Parsimonious prediction of Wechsler Memory Scale--III memory indices

Equations for prorating the Wechsler Memory Scale--III (WMS-III) Index scores were derived and validated on a sample of 252 mixed clinical cases. Regression equations were performed using age-scaled scores as predictors and the sum of age-scaled scores for Immediate Memory (IM) and General Memory (GM) as the criteria. Including Logical Memory and Verbal Paired Associates with either Faces or Family Pictures resulted in estimated scores that accounted for 95% to 97% of the variance for IM and GM. Over 80% of these cases had estimated sum of scaled scores that fell within 3 points of actual sum of scaled scores, within 1 standard error of measurement. When only Logical Memory and Verbal Paired Associates were included, estimations accounted for only 87% of the variance, and only 60% of the estimated scores fell within 3 points of actual sum of scaled scores. The regression equations are presented, as are the confidence intervals derived from a bootstrapping procedure that created 15,000 different samples.

Repetitive transcranial magnetic stimulation does not replicate the Wada test

The authors compared inferior frontal speech arrest from repetitive transcranial magnetic stimulation (rTMS) with bilateral Wada tests in 17 epilepsy surgery candidates. Although rTMS lateralization correlated with the Wada test in most subjects, rTMS also favored the right hemisphere at a rate significantly greater than the Wada test. Postoperative language deficits were more consistent with Wada results. Available methods for inducing speech arrest with rTMS do not replicate the results of Wada tests.

A confrontational naming task produces congruent increases and decreases in PET and fMRI

This work uses the well-established (by PET) confrontation naming task to compare PET and fMRI in a cognitive activation experiment. The signal changes from this task are much less than the changes caused by visual or motor activation tasks used in previous comparisons. ANOVA methods adjusted for multiple comparisons were used to determine significant changes in signal between confrontation naming and figure size discrimination tasks. All 17 significantly increased regions (confrontation naming signal greater) seen on one modality were increased on both modalities. Ten of 13 regions that were significantly decreased on one modality were decreased on the other. Three mismatched regions showed a significant decrease on one modality and a nonsignificant increase on the other. This study could not detect a consistent difference in activation site location between PET and fMRI.

Task decomposition analysis of intertrial free recall performance on the Rey Auditory Verbal Learning Test in normal aging and Alzheimer's disease

Task decomposition provides supplementary data that complement traditionally computed performance indexes of multi-trial list learning. Both traditional and decomposition approaches can be combined to permit a thorough assessment of multiple aspects of learning and memory in patients with memory impairment. We applied task decomposition to investigate the relative roles of acquisition and consolidation in mediating the multi-trial learning deficit in patients with Alzheimer's disease. This goal was accomplished by decomposing recall performance across the five study-and-test trials of the Rey Auditory Verbal Learning Tests into measures that presumably tap intertrial acquisition and intertrial consolidation. As compared to matched controls, patients diagnosed with mild Alzheimer's disease showed lower gained access across trials, indicating that Alzheimer's disease impairs the ability to produce a stable memory representation of new material in long-term memory. Additionally, patients with Alzheimer's disease manifested higher lost access, which suggests that deficient consolidation leading to rapid intertrial forgetting also contributes to their poor learning. We argue that analytically decomposing learning curves will help both in uncovering the cognitive processes that underlie disease-related learning deficits in persons with memory disorders and can help to characterize potential areas for remediation.

Butanol is superior to water for performing positron emission tomography activation studies

[15(O)]Butanol has been shown to be superior to [15(O)]water for measuring cerebral blood flow with positron emission tomography. This work demonstrates that it is also superior for performing activation studies. Data were collected under three conditions: a visual confrontation animal-naming task, nonsense figure size discrimination, and a nonvisual darkroom control task. Time-activity curves (TAC) were obtained for regions known to be activated by the confrontation naming task to compare absolute uptake and the different kinetics of the two tracers. Also, t statistic maps were calculated from the data of 10 subjects for both tracers and compared for magnitude of change and size of activated regions. Peak uptake in the whole-brain TAC were similar for the two tracers. For all regions and conditions, the washout rate of [15(O)]butanol was 41% greater than that of [15(O)]water. At a threshold of 0, the [15(O)]water and [15(O)]butanol percent difference (nonnormalized) and t statistic (global normalization) images are nearly identical, indicating that the same property is being measured with both tracers. The [15(O)]butanol parametric images displayed at a threshold of /t/ = 5 look similar to the [15(O)]water parametric maps displayed at a threshold of /t/ = 4, which is consistent with the observation that t statistic values in [15(O)]butanol images are generally greater. The t statistic values were equal when the [15(O)]butanol parametric map was created from any subset of 6 subjects and the [15(O)]water parametric map was created from all 10 subjects. Fewer subjects need to be studied with [15(O)]butanol to reach the same statistical power as an [15(O)]water-based study.

Convergent and discriminant validity of the CVLT (dementia version). California Verbal Learning Test

This study investigated the convergent and discriminant validity of the 9-item "dementia version'' of the California Verbal Learning Test (CVLT-9) in a sample of 130 geriatric patients evaluated for memory complaints. Moderate correlations were observed between the CVLT-9 sum of words recalled for trials 1-5 (Trial 1-5 Recall) and Long-Delay Free Recall (LDFR) measures and the immediate and delayed Logical Memory (LM I and LM II) and Visual Reproduction (VR I and VR II) subtests from the Wechsler Memory Scale-Revised (WMS-R). However, the CVLT-9 Trial 1-5 Recall and VR I measures demonstrated significant correlations with a number of additional measures of language and visuospatial ability. The CVLT-9 LDFR, and the WMS-R LM I, LM II, and VR II showed less overlap with non-episodic memory functioning. A principal components analysis yielded a three-component solution consisting of a general or "g'' component, a specific memory component, and a mood component. The CVLT-9 Trial 1-5 Recall and VR I loaded on both the "g'' and the memory components, whereas LM I, LM II, and VR II loaded on only the memory component. We conclude that the CVLT-9 Trial 1-5 Recall and VR I demonstrate low discriminant validity, suggesting diminished specificity as memory measures.

Interpretative guidelines for neuropsychiatric measures with dichotomously scored items

Neuropsychiatric measures consisting of dichotomously scored items are commonly used in clinical assessment. After summing these items, clinical guidelines frequently recommend cutoff scores to determine the presence or degree of a particular attribute, such as depression. However, blind application of such cutoffs neglects whether the total score is significantly different from chance. This confounding problem is illustrated using the Geriatric Depression Scale (GDS), and recommendations for interpreting the degree to which a GDS score significantly exceeds chance are presented. Specifically, GDS scores between 11 and 20, inclusive, were found not to differ significantly from chance (p > 0.05), assuming a random response pattern. The importance of supportive clinical evidence of depressive symptomatology is increased for scores in this range. These guidelines will be helpful in using such measures with patients who may vary with respect to response accuracy, and in assessing possible incomplete effort or random responding.

Compensatory recruitment of neural resources during overt rehearsal of word lists in Alzheimer's disease

Functional neuroanatomical correlates subserving maintenance rehearsal relative to a reading control task were investigated with positron emission tomography imaging of cerebral blood flow in 6 healthy older participants and 6 patients with mild Alzheimer's disease (AD). Rehearsal and reading rates and number of unique words rehearsed did not differ significantly for the 2 groups. The right dorsolateral prefrontal cortex was activated in both groups during rehearsal, highlighting this region's role in short-term maintenance of verbal information. A shift in cortical processing resources to more anterior brain regions with increased rehearsal list length was seen, likely reflecting greater demands on frontal cortex as cognitive load grows. Whereas controls showed unilateral right frontal activation during rehearsal, AD patients demonstrated bilateral frontal activation, possibly reflecting compensatory recruitment of neural resources.

An analysis of test bias and differential item functioning due to race on the Mattis Dementia Rating Scale

The Mattis Dementia Rating Scale (MDRS) is a commonly used cognitive measure designed to assess the course of decline in progressive dementias. However, little information is available about possible systematic racial bias on the items presented in this test. We investigated race as a potential source of test bias and differential item functioning in 40 pairs of African American and Caucasian dementia patients (N = 80), matched on age, education, and gender. Principal component analysis revealed similar patterns and magnitudes across component loadings for each racial group, indicating no clear evidence of test bias on account of race. Results of an item analysis of the MDRS revealed differential item functioning across groups on only 4 of 36 items, which may potentially be dropped to produce a modified MDRS that may be less sensitive to cultural factors. Given the absence of test bias because of race, the observed racial differences on the total MDRS score are most likely associated with group differences in dementia severity. We conclude that the MDRS shows no appreciable evidence of test bias and minimal differential item functioning (item bias) because of race, suggesting that the MDRS may be used in both African American and Caucasian dementia patients to assess dementia severity.

Compensatory recruitment of neural resources during overt rehearsal of word lists in Alzheimer's disease

Functional neuroanatomical correlates subserving maintenance rehearsal relative to a reading control task were investigated with positron emission tomography imaging of cerebral blood flow in 6 healthy older participants and 6 patients with mild Alzheimer's disease (AD). Rehearsal and reading rates and number of unique words rehearsed did not differ significantly for the 2 groups. The right dorsolateral prefrontal cortex was activated in both groups during rehearsal, highlighting this region's role in short-term maintenance of verbal information. A shift in cortical processing resources to more anterior brain regions with increased rehearsal list length was seen, likely reflecting greater demands on frontal cortex as cognitive load grows. Whereas controls showed unilateral right frontal activation during rehearsal, AD patients demonstrated bilateral frontal activation, possibly reflecting compensatory recruitment of neural resources.

Normative data for equivalent, parallel forms of the Judgment of Line Orientation Test

The Judgment of Line Orientation Test (JLO; Benton, Hamsher, Varney, & Spreen, 1983) permits assessment of visuospatial processing without making demands on motor skills. However, its administration can be time-intensive and frustrating for patients, particularly when used in a geriatric population. We present a single set of normative data to be used for both the odd-item and even-item forms derived from Form V of the JLO based on responses from a healthy geriatric sample. Mean scores and distributions of odd-item and even-item forms were nearly identical, and both forms showed significant correlations with the Developmental Test of Visual- Motor Integration. Cross-validation using the odd form of the JLO on an independent sample from a different geographic location suggested good generalizability of the normative data. We conclude that these JLO short-form normative data may be used in clinical screening situations or when serial assessments are needed.

Early detection of Alzheimer disease: methods, markers, and misgivings

There is at present no reliable predictive test for most forms of Alzheimer disease (AD). Although some information about future risk for disease is available in theory through ApoE genotyping, it is of limited accuracy and utility. Once neuroprotective treatments are available for AD, reliable early detection will become a key component of the treatment strategy. We recently conducted a pilot survey eliciting attitudes and beliefs toward an unspecified and hypothetical predictive test for AD. The survey was completed by a convenience sample of 176 individuals, aged 22-77, which was 75% female, 30% African-American, and of which 33% had a family member with AD. The survey revealed that 69% of this sample would elect to obtain predictive testing for AD if the test were 100% accurate. Individuals were more likely to desire predictive testing if they had an a priori belief that they would develop AD (p = 0.0001), had a lower educational level (p = 0.003), were worried that they would develop AD (p = 0.02), had a self-defined history of depression (p = 0.04), and had a family member with AD (p = 0.04). However, the desire for predictive testing was not significantly associated with age, gender, ethnicity, or income. The desire to obtain predictive testing for AD decreased as the assumed accuracy of the hypothetical test decreased. A better short-term strategy for early detection of AD may be computer-based neuropsychological screening of at-risk (older aged) individuals to identify very early cognitive impairment. Individuals identified in this manner could be referred for diagnostic evaluation and early cases of AD could be identified and treated. A new self-administered, touch-screen, computer-based, neuropsychological screening instrument called Neurobehavioral Evaluation System-3 is described, which may facilitate this type of screening.

Controlled and automatic forms of memory and attention: process purity and the uniqueness of age-related influences

Estimates of controlled and automatic processes hypothesized to underlie performance in a memory task and in an attention task were derived for 115 participants from 18 to 78 years of age using the process-dissociation procedure. Participants also performed speed and neuropsychological tests that were suspected to be negatively related to age. Process estimates showed good reliability (from .76 to .98), and the qualitative distinction between processes was supported by the overall pattern of correlations among measures. However, only estimated automatic processes exhibited unique variance, as they were either weakly related or unrelated both to performance on the other tests and to each other. Estimates of the control processes, in contrast, shared considerable variance with measures from other tests, and there were no unique, or independent, age-related effects on these measures. The results highlight the need to distinguish between process purity and the uniqueness of age-related influences in accounting for age differences in cognition.

Examination of age-related deficits on the Wisconsin Card Sorting Test

Adult age differences in Wisconsin Card Sorting Test (WCST) measures were examined before and after statistical control of age-related differences in measures of feedback usage, working memory, and perceptual-comparison speed. The proportion of age-related variance associated with a summary measure of WCST performance was greatly reduced after controlling for measures of feedback usage, working memory, and perceptual-comparison speed. Furthermore, the age-related variance associated with the feedback-usage measure was reduced after controlling for working memory and perceptual-comparison speed measures. These results are consistent with the idea that age-related performance differences in the WCST are partially mediated by adult age differences in feedback usage and that age differences in feedback usage are mediated by age differences in working memory, which are in turn-mediated by age-related reductions in processing speed, indexed by measures of perceptual-comparison speed.

Functional outcome of cognitively impaired hip fracture patients on a geriatric rehabilitation unit

OBJECTIVES

To compare outcomes (physical functions and discharge destinations) of cognitively impaired and intact older hip fracture patients, and to identify cognitive skills related to functional gains.

DESIGN

Prospective longitudinal study of hip fracture patients treated on an acute inpatient rehabilitation service, with evaluation of functional performance and living status determined at admission and discharge.

SETTING

A specialized inpatient geriatric rehabilitation program at Wesley Woods Geriatric Hospital, which is affiliated with Emory University School of Medicine.

SUBJECTS

Fifty-eight hip fracture patients, 35 with and 23 without cognitive impairment.

MEASUREMENTS

Cognitive functioning measured by the Mattis Dementia Rating Scale (MDRS); functional outcome assessed by the Functional Independence Measure (FIM); comparison of pre-fracture with discharge living environments.

MAIN RESULTS

Both cognitively impaired and intact hip fracture patients exhibited similar overall FIM motor improvements as well as functional gains in specific FIM areas measuring self-care, sphincter control, and locomotion (e.g., walking). Cognitively intact patients, however, displayed significantly greater gains in mobility (e.g., transfers) at discharge. Cognitively impaired patients who lived in the community were as likely as intact patients to return to the community. Patients who entered the program at a modified dependence level (FIM 3-5) and achieved motor independence at discharge (FIM 6-7) had higher MDRS initiation/ perseveration and memory scores.

CONCLUSIONS

Hip fracture patients with cognitive impairments can achieve positive outcomes as defined by functional improvement and discharge destination. Intensive post-fracture rehabilitation in the early phase of recovery may promote functional independence and a return to the community for older patients at risk for nursing home placement. Future research should examine the long-term maintenance of these improvements and explore how rehabilitation interventions can be altered to enhance outcome.

Short-form alternatives to the Judgment of Line Orientation Test

The Judgment of Line Orientation Test (JLO; Benton, Hamsher, Varney, & Spreen, 1983) is frequently used as a motor-free method of evaluating visuospatial processing but can be time-consuming to administer. We investigated the internal consistency, validity, and utility of two parallel JLO short forms in a mixed clinical sample of 386 patients. Mean scores were equivalent, and correlational analyses supported the internal consistency and validity of both short forms. When compared to the standard JLO, the odd- and even-item short forms demonstrated good sensitivity, specificity, overall hit rate and predicted positive and negative accuracy. We conclude that the JLO short forms possess sufficient internal consistency, validity, and utility for serial assessment in research studies. The JLO short forms may potentially be used in clinical screening situations by applying a single cut-off score to differentiate levels of performance. However, more detailed clinical use of these JLO short forms will necessitate collection of normative data in order to generate accurate percentile rankings.

Treatment of advanced Parkinson's disease by posterior GPi pallidotomy: 1-year results of a pilot study

The effects of posterior internal pallidal ablation (GPi pallidotomy) on parkinsonian signs and symptoms were studied in 15 patients with medically intractable Parkinson's disease (PD). The sensorimotor territory of the internal portion of the globus pallidus and the adjacent optic tract and internal capsule were identified with microelectrode recording and stimulation. Radiofrequency lesions were then created in the identified sensorimotor territory. Pallidotomy significantly improved all cardinal parkinsonian motor signs (tremor, rigidity, akinesia/bradykinesia, and gait dysfunction) and reduced drug-induced motor fluctuations and dyskinesias. The improvements occurred predominately contralateral to the lesion, but were also present ipsilaterally. Early postoperative (3-month), mean total United Parkinson's Disease Rating Scale scores improved by 30.1% from preoperative values. Mean combined "on/off" Schwab and England Scale scores, a measure of functional independence, increased from 48.8% to 73.0% postoperatively. The mean total United Parkinson's Disease Rating Scale and Schwab and England scores did not show a statistically significant decline over the 1-year postoperative period. Surgery resulted in little morbidity, including a lack of significant deficits on neuropsychological and psychiatric testing. Physical and social functioning and vitality measures on the Medical Outcome Scale also showed significant improvement over the postoperative period. The findings of this pilot study demonstrate that ablation of the sensorimotor portion of the internal pallidum is a highly effective treatment for advanced PD, with benefits sustained at 1 year.

Development of a computer-based battery designed to screen adults for neuropsychological impairment

The initial step in the development of a new computer-based neuropsychological testing system is described. A new hardware-software system and a screening battery consisting of an orientation task and five cognitive tests has been implemented. This novel screening battery is designed for use in identifying individuals among exposed groups who may require more extensive follow-up neuropsychological evaluation. Sophisticated, but currently available, and relatively inexpensive hardware and software technology are employed, introducing an improvement over existing computer-based batteries. Use of a digitized speech production device for producing instructions facilitates testing of illiterate subjects, use of auditory stimulus materials, and relatively easy translation of the testing instructions to other languages. Use of a pen-based notebook computer enables responding by the subject in a manner that is both natural and analogous to that used in existing paper-and-pencil testing instruments. Five neuropsychological tests were developed to cover a range of cognitive domains: 1) verbal list learning and recognition memory, 2) visual memory span, 3) conceptual and motor tracking, 4) psychomotor speed and accuracy, and 5) delayed verbal recognition. The screening instrument has been pilot-tested for feasibility of use among outpatients at an occupational medicine clinic and among community-dwelling older adults. This instrument is intended to provide a standardized efficient, cost-effective method for widespread use in occupational medicine and public health to detect and track subclinical neurotoxic effects and to prevent additional harmful exposure. Additional aspects of development of the computer-based testing system are discussed.