Although amyloid deposition remains a marker of the development of Alzheimer's disease, results linking amyloid and cognition have been equivocal. Twenty-five community-dwelling non-demented older adults were examined with 18F-flutemetamol, an amyloid imaging agent, and a cognitive battery, including an estimate of premorbid intellect and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). In the first model, 18F-flutemetamol uptake significantly correlated with the Delayed Memory Index of the RBANS (r = −.51, p = .02) and premorbid intellect (r = .43, p = .03). In the second model, the relationship between 18F-flutemetamol and cognition was notably stronger when controlling for premorbid intellect (e.g., three of the five RBANS Indexes and its Total score significantly correlated with 18F-flutemetamol, r's = −.41 to −.58). Associations were found between amyloid-binding 18F-flutemetamol and cognitive functioning in non-demented older adults. These associations were greatest with delayed memory and stronger when premorbid intellect was considered, suggesting that cognitive reserve partly compensates for the symptomatic expression of amyloid pathology in community-dwelling elderly.
Amyloid; Neuroimaging; Neuropsychology; Alzheimer's disease; Premorbid intellect
Cognitive difficulties appear to be a more prevalent clinical feature in progressive supranuclear palsy (PSP) than previously thought, and significant cognitive impairment is prevalent in a majority of patients PSP patients not considered clinically demented. The neurocognitive performance of 200 patients with PSP across multiple sites was examined with a variety of commonly used neuropsychological tests. Results indicate primary executive dysfunction (e.g., 74% impaired on the Frontal Assessment Battery, 55% impaired on Initiation/Perseveration subscale of the Dementia Rating Scale), with milder difficulties in memory, construction, and naming. These results have important clinical implications for providers following patients with PSP.
Progressive supranuclear palsy; Frontal-executive; Parkinsonism; Dementia; Memory
Executive dysfunction (ED) is a characteristic of Huntington disease (HD), but its severity and progression is less understood in the prodromal phase, e.g., before gross motor abnormalities. We examined planning and problem-solving abilities using the Towers Task in HD mutation-positive individuals without motor symptoms (n = 781) and controls (n = 212). Participants with greater disease progression (determined using mutation size and current age) performed more slowly and with less accuracy on the Towers Task. Performance accuracy was negatively related to striatal volume while both accuracy and working memory were negatively related to frontal white matter volume. Disease progression at baseline was not associated with longitudinal performance over 4 years. Whereas the baseline findings indicate that ED becomes more prevalent with greater disease progression in prodromal HD and can be quantified using the Towers task, the absence of notable longitudinal findings indicates that the Towers Task exhibits limited sensitivity to cognitive decline in this population.
Huntington's disease; Genetic disorders; Executive functions; Neuroimaging (structural); Norms/normative studies; Practice effects/reliable change; longitudinal change
Repeated assessments are a relatively common occurrence in clinical neuropsychology. The current paper will review some of the relevant concepts (e.g., reliability, practice effects, alternate forms) and methods (e.g., reliable change index, standardized based regression) that are used in repeated neuropsychological evaluations. The focus will be on the understanding and application of these concepts and methods in the evaluation of the individual patient through examples. Finally, some future directions for assessing change will be described.
Reliable change; Practice effects; Assessment
Although initially developed as a brief dementia battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has not yet demonstrated its sensitivity, specificity, and positive and negative predictive powers in detecting cognitive impairment in patients with Alzheimer's disease (AD). Therefore, the current study examined the clinical utility of the RBANS by comparing two age-, education-, and gender-matched groups: patients with AD (n=69) and comparators (n=69). Significant differences (p<0.001) were observed on the RBANS Total score, all 5 Indexes, and all 12 subtests, with patients performing worse than the comparison participants. An optimal balance between sensitivity and specificity on RBANS scores was obtained when cutoffs of one and one and a half standard deviations below the mean of the comparison sample were implemented. Areas under the Receiver Operating Characteristic curves for all RBANS Indexes were impressive though Immediate and Delayed Memory Indexes were excellent (0.96 and 0.98, respectively). Results suggest that RBANS scores yield excellent estimates of diagnostic accuracy and that the RBANS is a useful screening tool in detection of cognitive deficits associated with AD.
Alzheimer's disease; Dementia; Diagnostic accuracy; Repeatable Battery for the Assessment of Neuropsychological Status
The Effort Index (EI) of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was developed to identify inadequate effort. Although researchers have examined its validity, the reliability of the EI has not been evaluated. The current study examined the temporal stability of the EI across 1 year in two independent samples of older adults. One sample consisted of 445 cognitively intact older adults (mean age = 72.89; 59% having 12–15 years of education) and the second sample consisted of 51 individuals diagnosed with amnestic Mild Cognitive Impairment (mean age = 82.41; 41% having 12–15 years of education). For both samples, the EI was found to have low stability (Spearman's ρ = .32–.36). When participants were divided into those whose EI stayed stable or improved versus those whose EI worsened (i.e., declining effort) on retesting, it was observed that individuals with lower baseline RBANS Total scores tended to worsen on the EI across time. Overall, the findings suggest low temporal stability of the EI in two geriatric samples. In particular, individuals with poorer cognition at baseline could present with poorer effort across time. These findings also suggest the need to further examine the temporal stability of other effort measures.
Malingering/symptom validity testing; Elderly/geriatrics/aging; Mild cognitive impairment
Formulae to estimate premorbid memory functioning in a sample of cognitively intact older adults have been developed. These formulae were validated in a small sample of patients with amnestic Mild Cognitive Impairment. However, further validation is clearly needed. The current study applied these formulae to a sample of 1,059 patients referred to a dementia clinic and compared the premorbid estimates of memory functioning with current memory abilities. Large and statistically significant differences were observed in the current sample, with premorbid memory scores exceeding current memory scores. Although some cautions should be observed when using these estimates clinically, growing support for these estimates of premorbid memory abilities may aid clinicians in determining change across time in older patients.
Predicting cognition; Learning and memory; Assessment
Although delirium is a common medical comorbidity with altered cognition as its defining feature, few publications have addressed the neuropsychological prodrome, profile, and recovery of patients tested during delirium. We characterize neuropsychological performance in 54 hemapoietic stem cell/bone marrow transplantation (BMT) patients shortly before, during, and after delirium and in BMT patients without delirium and 10 healthy adults. Patients were assessed prospectively before and after transplantation using a brief battery. BMT patients with delirium performed more poorly than comparisons and those without delirium on cross-sectional and trend analyses. Deficits were in expected areas of attention and memory, but also in psychomotor speed and learning. The patients with delirium did not return to normative “average” on any test during observation. Most tests showed a mild decline in the visit before delirium, a sharp decline with delirium onset, and variable performance in the following days. This study adds to the few investigations of neuropsychological performance surrounding delirium and provides targets for monitoring and early detection; Trails A and B, RBANS Coding, and List Recall may be useful for delirium assessment.
Bone marrow transplantation; Cognition; Cancer; Attention; Delirium
The estimation of premorbid abilities is an essential part of a neuropsychological evaluation, especially in neurodegenerative conditions. Although word pronunciation tests are one standard method for estimating the premorbid level, research suggests that these tests may not be valid in neurodegenerative diseases. Therefore, the current study sought to examine two estimates of premorbid intellect, the Wide Range Achievement Test (WRAT) Reading subtest and the Barona formula, in 93 patients with mild to moderate Huntington's disease (HD) to determine their utility and to investigate how these measures relate to signs and symptoms of disease progression. In 89% of participants, WRAT estimates were below the Barona estimates. WRAT estimates were related to worsening memory and motor functioning, whereas the Barona estimates had weaker relationships. Neither estimate was related to depression or functional capacity. Irregular word reading tests appear to decline with HD progression, whereas estimation methods based on demographic factors may be more robust but overestimate premorbid functioning.
Huntington's disease; movement disorders; basal ganglia; assessment; dementia
The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has demonstrated adequate sensitivity in detecting cognitive impairment in a number of neuropsychiatric conditions, including Alzheimer's disease. However, its ability to detect milder cognitive deficits in the elderly has not been examined. The current study examined the clinical utility of the RBANS by comparing two groups: Patients with Mild Cognitive Impairment (MCI; n = 72) and cognitively intact peers (n = 71). Significant differences were observed on the RBANS Total score, 3 of the 5 Indexes, and 6 of the 12 subtests, with individuals with MCI performing worse than the comparison participants. Specificity was very good, but sensitivity ranged from poor to moderate. Areas under the receiver operating characteristic curves for the RBANS Immediate and Delayed Memory Indexes and the Total Scale score were adequate. Although significant differences were observed between groups and the areas under the curves were adequate, the lower sensitivity values of the RBANS suggests that caution should be used when diagnosing conditions such as MCI.
Mild Cognitive Impairment; Diagnostic accuracy; Repeatable Battery for the Assessment of Neuropsychological Status
Assessing cognitive change in older adults is a common use of neuropsychological services, and neuropsychologists have utilized several strategies to determine if a change is “real,” “reliable,” and “meaningful.” Although standardized regression-based (SRB) prediction formulas may be useful in determining change, SRBs have not been widely applied to older adults. The current study sought to develop SRB formulas on a group of 127 community-dwelling older adults for several widely used neuropsychological measures. In addition to baseline test scores and demographic information, the current study also examined the role of short-term practice effects in predicting test scores after 1 year. Consistent with prior research on younger adults, baseline test performances were the strongest predictors of future test performances, accounting for 25%–58% of the variance. Short-term practice effects significantly added to the predictability of all nine of the cognitive tests examined (3%–22%). Future studies should continue extending SRB methodology for older adults, and the inclusion of practice effects appears to add to the prediction of future cognition.
Predicting cognition; Practice effects
Memory assessment is an important component of a neuropsychological evaluation, but far fewer visual than verbal memory instruments are available. We examined the preliminary psychometric properties and clinical utility of a novel, motor-free paper and pencil visuospatial memory test, the Indiana faces in places test (IFIPT). The IFIPT and general neuropsychological performance were assessed in 36 adults with amnestic mild cognitive impairment (aMCI) and 113 older adults with no cognitive impairment at baseline, 1 week, and 1 year. The IFIPT is a visual memory test with 10 faces paired with spatial locations (three learning trials and non-cued delayed recall). Results showed that MCI participants scored lower than controls on several variables, most notably total learning (p < .001 at all three time points), delayed recall (baseline p = .03, 1 week p < .001, 1 year p < .001), and false-positive errors (range p = .03 to <0.001). The IFIPT showed similar test–retest reliability at 1-week and 1-year follow-up to other neuropsychological tests (r = 0.71–0.84 for MCI and 0.53–0.72 for controls). Diagnostic accuracy was modest for this sample (areas under the receiver operating characteristic curve between 0.64 and 0.66). Preliminary psychometric analyses support further study of the IFIPT. The measure showed evidence of clinical utility by demonstrating group differences between this sample of healthy adults and those with MCI.
Mild cognitive impairment; Visual memory; Face memory; Test–retest reliability
Although initially developed as a brief dementia battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has not yet demonstrated its sensitivity, specificity, and positive and negative predictive powers in detecting cognitive impairment in patients with Alzheimer’s disease (AD). Therefore, the current study examined the clinical utility of the RBANS by comparing two age-, education-, and gender-matched groups: patients with AD (n=69) and comparators (n=69). Significant differences (p<0.001) were observed on the RBANS Total score, all five Indexes, and all twelve subtests, with patients performing worse than the comparison participants. An optimal balance between sensitivity and specificity on RBANS scores was obtained when cutoffs of one and one and a half standard deviations below the mean of the comparison sample were implemented. Areas under the Receiver Operating Characteristic curves for all RBANS Indexes were impressive though Immediate and Delayed Memory Indexes were excellent (0.96 and 0.98, respectively). Results suggest that RBANS scores yield excellent estimates of diagnostic accuracy and that the RBANS is a useful screening tool in detection of cognitive deficits associated with AD.
Alzheimer’s disease; dementia; diagnostic accuracy; Repeatable Battery for the Assessment of Neuropsychological Status
Practice effects, defined as improvements in cognitive test performance due to repeated exposure to the test materials, have traditionally been viewed as sources of error. However, they might provide useful information for predicting cognitive outcome. The current study used three separate patient samples (older adults with mild cognitive impairments, individuals who were HIV +, individuals with Huntington’s disease) to examine the relationship between practice effects and cognitive functioning at a later point. Across all three samples, practice effects accounted for as much as 31 to 83% of the variance in the follow-up cognitive scores, after controlling for baseline cognitive functioning. If these findings can be replicated in other patients with neurodegenerative disorders, clinicians and researchers may be able to develop predictive models to identify the individuals who are most likely to demonstrate continued cognitive decline across time. The ability to utilize practice effects data would add a simple, convenient, and non-invasive marker for monitoring an individual patient’s cognitive status. Additionally, this prognostic index could be used to offer interventions to patients who are in the earliest stages of progressive neurodegenerative disorders.
practice effects; cognitive outcome; Mild Cognitive Impairment; HIV; Huntington’s disease