Odorant-induced brain activation as a function of normal aging and Alzheimer's disease: A preliminary study.

Olfactory dysfunction consistently occurs in patients with Alzheimer's disease (AD), beyond the mild and gradual decline in olfactory ability found in normal aging. This dysfunction begins early in the disease course, typically before clinical diagnosis, and progresses with disease severity. While odor identification and detection deficits clearly differentiate AD from controls, there remains uncertainty as to whether these are determined by olfactory threshold.

Olfaction Modulates Inter-Subject Correlation of Neural Responses.

Odors can be powerful stimulants. It is well-established that odors provide strong cues for recall of locations, people and events. The effects of specific scents on other cognitive functions are less well-established.

The impact of anxiety on conversion from mild cognitive impairment to Alzheimer's disease.

Objective: To compare state and trait anxiety in mild cognitive impairment (MCI) patients and matched control subjects, and to assess the impact of these variables in predicting conversion to Alzheimer's disease.

Methods: One hundred and forty-eight patients with MCI, broadly defined, were assessed and followed systematically. Baseline predictors for follow-up conversion to AD (entire sample: 39/148 converted to Alzheimer's disease (AD)) included the Spielberger State-Trait Anxiety Inventory (STAI).

Olfactory identification deficits and MCI in a multi-ethnic elderly community sample.

Odor identification deficits occur in Alzheimer's disease (AD) and mild cognitive impairment (MCI), and predict clinical conversion from MCI to AD. In an epidemiologic study conducted in a multi-ethnic community elderly sample (average 80 years old), the University of Pennsylvania Smell Identification Test (UPSIT, range 0-40) was administered to 1092 non-demented subjects. Women (mean 26.

Combining early markers strongly predicts conversion from mild cognitive impairment to Alzheimer's disease.

Background: The utility of combining early markers to predict conversion from mild cognitive impairment (MCI) to Alzheimer's Disease (AD) remains uncertain.

Methods: Included in the study were 148 outpatients with MCI, broadly defined, followed at 6-month intervals. Hypothesized baseline predictors for follow-up conversion to AD (entire sample: 39/148 converters) were cognitive test performance, informant report of functional impairment, apolipoprotein E genotype, olfactory identification deficit, and magnetic resonance imaging (MRI) hippocampal and entorhinal cortex volumes.

Mild Parkinsonian signs are associated with lower olfactory test scores in the community-dwelling elderly.

Mild Parkinsonian signs (MPS, impaired gait, rigidity, bradykinesia, rest tremor) are commonly found during the clinical examination of older people and may be a precursor to Parkinson's disease (PD) or Alzheimer's disease (AD). Marked deficits in olfaction occur in PD and AD. The objective of this study was to determine whether University of Pennsylvania Smell Test (UPSIT) scores were lower in nondemented community-dwelling elderly with versus without MPS.

Randomized double-blind placebo-controlled donepezil augmentation in antidepressant-treated elderly patients with depression and cognitive impairment: a pilot study.

Objective: To assess combined antidepressant and cognitive enhancer treatment in elderly patients presenting with depression plus cognitive impairment.

Methods: Twenty-three elderly (>50 years old) depressed, cognitively impaired (DEP-CI) patients participated in a pilot study. We evaluated whether, after 8 weeks of open antidepressant treatment, donepezil HCl (Aricept) would afford added cognitive benefit compared to placebo in a randomized 12-week trial.

Validation and optimization of statistical approaches for modeling odorant-induced fMRI signal changes in olfactory-related brain areas.

Recent neuroimaging studies have converged to show that odorant-induced responses to prolonged stimulation in primary olfactory cortex (POC) are characterized by a rapidly habituating time course. Different statistical approaches have effectively modeled this time course. One approach explicitly modeled rapid habituation using an exponentially decaying reference waveform that decreased to baseline levels within 30 to 40 s.

Olfactory dysfunction as a predictor of neurodegenerative disease.

Olfactory dysfunction is present in patients diagnosed with Alzheimer's disease or idiopathic Parkinson's disease and can differentiate each of these disorders from related disorders with similar clinical presentations. The pathologic hallmarks of each disease are present in brain regions involved in processing olfactory input. Both the olfactory functional deficits and the corroborating pathologic lesions are present in asymptomatic subjects with increased risk of developing these diseases.

Neuropsychological prediction of conversion to Alzheimer disease in patients with mild cognitive impairment.

Context: The likelihood of conversion to Alzheimer disease (AD) in mild cognitive impairment (MCI) and the "optimal" early markers of conversion need to be established.

Objectives: To evaluate conversion rates to AD in subtypes of MCI and to identify neuropsychological measures most predictive of the time to conversion.

Design: Patients were followed up semiannually and controls annually.

PET network abnormalities and cognitive decline in patients with mild cognitive impairment.

Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri.

A 10-item smell identification scale related to risk for Alzheimer's disease.

University of Pennsylvania Smell Identification Test data from control subjects (n = 63), patients with mild cognitive impairment (n = 147), and patients with Alzheimer's disease (n = 100) were analyzed to derive an optimal subset of items related to risk for Alzheimer's disease (ie, healthy through mild cognitive impairment to early and moderate disease stages). The derived 10-item scale performed comparably with the University of Pennsylvania Smell Identification Test in classifying subjects, and it strongly predicted conversion to Alzheimer's disease on follow-up evaluation in patients with mild cognitive impairment. Independent replication is needed to validate these findings.

Predictive utility of apolipoprotein E genotype for Alzheimer disease in outpatients with mild cognitive impairment.

Background: In cognitively impaired patients without dementia, the utility of apolipoprotein E (APOE) genotyping is unclear.

Objective: To evaluate the predictive utility of the APOE epsilon4 genotype for conversion to probable Alzheimer disease (AD).

Design: Naturalistic, longitudinal study.

Altered PET functional brain responses in cognitively intact elderly persons at risk for Alzheimer disease (carriers of the epsilon4 allele).

Objective: Few previous studies have investigated the association between APOE genotype and brain activation during performance of cognitive tasks in healthy middle-aged and elderly subjects, and the results have been mixed. The authors investigated APOE-mediated differential brain activation in a group of healthy elderly subjects.

Methods: Using H215O positron emission tomography (PET), they imaged 32 healthy subjects (26 non-epsilon4 carriers and 6 epsilon4 carriers) performing a serial shape-recognition memory task under two conditions: Simple Demand (SD), in which one shape was presented in each study trial, and Titrated Demand (TD), in which study list length was adjusted so that each subject recognized words at approximately 75% accuracy.

Covariance PET patterns in early Alzheimer's disease and subjects with cognitive impairment but no dementia: utility in group discrimination and correlations with functional performance.

Although multivariate analytic techniques might identify diagnostic patterns that are not captured by univariate methods, they have rarely been used to study the neural correlates of Alzheimer's disease (AD) or cognitive impairment. Nonquantitative H2(15)O PET scans were acquired during rest in 17 probable AD subjects selected for mild severity [mean-modified Mini Mental Status Examination (mMMS) 46/57; SD 5.1], 16 control subjects (mMMS 54; SD 2.