Recognition memory span in mildly and moderately demented patients with Alzheimer's disease

Inhibition of Rac1-dependent forgetting alleviates memory deficits in animal models of Alzheimer's disease

Accelerated forgetting has been identified as a feature of Alzheimer's disease (AD), but the therapeutic efficacy of the manipulation of biological mechanisms of forgetting has not been assessed in AD animal models. Ras-related C3 botulinum toxin substrate 1 (Rac1), a small GTPase, has been shown to regulate active forgetting in Drosophila and mice. Here, we showed that Rac1 activity is aberrantly elevated in the hippocampal tissues of AD patients and AD animal models. Moreover, amyloid-beta 42 could induce Rac1 activation in cultured cells. The elevation of Rac1 activity not only accelerated 6-hour spatial memory decay in 3-month-old APP/PS1 mice, but also significantly contributed to severe memory loss in aged APP/PS1 mice. A similar age-dependent Rac1 activity-based memory loss was also observed in an AD fly model. Moreover, inhibition of Rac1 activity could ameliorate cognitive defects and synaptic plasticity in AD animal models. Finally, two novel compounds, identified through behavioral screening of a randomly selected pool of brain permeable small molecules for their positive effect in rescuing memory loss in both fly and mouse models, were found to be capable of inhibiting Rac1 activity. Thus, multiple lines of evidence corroborate in supporting the idea that inhibition of Rac1 activity is effective for treating AD-related memory loss.

Diagnostic Accuracy of Memory Measures in Alzheimer's Dementia and Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

With an increasing focus on biomarkers in dementia research, illustrating the role of neuropsychological assessment in detecting mild cognitive impairment (MCI) and Alzheimer's dementia (AD) is important. This systematic review and meta-analysis, conducted in accordance with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) standards, summarizes the sensitivity and specificity of memory measures in individuals with MCI and AD. Both meta-analytic and qualitative examination of AD versus healthy control (HC) studies (n = 47) revealed generally high sensitivity and specificity (≥ 80% for AD comparisons) for measures of immediate (sensitivity = 87%, specificity = 88%) and delayed memory (sensitivity = 89%, specificity = 89%), especially those involving word-list recall. Examination of MCI versus HC studies (n = 38) revealed generally lower diagnostic accuracy for both immediate (sensitivity = 72%, specificity = 81%) and delayed memory (sensitivity = 75%, specificity = 81%). Measures that differentiated AD from other conditions (n = 10 studies) yielded mixed results, with generally high sensitivity in the context of low or variable specificity. Results confirm that memory measures have high diagnostic accuracy for identification of AD, are promising but require further refinement for identification of MCI, and provide support for ongoing investigation of neuropsychological assessment as a cognitive biomarker of preclinical AD. Emphasizing diagnostic test accuracy statistics over null hypothesis testing in future studies will promote the ongoing use of neuropsychological tests as Alzheimer's disease research and clinical criteria increasingly rely upon cerebrospinal fluid (CSF) and neuroimaging biomarkers.

Recognition memory span in autopsy-confirmed Dementia with Lewy Bodies and Alzheimer's Disease

Evidence from patients with amnesia suggests that recognition memory span tasks engage both long-term memory (i.e., secondary memory) processes mediated by the diencephalic-medial temporal lobe memory system and working memory processes mediated by fronto-striatal systems. Thus, the recognition memory span task may be particularly effective for detecting memory deficits in disorders that disrupt both memory systems. The presence of unique pathology in fronto-striatal circuits in Dementia with Lewy Bodies (DLB) compared to AD suggests that performance on the recognition memory span task might be differentially affected in the two disorders even though they have quantitatively similar deficits in secondary memory. In the present study, patients with autopsy-confirmed DLB or AD, and Normal Control (NC) participants, were tested on separate recognition memory span tasks that required them to retain increasing amounts of verbal, spatial, or visual object (i.e., faces) information across trials. Results showed that recognition memory spans for verbal and spatial stimuli, but not face stimuli, were lower in patients with DLB than in those with AD, and more impaired relative to NC performance. This was despite similar deficits in the two patient groups on independent measures of secondary memory such as the total number of words recalled from long-term storage on the Buschke Selective Reminding Test. The disproportionate vulnerability of recognition memory span task performance in DLB compared to AD may be due to greater fronto-striatal involvement in DLB and a corresponding decrement in cooperative interaction between working memory and secondary memory processes. Assessment of recognition memory span may contribute to the ability to distinguish between DLB and AD relatively early in the course of disease.

Pattern separation and pattern completion in Alzheimer's disease: evidence of rapid forgetting in amnestic mild cognitive impairment

Over the past four decades, the characterization of memory loss associated with Alzheimer's disease (AD) has been extensively debated. Recent iterations have focused on disordered encoding versus rapid forgetting. To address this issue, we used a behavioral pattern separation task to assess the ability of the hippocampus to create and maintain distinct and orthogonalized visual memory representations in patients with amnestic mild cognitive impairment (aMCI) and mild AD. We specifically used a lag-based continuous recognition paradigm to determine whether patients with aMCI and mild AD fail to encode visual memory representations or whether these patients properly encode representations that are rapidly forgotten. Consistent with the rapid forgetting hypothesis of AD, we found that patients with aMCI demonstrated decreasing pattern separation rates as the lag of interfering objects increased. In contrast, patients with AD demonstrated consistently poor pattern separation rates across three increasingly longer lags. We propose a continuum that reflects underlying hippocampal neuropathology whereby patients with aMCI are able to properly encode information into memory but rapidly lose these memory representations, and patients with AD, who have extensive hippocampal and parahippocampal damage, cannot properly encode information in distinct, orthogonal representations. Our results also revealed that whereas patients with aMCI demonstrated similar behavioral pattern completion rates to healthy older adults, patients with AD showed lower pattern completion rates when we corrected for response bias. Finally, these behavioral pattern separation and pattern completion results are discussed in terms of the dual process model of recognition memory.

Functional connectivity during recognition memory in individuals genetically at risk for Alzheimer's disease

The medial temporal lobes (MTL) and frontal cortex have been shown to subserve memory processes. Neurodegenerative diseases, such as Alzheimer's disease (AD), disrupt the neuronal networks that underlie memory processing. The ε4 allele of the apolipoprotein E gene is a genetic risk factor for AD and is associated with decrements in memory and in olfactory function. The present study utilized EQS, a structural equation modeling software program, to examine differences in the neuronal networks between non-demented ε4 carriers and ε4 noncarriers during a cross-modal olfactory recognition memory paradigm. Prior to fMRI scanning, participants were presented with 16 odors. During two scans, participants discriminated between names of odors presented before scanning (targets) or not presented (foils). The results indicate significant connections between bilateral frontal lobes and MTL for ε4 carriers when they misidentified a foil as a target. When ε4 noncarriers correctly identified a target, there were greater associations between the amygdala, MTL, and right frontal lobe; these associations also modeled the brain's response when ε4 noncarriers misidentified a foil as a target. During memory retrieval, affective cues may facilitate retrieval in ε4 noncarriers relative to ε4 carriers. Last, no model was found that best represented the functional network used by ε4 carriers when they correctly identified a target, which may reflect variability of neuronal recruitment within this population.

Apolipoprotein E epsilon4 genotype and gender: effects on memory

OBJECTIVE

Episodic recognition memory for odors and visual was assessed in apolipoprotein E (ApoE) epsilon4-positive and epsilon4-negative men and women diagnosed with Alzheimer disease (AD) and a healthy age- and gender-matched comparison group.

METHODS

A total of 38 AD patients and 38 age- and gender-matched healthy older adults completed a recognition memory task involving three categories of stimuli: odors, faces, and symbols.

RESULTS

In the healthy comparison group, men who were epsilon4 negative outperformed epsilon4-positive men in recognition memory for odors and committed fewer false-positive errors. However, there were no significant differences between epsilon4-negative and epsilon4-positive women in the comparison group. No significant gender or ApoE status differences were detected in recognition memory for faces or symbols in the comparison group. In patients with AD, epsilon4-negative women outperformed epsilon4-positive women in recognition memory for odors and committed significantly fewer false-positive errors. However, there were no significant differences between epsilon4-positive and epsilon4-negative men. There were no significant gender or ApoE status differences in recognition memory for faces or symbols in AD patients.

CONCLUSION

The results demonstrate that recognition memory for olfactory stimuli may be particularly impaired in healthy older men with the epsilon4 allele. In patients with AD, odor memory impairments may be less severe in women who are negative for the epsilon4 allele. The results offer new insight into how recognition memory is affected by gender, the epsilon4 allele, and the modality of the stimulus to be remembered in healthy older adults and patients with AD.

Alpha rhythms in mild dements during visual delayed choice reaction time tasks: A MEG study

Can simple delayed response tasks affect latency and amplitude of magnetoencephalographic midline alpha rhythms (6-12 Hz) in early dementia? We recruited 15 mild Alzheimer's disease (AD) and 10 vascular dementia (VaD) patients (paired mini mental state exam of 17-24). The control groups comprised 18 young and 22 elderly normal subjects. In the first task, a simple "cue" stimulus (one bit) was memorized along a brief delay period (3.5-5.5s) up to a "go" stimulus triggering (right or left) button press. In the second task, the "cue" stimulus remained available along the delay period. Event-related reduction in power of the alpha rhythms indexed the cortical activation (event-related desynchronization, ERD) for the trials associated with correct behavioral responses. Behavioral performances to both tasks were lower in the AD and VaD patients than in the normal subjects. In particular, just four AD and five VaD patients executed a sufficient amount of correct responses for the alpha ERD analysis, so they were included in a unique group. In both tasks, the alpha ERD peak was later in latency in the demented and normal elderly subjects than in the normal young subjects. Furthermore, the alpha ERD peak was stronger in amplitude in the demented patients than in the normal subjects. These results suggest that simple delayed response tasks during physiological recordings are quite difficult for patients even at an early dementia stage. Such difficulty may induce the abnormal amount of the related cortical activation in dementia as revealed by the alpha ERD.

Relationship between cognitive function and regional cerebral blood flow in Alzheimer's disease

The Mini-Mental State examination (MMSE) is frequently used to assess the cognitive function of neurological patients. The purpose of this study was to investigate associations between regional cerebral blood flow (rCBF) and MMSE scores in Alzheimer's disease (AD) and localization of cognitive functions. Fifty-nine patients with probable AD (21 males and 38 females; mean age 74 years) and 12 normal volunteers (five males and seven females; mean age 73 years) were studied. CBF was measured by SPECT using the N-isopropyl-p-[(123)I]iodoamphetamine autoradiography method. The CBF images were reconstructed in parallel with the orbitomeatal line and parallel to the long axis of the temporal cortex. Regions of interest were set in the cerebral and cerebellar cortex. Multivariate analysis was performed by the step-wise method, using each section of the MMSE as the dependent variable and the rCBF ratio as the independent variable. The decline in rCBF in the parietal cortex and hippocampus reflected disorientation, and the most significant cortex affecting scores on each section of the MMSE were found to be the anterior temporal cortex for registration, the frontal cortex for attention and calculation, the medial temporal cortex for recall, and the posterior temporal cortex for language.

Fluctuations in spatial recognition memory across the menstrual cycle in female rhesus monkeys

Findings are inconsistent regarding whether women's cognitive performance fluctuates across phases of the menstrual cycle, but differences in methodology and the use of reported cycle phase rather than precise hormonal measures may underlie these disparities. Studies in monkeys may help resolve these discrepant findings, since hormonal status can be reliably determined. We tested four young (5-7 years old) female rhesus monkeys daily during one entire menstrual cycle on three cognitive tasks displayed on a computerized touch-screen system: a Matching to Sample task with a 30 s delay (MTS-30s), a Matching to Sample task without delay (MTS-no delay) and the spatial condition of the Delayed Recognition Span Test (spatial-DRST). Blood samples were collected at specific time intervals throughout the cycle and assayed for estradiol and progesterone in order to identify hormonal status. There was a nonsignificant trend for the MTS-30s scores to be better during the follicular and luteal phases, when estradiol levels were low, than during the peri-ovulatory phase, when estradiol levels were at their highest. MTS-no delay performance did not vary as a function of hormonal status. Spatial-DRST scores were significantly better during the follicular and luteal phases than during the peri-ovulatory phase of the cycle. These data in the female rhesus monkey support the hypothesis that spatial memory performance is sensitive to estradiol variations across the menstrual cycle, with better performance associated with low estradiol levels.

Cognitive screening and neuropsychological assessment in early Alzheimer's disease

Cognitive screening and detailed neuropsychological assessment provide a reliable means of detecting dementia in its earliest stages, tracking the progression of cognitive decline over time, and aiding in the differential diagnosis of various dementing disorders. In addition, recent studies have shown that mild cognitive changes, and particularly declines in memory function, are evident in the "preclinical" phase of Alzheimer's disease and may help to identify elderly individuals who are likely to develop dementia in the near future. Until effective and easily obtainable biological markers for detecting the onset and progression of Alzheimer's disease are developed, neuropsychological assessment will continue to have an important role in the dementia evaluation.

Effects of aging on myelinated nerve fibers in monkey primary visual cortex

In monkeys, myelin sheaths of the axons in the vertical bundles of nerve fibers passing through the deeper layers of primary visual cortex show age-related alterations in their structure. These alterations have been examined by comparing the myelin sheaths in young monkeys, 5-10 years old, with those in old monkeys, between 25 and 33 years of age. The age-related alterations are of four basic types. In some sheaths, there is local splitting of the major dense line to accommodate dense cytoplasm derived from the oligodendrocytes. Other sheaths balloon out, and in these locations, the intraperiod line in that part of the sheath opens up to surround a fluid-filled space. Other alterations are the formation of redundant myelin so that a sheath is too large for the enclosed axon and the formation of double sheaths in which one layer of compact myelin is surrounded by another one. These alterations in myelin increase in frequency with the ages of the monkeys, and there is a significant correlation between the breakdown of the myelin and the impairments in cognition exhibited by individual monkeys. This correlation also holds even when the old monkeys, 25 to 33 years of age, are considered as a group. It is suggested that the correlation between the breakdown of myelin in the old monkeys and their impairments in cognition has not to do specifically with visual function but to the role of myelin in axonal conduction throughout the brain. The breakdown of myelin could impair cognition by leading to a change in the conduction rates along axons, resulting in a loss of synchrony in cortical neuronal circuits.

Ideomotor apraxia in early Alzheimer's disease: time and accuracy measures

Twenty-six Alzheimer's disease (AD) and 42 healthy control (NC) subjects were evaluated with neuropsychological and apraxia batteries. ADs produced a greater range of error types, but did not differ from NCs in their most frequent error types. Hand sequencing ability contributed significantly to AD praxis with no predictors for NCs. Although groups did not differ in gesture time, the AD group had significantly longer response latencies for periods prior to gesture execution and the effect was prominent for transitive tasks and nondominant hand use. Results illustrate the sensitivity of timing measures in identifying abnormal praxis in early stages of AD.

Differential Subtest Scores on the Rivermead Behavioural Memory Test (RBMT) in an Elderly Population With Diagnosis of Vascular or Nonvascular Dementia

A retrospective analysis of subtest scores on the Rivermead Behavioural Memory Test (RBMT), a test of day-to-day memory, was completed for a clinical sample of older people. The aim was to determine whether profile and screening scores discriminated between cases classified as vascular dementia (VAD) or nonvascular dementia (NVG). Diagnosis was made on the basis of CT scan, neuropsychological assessment, and Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) criteria for dementia. The sample comprised 74 cases with a mean age of 74: 77 years (range = 60-89). A nonparametric statistical analysis indicated significant differences between the VAD and the NVG on bath the profile and screening scores and on 5 of the 12 RBMT subtests. Discriminant analysis indicated that a combination of four subtests resulted in an error rate of 3% in classifying cases as VAD or NVG in this sample. Areas for further investigation are outlined.

Patterns of cognitive decline in aged rhesus monkeys

Although cognitive decline has been well established as a consequence of aging in non-human primate models, the prevalence or frequency of impairment for specific age ranges has not been described. The first aim of this study was to estimate prevalence of cognitive impairment on each of the six tests of cognitive performance by comparing the performance of early-aged (19-23 years old), advanced-aged (24-28 years old), and oldest-aged (29+ years old) monkeys to that of young adults (< 15 years old). The second aim was to derive a single overall measure of cognitive performance to help classify behavioral function in our aged monkeys. Accordingly, we obtained performance measures for these age groups on six behavioral measures: (1) acquisition of the delayed non-matching-to-sample task (DNMS); (2) performance of the DNMS with a delay of 120 sec; (3) the spatial condition of the delayed recognition span test (DRST); (4) the color condition of the DRST; (5) spatial reversal learning; and (6) object reversal learning. Early-aged monkeys displayed prevalence rates of impairment significantly greater than zero on all tasks except the DRST-color. The highest prevalence of impairment was observed in this age group in a task measuring spatial memory (DRST). Significant trends toward progressively higher impairment rates in advanced-aged and oldest-aged monkeys were observed for DNMS-acquisition, DRST-color and spatial reversal learning tasks. A linear transformation of standardized scores on the six cognitive tests was derived by means of principal components analysis (PCA). The first PCA (PCA1) included data from 30 monkeys with available data on all six measures, and yielded a composite measure which declined linearly with increasing age (r = -0.74). A second PCA (PCA2) was performed on data from 53 monkeys for which three test scores (DNMS-acquisition, DNMS-120s delay, and DRST-spatial condition) were available. The composite score derived from this analysis was highly correlated (r = 0.93) with the composite score from PCA1, suggesting that a score based on only three tests may provide an adequate classification of global cognitive ability.

Recognition memory span in rhesus monkeys of advanced age

Assessment of recognition memory was performed on eight rhesus monkeys of advanced age (25 to 27 years of age) using the delayed recognition span test (DRST). Their performance was compared to that of five young adult animals (5 to 7 years of age) on two stimulus conditions of the DRST: spatial position and color. Both trial unique and repeating series were used for each of the two conditions. As a group, aged monkeys were impaired on both the spatial and color conditions of the DRST, achieving about two-thirds of the span of the young adult group in each condition. Error analyses revealed that monkeys in the aged group also produced more perseverative responses (i.e., displacing the previously correct disk) than did young adults. Together the findings suggest that monkeys of advanced age are impaired on tasks with memory loading demand characteristics.

Visuoperceptual-spatial ability and visual memory in vascular dementia and dementia of the Alzheimer type

This study investigated the relationship between visuoperceptual ability and visual memory in dementia. Twenty individuals with probable dementia of the Alzheimer type, 24 individuals with probable vascular dementia, and 20 healthy, elderly adults underwent neuropsychological evaluation. Hierarchical multiple regression analyses suggested that perceptual organization skills contributed to a significant amount of the variance in novel, but not famous, face recognition. This finding was most robust in the clinical groups. Causality cannot be attributed from this regression model. Results suggest, however, that visual processing deficits are more strongly related to the memory process at the time of encoding rather than during recognition of remote information.

The pattern of deficit in different memory components in normal aging and dementia of Alzheimer's type

The study explored differential patterns of deficits in different memory components as a function of dementia severity. Three groups of 58 subjects each were used: (1) highly functioning elderly who are free of neurological or psychiatric symptoms; (2) individuals with early signs of memory disturbance, whose MMSE scores were > or = 24; and (3) individuals with MMSE scores below 24, who meet criteria for DAT. Performance on the tests that assess different memory components was compared for the three groups. Results suggest pronounced change in acquisition component of memory at the onset of dementia, whereas retrieval from remote memory discriminates well between the mild and the more advanced phases of the disease. Retrieval from recent memory deteriorates more gradually. Based on these results, efficiency of different memory mechanisms was discussed.

Differential rates of forgetting from long-term memory in Alzheimer's and multi-infarct dementia

In this study we explored the rate of forgetting from long-term memory in Alzheimer's (AD) and multi-infarct (MID) dementia. For this purpose, we administered to 15 AD, 15 MID, and 22 control subjects two tasks exploring, respectively, long-term verbal and long-term visuo-spatial memory. The absolute rate of forgetting in both tasks was computed as the difference between immediate and delayed recall of memorandum. Since level of immediate recall was significantly different between groups, a proportional rate of forgetting (percentage of memorandum lost passing from immediate to delayed recall) was computed for each patient. In the verbal task (Rey's 15 words) AD patients displayed significantly larger absolute and proportional rates of forgetting than MID and control subjects. In the spatial task (Corsi block supraspan), the absolute rate of forgetting was only marginally different between groups. Nevertheless, AD patients demonstrated a larger proportional rate of forgetting than MID and normal subjects. These results point out an exalted decay of information from long-term memory store in AD patients. In the light of previous data (Corkin et al., 1984; Kopelman, 1985) we propose that long-term memory deficits in AD is due, at least in part, to an abnormal forgetting of information within the first few minutes following acquisition. Information still present in the subsequent period (10 min to several days) is retained normally. The normal rate of forgetting in MID patients, further, suggests different mechanisms underlying memory disorders in vascular and degenerative dementias.

The diagnostic utility of savings scores: differentiating Alzheimer's and Huntington's diseases with the logical memory and visual reproduction tests

Recent research has demonstrated that patients with dementia of the Alzheimer type (DAT) evidence more rapid forgetting than do patients with Huntington's disease (HD). The present study focused on whether such group differences translated into measures with adequate sensitivity and specificity at different stages of these disorders. It was found that measures of forgetting (i.e., savings scores) based upon the Logical Memory and Visual Reproduction tests of the Wechsler Memory Scale--Revised had satisfactory to excellent sensitivity and specificity in differentiating DAT and HD patients from healthy control subjects. Savings scores also had good sensitivity and specificity in differentiating DAT from HD in the early stages of the diseases. However, unsatisfactory specificity may limit the utility of savings scores in differentiating among patients with moderate DAT and HD.

Electrophysiological and neuropsychological effects of a central alpha 2-antagonist atipamezole in healthy volunteers

We studied the electrophysiological and neuropsychological effects of acute modulation of central noradrenergic (NA) transmission using a specific alpha 2-antagonist atipamezole (ATI) in sic healthy volunteers. ATI had effects on resting EEG, auditory event-related potentials and neuropsychological tests. Quantitative EEG revealed increased total power in frontal, parietal and temporo-occipital areas without significant changes in the mean or peak frequencies. Event-related potentials showed no effects on the active attention-related processing negativity or the passive mismatch negativity, but frontally recorded mean amplitude of target-P300 was decreased. Neuropsychological tests after ATI revealed improvement in Digit Span, more errors in Word Recognition task, and no effects on Moss spatial recognition task. In healthy subjects with intact NA systems and without any attention deficit, ATI produced evident NA overactivity. ATI decreased the spontaneous thalamocortical oscillation of EEG and improved focused attention (Digit Span). It impaired, however, more divided attention (decreased mean P300 amplitude, increased errors in Word Recognition).

Memory deficits in Alzheimer's patients: a comprehensive review

Despite considerable experimental work on Alzheimer's disease (AD), the underlying cognitive mechanisms as well as the precise localization of neuropathological changes critical for memory loss remains undefined. A review of the neuropsychological literature on long-term memory deficits in AD patients suggests that AD patients display (a) a pervasive deficit of explicit memory, (b) a partial deficiency of implicit memory for verbal and visuoperceptual material (as measured by repetition priming procedures), and (c) a substantial sparing of implicit memory for visuomotor skills. The explicit memory loss is likely a result of encoding as well as consolidation difficulties. A faulty lexical-semantic knowledge structure appears responsible for deficient repetition priming effects. Since neuropathological changes diffusely affect the brain of AD patients, establishing a clear relationship between localization of cerebral lesions and memory deficits is particularly difficult. Nevertheless, data suggest that extensive involvement of the hippocampal-amygdala complex plays a major role in explicit memory loss. Damage to associative cortical areas likely is involved in repetition priming deficits. The relative integrity of primary motor and sensory cortical areas and of the basal ganglia likely subsume, by contrast, the normal learning of visuomotor skills.

Recognition memory for words and faces in primary degenerative dementia of the Alzheimer type and normal old age

The suitability of Warrington's Recognition Memory Test (RMT) for discriminating between patients with dementia of the Alzheimer type and nondemented elderly subjects was tested in a study with 44 patients (aged 59 to 94) and 45 normal elderly (aged 69 to 92). The patients showed a significant memory deficit, both in Recognition Memory for Words (RMW) and Recognition Memory for Faces (RMF), even when the scores were corrected for verbal intelligence score (WAIS Vocabulary) or a measure of visuoperceptual ability (Raven's Coloured Progressive Matrices, CPM). Word-face discrepancy scores did not differentiate between dementia and normal old age. At the 95%-specificity level, the sensitivity of RMW and RMF for the detection of memory impairment in dementia was 81% and 100% for subjects below 80, and, less satisfactory, 59% and 76% for subjects of 80 years or older. Correlational analysis showed that the patients' RMW and RMF scores were moderately correlated (r = .40). The significant correlation (r = .45) between CPM and RMF suggests that visuoperceptual deficits are involved in deficient face recognition.

Preliminary analysis of effects of "normal" aging on different memory processes and abilities

Visual recognition-memory span, name-face association, and verbal memory with selective reminding were tested in two groups of 24 normal healthy volunteers (above and below age 50 yr.). The preliminary study suggests differential effects of aging on specific memory components and warrants careful exploration.

Longitudinal cognitive decline in patients with Alzheimer's disease

Progressive cognitive impairment is a defining feature of the dementia of Alzheimer's disease (AD), yet disagreement exists over which abilities decline most precipitously and which cognitive tests are more sensitive. In this study, 51 AD patients in the early to middle stages of illness and 22 age-matched normal controls were administered a battery of neuropsychological tests at 6-month intervals over a 2-year period. While the performance of the normal controls remained stable over the 2 years, the AD patients displayed progressive decline on all tests. The greatest declines occurred on tests requiring lexical/semantic processing (Boston Naming Test) and comprehension of syntactic relationships (Token Test). Performance on visuospatial tests (Wechsler Adult Intelligence Scale-Revised Block Design, Benton Visual Retention Test, Spatial Delayed Recognition Span Test) declined less rapidly. The findings support previous reports that language impairment may be central to the dementia of AD, and that confrontation naming is particularly sensitive to decline in this illness.