Dementia with lewy bodies

In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a man with dementia with Lewy bodies. Dementia with Lewy bodies might be the second most common form of degenerative dementia in the elderly. Progressive cognitive decline, well-formed visual hallucinations, and parkinsonism are core features of this disease. This case was marked by preserved verbal expression despite impairment in memory, visuospatial skills, and attention span. Development of visual symptoms and parkinsonism occurred very early in the course of the disease.

Cortical basal ganglionic degeneration

In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a retired mason's assistant with cortical basal ganglionic degeneration (CBGD). CBGD is an extremely rare neurodegenerative disease that is categorized under both Parkinsonian syndromes and frontal lobe dementias. It affects men and women nearly equally, and the age of onset is usually in the sixth decade of life. CBGD is characterized by Parkinson's-like motor symptoms and by deficits of movement and cognition, indicating focal brain pathology. Neuronal cell loss is ultimately responsible for the neurological symptoms.

Clinical correlates of action tremor in Parkinson disease

BACKGROUND

Action tremor is often noted in patients with Parkinson disease (PD), yet the clinical correlates of this type of tremor have been the focus of few studies. It is not clear whether this action tremor is a manifestation of the underlying basal ganglia disease.

OBJECTIVE

To determine whether the severity of action tremor in PD is associated with age, age at disease onset, disease duration, levodopa dose, severity of rest tremor, or other motor (ie, bradykinesia, rigidity) and nonmotor manifestations of PD.

METHODS

Patients with PD (N = 197) were ascertained as part of a familial aggregation study. All patients underwent a neurological examination. Rest tremor was rated with the Unified Parkinson Disease Rating Scale; and action tremor, with the Washington Heights-Inwood Genetic Study of Essential Tremor Rating Scale.

RESULTS

Action tremor was present in 184 (93.4%) of 197 patients. Four patients (2%) met criteria for definite essential tremor. The action tremor score was not associated with age, age at onset, or disease duration. The action tremor score was associated with the rest tremor score (r = 0.37; P<.001), and more strongly with the ipsilateral than contralateral rest tremor score. The association between the action tremor score and the rest tremor score was diminished but still significant (r = 0.21, P<.02) even when we excluded these 63 patients with re-emergent tremor. Neither the action nor the rest tremor score was associated with the bradykinesia or rigidity scores, Hoehn and Yahr scale score, or modified Mini-Mental State Examination score.

CONCLUSIONS

Action tremor was associated with rest tremor in PD, suggesting that, at least in part, action tremor is a manifestation of the underlying basal ganglia disease. Neither tremor was associated with other motor and nonmotor manifestations of PD. This in turn suggests that tremor in PD may represent an underlying pathophysiological process different from these other manifestations.

Objective assessment of progression in Huntington's disease: a 3-year follow-up study

Objective measures to assess progression of Huntington's disease (HD) are desirable. The authors have previously found that patients with HD with higher Unified Huntington's Disease Rating Scale (UHDRS) motor scores exhibited higher variability of isometric grip forces while grasping an object. Therefore, the authors assessed grip force variability during this task in 10 HD patients with a 3-year follow-up. Grip force variability increased in all patients at the follow-up. Thus, grip force variability during grasping might be an objective and quantitative measure to assess motor deficits associated with the progression of HD.

Longitudinal study of quality of life in people with advanced Alzheimer's disease

The authors examined three indicators of health-related quality of life in people with advanced Alzheimer's disease ([AD]; N=150): confinement to home, null activity, and null positive affect, as reported by patient proxies. Dementia severity predicted time-to-onset for all three disease milestones in models that controlled for sociodemographic indicators, nursing home status, and death in the follow-up period. Patients whose dementia worsened over follow-up were more likely to reach each milestone. These outcomes represent key milestones in the care of patients; they are sensitive to disease progression, and they are likely to be useful for studying treatment in advanced AD.

Altered movement trajectories and force control during object transport in Huntington's disease

Individuals with Huntington's Disease (HD) have difficulty grasping and transporting objects, however, the extent to which specific impairments affect their performance is unknown. The present study examined the kinematics and force coordination during transport of an object in 12 subjects with HD and 12 age-matched controls. Subjects grasped an object between their thumb and index finger, transported it 25 cm forward, replaced and released it while their fingertip forces and the object's position were recorded. Five trials were performed with each of three weights (200 g, 400 g, and 800 g). While bradykinesia was evident in subjects with HD, this slowness was not consistently observed in all phases of the movement. The slowness of movement seen during the task appears to be due to impairments in sequencing and the movement strategies selected by the subjects. Compared to control subjects, subjects with HD produced highly curvilinear hand paths and more variable grip forces that were dependent on the weight of the object. Isometric force development and movement speed during transport were unaffected by the disease. The results suggest that prolonged task durations in subjects with HD are not necessarily due to slowness of movement, per se. These findings have clinical implications for understanding the task-specific nature of movement impairments in HD and developing effective intervention strategies.

HIV-1 reverse transcriptase sequence in plasma and cerebrospinal fluid of patients with AIDS dementia complex treated with Abacavir

OBJECTIVE

To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001).

DESIGN

One-hundred and five HIV-1 infected adults with ADC were randomized to receive either ABC (600 mg twice daily) or ABC-matched placebo (twice daily) in addition to SBG for 12 weeks.

METHODS

Plasma and CSF were collected for population sequencing at baseline and week 12 (CSF optional). Sequences were analyzed for mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI).

RESULTS

Sixty out of sixty-seven subjects with baseline plasma HIV-RT sequence data harbored virus with > or = 1 NRTI-associated mutations; 50 out of 67 had the M184V mutation. At week 12, more subjects in the ABC group had plasma HIV-1 RNA < or = 400 copies/ml than the SBG group (46% versus 13%, P = 0.002). Non-response to ABC was associated with multiple baseline zidovudine (ZDV)/stavudine (d4T)-associated mutations. Baseline RT mutation patterns differed in 14 out of 21 (67%) paired samples from plasma and CSF. Four subjects experienced > 1 log10 copies/ml reductions in CSF HIV-1 RNA, two in the absence of reductions in plasma HIV-1 RNA and two with undetectable plasma HIV-1 RNA at baseline.

CONCLUSIONS

Substantial decreases in plasma and CSF HIV-1 RNA following addition of ABC were not precluded by baseline HIV-1 NRTI-associated mutations, including the M184V mutation, but non-responders commonly harbored multiple ZDV/d4T-associated mutations. HIV-1 RNA responses and RT genotype appear to be discordant between CSF and plasma in some subjects.

Pharmacological frontiers in the treatment of AIDS dementia

Even in the era of highly active antiretroviral therapy, AIDS dementia remains an important and devastating complication of human immunodeficiency virus (HIV-1) infection. Based on the 1997 AIDS case rate of 56 per 100 000 population in the USA, a reasonable estimated incidence of AIDS dementia is 3-8 per 100000, similar to that of multiple sclerosis. The pharmacology of AIDS dementia has been dominated by antiretroviral therapies, the best studied of which is azidothymidine. New and specific therapies are needed to treat and prevent brain injury in the setting of HIV infection. Rational therapy has been limited by the absence of large, adequate and well-controlled clinical trials using neuroprotective agents or those with disease-modifying potential, as well as by an incomplete understanding of the pathophysiology of AIDS dementia. In this review, a summary of evidence-based hypotheses of HIV-associated brain injury is followed by information on current nonantiretroviral therapeutic trials and their scientific rationale.

An investigation of clinical correlates of Lewy bodies in autopsy-proven Alzheimer disease

BACKGROUND

Studies of patients meeting clinical and pathologic criteria for Alzheimer disease (AD) have not consistently found associations between the presence of Lewy bodies (LBs) at postmortem examination and a higher frequency during life of the clinical features of dementia with LBs.

OBJECTIVE

To evaluate the clinical correlates of LBs in patients with AD.

DESIGN AND METHODS

Fifty-one patients were diagnosed as having probable AD during life and met pathologic criteria for AD. Semiquantitative ratings for LBs were obtained in 4 brain regions: substantia nigra, cingulate, insular cortex, and hippocampus. The patients had been followed up semiannually for up to 9.9 years before death, and clinical features associated with dementia with LBs, including extrapyramidal signs and visual hallucinations, were assessed at each study visit. Logistic regression analyses determined whether patients who had LBs were more likely than those without LBs to express specific clinical signs during follow-up. Cox analyses determined whether patients with LBs developed clinical signs or died earlier. Generalized estimating equations were used to compare rates of cognitive or functional change.

RESULTS

Nineteen of the 51 patients had at least 1 LB in one of the studied regions. In no case was a significant relation noted between LBs and the presence of a measured clinical sign. No LB measure was associated with an increased risk of developing any of the evaluated clinical signs earlier in the disease. There was no association between the presence of LBs and more rapid mortality or more rapid disease progression.

CONCLUSIONS

In patients diagnosed as having AD during life, we did not observe a relation of LBs noted during postmortem examination with the presence of any clinical feature that we assessed or with the rapidity of disease progression. The relation between LBs and specific clinical manifestations may be tenuous in these patients.

Clinical trials in HIV-associated cognitive impairment: cognitive and functional outcomes

Cognitive and functional outcomes are of primary interest in the design of efficacy trials in HIV-associated cognitive impairment. In a longitudinal cohort study, weak associations were found between measures of cognitive performance and commonly used measures of daily functioning (mostly self-report measures) in HIV-infected individuals. Modifications of current functional scales or new functional instruments are needed to assess the clinical relevance of cognitive changes in clinical trials of HIV-associated cognitive impairment.

Apolipoprotein E and functional recovery from brain injury following postacute rehabilitation

OBJECTIVE

APOE epsilon4 has been associated with late-onset familial and sporadic AD and delayed recovery from head injury. The authors examined the relationship between functional recovery of patients with head injury and the APOE alleles.

METHODS

Thirty-one patients with head injury who had completed the Acute Neurorehabilitation Program at Helen Hayes Hospital were evaluated for presence of APOE epsilon4 and assessed for recovery based on Functional Independence Measures (FIM).

RESULTS

Analysis of covariance (using coma days as the covariate to control for differences in initial severity of injury between subjects with and without APOE epsilon4) revealed a significant difference for both total FIM and motor FIM scores between the subjects with and without APOE epsilon4. Specifically, there were lower scores for total FIM (df = 30; F = 3.341; p = 0.05) and motor FIM (df = 30; F = 4.189; p = 0.026) in APOE epsilon4 carriers. No difference was found for the cognitive portion of the FIM.

CONCLUSIONS

The data suggest that the presence of the lipoprotein APOE epsilon4 adversely affects rehabilitation outcome for traumatic brain injury survivors.

Different brain networks mediate task performance in normal aging and AD: defining compensation

OBJECTIVE

To determine whether the pathologic mechanisms of AD alter the brain networks subserving performance of a verbal recognition task.

BACKGROUND

Functional imaging studies comparing task-related activation in AD patients and controls generally have not used network analysis and have not controlled for task difficulty.

METHODS

H2 15O PET was used to measure regional cerebral blood flow in 14 patients and 11 healthy elders during the performance of a serial verbal recognition task under two conditions: low demand, with study list size (SLS) equal to one; and titrated demand, with SLS adjusted so that each subject recognized words at 75% accuracy. The Scaled Subprofile Model was used to identify networks of regionally covarying activity across these task conditions.

RESULTS

In the elders, higher SLS was associated with the recruitment of a network of brain areas involving left anterior cingulate and anterior insula (R2 = 0.94; p < 0.0001). Three patients also expressed this network. In the remaining patients, higher SLS was associated with the recruitment of an alternate network consisting of left posterior temporal cortex, calcarine cortex, posterior cingulate, and the vermis (R2 = 0.81, p < 0.001). Expression of this network was unrelated to SLS in the elders and more intact AD patients.

CONCLUSIONS

The patients' use of the alternate network may indicate compensation for processing deficits. The transition from the normal to the alternate network may indicate a point where brain disease has irreversibly altered brain function and thus may have important implications for therapeutic intervention.

The role of routine laboratory studies and neuroimaging in the diagnosis of dementia: a clinicopathological study

OBJECTIVE

To determine the neuropathological diagnoses of longitudinally followed patients with potentially reversible causes of dementia and to examine the results of the "dementia work-up," especially neuroimaging, by comparison with the pathological diagnosis.

DESIGN

A neuropathologic series of 61 consecutive patients, with review of clinical, laboratory, neuroimaging, and pathological results.

RESULTS

Of the 61 patients, forty-eight (79%) had a clinical diagnosis of probable or possible Alzheimer's disease (AD). Compared with the pathological diagnosis, the sensitivity and specificity of the clinical diagnosis of AD were 96% and 79%, respectively. Of the 61 patients, 9 had abnormal laboratory tests, the correction of which did not improve the subsequent course. These patients were found to have AD8 and frontotemporal dementia on pathology. In two patients, neuroimaging was helpful in the clinical diagnoses of frontotemporal dementia and progressive supranuclear palsy (PSP). Neuroimaging revealed cerebrovascular disease in 18 patients, only two of whom were suspected clinically. Pathology confirmed AD in 17 and PSP in 1 of these patients. Sensitivity and specificity for the clinical diagnosis of cerebrovascular disease in comparison with pathology were 6% and 98%, respectively. With the added information from neuroimaging, that sensitivity increased to 59% and specificity decreased to 81%.

CONCLUSIONS

All cases with abnormal laboratory or neuroimaging results had AD or some other neurodegenerative disease on pathology. The "dementia work-up" did not reveal any reversible causes for dementia in this group of patients. Neuroimaging may have a role, especially in the diagnosis of possible AD with concomitant cerebrovascular disease.

Olfactory deficits in patients with mild cognitive impairment predict Alzheimer's disease at follow-up

OBJECTIVE

This study evaluated the predictive utility of olfactory identification deficits in patients with mild cognitive impairment for follow-up diagnosis of probable Alzheimer's disease.

METHOD

Ninety outpatients with mild cognitive impairment were examined at 6-month intervals. Matched healthy comparison subjects (N=45) were examined annually. The University of Pennsylvania Smell Identification Test was given at baseline.

RESULTS

Olfaction scores were lower in patients with mild cognitive impairment than in healthy comparison subjects. Seventy-seven patients were followed up; 19 were diagnosed with Alzheimer's disease by 2 years. Patients with low olfaction scores (< or =34 of 40), and patients with low olfaction scores who reported no subjective problems smelling, were more likely to develop Alzheimer's disease than other patients. In a Cox proportional hazards model adjusted for age, sex, modified Mini-Mental State score, and education, low olfaction scores did not predict time until development of Alzheimer's disease, but low olfaction scores accompanied by lack of awareness of olfactory deficits predicted time to development of Alzheimer's disease. This effect remained when attention or memory measures replaced modified Mini-Mental State score in the model. In patients with high Mini-Mental State scores (> or =27 of 30), low olfaction with lack of awareness remained a significant predictor of Alzheimer's disease. Olfaction scores of 30-35 showed moderate to strong sensitivity and specificity for diagnosis of Alzheimer's disease at follow-up.

CONCLUSIONS

In patients with mild cognitive impairment, olfactory identification deficits, particularly with lack of awareness of olfactory deficits, may have clinical utility as an early diagnostic marker for Alzheimer's disease.

Dystonia-predominant adult-onset Huntington disease: association between motor phenotype and age of onset in adults

BACKGROUND

In juvenile Huntington disease (HD), dystonia as well as parkinsonism and eye movement abnormalities may be the predominant motor signs rather than chorea. Several patients have come to our attention with adult-onset HD in whom there is prominent dystonia and minimal chorea (ie, an adult-onset form of HD that resembles juvenile HD).

OBJECTIVES

To estimate the prevalence of these cases of dystonia-predominant HD in a clinic and to study the relationship between the motor phenotype and age of onset in HD.

METHODS

The Unified Huntington's Disease Rating Scale (UHDRS) was administered to 127 subjects during their initial visit to the Huntington's Disease Center at the New York State Psychiatric Institute, where dystonia, chorea, bradykinesia, rigidity, and eye movements were rated. The dystonia score was the mean UHDRS rating of dystonia in 5 body regions; the chorea score, the mean rating of chorea in 7 regions; the bradykinesia score, the mean rating of axial and limb bradykinesia; the rigidity score, the mean rating of rigidity in both arms; and the eye movement score, the mean rating of ocular pursuit, saccade initiation, and velocity. Dystonia-predominant HD was defined by the severity of dystonia relative to the severity of chorea.

RESULTS

Fifteen (11.8%) of 127 subjects had dystonia-predominant HD. Age of onset correlated negatively (r= -0. 22, P=.02) with the dystonia score divided by the chorea score and negatively (r= -0.28, P=.002) with the severity of dystonia, bradykinesia, and eye movement abnormalities relative to chorea (ie, [(dystonia score + bradykinesia score + eye movement score)/3] - chorea score), suggesting that subjects with younger ages of onset had more severe dystonia, bradykinesia, and eye movement abnormalities relative to chorea.

CONCLUSIONS

Cases of adult-onset HD with prominent dystonia and a paucity of chorea may represent 1 in 8 cases in specialty clinics. Age of onset was clearly associated with the motor phenotype. A younger age of onset was associated with more severe dystonia, bradykinesia, and eye movement abnormalities relative to chorea, supporting the notion that in adult-onset HD, the motor phenotype forms a continuum with respect to age of onset.

Motor impairment in PD: relationship to incident dementia and age

OBJECTIVE

To analyze the relationship of specific motor impairment in idiopathic PD to incident dementia.

BACKGROUND

The total Unified PD Rating Scale (UPDRS) motor score at baseline has been associated with an increased risk of developing dementia in PD.

METHODS

A cohort of 214 nondemented community-dwelling patients with PD was followed annually with neurologic and neuropsychological evaluations. The association of baseline motor impairment with incident dementia was analyzed using Cox proportional hazards models. Facial expression, tremor, rigidity, and bradykinesia were analyzed as part of subscore A (indicative of dopaminergic deficiency); speech and axial impairment were analyzed as part of subscore B (indicative of predominantly nondopaminergic deficiency). The correlation between the six motor domains and age was also analyzed.

RESULTS

Of 173 patients followed for at least 1 year, 50 became demented according to the Diagnostic and Statistical Manual of Mental Disorders, revised 3rd edition (DSM III-R) criteria (mean follow-up, 3.6 +/- 2. 2 years). When both subscores A and B were entered into the Cox model, subscore B was associated with incident dementia (relative risk = 1.19; 95% CI, 1.09 to 1.30; p = 0.0001), in addition to gender, age, and education, whereas subscore A was not (relative risk = 1.03; 95% CI, 0.99 to 1.07; p = 0.19). Of the six motor domains, speech and bradykinesia were associated with incident dementia (p < 0.05), and axial impairment approached significance (p = 0.06). Only axial impairment was correlated with age (correlation coefficient = 0.32; p < 0.001).

CONCLUSION

The findings suggest that motor impairment mediated predominantly by nondopaminergic systems is associated with incident dementia in PD. Axial impairment may be the result of a combined effect of the disease and the aging process.

Validity of family history for the diagnosis of dementia among siblings of patients with late-onset Alzheimer's disease

We examined 180 siblings of 127 probands with probable or possible Alzheimer's dementia (AD) in a family study of AD. The overall sensitivity of a simple family history questionnaire was 64% and the specificity was 84%. Sensitivity improved 90-100% with minimal decline in specificity when we considered clinic-based vs. population survey patients. Higher education among informants and the availability of a spouse or a sibling as informant significantly increased sensitivity. Awareness of such factors may improve the yield of the family history in AD using a simple questionnaire.

Coordination of prehensile forces during precision grip in Huntington's disease

The present study examined the coordination of prehensile forces during precision grip in subjects with Huntington's disease (HD). Fingertip forces were measured in 12 subjects with HD and 12 age-matched controls during the lifting of an instrumented object whose weight and surface texture were varied. The results indicate that subjects with HD have impaired initiation and delayed transitions between movement sequences and produce excessive and variable forces. However, subjects with HD demonstrated anticipatory scaling of force development based on the object's expected physical properties (planning) and adjustment of the force to the object's actual physical properties (sensorimotor integration). The observed findings generally were unrelated to the overall disease severity. However, the variability in forces was correlated with functional capacity and motor performance suggesting that variability is a key feature of the motor deficit. These results provide insights into the impaired hand function observed in individuals with HD.

Mitochondrial DNA mutations in complex I and tRNA genes in Parkinson's disease

OBJECTIVE

To identify mitochondrial DNA (mtDNA) mutations that predispose to PD.

BACKGROUND

Mitochondrial complex I activity is deficient in PD. mtDNA mutations may account for the defect, but the specific mutations have not been identified.

METHODS

Complete sequencing was performed of all mtDNA-encoded complex I and transfer RNA (tRNA) genes in 28 PD patients and 8 control subjects, as well as screening of up to 243 additional PD patients and up to 209 control subjects by restriction digests for selected mutations.

RESULTS

In the PD patients, 15 complex I missense mutations and 9 tRNA mutations were identified. After screening additional subjects, rare PD patients were found to carry complex I mutations that altered highly conserved amino acids. However, no significant differences were found in the frequencies of any mutations in PD versus control groups. The authors were unable to confirm previously reported associations of mutations at nucleotide positions (np) 4336, 5460, and 15927/8 with PD. Complex I mutations previously linked to Leber's hereditary optic neuropathy, one of which has been linked to atypical parkinsonism, were not associated with PD.

CONCLUSIONS

mtDNA mutations with a high mutational burden (present in a high percentage of mtDNA molecules in an individual) in complex I or tRNA genes do not play a major role in the risk of PD in most PD patients. Further investigations are necessary to determine if any of the rare mtDNA mutations identified in PD patients play a role in the pathogenesis of PD in those few cases.

Rate of functional decline in Huntington's disease. Huntington Study Group

OBJECTIVE

To determine the rate of functional decline in a large cohort of patients with Huntington's disease (HD) followed at 43 sites by the Huntington Study Group (HSG).

METHODS

The annual rate of functional decline was measured using the Total Functional Capacity Scale (TFC) and the Independence Scale (IS) in 960 patients with definite HD followed prospectively for a mean of 18.3 months. All patients were rated with the Unified Huntington's Disease Rating Scale (UHDRS). Sample size calculations for hypothetical clinical trials were calculated.

RESULTS

A factor analysis of the UHDRS at baseline yielded 15 factors accounting for 77% of the variance. The TFC score declined at a rate of 0.72 units/year (standard error [SE] 0.04) and the IS score declined at a rate of 4.52 units/year (SE 0.23). Lower TFC score at baseline, indicating more severe impairment, was associated with less rapid annual decline in TFC score, perhaps reflecting the floor effect of the scale. The annual rate of decline for 575 patients with baseline TFC scores of 7 to 13 was 0.97 (SE 0.06), was 0.38 (SE 0.08) for 270 patients with baseline TFC scores of 3 to 6, and was 0.06 (SE 0.1) for 101 patients with TFC scores of 0 to 2. In multivariate analysis (n = 960), longer disease duration and better cognitive status at baseline were associated with a less rapid rate of decline in TFC score, whereas depressive symptomatology was the only factor associated with more rapid decline on the IS score. Age at onset of HD, sex, weight, and education did not affect decline on either score.

CONCLUSIONS

The comparable rates of decline on the TFC and the IS scores with other published studies suggest that these estimates of functional decline are representative of HD patients who are evaluated at HSG research sites. In longitudinal analysis, longer disease duration and better neuropsychological performance at baseline were associated with a less rapid rate of decline in TFC score, whereas depressive symptomatology at baseline was associated with a more rapid decline in the IS score. These rates of functional decline and the covariates that modify them should be considered in estimating statistical power and designing future therapeutic trials involving HD patients with early or moderately severe disease.

Transdermal selegiline in HIV-associated cognitive impairment: pilot, placebo-controlled study

The authors conducted a pilot randomized, double-blind, placebo-controlled clinical trial of the transdermal administration of selegiline in HIV+ patients to obtain preliminary data to assess its safety, tolerability, and impact on HIV-associated cognitive impairment. Both selegiline and placebo were well tolerated with few adverse events. Improvements favoring the selegiline group were suggested on single tests of verbal memory and motor/psychomotor performance, warranting a larger study.

Familial aggregation of Alzheimer disease among whites, African Americans, and Caribbean Hispanics in northern Manhattan

BACKGROUND

Alzheimer disease (AD) aggregates in families.

OBJECTIVE

To compare the familial aggregation and lifetime risk of AD to the age of 90 years in the first-degree relatives of patients with AD and unrelated controls among Caribbean Hispanics, African Americans, and whites in Washington Heights, Manhattan, New York, NY.

METHODS

Family history of AD and demographic information were obtained from informants of 435 patients with probable or possible AD concerning 1577 siblings and parents and from 1094 controls without dementia concerning 3952 siblings and parents.

RESULTS

Lifetime risk of AD to the age of 90 years was 25.9% in relatives of patients and 19.1% in relatives of controls. Rate ratio (RR) for AD in relatives of patients compared with relatives of controls was 1.5 overall (95% confidence interval [CI], 1.2-1.9), and was greater for siblings (RR, 1.8; 95% CI, 1.2-2.5) than for parents (RR, 1.2; 95% CI, 0.9-1.8). Within ethnic groups, RR for AD among relatives was significantly elevated in whites (RR, 2.0; 95% CI, 1.2-3.3) and Hispanics (RR, 1.5; 95% CI, 1.1-2.1), but the difference did not reach statistical significance in African Americans (RR, 1.4; 95% CI, 0.7-2.7). Risk of AD was greater among relatives who were women compared with men (RR, 1.5; 95% CI, 1.2-1.9).

CONCLUSIONS

Familial aggregation of AD was increased among families of patients compared with those of controls in all 3 ethnic groups. Risk of AD was highest among siblings and women relatives.

Influence of APOE genotype on familial aggregation of AD in an urban population

OBJECTIVE

To examine the influence of the proband's APOE genotype on AD among first-degree relatives in a community-based study of African Americans, whites, and Caribbean Hispanics.

METHODS

History of AD and demographic information were obtained on 1,073 siblings and parents of 312 patients with AD and 2,722 siblings and parents of 802 nondemented controls. APOE genotyping was performed on all 1,114 patients and controls.

RESULTS

A higher proportion of patients with AD (35%) than controls (27%) had one or more APOE-epsilon4 alleles (p = 0.03). When compared with relatives of controls without an APOE-epsilon4 allele, the risk for AD was increased in first-degree relatives of both patients (rate ratio [RR] = 1.9, 95% confidence interval [CI] = 1.2 to 3.1) and controls (RR = 1.8, 95% CI = 1.2 to 2.6) with one or more APOE-epsilone alleles, regardless of ethnic group. There was a similar trend of increased risk in relatives of patients without an APOE-epsilon4 allele, but this was limited to Hispanics and African Americans.

CONCLUSIONS

The presence of an APOE-epsilon4 allele increases risk for AD among first-degree relatives, regardless of the probands' disease status, among all ethnic groups. Relatives of patients without an APOE-epsilon4 allele were also at increased risk for AD among Hispanics and African Americans, suggesting that other genes or risk factors may influence risk.