Prediction of longitudinal cognitive decline in normal elderly with subjective complaints using electrophysiological imaging.

An extensive literature reports changes in quantitative electroencephalogram (QEEG) with aging and a relationship between magnitude of changes and degree of clinical deterioration in progressive dementia. Longitudinal studies have demonstrated QEEG differences between mild cognitively impaired (MCI) elderly who go on to decline and those who do not. This study focuses on normal elderly with subjective cognitive complaints to assess the utility of QEEG in predicting future decline within 7 years. Forty-four normal elderly received extensive clinical, neurocognitive and QEEG examinations at baseline. All study subjects (N = 44) had only subjective complaints but no objective evidence of cognitive deficit (evaluated using the Global Deterioration Scale [GDS] score, GDS stage = 2) at baseline and were re-evaluated during 7-9 year follow-up. Baseline QEEGs of Decliners differed significantly (p < 0.0001, by MANOVA) from Non-Decliners, characterized by increases in theta power, slowing of mean frequency, and changes in covariance among regions, especially on the right hemisphere. Using logistic regression, an R2 of 0.93 (p < 0.001) was obtained between baseline QEEG features and probability of future decline, with an overall predictive accuracy of 90%. These data indicate high sensitivity and specificity for baseline QEEG as a differential predictor of future cognitive state in normal, subjectively impaired elderly.

Longitudinal CSF and MRI biomarkers improve the diagnosis of mild cognitive impairment.

The diagnosis of Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI) is limited because it is based on non-specific behavioral and neuroimaging findings. The lesions of Alzheimer's disease: amyloid beta (Abeta) deposits, tau pathology and cellular oxidative damage, affect the hippocampus in the earlier stages causing memory impairment. In a 2-year longitudinal study of MCI patients and normal controls, we examined the hypothesis that cerebrospinal fluid (CSF) markers for these pathological features improve the diagnostic accuracy over memory and magnetic resonance imaging (MRI)-hippocampal volume evaluations. Relative to control, MCI patients showed decreased memory and hippocampal volumes and elevated CSF levels of hyperphosphorylated tau and isoprostane. These two CSF measures consistently improved the diagnostic accuracy over the memory measures and the isoprostane measure incremented the accuracy of the hippocampal volume achieving overall diagnostic accuracies of about 90%. Among MCI patients, over 2 years, longitudinal hippocampal volume losses were closely associated with increasing hyperphosphorylated tau and decreasing amyloid beta-42 levels. These results demonstrate that CSF biomarkers for AD contribute to the characterization of MCI.

Is the functional decline of Parkinson's disease similar to the functional decline of Alzheimer's disease?

Since many Parkinson's disease (PD) subjects develop dementia, we determined whether the correlation between functional and cognitive decline seen in Alzheimer's disease (AD) is seen in PD. Seventy-five PD subjects with and without dementia and 103 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), the UPDRS motor portion, and the MMSE. In AD/MCI subjects, changes in FAST and GDS scores correlated with MMSE (rho=-0.814, P<0.001; rho=-0.840, P<0.001, respectively). In PD subjects, the FAST and GDS also correlated with MMSE (rho=-0.675, P<0.001; rho=-0.647, P<0.001, respectively). The UPDRS correlated with the GDS and FAST more closely in PD than in AD. Similar to AD, functional declines in PD correlates with cognitive decline and may be influenced by motor disability in PD.

Relationships between regional neuronal loss and neurofibrillary changes in the hippocampal formation and duration and severity of Alzheimer disease.

The total numbers of neurons with and without neurofibrillary changes in the hippocampal subdivisions were estimated in 16 subjects with Alzheimer disease (AD) and in 5 normal elderly controls. On the basis of clinical symptoms, AD patients were subdivided into relatively less (AD-1. Functional Assessment Staging [FAST] stages 7a to 7c) and more severely affected (AD-2, FAST stages 7e to 7f) patient groups. In the AD-1 group relative to controls, the total number of neurons was reduced only in CA1 and in the subiculum. In the AD-2 group, neuronal losses were found in all sectors of the cornu Ammonis and in the subiculum and ranged from 53% in CA3 to 86% in CA1. The dentate gyrus was the only hippocampal subdivision without significant neuronal loss. Within the combined AD patient groups, significant correlations were noted between both clinical stage and duration of AD and both the total number of neurons and the percentage of neurons with neurofibrillary changes in CA1, CA4, and the subiculum. Regression analyses predicted neuronal losses over the maximal observed duration of 22 years of 87% in CA1, 63% in CA4, and 77% in the subiculum. Our data suggest that over the course of AD, continuous neurofibrillary tangle formation and continuous neuronal loss occur in the hippocampal subdivisions. The rate of neuronal loss appears to be similar for CA1, CA4, and the subiculum.

Sister chromatid exchanges and cell cycle kinetics in Alzheimer's disease.

Six female outpatients with Alzheimer's disease (AD) along with four female controls of a similar age range were analyzed for sister chromatid exchangers (SCEs), cell cycle kinetics, and sensitivity to mutagens, in lymphocyte cultures. The mean level of SCEs for the AD patients was 11.40 SCEs/metaphase, while that for the controls was 9.12. The difference between the two groups was significant as shown by the Wilcoxon rank-sum test (p = 0.05). Cell cycle was 50% longer both in the AD patients (31.7 hr) and aged controls (31.5 hr) than in normal young adults (21.76 hr). Mitomycin-C (MMC) decreased the mitotic index in AD patients by 35% and in controls by only 12%. MMC also increased the cell cycle duration in AD patients by a greater extent (20%) than it did in the controls (13.5%), and AD cells were more sensitive to the toxic effects of bromodeoxyuridine. What appeared to be chromosomes with prematurely divided centromeres were also observed in AD cells.

Abnormal temporal lobe response in Alzheimer's disease during cognitive processing as measured by 11C-2-deoxy-D-glucose and PET.

Elderly controls and probable Alzheimer's disease patients underwent serial positron emission tomography (PET) studies during a baseline condition and while performing a verbal memory task. For the temporal lobes, all 7 Alzheimer patients demonstrated a relative shift in glucose metabolic rates to the right hemisphere during the memory condition relative to baseline, and 5 of 7 controls showed a shift to the left hemisphere. Baseline absolute regional metabolic rates replicate previous findings and were somewhat less useful than the memory challenge in differentiating patients from controls. These results indicate that a temporal lobe abnormality in Alzheimer's disease is related to memory performance.

Computed tomography and positron emission transaxial tomography evaluations of normal aging and Alzheimer's disease.

Young normal subjects, old normal subjects, and patients with senile dementia of the Alzheimer's type (SDAT) were studied with both computed tomography (CT) and positron emission transaxial tomography (PETT). Increases in ventricular size with both aging and disease were measured. Regional glucose metabolic rate was not affected by age, but was markedly reduced in SDAT patients. These data indicate that in normal aging, structural brain changes may be more salient than biochemical changes. Although both structural and biochemical changes occur in SDAT, the biochemical changes are more marked. The results suggest that PETT is potentially more useful than CT in the in vivo diagnosis of SDAT.

Quantitative EEG correlates of cognitive deterioration in the elderly.

We report on the quantitative analysis of the EEG (QEEG), using the Neurometric method, in large samples of normal elderly; normal subjectively impaired elderly; patients with mild cognitive impairment; patients presenting with a continuum of primary cognitive deterioration from mild to moderately severe as measured by the Global Deterioration Scale (GDS), compatible with dementia of the Alzheimer's type (DAT). Neurometric QEEG measures were found to be a sensitive index of degree of cognitive impairment, especially reflected in increased absolute and relative power in the theta band, with delta increasing in later stages of deterioration. While these abnormalities were widespread, neither localized or lateralized, MANOVA's for GDS and relative power in theta reached highest significance in a bilateral temporo-parietal arc. A possible relationship between hippocampal dysfunction, cognitive deterioration, and theta abnormalities is discussed in relation to these findings. The results suggest that Neurometric QEEG features are sensitive to the earliest presence of subjective cognitive dysfunction and might be useful in the initial evaluation of patients with suspected dementia, as well as in estimating the degree of cognitive deterioration in DAT patients.

Computed tomography evaluations of brain-behavior relationships in senile dementia of the Alzheimer's type.

Neuropathological investigations have demonstrated brain-behavior relationships in senile dementia of the Alzheimer's type (SDAT), but CT studies have not produced consistent findings. We hypothesized that these discouraging results were in part due to limitations in the methods of CT scan evaluations, and to non-homogeneity of patient populations. The present study examined 43 out-patients with the presumptive diagnosis of SDAT using 37 cognitive test measures and 3 independent CT evaluation strategies. The CT methods included a new rank ordering procedure and two previously used techniques, physical measurement and 4-point rating. Highly significant (p less than or equal to 0.01) brain-behavior correlations were attained using the ranking and rating procedures for evaluation of ventricular and cortical pathology. It was found that rank ordering has high interrater reliability and is superior to the other methods for the evaluation of the ventricular system. The physical measurement of the third ventricle is the single most powerful linear correlate of cognitive impairment. Measurement of cortical sulci are of no correlational significance. Multiple regression analyses indicated that global assessments are the best cognitive predictors of both ventricular and cortical pathology. Thus the present study has demonstrated brain-behavior relationships in vivo in SDAT.

Neurofibrillary pathology--correlation with hippocampal formation atrophy in Alzheimer disease.

The three-dimensionally reconstructed hippocampal formations in three patients with very severe, immobile Alzheimer disease (AD) and three age-matched nondemented individuals were examined for a correlation between atrophy of hippocampal formation subdivisions and neurofibrillary changes, neuronal loss, and extent of amyloid deposition in plaques and vessels. In AD, a similar severe volume loss was observed in both cellular layers and layers composed of fibers. A strong correlation between the decrease in the volume of hippocampal formation subdivisions and the decrease in the total number of neurons suggests a causative role for neuronal loss in hippocampal formation volumetric loss. Strong regional correlations between the relative decreases in the total number of neurons and the relative increases in the total number of neurofibrillary tangles implicates neurofibrillary pathology as a possible etiologic proximate factor in neuronal and volumetric loss in the hippocampal formation of AD patients.

Positron emission tomography in the study of aging and senile dementia.

(18)F-2-deoxy-2-fluoro-D-glucose ((18)FDG) is a positron emitting tracer for rate of glucose utilization in brain. When used in conjunction with positron emission tomography (PET), the PET-FDG technique permits in vivo quantitation of regional brain metabolism in man. We have applied this technique to the study of regional brain function in normal aging and senile dementia. Preliminary results for 7 patients with senile dementia of the Alzheimer's type (SDAT) and 3 elderly normal subjects indicated a large, statistically significant (p < 0.01) diminution in rate of glucose utilization in SDAT. Furthermore, the degree of diminution in metabolic activity in SDAT was highly correlated with objective measures of degree of cognitive impairment. These results demonstrate the feasibility and potential utility of the PET-FDG technique for studying regional brain function in normal aging and dementia.

Frequency of hippocampal formation atrophy in normal aging and Alzheimer's disease.

We used CT and MR to examine the frequency of occurrence of hippocampal formation atrophy (HA) in a research clinic population of 130 normal elderly, 72 nondemented patients with very mild memory and cognitive impairments (MCI), 73 mild Alzheimer's disease (AD) patients, and 130 patients with moderate to severe AD. HA was found in 29% of the normal elderly group and its frequency of occurrence was strongly related to increasing age. For normal elderly 60-75 years of age, 15% had HA: the proportion rose to 48% in subjects 76-90 years of age. Among the three groups of impaired patients, the frequencies of HA ranged from 78% in the MCI patients to 96% in the advanced AD group. Unlike the normal elderly group, the percentages were not related to age. In both the normal elderly group and MCI group disproportionately more males than females had HA. After controlling for learning and the effects of generalized brain changes as reflected in ventricular size, only in the normal group was HA associated with reduced delayed verbal recall performance. Follow-up examinations for 15 individuals with baseline HA. 4 who at entry were MCI and 11 probable AD, yielded clinical and neuropathologic diagnoses of AD in all cases. The results of the present study indicate that hippocampal formation atrophy is associated with memory and cognitive impairments. Further longitudinal and neuropathologic work is required to validate the relationship between hippocampal formation atrophy and AD.

An overview of pharmacologic treatment of cognitive decline in the aged.

The most widely known substances that have been investigated for treating cognitive deterioration in the aged are cerebral vasodilators, Gerovital H3, psychostimulants, "nootropics," neuropeptides, and neurotransmitters. The rationale for the choice of specific agents has shifted as our conceptions regarding the origins of cognitive decline have changed; we now know that most cognitive deterioration occurs independently of arteriosclerotic vascular changes. Substances currently being investigated because of their effects on brain electrophysiology, on neurohumoral processes, or on central neurotransmitters show promise.

The Global Deterioration Scale for assessment of primary degenerative dementia.

Cognitive decline associated with old age and consistent with the diagnosis of primary degenerative dementia is a unique clinical syndrome with characteristic phenomena and progression. The authors describe a Global Deterioration Scale for the assessment of primary degenerative dementia and delineation of its stages. The authors have used the Global Deterioration Scale successfully for more than 5 years and have validated it against behavioral, neuroanatomic, and neurophysiologic measures in patients with primary degenerative dementia.

A curriculum for education in geriatric psychiatry.

The authors present recommendations for educating medical students and psychiatric residents in geropsychiatry. They are primarily concerned with the objectives and methods rather than the content of training. Proposals are structured in terms of training objectives and educational settings in which such training takes place. The proposals are intended to be specific enough to be truly useful and at the same time sufficiently generalizable to adapt to geropsychiatric training in a variety of institutions. Priority is given to integrating knowledge of normal and abnormal aging with the clinical skills and empathy necessary to approach patients with competence and understanding.

Dexamethasone suppression in dementia, depression, and normal aging.

Dexamethasone suppression tests (DSTs) were performed for 18 moderately demented elderly patients, 66 depressed elderly outpatients, and 25 age- and sex-matched healthy elderly control subjects. Seventeen percent of the demented patients and 4% of the normal subjects were DST nonsuppressors, compared to 38% of the total depressed group. The postdexamethasone plasma cortisol levels of the dementia group fell between those of the normal and the depressed subjects. In addition, demented patients had postdexamethasone cortisol levels significantly lower than those of depressed patients with high Hamilton depression scores. Older subjects in all diagnostic categories, including normal subjects, had higher postdexamethasone plasma cortisol levels.

The neurologic syndrome of severe Alzheimer's disease. Relationship to functional decline.

OBJECTIVE: To assess the possible association between functional decline and noncognitive neurologic signs in the severe stages of Alzheimer's disease (AD). DESIGN: Case series. SETTING: Subjects from a dementia research referral center, longitudinally followed, when necessary, into residential home and nursing home settings. PATIENTS: A consecutive sample of 56 patients (16 men, 40 women; mean age, 74.6 years) with a clinical diagnosis of probable AD in the moderately severe and severe stages. MAIN OUTCOME MEASURE: For global dementia severity, the Global Deterioration Scale and Mini-Mental State examination; for functional assessment, the Functional Assessment Staging Scale; and for assessment of neurologic function, nine release signs (primitive reflexes), 10 measures of extrapyramidal function, and five measures of pyramidal function, including deep-tendon reflexes and plantar signs. Changes in activity or presence of neurologic signs were rated on a seven-point scale. Results were analyzed in terms of prevalence and magnitude of change in relation to functional impairment. RESULTS: Prevalence and mean scores of certain release signs, certain extrapyramidal measures commonly referred to as bradykinesia, and certain pyramidal signs showed significant associations with the magnitude of functional impairment. Other neurologic measures, for example, the palmomental reflex, and certain extrapyramidal measures commonly seen in Parkinson's disease, including the glabellar blink reflex, cogwheeling, tremor, shuffling gait, and festination, did not show significant increments with continuing functional decline in AD. CONCLUSIONS: Functional decline in the advanced stages of AD appears to be associated with a particular combination of progressive cortical, extrapyramidal, and pyramidal system dysfunction. The characteristics of this neurologic syndrome of the severe stages of AD differ from those of other neurologic disorders. For example, the pattern of extrapyramidal system disease is different from that seen in Parkinson's disease. The neurologic syndrome of the severe stages of AD is amenable to description and deserves further investigation.

Cognition-independent neurologic symptoms in normal aging and probable Alzheimer's disease.

Deep tendon reflexes, plantar responses, muscle tone, and release signs were studied as 14 individual clinical variables and as five summary variables in 135 aged subjects, including 27 control subjects, 20 subjects with mild cognitive impairment, and 88 subjects with successive stages of probable Alzheimer's disease. Changes in activity of elicited responses were rated on a seven-point scale. Results were analyzed both as prevalence and mean degree of change in activity. Rating on a variable combining all 14 individual variables was significantly higher in a group with mild cognitive impairment than in a control group. Subjects with an early stage of Alzheimer's disease had both higher prevalence of increased activity and increased mean scores of deep tendon reflexes and muscle tone. They had a higher prevalence of increased activity on a variable combining three release signs. Patients with a late stage of Alzheimer's disease had significantly increased prevalence and mean scores of muscle tone and grasping and sucking reflexes compared with control subjects and patients with the early stage of Alzheimer's disease.

Topography of cross-sectional and longitudinal glucose metabolic deficits in Alzheimer's disease. Pathophysiologic implications.

Positron emission tomographic studies of cerebral glucose metabolism have shown high diagnostic specificity in distinguishing among the degenerative dementias and differentiating between Alzheimer's disease (AD) and normal aging. The current investigation was undertaken to characterize the regional glucose metabolic deficits in AD, using cross-sectional and longitudinal study designs. All subjects met the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD (n = 45) or were normal (n = 20), and the AD subjects were subdivided into incipient and mild AD and moderate plus moderately severe subgroups based on the Global Deterioration Scale. The subjects underwent a non-contrast computed tomographic scan and a positron emission tomographic (PETT VI) scan. The AD subjects (n = 14) and normal control subjects (n = 15) received evaluations 2 to 3 years after baseline study. The brain regions that show glucose metabolic deficits cross-sectionally (temporal and parietal association areas, with lesser degrees of deficit in subcortical gray matter structures), over the stages of AD, also show further deficits longitudinally within the same AD subjects. The reduction in glucose metabolism is greater than would be expected from the degree of brain atrophy. The glucose metabolic deficits are discussed in the context of neuropathologic findings and neurotransmitter deficits in AD.

Mild cognitive impairment in the elderly: predictors of dementia.

We conducted full diagnostic evaluations, including a comprehensive cognitive assessment battery, of a group of 32 elderly subjects with a clinically identified mild cognitive impairment and a group of 32 age-matched and education-matched normal subjects. The mildly impaired subjects performed significantly more poorly than the controls on tests of recent memory, remote memory, language function, concept formation, and visuospatial praxis. Follow-up evaluations of cognitive status 2 years later revealed clinically detectable cognitive decline relative baseline in 23 (72%) of the mildly impaired subjects. Several of the objective psychological tests accurately discriminated at baseline between the decliners and nondecliners in the mildly impaired group. Among the 20 mildly impaired subjects with no complicating conditions, 16 exhibited cognitive deterioration between baseline and follow-up. These results suggest that most elderly subjects with mild cognitive deficits, as determined by clinical evaluation and objective psychological testing, will manifest the progressive mental deterioration characteristic of dementia and that psychometric predictors can be used to distinguish between benign and more significant underlying disorders in mildly impaired elderly subjects.