Which factors influence cognitive decline in older adults suffering from dementing disorders?

BACKGROUND: Although extensive research has been done on dementing disorders in recent decades, their natural course and prognosis are not yet well understood. The aim of our study was to assess cognitive decline in a representative sample of demented elderly and to analyse the predictive value of a broad spectrum of sociodemographic, neurological and clinical variables. METHODS: A random sample of elderly patients in primary care (n = 407) was drawn from a total of 3721 patients. The sample has been stratified according to the degree of cognitive impairment as assessed by their GPs. The patients were examined by means of a standardized research interview, including comprehensive cognitive testing (Hierarchic Dementia Scale) and the assessment of neurologic and physical impairments as well as of mental state (CAMDEX criteria). After a mean interval of 28 months, a follow-up study was conducted using essentially the same instruments. RESULTS: At baseline, 117 of the 407 patients were identified as suffering from mild, moderate, or severe dementia. The two-year follow-up of those patients revealed high mortality rates (53/117). The surviving patients showed significant cognitive decline, although the rate varied considerably between individuals. The rate of progression was strongly related to the initial degree of severity, but also to the use of psychotropic medication, which was associated with a more rapid deterioration. CONCLUSIONS: There are some prognostic indicators that can help to establish the prognosis for dementia patients. The best indicator for both--the rate of cognitive decline and the probability of survival--is the severity of 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.     

Race and cognitive decline among community-dwelling elders with mild cognitive impairment: findings from the Memory and Medical Care Study

Objective: Previous studies have reported conflicting findings on the relationship between race and cognitive decline in elders with dementia. Few studies have examined the role of race in cognitive decline in mild cognitive impairment (MCI). We investigate the relationship between race and cognitive decline in participants with MCI in a community-based, longitudinal study of cognitively impaired elders.

Method: Based on a validated method utilizing a neuropsychiatric battery, 133 subjects [mean age: 78.7 years (SD?=?6.5); female: 112 (76.7%); black: 59 (44.4%)] out of 512 participants in the Memory and Medical Care Study were diagnosed with MCI. The main outcome measure was the Telephone Interview for Cognitive Status (TICS) score over three years. Other baseline subject characteristics (demographics, health-related variables, behavioral, and psychiatric symptoms) were included in the analysis.

Results: Overall, the three-year decline in mean TICS score was significantly higher among African Americans than non-African Americans [3.31 (SD: 7.5) versus 0.96 (SD: 3.0), t-value?=?1.96, p-value?=?0.05]. General estimating equation analyses revealed that African American race was associated with a faster rate of cognitive decline in all models.

Conclusion: The rate of cognitive decline in MCI appears to be faster in African Americans than non-African Americans in the community. Diagnosis of MCI among African American elders could lead to early interventions to prevent or delay cognitive decline in the future.     

Association of lung function with cognitive decline and dementia: the Atherosclerosis Risk in Communities (ARIC) Study

Background: Previous studies reported a higher risk of cognitive decline and dementia amongst individuals with impaired lung function. However, many did not adjust for important confounders or did not include women and non‐whites. Methods: We studied 10 975 men and women aged 47–70 years (23% African‐Americans) enrolled in the Atherosclerosis Risk in Communities Study. Pulmonary function tests and a cognitive assessment, including the Delayed Word Recall, the Digit Symbol Substitution, and the World Fluency Tests, were carried out in 1990–1992. Repeated cognitive assessments were performed in 1996–1998 for the entire cohort, and in 1993–1995, and 2004–2006 in 904 eligible individuals. Dementia hospitalization was ascertained through 2005. Results: In analysis adjusted for lifestyles, APOE genotype, and cardiovascular risk factors, impaired lung function was associated with worse cognitive function at baseline. No association was found between lung function and cognitive decline over time. Impaired lung function at baseline was associated with higher risk of dementia hospitalization during follow‐up, particularly amongst younger individuals. The hazard ratios (95% confidence intervals) of dementia hospitalization were 1.6 (0.9, 2.8) and 2.1 (1.2, 3.7) comparing the lowest with the highest quartile of forced expiratory volume in 1 s and forced vital capacity, respectively. Presence of a restrictive ventilatory pattern, but not of an obstructive pattern, was associated with reduced cognitive scores and higher dementia risk. Conclusion: Reduced lung function was associated with worse performance in cognitive assessments and with an increased risk of dementia hospitalization. Future research should determine whether maintaining optimal pulmonary health might prevent cognitive impairment and dementia.     

Suspected dementia: evaluation of 323 consecutive referrals

A neurological outpatient department studied 323 consecutive referrals for suspected dementia: 135 (41.8%) were not demented. Of the patients 12.1% had diffuse cognitive disorder; 10.2% circumscribed memory disorder; 0.9% other circumscribed cognitive disorder, 14.2% psychiatric disorder, and 4.3% were judged to be normal. Of the nondemented, 44.1% had a potentially treatable cause for their cognitive symptoms; in 27.4% it was depression. The total of demented patients was 188 (58.2%): 38.8% had primary degenerative dementia; 37.2% vascular dementia including combined degenerative and vascular dementia; and 23.4% had a specific cause. Patients with specific cause were significantly younger than those with other causes of dementia. A potentially treatable cause was found in 10.7% of all demented patients, the most common being metabolic disorders, meningioma, hydrocephalus, subdural haematoma, and depressive pseudodementia.     

Nutrition and Alzheimer's disease: pre-clinical concepts

Alzheimer's disease (AD) is a progressive condition characterized by neurodegeneration and the dense deposition of proteins in the brain. There is no cure for AD and current treatments usually only provide a temporary reduction of symptoms. There is thus a strong unmet need for effective preventative and therapeutic strategies and the potential role for nutrition in such strategies is rapidly gaining interest. An Alzheimer's brain contains fewer synapses and reduced levels of synaptic proteins and membrane phosphatides. Brain membrane phosphatide synthesis requires at least three dietary precursors: polyunsaturated fatty acids, uridine monophosphate (UMP) and choline. Animal studies have shown that administration of these nutrients increases the level of phosphatides, specific pre- or post-synaptic proteins and the number of dendritic spines – a requirement for new synapse formation. These effects are markedly enhanced when animals receive all three compounds together. This multi-nutrient approach in animals has also been shown to decrease amyloid beta protein (Aβ) plaque burden, improve learning and memory through increased cholinergic neurotransmission and have a neuroprotective effect in several mouse models of AD. Whether these potential therapeutic effects of a multi-nutrient approach observed in animal models can also be replicated in a clinical setting warrants further investigation.     

Personality change in dementia of the Alzheimer type

Although cognitive impairment is the predominant feature of dementia, personality changes are also frequently reported. This study aimed to describe the nature of personality change in dementia of the Alzheimer type (DAT) and the relationship of this change to cognitive decline. An informant-based instrument was developed based on a personality inventory designed by Lewis Goldberg for measuring personality in the normal population. Twenty-eight clinicians used this inventory to rate the difference between people suffering from DAT and normal elderly people. Differences were found in all five factors of personality, with Conscientiousness and Intellect showing the most difference and Agreeableness showing the least difference. Based on the findings of this first study, a smaller questionnaire of 46 traits was developed. This was completed by 50 relatives of DAT patients, 50 relatives of controls and 167 carers of dementia sufferers recruited from Alzheimer’s Association support groups. Principal components analysis revealed a large factor which accounted for 33% of the variance suggesting a global change in personality. Rotation revealed three meaningful factors. Two of these factors were highly correlated to cognitive decline while the third showed only a moderate correlation. The significance of these results is discussed.     

A population-based study of the association between coronary artery bypass graft surgery (CABG) and cognitive decline: the Cache County study

BACKGROUND: The relationship between coronary artery bypass graft (CABG) surgery and cognitive decline remains uncertain, in particular with regard to whether there is delayed cognitive decline associated with this procedure. METHODS: This was a population-based cohort study involving participants in the Cache County Study of Memory Health and Aging. At baseline the study enrolled 5,092 persons age 65 and older and followed them up three years later and again four years after that. Individuals who reported having undergone CABG surgery at study baseline or had this surgery in between follow-up waves were compared to individuals who never reported having the surgery. The main outcome measure was the Modified Mini Mental State (3MS). Multilevel models were used to examine the relationship between CABG surgery and cognitive decline over time. RESULTS: Study participants who had CABG surgery evidenced 0.95 points of greater decline relative to baseline on the 3MS at the first follow-up interview after CABG, and an average of 1.9 points of greater decline at the second follow-up interview, than those without CABG (t = -2.51, df = 2,316, p = 0.0121), after adjusting for several covariates, including number of vascular conditions. This decline was restricted to individuals who were more than five years past the procedure and was not evident in the early years after the surgery. CONCLUSIONS: CABG surgery is associated with accelerated cognitive decline more than five years after the procedure in a long-lived population. This decline is small and its clinical significance is uncertain. We could not find an association between CABG and decline in the first five post-operative years.