Vascular dementia: dead or alive?

Longitudinal trajectories of cognitive decline among older adults with cardiovascular disease

BACKGROUND

The long-term course of cognitive impairments secondary to cardiovascular disease (CVD) is unclear. In this study, we prospectively investigated the temporal pattern, rate and hierarchy of cognitive decline attributable to CVD--a risk factor for the development of vascular cognitive impairment (VCI)--and examined the influence of cardiac surgery and heart failure on cognitive decline.

METHODS

A total of 172 older adults with CVD were administered a comprehensive battery of neuropsychological tests at study entry, and at 12 and 36 months thereafter. Random coefficient regressions were used to investigate the temporal course, rate and hierarchy of cognitive decline, as well as to examine the effect of heart failure (reported by 21% of the sample) and cardiac surgery (reported by 44% of the sample) on trajectories of cognitive change.

RESULTS

The course of decline in cognition was linear for language and attention-executive function-psychomotor speed, and curvilinear for visuospatial abilities, memory and overall cognition. The decline in attention-executive function-psychomotor speed was smaller than the decline in other domains. The greatest decline occurred in visuospatial abilities. The rate of decline in cognition was not altered by a history of heart failure. Patients who had undergone cardiac surgery exhibited slower deceleration in their rates of decline in overall cognition. At baseline, patients with a history of heart failure had comparatively poorer attention-executive function-psychomotor speed, overall cognition and, to a lesser extent, visuospatial scores.

CONCLUSION

There is measurable decline in neurocognitive function among patients with CVD. This decline is linear in some cognitive domains and curvilinear in others and is not attributable to the normal aging process. Cardiac surgery, but not heart failure, significantly affects the trajectory of cognitive decline. Because most vascular risk factors are modifiable, preventive measures such as lifestyle changes may be useful in retarding cognitive decline among patients with CVD, thus preventing the onset of VCI.

Neuroprotective effect of modified Wu-Zi-Yan-Zong granule, a traditional Chinese herbal medicine, on CoCl2-induced PC12 cells

AIM OF THE STUDY

To investigate the neuroprotective effect of aqueous extract of modified Wu-Zi-Yan-Zong granule (MWG), a traditional Chinese herbal medicine, against CoCl(2)-induced neurotoxicity in PC12 cells.

MATERIALS AND METHODS

Cell viability assay, apoptosis rate assay, ROS detection and mitochondrial membrane potential (MMP) assay were performed. In addition, cytochrome c, caspase-3, PARP and MAPKs were also detected by Western blotting.

RESULTS

MWG extract increased viability and suppresses early and middle/late stage apoptosis in a dose-dependent manner in CoCl(2)-induced PC12 cells. Moreover, MWG extract decreased the level of intracellular reactive oxygen species (ROS), increased MMP, regulated Bcl-2 family protein expression (Bcl-2 and Bcl-XL) and inhibited the release of cytochrome c from the mitochondria. In addition, MWG extract attenuated activation of caspase-3 and poly ADP-ribose polymerase (PARP) and inhibited the phosphorylation of ERK, c-Jun NH(2)-terminal kinase (JNK) and p38 MAPKs.

CONCLUSIONS

MWG extract exhibited significant neuroprotective effect on PC12 cells, and this effect may be associated with the suppression of ROS generation and inhibition of mitochondria-mediated caspase and MAPK signaling pathways.

VASCULAR DEMENTIA AND ALZHEIMER'S DISEASE: THE UNSOLVED PROBLEM OF CLINICAL AND NEUROPSYCHOLOGICAL DIFFERENTIAL DIAGNOSIS

The definition of clinical criteria for differential diagnosis of Vascular Dementia (VaD) and Alzheimer's disease (AD) remains controversial. A large group of patients selected was affected by chronic cerebrovascular disease classified as VaD or not (VND), according to DSM IV criteria. Neuropsychological performances of VaD patients were compared with a group of patients affected by probable AD, matched for age, education, and severity of disease. The comparison of performances did not reach statistical significance in single neuropsychological tasks. The results suggest that neuropsychological examination might not clearly differentiate between VaD and AD patients; the similar pattern of cognitive impairment is probably indicative of several common pathogenetic mechanisms.

Neuropsychological performance in Alzheimer's disease and vascular dementia: comparisons in a memory clinic population

OBJECTIVES

To compare the performances of two matched groups of patients with Alzheimer's disease (AD) and vascular dementia (VaD) on a battery of neuropsychological tests.

METHODS

325 patients attending a memory clinic were given a detailed multi-disciplinary diagnostic assessment, including a battery of neuropsychological tests administered by a psychologist and a speech and language therapist. The performances of two groups of patients meeting ICD-10 criteria for AD (n = 103) and VaD (n = 68) were compared, adjusting for age, gender, dementia severity and pre-morbid IQ. Patients with co-morbid depression and mixed AD+VaD were excluded.

RESULTS

After adjustment, the AD and VaD groups differed significantly on the Graded Naming Test (VaD superior), AMIPB Complex Design immediate and delayed recall (VaD superior), the Trail Making Test error score (Part B) (VaD superior), and Verbal Picture Description (VaD superior).

CONCLUSIONS

These findings support previous evidence that language function and non-verbal memory are selectively more impaired in AD. The better performance by VaD patients on the Trail Making Test (B) runs counter to previous suggestions that there is an excess of frontal executive dysfunction in this disorder. It may be that this test is more sensitive to the early impairment of concurrent manipulation of information in AD.

Understanding and managing behavioural symptoms in Alzheimer's disease and related dementias: focus on rivastigmine

Behavioural and psychological symptoms of dementia (BPSD) are among the most distressing manifestations of dementia and result in considerable social and economic costs. Practical, non-pharmacological approaches such as environmental and behavioural changes may provide some benefit for patients in managing mild BPSD. In addition, various pharmacological approaches to treatment have been employed, such as neuroleptics and atypical antipsychotics, which differ in neurochemical target and clinical effectiveness. Growing evidence suggests that the neurobiological basis of BPSD in Alzheimer's disease (AD) and related dementias is a loss of cholinergic neurones and a resultant decline in acetylcholine (ACh) in brain regions which regulate behavioural and emotional responses, such as the limbic system. This cholinergic deficit can be partly corrected by inhibiting cholinesterase enzymes (ChEs). Studies of ChE inhibitors have shown positive effects to improve or stabilise existing BPSD and delay the emergence of new behavioural symptoms. In placebo-controlled studies, donepezil has reported efficacy in non-institutionalised moderate to moderately severe patients over a period of 24 weeks, but has failed to demonstrate efficacy in mild to moderate AD and in institutionalised patients with severe disease. Galantamine has been shown to delay the onset of BPSD in mild to moderate AD patients in one placebo-controlled study, and improve BPSD in a similar study of patients with cerebrovascular disease or probable vascular dementia. Studies with rivastigmine have shown efficacy in placebo-controlled studies of mild to moderately severe AD and in patients with Lewy body variant AD. Institutionalised patients with severe disease also show symptomatic benefits in BPSD with rivastigmine, resulting in a reduction in concomitant psychoactive medication use. Symptom complexes responding to ChE inhibitors appear to differ - all agents improve apathy, depression and anxiety, while rivastigmine additionally improves hallucinations and delusions, possibility as a result of dual inhibition of acetylcholinesterase and butyrylcholinesterase. The presence of hallucinations has been shown to predict response to rivastigmine. Accumulating data from studies of ChE inhibitors suggest that early intervention and long-term treatment, in addition to providing cognitive benefits, improves BPSD and offers potential to enhance quality of life. Differences seen between the agents in terms of efficacy in BPSD, tolerability and safety profiles may be the result of differences in neuropharmacological profiles.

Methodological issues and therapeutic perspectives in vascular dementia: a review

Vascular dementia (VaD) is the most common form of dementia after Alzheimer's disease (AD). However, it is now increasingly recognized that not only is VaD a heterogeneous syndrome but also that VaD and AD are not mutually exclusive. Thus, the currently used criteria may no longer be sufficient for an accurate diagnosis of VaD. In addition, although it is widely assumed that risk factors for vascular disease are also risk factors for VaD, the evidence, in most cases, is circumstantial. For the effective prevention of VaD, therefore, large-scale and long-term clinical trials are required to investigate the validity of these putative risk factors. These trials should also include the VaD subtypes in their outcome measurements and to this end a simplified classification system should be adopted. Additional large-scale trials are required to facilitate the secondary prevention and symptomatic treatment of VaD, in particular to investigate the potential application of several nootropic and neuroprotective drugs. In both cases, these clinical trials should aim to move the field of VaD from opinion-based medicine to evidence-based medicine.

Cerebrovascular disease and late life depression: an age old association revisited

OBJECTIVES

To examine the relationship between depression and cerebrovascular disease in three distinct settings: depression in established cerebrovascular disease, cerebrovascular disease in established depression and depression in vascular dementia.

METHODS

Medline, EMBASE, PsychLit and PsychInfo databases were scanned to locate relevant articles. Data were also extracted from other articles, cited by those articles generated from the above databases.

RESULTS

Using operational criteria, the prevalence of depression is higher than controls only within the first year after stroke, but most studies have not employed control groups. The prevalence of depression in vascular dementia compared with Alzheimer's disease is higher in the majority of studies, but matching for sociodemographic factors and severity of cognitive impairment has been inconsistent. An association between frontal/subcortical cerebrovascular lesions and depression in later life has been observed, but there may be methodological flaws underlying this observation in some computerized tomography studies.

CONCLUSION

There is some evidence that cerebrovascular disease has an aetiopathological role in late life depression. The increased likelihood of damage to frontal/subcortical brain circuitry following stroke, transient ischaemia and hypertension may explain the high prevalence of depression in older people with vascular risk factors. More valid definitions of lesion location and the use of appropriately matched control groups would seek to clarify this issue. The extrapolation to care settings from the high prevalence of depression accompanying cerebrovascular disease and the prolongation of disability in depressed people with stroke, suggests closer liaison between old age psychiatrists, neurologists and physicians caring for the elderly.

Differentiation of vascular dementia from AD on neuropsychological tests

BACKGROUND

The concept of vascular dementia (VaD) is currently in a state of evolution. Memory impairment is emphasized as a primary criterion, reflecting the influence of AD on the concept of dementia. We have systematically reviewed whether the nature of neuropsychological dysfunction is distinct in AD and VaD, and whether similar defining criteria for the concept of dementia in both disorders can be supported.

METHODS

We searched five bibliographic databases (Medline, Biological Abstracts, EMBASE, PsychINFO, PsychLIT) for research articles in which VaD and AD had been compared using neuropsychological tests and that met criteria for scientific merit.

RESULTS

Of the 45 studies, 18 were excluded because of inadequacies, and the remaining 27 were analyzed. There were a number of similarities of dysfunction between VaD and AD. However, when matched for age, education, and severity of dementia, VaD patients had relatively superior function in verbal long-term memory and more impairment in frontal executive functioning compared with AD patients. Interpretation of the results is limited by uncertainty in diagnostic criteria for VaD, possible inclusion bias due to use of clinical diagnosis alone, possible overlap of AD and VaD, and the methodologic shortcomings of some studies.

CONCLUSIONS

The neuropsychological differentiation of VaD from AD was consistent with the different neuroimaging findings in the two disorders, and argues for differential criteria for the definition of the syndromes. The simple application of Alzheimer's dementia criteria to VaD, with the inclusion of cerebrovascular disease etiology, may not be sufficient to capture the uniqueness of VaD.