The EADC-ADNI Harmonized Protocol for manual hippocampal segmentation on magnetic resonance: evidence of validity.

Background: An international Delphi panel has defined a harmonized protocol (HarP) for the manual segmentation of the hippocampus on MR. The aim of this study is to study the concurrent validity of the HarP toward local protocols, and its major sources of variance.

Methods: Fourteen tracers segmented 10 Alzheimer's Disease Neuroimaging Initiative (ADNI) cases scanned at 1.

Delphi definition of the EADC-ADNI Harmonized Protocol for hippocampal segmentation on magnetic resonance.

Background: This study aimed to have international experts converge on a harmonized definition of whole hippocampus boundaries and segmentation procedures, to define standard operating procedures for magnetic resonance (MR)-based manual hippocampal segmentation.

Methods: The panel received a questionnaire regarding whole hippocampus boundaries and segmentation procedures. Quantitative information was supplied to allow evidence-based answers.

Visuoperceptive region atrophy independent of cognitive status in patients with Parkinson's disease with hallucinations.

Visual hallucinations are frequent, disabling complications of advanced Parkinson's disease, but their neuroanatomical basis is incompletely understood. Previous structural brain magnetic resonance imaging studies suggest volume loss in the mesial temporal lobe and limbic regions in subjects with Parkinson's disease with visual hallucinations, relative to those without visual hallucinations. However, these studies have not always controlled for the presence of cognitive impairment or dementia, which are common co-morbidities of hallucinations in Parkinson's disease and whose neuroanatomical substrates may involve mesial temporal lobe and limbic regions.

Selected findings from the Religious Orders Study and Rush Memory and Aging Project.

The Religious Orders Study and the Rush Memory and Aging Project are both cohort studies of aging and dementia that include organ donation at death. Together, more than 2,700 persons have agreed to annual clinical evaluation and brain donation at death. A subset of participants also participated in a substudy that included ante-mortem imaging.

Entorhinal cortex atrophy differentiates Parkinson's disease patients with and without dementia.

Volumetric measures of mesial temporal lobe structures on MRI scans recently have been explored as potential biomarkers of dementia in patients with PD, with investigations primarily focused on hippocampal volume. Both in vivo MRI and postmortem tissue studies in Alzheimer's disease, however, demonstrate that the entorhinal cortex (ERC) is involved earlier in disease-related pathology than the hippocampus. The ERC, a region integral in declarative memory function, projects multimodal sensory information to the hippocampus through the perforant path.

Association of common genetic variants in GPCPD1 with scaling of visual cortical surface area in humans.

Visual cortical surface area varies two- to threefold between human individuals, is highly heritable, and has been correlated with visual acuity and visual perception. However, it is still largely unknown what specific genetic and environmental factors contribute to normal variation in the area of visual cortex. To identify SNPs associated with the proportional surface area of visual cortex, we performed a genome-wide association study followed by replication in two independent cohorts.

Mild cognitive impairment: pathology and mechanisms.

Mild cognitive impairment (MCI) is rapidly becoming one of the most common clinical manifestations affecting the elderly. The pathologic and molecular substrate of people diagnosed with MCI is not well established. Since MCI is a human specific disorder and neither the clinical nor the neuropathological course appears to follow a direct linear path, it is imperative to characterize neuropathology changes in the brains of people who came to autopsy with a well-characterized clinical diagnosis of MCI.

Survey of protocols for the manual segmentation of the hippocampus: preparatory steps towards a joint EADC-ADNI harmonized protocol.

Manual segmentation from magnetic resonance imaging (MR) is the gold standard for evaluating hippocampal atrophy in Alzheimer's disease (AD). Nonetheless, different segmentation protocols provide up to 2.5-fold volume differences.

Age-related changes in the mesial temporal lobe: the parahippocampal white matter region.

The perforant pathway originates from cells in the entorhinal cortex and relays sensory information from the neocortex to the hippocampus, a region critical for memory function. Imaging studies have demonstrated structural alterations in the parahippocampal white matter in the region of the perforant pathway in people at risk for developing Alzheimer's disease. It is not clear, however, if changes noted in this region are indicative of pathological aging or are a function of the normal aging process.

Entorhinal cortex volume is associated with episodic memory related brain activation in normal aging and amnesic mild cognitive impairment.

The present study examined the relationship between entorhinal cortex and hippocampal volume with fMRI activation during episodic memory function in elderly controls with no cognitive impairment and individuals with amnesic mild cognitive impairment (aMCI). Both groups displayed limited evidence for a relationship between hippocampal volume and fMRI activation. Smaller right entorhinal cortex volume was correlated with reduced activation in left and right medial frontal cortex (BA 8) during incidental encoding for both aMCI and elderly controls.

Atrophy and dysfunction of parahippocampal white matter in mild Alzheimer's disease.

In addition to atrophy of mesial temporal lobe structures critical for memory function, white matter projections to the hippocampus may be compromised in individuals with mild Alzheimer's disease (AD), thereby compounding the memory difficulty. In the present study, high-resolution structural imaging and diffusion tensor imaging techniques were used to examine microstructural alterations in the parahippocampal white matter (PWM) region that includes the perforant path. Results demonstrated white matter volume loss bilaterally in the PWM in patients with mild AD.

Regional differences in relationships between apparent white matter integrity, cognition and mood in patients with ischemic stroke.

White matter changes are one potential etiology of behavioral changes in cerebrovascular disease. Whole brain diffusion tensor imaging-fractional anisotropy (DTI-FA) as a measure of apparent white matter integrity is related to cognitive function in cerebrovascular disease. However, white matter changes are not uniform, nor are their effects.

Gray matter atrophy in patients with ischemic stroke with cognitive impairment.

Background And Purpose: Patients with ischemic stroke are at risk for developing vascular cognitive impairment ranging from mild impairments to dementia. MRI findings of infarction, white matter hyperintensities, and global cerebral atrophy have been implicated in the development of vascular cognitive impairment. The present study investigated regional gray matter volume differences between patients with ischemic stroke with no cognitive impairment and those with impairment in at least one domain of cognitive function.

Hippocampal atrophy and disconnection in incipient and mild Alzheimer's disease.

Quantitative imaging techniques allow the in vivo investigation of age and disease related changes in the brain and their relation to cognitive function. In this chapter we review imaging evidence indicating that the entorhinal cortex and hippocampus show atrophy very early in Alzheimer's disease (AD) and in individuals who are at risk of developing AD compared to age appropriate controls. Furthermore, the extent and rate of atrophy of the entorhinal cortex, a brain region pathologically involved very early in the disease process, can predict who among the elderly will develop AD.

Hippocampal disconnection contributes to memory dysfunction in individuals at risk for Alzheimer's disease.

The concept of amnestic mild cognitive impairment (MCI) describes older people who show a decline predominantly in memory function, but who do not meet criteria for dementia. Because such individuals are at high risk for developing Alzheimer's disease, they are of great interest for understanding the prodromal stages of the disease process. The mechanism underlying memory dysfunction in people with MCI is not fully understood.

Basic research in epilepsy and aging.

A PubMed search of the years 1965 to 2003 found only 30 articles that were directly related to modeling seizures or epilepsy in aged animals. This lack of research is disturbing but explainable because of the high cost of aged animals and their increasing infirmity. Many changes occur in the older brain: cell loss in the hippocampal formation, changes in long-term potentiation maintenance, alteration in kindling, increased susceptibility to status epilepticus, and neuronal damage from stroke.

Longitudinal changes in white matter following ischemic stroke: a three-year follow-up study.

Information on longitudinal changes in white matter after stroke is limited. The aim of the present study was to quantitatively investigate longitudinal changes in the microstructural integrity of non-lesioned white matter at 1-3 years following ischemic stroke. In a sample of 80 ischemic stroke patients, we obtained diffusion tensor imaging (DTI) measures of fractional anisotropy (FA), an apparent measure of white matter integrity, in radiologically normal-appearing white matter at baseline and 3 years of follow-up.

Relating medial temporal lobe volume to frontal fMRI activation for memory encoding in older adults.

Neuroimaging research on the brain basis of memory decline in older adults typically has examined age-related changes either in structure or in function. Structural imaging studies have found that smaller medial temporal lobe (MTL) volumes are associated with lower memory performance. Functional imaging studies have found that older adults often exhibit bilateral frontal-lobe activation under conditions where young adults exhibit unilateral frontal activation.

White matter changes in mild cognitive impairment and AD: A diffusion tensor imaging study.

Diffusion tensor imaging (DTI) can detect, in vivo, the directionality of molecular diffusion and estimate the microstructural integrity of white matter (WM) tracts. In this study, we examined WM changes in patients with Alzheimer's disease (AD) and in subjects with amnestic mild cognitive impairment (MCI) who are at greater risk for developing AD. A DTI index of WM integrity, fractional anisotropy (FA), was calculated in 14 patients with probable mild AD, 14 participants with MCI and 21 elderly healthy controls (NC).

The pattern of neuropsychological deficits in Vascular Cognitive Impairment-No Dementia (Vascular CIND).

We examined the pattern of neuropsychological deficits in Vascular Cognitive Impairment-No Dementia (Vascular CIND) by comparing the cognitive and behavioral performance of 41 post-stroke Vascular CIND patients to that of 62 post-stroke patients with no cognitive impairment (NCI). Neuropsychological test scores were grouped into seven cognitive and four behavioral domains, then converted to standardized, weighted principle component scores (PCS) for each domain. Multivariate logistic regression models built on cognitive domains found the immediate recall and psychomotor domains to best predict diagnostic group membership.

MRI-derived entorhinal volume is a good predictor of conversion from MCI to AD.

With high-resolution quantitative magnetic resonance imaging (MRI) techniques, it is possible to examine alterations in brain anatomy in vivo and to identify regions affected in the earliest stages of Alzheimer's disease (AD). In the present study, 27 patients diagnosed with mild cognitive impairment (MCI) received a high-resolution MRI scan at baseline and were followed with yearly clinical evaluations. Ten of the 27 patients converted to AD during a 36-month period following the baseline clinical evaluation.

Differential associations between entorhinal and hippocampal volumes and memory performance in older adults.

Magnetic resonance imaging-derived entorhinal and hippocampal volumes were measured in 14 nondemented, community-dwelling older adults. Participants were selected so that memory scores from 2 years prior to scanning varied widely but were not deficient relative to age-appropriate norms. A median split of these memory scores defined high-memory and low-memory groups.

The localizing yield of sphenoidal and anterior temporal electrodes in ictal recordings: a comparison study.

Purpose: To compare the localizing yield of sphenoidal electrodes placed under fluoroscopic guidance (SEs) and anterior temporal electrodes (ATEs) in ictal recordings from a group of patients with seizure disorders of anterior temporal origin.

Methods: We compared ictal recordings of 156 seizures obtained with SEs and ATEs from 40 consecutive patients with seizures of anterior temporal origin. Four electroencephalographers reviewed ictal recordings independently and blind to the patients' identity, presurgical data, and inclusion of ATEs or SEs.