Epidemiology of non-AD dementias

Atypical parkinsonian syndromes in a North African tertiary referral center

INTRODUCTION

Data on epidemiology of atypical parkinsonian syndromes (APS) in North African countries are limited. Our objective was to study the epidemiological features of APS in a Tunisian population.

METHODS

We conducted a 17-year retrospective cross-sectional descriptive study in the Department of Neurology at Razi University Hospital. We included all patients responding to consensus diagnosis criteria of APS. We recorded demographic and clinical data. Group differences were assessed with a post hoc ANOVA with a Bonferroni error correction.

RESULTS

We included 464 APS patients. Hospital prevalence of APS among all parkinsonism cases was 20.6%. Mean annual increase of incidence defined as newly diagnosed APS cases per year reached 38.8%/year. APS were divided into 4 etiological subgroups: dementia with Lewy bodies (DLB; 56.7%); progressive supranuclear palsy(PSP; 16.2%); multiple system atrophy (MSA; 14.6%); and finally corticobasal syndrome (CBS; 12.5%). Sex-ratio was 1.2. This male predominance was found in all subgroups except MSA (p = .013). Mean age at onset was 68.5 years, most belated in DLB (69.7 years; p < .001). Young-onset parkinsonism (<40 years) was found only in MSA subgroup (p = .031). Parkinsonism was of late onset (>70 years) in 50.7% of patients and was significantly associated with DLB subgroup (p = .013). Inaugural parkinsonism was associated with CBS and MSA (p = .0497), and gait disorders at disease onset were associated with PSP and MSA (p = .0062). Cognitive and mood disorders were more marked in DLB and most preserved in MSA. Consanguinity was more marked in CBS (p = .037), and family history of dementia and psychiatric diseases was more common in DLB. Thirty-seven families with similar cases of APS were identified.

CONCLUSIONS

This is the largest African epidemiological study on APS. In our population, APS were frequent and dominated by DLB. The age of onset of parkinsonism was the most decisive feature for differential diagnosis.

The effect of scalp point cluster-needling on learning and memory function and neurotransmitter levels in rats with vascular dementia

We observed the effect of scalp point cluster-needling treatment on learning and memory function and neurotransmitter levels in rats with vascular dementia (VD). Permanent ligation of the bilateral carotid arteries was used to create the VD rat model. A Morris water maze was used to measure the rats' learning and memory function, and the changes in neurotransmitter levels in the rats' hippocampus were analyzed. The results show that scalp point cluster-needling can increase the VD rat model's learning and memory score. The VD rat model's learning and memory score was significantly different when compared with that of the sham operation group (P < 0.05). Hippocampal acetylcholine (ACh), dopamine (DA), and 5-hydroxytryptamine (5-HT) concentrations significantly decreased in the rat model. Compared with the model group, the scalp point cluster-needling group's ACh concentration markedly increased and DA and 5-HT levels increased as well. In conclusion, scalp point cluster-needling can improve learning and memory function in VD rats, and its function may be related to an increase in neurotransmitter release.

The 5 Objects Test: a novel, minimal-language, memory screening test

Very brief screening tests are useful in primary care, but may show reduced sensitivity in detecting Alzheimer's disease or other dementias in the early stages and may show an education or age bias. We examined the reliability, validity, sensitivity, specificity and relationship with demographic variables of a novel, very brief memory screening test that makes limited language demands. Participants were 452 neurological patients with different diagnoses and a community-dwelling sample of 119 middle-aged and older controls. The 5 Objects Test requires the recall of the locations of five everyday objects, immediately after placement and after a brief period of time. The test was unaffected by age and education and showed good reliability and discriminant validity. In receiver operating characteristic (ROC) analyses, specificity was high across a range of sensitivities in all four main comparisons (AD cases versus controls; all dementia cases versus controls; memory-impaired versus non memory-impaired patients; MCI cases versus controls), and sensitivity was lowest in differentiating MCI cases from controls. The test showed similar areas under the ROC curve to the much longer modified Mini Mental State Examination. The 5 Objects Test is a reliable and valid very brief screening test that is suitable for primary care. Because of its limited linguistic demands, the test is appropriate for persons with limited language use or from different linguistic backgrounds.

Distinct patterns of medial temporal impairment in degenerative dementia: a brain SPECT perfusion study in Alzheimer's disease and frontotemporal dementia

PURPOSE

Medial temporal impairment can be detected clinically and by morphological imaging during Alzheimer's disease (AD), but the existence of a functional impairment in this area seems to be less well established. Yet such functional impairment is classically found in other degenerative cortical dementias, such as the frontal variant of frontotemporal dementia (fv-FTD). The aim of this study was to characterize and compare brain SPECT perfusion of the medial temporal lobe in AD and fv-FTD.

METHODS

Voxel-based comparisons were performed using SPM8 between cerebral SPECT images from 85 AD patients, 25 fv-FTD patients and 12 healthy controls at the whole-brain level and the medial temporal lobe level using a region of interest approach (p < 0.001, corrected for the cluster).

RESULTS

In the free and cued selective reminding test, used to evaluate medial temporal memory function, AD patients had significantly lower scores than the fv-FTD patients (p < 0.005). AD and fv-FTD patients showed hypoperfused medial temporal structures in comparison to normal controls. However, fv-FTD patients had more pronounced hypoperfusion in this area, with a different topography, more anterior and more parahippocampal.

CONCLUSION

These results show that medial temporal hypoperfusion can be detected in degenerative dementias by SPECT. Paradoxically, the hypoperfusion is more severe in fv-FTD than in AD patients, even though the mnesic profile of AD is more altered, suggesting the existence of inefficient compensatory mechanisms.

Prevalence and causes of early-onset dementia in Japan: a population-based study

BACKGROUND AND PURPOSE

Few studies are available that have addressed the prevalence of early-onset dementia (EOD), including early-onset Alzheimer disease and other forms of dementia in Japan.

METHODS

A 2-step postal survey was sent to all of the 2475 institutions providing medical or care services for individuals with dementia in Japan's Ibaraki prefecture (population, 2 966 000) requesting information on EOD cases. Data were then reviewed and collated.

RESULTS

We identified 617 subjects with EOD. The estimated prevalence of EOD in the target population was 42.3 per 100 000 (95% CI, 39.4 to 45.4). Of the illnesses that cause EOD, vascular dementia was the most frequent (42.5%) followed by Alzheimer disease (25.6%), head trauma (7.1%), dementia with Lewy bodies/Parkinson disease with dementia (6.2%), frontotemporal lobar degeneration (2.6%), and other causes (16.0%).

CONCLUSIONS

The prevalence of EOD in Japan appeared to be similar to that in Western countries with the notable exception that vascular dementia was the most frequent cause of EOD in Japan.

Risk factors for dementia in a rural area of Northeastern Brazil

OBJECTIVE: To identify risk factors for dementia among the elderly in a rural area of Northeastern Brazil. METHOD: The subjects assessed were all 60 years old or older, and lived in a rural region of Bahia, a Northeastern State of Brazil. CAMDEX, a structured clinical evaluation protocol, was used for diagnosis, and applied at the home of the subjects. RESULTS: The risk factors identified were divided in accordance with socio-demographic characteristics, the presence of co-morbid conditions, and the use of medications. The variables with strong association with dementia were age, history of stroke, arterial hypertension, and sight impairment. CONCLUSION: Advanced age, arterial hypertension, and vascular brain injury were the main risk factors associated with dementia, which suggests that public health measures adopted to prevent and control modifiable risk factors can mitigate the prevalence of high rates of dementia.

Aging effects on cerebral blood and cerebrospinal fluid flows

Phase-contrast magnetic resonance imaging (PC-MRI) is a noninvasive reliable technique, which enables quantification of cerebrospinal fluid (CSF) and total cerebral blood flows (tCBF). Although it is used to study hydrodynamic cerebral disorders in the elderly group (hydrocephalus), there is no published evaluation of aging effects on both tCBF and CSF flows, and on their mechanical coupling. Nineteen young (mean age 27+/-4 years) and 12 elderly (71+/-9 years) healthy volunteers underwent cerebral MRI using 1.5 T scanner. Phase-contrast magnetic resonance imaging pulse sequence was performed at the aqueductal and cervical levels. Cerebrospinal fluid and blood flow curves were then calculated over the cardiac cycle, to extract the characteristic parameters: mean and peak flows, their latencies, and stroke volumes for CSF (cervical and aqueductal) and vascular flows. Total cerebral blood flow was (P<0.01) decreased significantly in the elderly group when compared with the young subjects with a linear correlation with age observed only in the elderly group (R(2)=0.7; P=0.05). Arteriovenous delay was preserved with aging. The CSF stroke volumes were significantly reduced in the elderly, at both aqueductal (P<0.01) and cervical (P<0.05) levels, whereas aqueduct/cervical proportion (P=0.9) was preserved. This is the first work to study aging effects on both CSF and vascular cerebral flows. Data showed (1) tCBF decrease, (2) proportional aqueductal and cervical CSF pulsations reduction as a result of arterial loss of pulsatility, and (3) preserved intracerebral compliance with aging. These results should be used as reference values, to help understand the pathophysiology of degenerative dementia and cerebral hydrodynamic disorders as hydrocephalus.