Children of Alzheimer patients: an overview

[Delayed effects of cerebrolysin in the prevention of cognitive impairment progression in the first degree relatives of patients with Alzheimer's disease: the role of the ApoE genotype]

OBJECTIVE

To assess the delayed effect of course therapy with cerebrolysin on the cognitive functioning of the first degree relatives of patients with Alzheimer's disease (AD), including, depending on the ApoE4 genotype.

MATERIAL AND METHODS

A cohort of 72 blood relatives of patients with AD, including 46 with objectively confirmed clinical and neuropsychological examination signs of mild cognitive dysfunction (group 1) and 26 (group 2) with cognitive impairment that meets the diagnostic criteria of mild cognitive impairment (ICD-10 F06.7), was studied. The dynamics of the initial (0 day) indicators of cognitive functioning was compared immediately after a four-week course of treatment with cerebrolysin infusions, as well as 1 and 2 months after its completion, depending on the presence of ApoE4(+) or ApoE4(-) genotype. Clinical, psychopathological, psychometric, follow-up, molecular-genetic and statistical methods were used.

RESULTS

A positive prolonged effect of course therapy with cerebrolysin on cognitive functioning of the first degree relatives of patients with AD was established in both groups. A significant negative effect of the ApoE4(+) genotype on the immediate and delayed effects of cerebrolysin treatment has been proven.

CONCLUSION

The results can form the basis for the development of therapeutic measures aimed at preventing the progression of cognitive impairment and the development of dementia in the first degree relatives of patients with AD as those with the highest risk of dementia.

Maternal dementia age at onset in relation to amyloid burden in non-demented elderly offspring

Family history (FH) of dementia is a major risk factor for Alzheimer's disease, particularly when the FH is maternal and when the age of dementia onset (AO) is younger. This study tested whether brain amyloid-beta deposition, measured in vivo with (11)C-Pittsburgh compound B (PiB), was associated with parental dementia and/or younger parental AO. Detailed FH and positron emission tomography (PiB) data were acquired in 147 nondemented aging individuals (mean age 75 ± 8). No participant had both positive maternal and paternal FH. A series of analyses revealed that those with maternal, but not paternal, FH had greater levels of PiB retention in a global cortical region than those without FH. PiB retention in maternal FH was not significantly greater than paternal FH. Younger maternal dementia AO was related to greater PiB retention in offspring, whereas younger paternal dementia AO was not. Overall, results suggest that not only is amyloid-beta burden greater in individuals with maternal FH, but also that the burden is greater in association with younger maternal AO.

Multiple Imputation of a Randomly Censored Covariate Improves Logistic Regression Analysis

Randomly censored covariates arise frequently in epidemiologic studies. The most commonly used methods, including complete case and single imputation or substitution, suffer from inefficiency and bias. They make strong parametric assumptions or they consider limit of detection censoring only. We employ multiple imputation, in conjunction with semi-parametric modeling of the censored covariate, to overcome these shortcomings and to facilitate robust estimation. We develop a multiple imputation approach for randomly censored covariates within the framework of a logistic regression model. We use the non-parametric estimate of the covariate distribution or the semiparametric Cox model estimate in the presence of additional covariates in the model. We evaluate this procedure in simulations, and compare its operating characteristics to those from the complete case analysis and a survival regression approach. We apply the procedures to an Alzheimer's study of the association between amyloid positivity and maternal age of onset of dementia. Multiple imputation achieves lower standard errors and higher power than the complete case approach under heavy and moderate censoring and is comparable under light censoring. The survival regression approach achieves the highest power among all procedures, but does not produce interpretable estimates of association. Multiple imputation offers a favorable alternative to complete case analysis and ad hoc substitution methods in the presence of randomly censored covariates within the framework of logistic regression.

Subjective memory complaints, cortical thinning, and cognitive dysfunction in middle-aged adults at risk for AD

Background

Subjective memory complaints (SMCs) represent an individual's perception of subtle changes in memory in the absence of objective impairment in memory. However, it is not fully known whether persons with SMCs harbor brain alterations related to Alzheimer's disease (AD) or whether they indeed demonstrate poorer cognitive performance.

Methods

The participants were 261 middle-age adults (mean age 54.30 years) enrolled in the Wisconsin Registry for Alzheimer's Prevention, a registry of cognitively normal adults at risk of AD. They answered a question pertaining to subjective memory, completed a comprehensive neuropsychological examination, and subsequently underwent a volumetric magnetic resonance imaging scan. Cortical thickness measurements were derived from 10 a priori regions of interest involved in AD. Analyses of covariance were conducted to investigate the group differences in cortical thickness and neuropsychological measures.

Results

Compared with individuals without SMCs, those with SMCs had significant cortical thinning in the entorhinal, fusiform, posterior cingulate, and inferior parietal cortices and significantly reduced amygdala volume. Similarly, those with SMCs had significantly lower test scores on measures of Immediate Memory, Verbal Learning & Memory, and Verbal Ability. Additional adjustment for depressive symptoms (which differed between the groups) attenuated only the findings for the entorhinal cortex (P = .061) and Verbal Ability (P = .076).

Conclusion

At-risk, cognitively healthy individuals with SMCs exhibit cortical thinning in brain regions affected by AD and poorer performance on objective memory tests. These findings suggest that, in some individuals, SMCs might represent the earliest stages of AD.

Rural Caregivers for a Family Member With Dementia

Forecasts of increasing prevalence of dementia in rural settings, coupled with reliance on family caregiver support, indicate that a greater understanding of caregiver distress in these contexts is necessary. The purpose of this study was to examine family caregiver burden and severity of distress on the day that a family member was diagnosed with dementia at a memory clinic that serves a rural population. Participants in this retrospective study were 231 primary family caregivers of a rural community-dwelling person with dementia. On the diagnostic day, women reported more burden and severity of distress than men and spouses reported more severity of distress than adult children. A structural equation model was not supported for the entire sample, but was supported for women caregivers only ( n = 161). Caregiver distress related to dementia-specific behaviors explained both global distress and burden. Patients’ functional decline was related to caregiver burden.

Caregiver Burden in Fragile X Families

Complex caregiving issues occur in multigenerational families carrying the fragile X mutation and premutation. The same family members may care for children or siblings with fragile X syndrome (FXS) and for elderly parents with fragile X-associated tremor/ataxia syndrome (FXTAS). Family caregivers experience anxiety, depression, neglect of personal health care needs, employment difficulties, and loss of social support, leading to isolation and further psychiatric consequences. There is growing awareness of caregiver burden with regard to parents of children with FXS, but much less is known about the needs of informal caregivers of patients with FXTAS. In this paper, we review the available literature to date and provide suggestions for further exploration of caregivers' needs. Evidence-based strategies to address these needs are included. Many more research studies exploring caregiver burden in multigenerational fragile X families are needed, as well as studies aimed at investigating interventions and their impact on reduction.

Family history of Alzheimer disease predicts hippocampal atrophy in healthy middle-aged adults

OBJECTIVE

To evaluate the longitudinal influence of family history (FH) of Alzheimer disease (AD) and apolipoprotein E ε4 allele (APOE4) on brain atrophy and cognitive decline over 4 years among asymptomatic middle-aged individuals.

METHODS

Participants were cognitively healthy adults with (FH+) (n = 60) and without (FH-) (n = 48) a FH of AD (mean age at baseline 54 years) enrolled in the Wisconsin Registry for Alzheimer's Prevention. They underwent APOE genotyping, cognitive testing, and an MRI scan at baseline and 4 years later. A covariate-adjusted voxel-based analysis interrogated gray matter (GM) modulated probability maps at the 4-year follow-up visit as a function of FH and APOE4. We also examined the influence of parent of origin on GM atrophy. Parallel analyses investigated the effects of FH and APOE4 on cognitive decline.

RESULTS

Neither FH nor APOE4 had an effect on regional GM or cognition at baseline. Longitudinally, a FH × APOE4 interaction was found in the right posterior hippocampus, which was driven by a significant difference between the FH+ and FH- subjects who were APOE4-. In addition, a significant FH main effect was observed in the left posterior hippocampus. No significant APOE4 main effects were detected. Persons with a maternal history of AD were just as likely as those with a paternal history of AD to experience posterior hippocampal atrophy. There was no longitudinal decline in cognition within the cohort.

CONCLUSION

Over a 4-year interval, asymptomatic middle-aged adults with FH of AD exhibit significant atrophy in the posterior hippocampi in the absence of measurable cognitive changes. This result provides further evidence that detectable disease-related neuroanatomic changes do occur early in the AD pathologic cascade.

Children of persons with Alzheimer disease: what does the future hold?

Children of persons with Alzheimer disease (AD), as a group, face an increased risk of developing AD. Many of them, throughout their adult lives, seek input on how to reduce their chances of one day suffering their parent's fate. We examine the state of knowledge with respect to risk and protective factors for AD and recommend a research agenda with special emphasis on AD offspring.

Two decades of research in Alzheimer disease: looking back to the first volume of ADAD

During the first two decades of the life of this Journal (ADAD) much progress has been made in our understanding of Alzheimer disease (AD). Advancing knowledge, however, has been accompanied by increasing appreciation of the complexity and heterogeneity of this disease. Prevention and cure continue to elude us as the number of afflicted and the cost of their care continues to increase. New techniques together with long-term prospective follow-up studies, as well as utilization of data accumulated in existing data bases, are needed to move the field forward. We expect that during the next two decades, as new information accrues, reports published in ADAD will continue to contribute to the dissemination and elucidation of critical issues in Alzheimer research.