David Arenberg

Visual memory predicts Alzheimer's disease more than a decade before diagnosis

Background: Recent studies have suggested that AD may reflect a chronic process that begins many years before the clinical expression of dementia. The current study examines premorbid Benton Visual Retention Test (BVRT) and Wechsler Adult Intelligence Scale–vocabulary (WAIS-voc) test scores in order to determine whether long-term deficits in these tests can predict the development of AD decades later in the Baltimore Longitudinal Study of Aging (BLSA). Method: Participants are volunteers from the BLSA, a multidisciplinary study of normal aging conducted by the National Institute on Aging. A total of 1,425 BLSA participants who were older than 60 years were included in the analyses. Cox proportional hazards models were used to estimate the relative risk of developing AD associated with BVRT and WAIS-voc scores at different time periods up to 20 years before the diagnosis of AD. Results: The relative risks for 6 or more BVRT errors vs less than 6 errors at 1 to 3, 3 to 5, 5 to 10, and 10 to 15 years before the diagnosis of AD were 5.69, 2.11, 1.76, and 1.83 (p < 0.05). The relative risk for 15 or more years before diagnosis was not significant (p > 0.10). WAIS-voc scores were not significantly associated with the risk of AD in any time period. Conclusions: A greater number of errors on the BVRT is associated with an increased risk of AD up to 15 years later. Poor visual memory performance may represent an early expression of AD years before diagnosis. This result suggests the need to continue to revise views on the natural history of AD and the possibility of an increased window of opportunity for preventive treatment before definitive diagnosis.

Declines in divergent thinking with age: cross-sectional, longitudinal, and cross-sequential analyses.

Six measures of divergent thinking were administered to 825 men ranging in age from 17 to 101 over the period from 1959 to 1972; repeat administrations were given to a subset of 278 men after a 6-year interval. Cross-sectional analyses showed curvilinear trends, with an increase in scores for men under 40 and a decline thereafter. Repeated measures analyses on subjects initially aged 33 to 74 generally replicated this finding, whereas cross-sequential analyses suggested a decline for all cohorts tested at a later time. Additional analyses suggested that not all of the decline could be attributed to reduced speed of response production. These longitudinal findings confirm earlier cross-sectional reports of decline in divergent thinking abilities with age.

Adult life span changes in immediate visual memory and verbal intelligence.

A sample of 558 women and 1,163 men 17 to 102 years old, screened for neurodegenerative and neuropsychiatric disease, was administered tests of immediate visual memory (Benton Visual Retention Test) and crystallized intelligence (Wechsler Adult Intelligence Scale Vocabulary subtest) from 1 to 5 times over 27.7 years. Cross-sectional and longitudinal evidence led to the conclusion that the 65-74-year decade was a watershed for decremental changes in immediate visual memory and verbal intelligence. Age accounted for considerably less variance in vocabulary than in immediate memory. The proportion of individuals whose longitudinal trajectories were contrary to group trends decreased substantially with increased age; observed age changes remained when analyses were restricted to individuals who had perfect or near-perfect mental status scores. Selected neuronal loss and slower reproduction times were considered as possible causes.

Changes in immediate visual memory predict cognitive impairment

Six-year changes in immediate visual memory performance assessed by the Benton Visual Retention (BVR) test predicted Alzheimers disease (AD) prior to its onset. Subjects of this study were 371 community-dwelling adult participants in the Baltimore Longitudinal Study of Aging, seven of whom received probable or definite AD diagnoses using DSM-III-R and NINCDS-ADRDA criteria. Subjects with diagnoses of AD had larger changes in immediate memory performance over the 6-year interval prior to the estimated onset of their disease than subjects without AD. Six-year longitudinal change as well as level in immediate visual memory performance also predicted subsequent cognitive performance 6-15 and 16-22 years later, even after adjusting for the influences of age, general ability, and initial immediate memory. These results provide evidence that change and level in immediate visual memory performance has long-term prognostic significance over as many as 16-22 years. These results further suggest that change in recent memory performance, an important component in AD diagnoses, may be an important precursor of the development of the disease.

A Classical Mnemonic for Older Learners: A Trip That Works.

A mnemonic procedure, a method of loci, was used with men and women over 60 years old in two studies of free recall. In this procedure, the learners take a mental trip through their residences stopping in order at 16 places. When they learn a list of words, they retrace the trip visualizing one of the items in association with each stopping place. This method was selected because it capitalizes on the familiarity of the stopping places and their natural order; these attributes provide strong retrieval cues that can be applied without adding to the information overload typically experienced by older learners. In the first study (N = 5), all subjects acquired the mnemonic readily and used it effectively during the training trials. An unexpected result was that the subjects did not use the mnemonic in a posttraining trial when no explicit instruction was given to use it. In the second study (N = 30), two experimental groups (with different instructional sets in a posttest trial) and a control group were incl...

A longitudinal study of cognitive performance in noninsulin dependent (type II) diabetic men

Diabetic men (noninsulin dependent, Type II) in the Baltimore Longitudinal Study of Aging were compared with nondiabetics on two cognitive performance tests--the Benton Visual Retention Test, a measure of nonverbal memory, and the Vocabulary subtest of the Wechsler Adult Intelligence Scale. Cross-sectional comparisons of 52 diabetics with matched controls and with 610 controls (covaried for age and education) found no group differences and no support for an accelerated cognitive aging effect of diabetes. In addition, longitudinal comparisons over six years and over twelve years found no effect of diabetes on change in cognitive performance. Possible reasons for disagreements of cross-sectional findings in the literature are discussed. One possibility is that only specific aspects of cognitive performance are adversely affected by diabetes. It is also possible that lower socio-economic status (as indexed by education) may be a risk factor in the effect of diabetes on cognitive performance, perhaps by delaying diagnosis and treatment.

Adult age differences in forgetting sentences.

Age comparisons of performance-based measures of forgetting were carried out. In Exp. 1, 18- to 21-year-olds and 55- to 64-year-olds (n = 24) forgot at an equal rate when compared at 30 s and at 3, 6, and 24 hr after acquisition. In Exp. 2, 17- to 21-year-olds and 65- to 74-year-olds (n = 24) were compared at the same 4 retention intervals. Initial learning was equated for the 2 groups. There was evidence for an age difference in forgetting rate in cued recall when a minimal learning level was required. In Exp. 3, 440 men and women 17 to 74 years old were assigned to a retention interval from 10 min to 7 hr. Age was related to 4 performance-based measures of forgetting rate. Although the age differences were small, they imply 2 decremental processes: 1 before 10 min, possibly a result of incomplete consolidation, and a later 1 that is continuously and cumulatively operative thereafter. Evidence relating initial level to forgetting rate is presented.

Changes with Age in Problem Solving

Reasoning is among the most cherished of man’s abilities. It is, however, an aspect of cognitive performance which has proved more difficult to study than several others such as intelligence, memory, and learning. As a result, the reasoning literature is more meager and less systematic than the literature in other areas; and, not surprisingly, that picture is reflected in the area of reasoning and aging as well.

Individual-differences assessment of the relationship between change in and initial level of adult cognitive functioning.

Methodological factors may have been partially responsible for the inconsistency in findings from previous investigations into the relationship between change in, and initial level of, adult cognitive functioning. An alternative data-analytic procedure is proposed and applied to data from 277 men (25-76 years of age at initial testing) over 3 measurement occasions (interwave intervals of 6.7 years). Performances on both the Benton Revised Visual Retention Test (BVRT) and the Wechsler Adult Intelligence Scale (WAIS) Vocabulary subtest were analyzed. The findings demonstrate that the significant negative relationships between change and initial status, found on both tests, were partially a function of measurement error. Once adjustments were made for errors of measurement, the previously significant negative relationship for the BVRT data became significantly positive, whereas for the WAIS the relationship remained significantly negative, although to a lesser degree. The importance of accounting for errors of measurement is discussed.

Age differences in cognition in healthy educated men: A factor analysis of experimental measures

Performance measures for a wide variety of cognitive laboratory tasks were factor analyzed, and the factors were identifiable as aspects of cognitive processing. The sample consisted of 96 healthy, educated men whose ages ranged from 20 to 80 yr. The factors were identified as speed of information processing, secondary memory, attention, and primary processing efficiency. Factor scores for each factor were correlated with age; r = -0.35, -0.30, -0.40, and -0.15 respectively, with better performance associated with lower age. The sample was divided into subsamples of 32 young (20-39), 32 middle (40-59), and 32 old (60-80) subjects; and each subsample was factor-analyzed separately to determine whether the factor structure was similar for all age groups. Evidence for factor-structure invariance with adult age was found in that all four factors in the primary analysis were identifiable in each of the age subsamples. The findings are consistent with a model of continual cognitive decline with age in healthy, educated adult males.