospatial impairment was the most sensitive (74%). As a result, VH at presentation were the best positive predictor of DLB at autopsy (positive predictive value: 83% versus 32% or less for all other variables), while lack of visuospatial impairment was the best negative predictor (negative predictive value: 90%). We conclude that the best model for differentiating DLB from Alzheimer's disease in the earliest stages of disease includes VH and visuospatial/constructional dysfunction, but not spontaneous EPS, as predictors. This suggests that clinical history plus a brief assessment of visuospatial function may be of the greatest value in correctly identifying DLB early during the course of disease.

Upregulation of amyloid precursor protein isoforms containing Kunitz protease inhibitor in dementia with Lewy bodies

Amyloid precursor protein (APP) is involved in the accumulation of alpha-synuclein, the main component of Lewy bodies. It is currently unknown, however, whether any of the APP isoforms is instrumental in alpha-synuclein deposition in dementia with Lewy bodies (DLB). Using real-time RT-PCR, we have studied relative mRNA expression levels of APP isoforms in frozen postmortem frontal cortices of DLB patients, Alzheimer disease (AD) patients, and control subjects. Of the three main APP isoforms, the two with a Kunitz protease inhibitory (KPI) motif (APP770 and APP751) were found to be specifically overexpressed in the frontal cortices of DLB patients when compared with controls and AD patients. These findings suggest a specific role of APP isoforms containing Kunitz protease inhibitor in DLB pathogenesis.

Démarche diagnostique devant un syndrome démentiel

PURPOSE

The high prevalence of dementia, particularly of Alzheimer's disease, the increase of their incidence with age, and the population aging make this group of diseases a major problem for public health. Nevertheless, diagnosis is difficult because it depends on evolution of disturbances that patients often cannot precisely relate, on complex neuropsychological explorations, and on pathological examination difficult to obtain. Today in France, geriatricians are fully implicated in the diagnosis of dementia and all the physicians who give care to elderly, should lead easily a diagnosis of dementia.

CURRENT KNOWLEDGE AND KEY POINTS

In February 2000 ANAES (French governmental agency for accreditation and evaluation of health system) published recommendations called "practical recommendations for the diagnosis of Alzheimer's disease". These recommendations allow physicians to standardize their practices and consist of a rigorous clinical history and examination, a neuropsychological analysis, standard investigations and application of diagnostic criteria already widely diffused and used.

FUTURE PROSPECTS AND PROJECTS

Deepening of knowledge, in particular in the domains of neuropsychology and functional cerebral imagery, should allow physicians to diagnose early dementia. These early diagnosis should allow to initiate a multidisciplinary, preventive and effective care for patients. Specific drugs, that will be available, will be intended mostly for patients with early diagnosis, ideally at a pre-dementia state.

Striatal monoaminergic terminals in Lewy body and Alzheimer's dementias

Vesicular monoamine transporter type 2 and benzodiazepine binding site expressions were examined with quantitative autoradiography in postmortem striata from 19 patients with dementia with Lewy bodies, seven patients with dementia with Lewy bodies and Alzheimer's disease, 12 patients with Alzheimer's disease, and eight neurologically normal subjects. Striatal vesicular monoamine transporter type 2 expression in dementia with Lewy bodies and in dementia with Lewy bodies plus Alzheimer's disease was reduced significantly, indicating degeneration of nigrostriatal projections. Striatal benzodiazepine binding site expression was unchanged, indicating preserved intrinsic striatal neuropil. Vesicular monoamine transporter type 2 and benzodiazepine binding site expressions were each preserved in Alzheimer's disease striatum. We conclude that dementia with Lewy bodies may be distinguished from Alzheimer's disease by postmortem examination or by future in vivo measurements of the striatal vesicular monoamine transporter type 2.

Prevalence of Alzheimer's disease, vascular dementia and dementia with Lewy bodies in a Japanese population

We studied the prevalence of dementing disorders in a rural town of Japan (Amino-cho), using a door-to-door two-phase design. Of the 170 persons screened as having cognitive impairment, 142 cases were diagnosed as having dementia. The prevalence (cases/100 aged 65 years older) was 3.8 for all types of dementia, 2.1 for Alzheimer's disease (AD), 1.0 for vascular dementia (VD) and 0.7 for other types of dementia. Among other types of dementia, there were four male patients with dementia with Lewy bodies (prevalence: 0.1), but no patients with frontotemporal lobar degeneration. The overall prevalence was higher in women for AD, while that of VD was the same in both sexes. With results similar to many previous studies in Western countries and some recent surveys in Japan, the present sudy clearly showed that AD is more prevalent than VD.

Behavior management and communication strategies for dental professionals when caring for patients with dementia

The impact of dementia and associated behavioral problems on the oral health of long-term-care-facility residents is increasing. The provision of oral hygiene care for these cognitively impaired residents is difficult and complex. Dental professionals and carers need good communication skills with cognitively impaired residents, and specific strategies for the management and prevention of their behavioral problems. Newer philosophies of dementia care enable dental professionals and carers to use more individualized and non-pharmacological approaches for dental treatment and preventive oral care provision. This paper reviews behavior management and communication strategies from the dental literature, and newer techniques and interventions from dementia research and literature.