Dementias that present with and without posterior cortical features: an important clinical distinction

Upper-Extremity Dual-Task Function: An Innovative Method to Assess Cognitive Impairment in Older Adults

BACKGROUND

Difficulties in orchestrating simultaneous tasks (i.e., dual-tasking) have been associated with cognitive impairments in older adults. Gait tests have been commonly used as the motor task component for dual-task assessments; however, many older adults have mobility impairments or there is a lack of space in busy clinical settings. We assessed an upper-extremity function (UEF) test as an alternative motor task to study the dual-task motor performance in older adults.

METHODS

Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal cognitive assessment (MoCA). Participants performed repetitive elbow flexion with their maximum pace, once single-task, and once while counting backward by one (dual-task). Single- and dual-task gait tests were also performed with normal speed. Three-dimensional kinematics was measured both from upper-extremity and lower-extremity using wearable sensors to determine UEF and gait parameters. Parameters were compared between the cognitively impaired and healthy groups using analysis of variance tests, while controlling for age, gender, and body mass index (BMI). Correlations between UEF and gait parameters for dual-task and dual-task cost were assessed using linear regression models.

RESULTS

Sixty-seven older adults were recruited (age = 83 ± 10 years). Based on MoCA, 10 (15%) were cognitively impaired. While no significant differences were observed in the single-task condition, within the dual-task condition, the cognitively impaired group showed significantly less arm flexion speed (62%, d = 1.51, p = 0.02) and range of motion (27%, d = 0.93, p = 0.04), and higher speed variability (88%, d = 1.82, p < 0.0001) compared to the cognitively intact group, when adjusted with age, gender, and BMI. Significant correlations were observed between UEF speed parameters and gait stride velocity for dual-task condition (r = 0.55, p < 0.0001) and dual-task cost (r = 0.28, p = 0.03).

CONCLUSION

We introduced a novel test for assessing dual-task performance in older adults that lasts 20 s and is based on upper-extremity function. Our results confirm significant associations between upper-extremity speed, range of motion, and speed variability with both the MoCA score and the gait performance within the dual-task condition.

Falls-related self-efficacy is independently associated with quality-adjusted life years in older women

BACKGROUND

falls-related self-efficacy is associated with falls, falls-related injury and subsequent functional decline which may lead to poor health-related quality-of-life (HRQL). To our knowledge, no previous studies have examined the independent contribution of falls-related self-efficacy to HRQL. Our primary objective was to determine whether falls-related self-efficacy is independently associated HRQL, measured by quality-adjusted life years (QALYs), in older women after accounting for known covariates.

METHOD

we conducted a secondary analysis of 135 community-dwelling older women aged 65-75 years who participated in a 12-month randomised controlled trial of resistance training. We assessed falls-related self-efficacy using the Activities-specific Balance Confidence Scale and QALYs calculated from the EuroQol EQ-5D (EQ-5D).

RESULTS

our multivariate linear regression model demonstrated that falls-related self-efficacy as assessed using the Activities-specific Balance Confidence Scale was independently associated with QALYs after accounting for age, group, education, functional co-morbidity index, general mobility, global cognition and physiological falls risk. The final model explained 52% of the variation in QALYs. The ABC Scale accounted for 5% of the total variance in the final model.

CONCLUSIONS

although falls-related self-efficacy was independently associated with QALYs after controlling for a number of known variables, there may well be other factors not investigated, such as risk taking behaviour and psychological measures, which could account for some of the association.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00426881.

The independent contribution of executive functions to health related quality of life in older women

Background

Cognition is a multidimensional construct and to our knowledge, no previous studies have examined the independent contribution of specific domains of cognition to health related quality of life. To determine whether executive functions are independently associated with health related quality of life assessed using Quality Adjusted Life Years (QALYs) calculated from the EuroQol EQ-5D (EQ-5D) in older women after adjusting for known covariates, including global cognition. Therefore, we conducted a secondary analysis of community-dwelling older women aged 65-75 years who participated in a 12-month randomized controlled trial of resistance training. We assessed global cognition using the Mini-Mental State Examination (MMSE) and executive functions using the: 1) Stroop Test; 2) Trail Making Test (Part B) and 3) Digits Verbal Span Backwards Test. We calculated QALYs from the EQ-5D administered at baseline, 6 months and 12 months.

Results

Our multivariate linear regression model demonstrated the specific executive processes of set shifting and working memory, as measured by Trail Making Test (Part B) and Digits Verbal Span Backward Test (p < 0.01) respectively, were independently associated with QALYs after accounting for age, comorbidities, general mobility, and global cognition. The final model explained 50% of the variation in QALYs.

Conclusions

Our study highlights the specific executive processes of set shifting and working memory were independently associated with QALYs -- a measure of health related quality of life. Given that executive functions explain variability in QALYs, clinicians may need to consider assessing executive functions when measuring health related quality of life. Further, the EQ-5D may be used to track changes in health status over time and serve as a screening tool for clinicians.

Trial Registration

ClinicalTrials.gov Identifier: NCT00426881.

Early Cognitive Impairment: Role of Clock Drawing Test

BACKGROUND

Folstein's Mini Mental Status Examination (MMSE) often fails to identify executive dysfunction even if quite severe. Detailed neuropsychological tests and extensive bedside tests are available to evaluate executive function, but most of them are time consuming. This study was done to determine the value of a Clock Drawing Test (CDT) as a simple tool to identify cognitive dysfunction in various neurological disorders and to assess its utility as an adjunct to MMSE in identifying executive dysfunction in a a busy out patient department (OPD).

METHODS

A total of 81 patients suffering from neurological disorders and 81 controls were studied. All subjects received the MMSE and the CDT. The CDT is divided into an unprompted task that is sensitive to executive control (CDT 1) and a copying task which is not (CDT 2).

RESULT

All the three tests (CDT 1, CDT 2 and MMSE) could recognize cognitive and executive function deficits, when compared with age and sex matched controls (p < 0. 001). CDT scores correlated strongly with the level of executive function deficits. CDT+MMSE detected 95% cases as abnormal as compared to 47% detected by MMSE alone.

CONCLUSION

CDT along with MMSE can detect executive control deficits and cognitive deficits. The CDT 1 tests executive control performance, while CDT 2 tests posterior cortical deficits.

Vascular cognitive impairment: current concepts and clinical developments

Vascular cognitive impairment (VCI) comprises a range of cognitive disorders related to cerebral vessel disease and has generally replaced the term multi-infarct dementia. Despite the heterogeneity of the VCI construct, some clinical patterns can be discerned, which enable subtypes, such as mixed dementia and VCI-no dementia, to be recognised. Diagnostic criteria for vascular dementia do not encompass the full range of the VCI construct, and clinical investigators now recognise the need for harmonised standards to study the many manifestations of VCI seen in daily practice and to inform the development of diagnostic criteria. Although executive dysfunction is a recognised feature of VCI, some data suggest a less exclusive role than was previously proposed. VCI might be preventable, although the evidence for this is not as complete as it is for the prevention of stroke. Future studies into specific therapies for VCI will need to consider the clinical features and outcomes carefully.

Clock drawing phenotypes in community-dwelling African Americans and Caucasians: results from the University of Alabama at Birmingham study of aging

BACKGROUND

Two dementia patterns have been described: 'type 1' dementia is characterized by executive function impairment and posterior cortical impairment, and 'type 2' dementia is characterized by executive impairment and relatively preserved posterior cortical function. The Executive Clock Drawing Task (CLOX) has been used to discriminate between type 1, type 2, and normal cognitive phenotypes. The aim of this study was to describe the prevalence of these phenotypes in community-dwelling African American and Caucasian elders.

METHODS

433 African Americans and 477 Caucasians over the age of 65 were recruited. Executive function was assessed using CLOX1, a command-directed clock drawing task. Posterior cortical impairment was assessed using CLOX2, a clock copy task. CLOX scores were combined to estimate the prevalence of type 1 phenotype (those with poor CLOX1 and CLOX2 performance) versus type 2 phenotype (those with only poor CLOX1 performance).

RESULTS

351 (39%) subjects had poor executive performance. Three hundred (33%) subjects had a type 1 phenotype and this pattern was 2.5 times more common among African Americans than Caucasians. One hundred and thirty-seven (15%) subjects had a type 2 phenotype with no significant difference between African Americans and Caucasians. African American ethnicity was independently associated with poor CLOX1 performance after adjusting for sociodemographic factors, posterior cortical function, and global cognition. CLOX2 performance was not associated with ethnicity.

CONCLUSION

The prevalence of poor executive performance in community-dwelling elders is high. African Americans were more likely to have a type 1 phenotype and these ethnic differences were not explained by sociodemographic variables alone.

Semantic clustering indexes for the Hopkins Verbal Learning Test-Revised: initial exploration in elder control and dementia groups

This study examined the validity of semantic clustering indexes developed for the Hopkins Verbal Learning Test-Revised (HVLT-R). Participants were healthy adults and patients diagnosed with probable dementia of the Alzheimer's type (DAT) or vascular dementia (VaD). Neuropsychological test records, which included the HVLT-R, were collected from an archival database. Ratio semantic clustering (RSC) scores were calculated for each HVLT-R recall trial. Factor analysis including RSC and other HVLT-R scores yielded high loadings of RSC scores on a distinct clustering factor. Group comparisons showed that normal controls had higher HVLT-R recall and RSC scores than DAT and VaD patients. Only the DAT group showed significant decline in RSC from the final learning trial to delayed recall, and only the DAT group performed more poorly than controls on other semantic processing measures (e.g., HVLT-R semantically-related false positives, Boston Naming Test). Results suggest that these newly developed semantic clustering indexes are easily calculated and potentially useful for discriminating between elder controls and dementia patients.

Insular Alzheimer's disease pathology as a cause of "age-related" autonomic dysfunction and mortality in the non-demented elderly

Only a few brain structures have been implicated in the autonomic control of blood pressure and heart rate. Among them are heteromodal association areas in the cortex, especially the insular cortex. Ischemic insular lesions have been associated with both cardiac arrhythmias and mortality. However, stroke may not be the only insular pathology with the potential to disrupt autonomic function. Alzheimer's disease (AD) is associated with both insular pathology and autonomic dysfunction. Alzheimer's dementia is merely the final stage of a pathological process that spans decades. Recent studies have demonstrated a hierarchichal sequence of AD pathology that includes the insular cortex. This may explain why AD has effects on BP and central autonomic cardio-regulatory functions. However, AD reaches the insular cortex at a "preclinical" stage in its development (i.e., before "dementia" can be diagnosed). Thus, AD pathology should also be considered as a possible explanation for autonomic morbidity and mortality in non-demented elderly persons. We hypothesize that autonomic dyscontrol, commonly seen in non-demented well elderly persons without significant cardiovascular disease (CVD), reflects subclinical stages of AD pathology affecting the insular cortex. If true, then preclinical AD pathology should be considered as a possible explanation for arrhythmia/fall related morbidity and mortality in non-demented elderly persons.

Principles and practice of geriatric assent

Geriatric assent involves health care professionals' active collaboration with cognitively impaired patients that takes account of their longstanding values in any major health care decisions. The main purpose of this paper is to assist geriatric health practitioners 'in the field' to understand how to apply geriatric assent in a variety of clinical situations to maximize incapacitated older adults' input into decision-making. A case example and algorithm are presented to illustrate the basic principles of implementing geriatric assent. Practice informed by the principles of geriatric assent will preserve respect for the current and future autonomy of patients across diverse cultural backgrounds.

Normal rates of cognitive change in successful aging: the freedom house study

We determined the rates of cognitive change associated with twenty individual measures. Participants included 547 noninstitutionalized septuagenarians and octogenarian residents of a comprehensive care retirement community who were studied over three years. Latent growth curves (LGC) of multiple cognitive measures were compared to a LGC model of the rates of change in Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL). All curves were standardized relative to each variable's baseline distribution. Baseline scores were within their expected normal age-specific ranges. Most measures showed significant rates of change over time. There was also significant variability about those rates, suggesting clinical heterogeneity. Many deteriorated over time, as did ADLs and IADLs. However, performance on some measures improved, consistent with learning effects. The rates of change in two measures, the Executive Interview and the Trail Making Test, were closely related to decline in IADLs. These results suggest that age-related cognitive decline is a dynamic longitudinal process affecting multiple cognitive domains. Heterogeneity in the rates of cognitive change may reflect the summed effects of age and comorbid conditions affecting cognition. Some measures may be ill-suited for measuring age-related changes in cognition, either because they are insensitive to change, or hindered by learning effects. Nonverbal measures appear to be particularly well suited for the prediction of age-related functional decline. These observations are relevant to the definition and diagnosis of "dementing" conditions.

An empiric approach to level of care determinations: the importance of executive measures

BACKGROUND

The ability to predict the level of care received by elderly retirees was compared in a discriminant model and using a classification tree derived from cognitive and noncognitive variables. Methods. Participants were 193 residents (mean age, 79.1+/-5.1 years) of a single, 1,500-bed, continuing care retirement community. They were given a battery of cognitive measures that included tests of general cognition, memory, and executive control function. A multivariate discriminant model of level of care was compared with a classification tree.

RESULTS

Residents in congregate high-rises (n=115) differed significantly from those in apartment settings (n=78) with respect to age, Executive Interview (EXIT 25), and the Executive Clock-Drawing Task (CLOX). Only age and executive control function measures (CLOX1, EXIT 25, and Trail Making Test Part B [Trails B]) contributed independently to a discriminant model of level of care (Wilke's lambda=0.92; F [df 4,170]=3.48; p <.01). Sixty-three percent of participants were correctly classified. A classification tree derived from the same variable set was more accurate (75% correctly classified). Age, CLOX1, and EXIT 25 made the most important contributions to the model. The EXIT 25 and CLOX1 thresholds empirically derived from this model coincide with the fifth percentiles for these instruments in a young adult sample.

CONCLUSIONS

Executive control function appears to be most responsible for the effect of cognition on level of care. Young adult norms may be most relevant when the effects of cognitive impairment on functional status are assessed.

Assessment Instruments

Assessment is the undergirding of palliative care and of geriatrics care. Both disciplines insist on a comprehensive assessment that includes personal and social aspects of the patient's illness experience. At the same time, both face challenges due to the amount of time and skill needed to encompass such a broad scope and the often heavy illness burden of the patients, which makes interaction stressful or difficult. This article examines question-based assessment instruments in palliative care for elders. Important in all aspects of medicine, reliance on verbal assessments is of special importance in palliative care.

Effect of vascular lesions on cognition in Alzheimer's disease: a community-based study

OBJECTIVES

To investigate whether clinical and neuropathological differences exist between Alzheimer's disease (AD) cases with and without vascular lesions neuropathologically diagnosed using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria.

DESIGN

Descriptive observational study.

SETTING

A community-based registry that identified incident dementia cases.

PARTICIPANTS

Of the 124 subjects with available clinical and neuropathological assessments, 30 had AD lesions alone, and 18 had AD with vascular lesions. Patients with other neuropathological findings were excluded.

MEASUREMENTS

Dependent measures included demographic, clinical, and neuropathological characteristics. Neuropathological diagnoses were made using the CERAD criteria and Braak and Braak staging.

RESULTS

Of the 124 autopsied cases, 85 cases were diagnosed with neuropathological AD. Of these, 30 had pathology consistent with "pure" AD, whereas 18 had AD pathology with significant vascular lesions (AD/V). There were no differences in age, sex, or education between groups. AD/V cases had higher baseline and final Mini-Mental State Examination (MMSE) scores than pure AD cases, but after adjusting for education, differences in MMSE scores were not statistically significant. The AD/V group had significantly lower Braak staging than the pure AD group, after adjusting for education and final MMSE scores.

CONCLUSION

In this comparison study of AD cases with and without vascular lesions, AD/V cases had less severe AD pathology than those with AD alone, indicating that cerebrovascular disease likely contributes to the severity of cognitive impairment in those with AD. Controlling for vascular risk factors in patients with AD may have a significant effect on severity of dementia.

The executive clock drawing task (CLOX) is a poor screening test for executive dysfunction in Chinese elderly patients with subcortical ischemic vascular disease

Executive dysfunction (ED) is a prominent feature of subcortical ischemic vascular disease. A screening test for ED is lacking among Chinese. The objective of the study is to investigate the validity and reliability of a Chinese version of the Executive clock drawing task (CLOX) in screening ED among Chinese elderly patients with small subcortical infarct (SSI). The Chinese version of CLOX correlated with MMSE, CDRS I/P, and WCST perseverative errors. However, multivariate regression analysis showed that only education (R(2) change=0.22, p < 0.001 ) and MMSE (R(2) change=0.35, p < 0.001), but none of the standard executive function tests, significantly accounted for the variance in the CLOX. Test-retest (r=0.84) and inter-rater reliability (r=0.84) were high for the CLOX. Conclusions. Although the CLOX is reliable, it is not valid in detecting ED in Chinese elderly patients with SSI.

Decline in learning ability best predicts future dementia type: the Freedom House Study

The authors studied longitudinal change in learning efficiency as a predictor of future dementia type among healthy, well-educated, noninstitutionalized elderly retirees. Serial assessments of memory were obtained using the California Verbal Learning Test (CVLT). Latent growth (LG) models were developed from the slopes of the subjects' performance over the first five CVLT learning trials at each of three serial administrations (e.g., cohort inception [i.e., baseline] [CVLT1], 18 months [CVLT2] and 36 months [CVLT3]). The resulting growth curves were incorporated into a higher order LG model representing the dynamic change in learning efficiency over time (DeltaCVLT). DeltaCVLT was used to predict each subject's "dementia type" (i.e., clinical state) at 36 months (e.g., no dementia, Type 1 [Alzheimer type] dementia or Type 2 [non-Alzheimer type] dementia), after adjusting for CVLT1, baseline age, and baseline dementia type. Nonlinear (logarithmic) LG models of CVLT1-CVLT3 and DeltaCVLT best fit the data. There was significant variability about both CVLT1 and DeltaCVLT, suggesting subgroups in the sample with significantly different baseline memory function, and different rates of deterioration in learning efficiency. Age, baseline dementia type, and DeltaCVLT made significant independent contributions to final dementia type. CVLT1 did not predict final dementia type independently of the other covariates. These data suggest that baseline memory performance in noninstitutionalized elderly retirees does not predict future dementia type independently of the dynamic rate of change in memory measures. Serial administrations of memory tests may help identify nondemented persons at greater or lesser risk for conversion to frank dementia in the near-term.

Validation of a Spanish translation of the CLOX for use in Hispanic samples: the Hispanic EPESE study

OBJECTIVES

Clock drawing tests (CDT) appear to be less vulnerable to linguistic, cultural, or educational bias than traditional dementia screening instruments. We investigated a Spanish language translation of CLOX: an executive CDT, in a community sample of Hispanic elders.

METHODS

In-home CLOX evaluations of 1309 Mexican-American elders were reviewed.

RESULTS

Both CLOX1 (an executive CDT) and CLOX2 (a constructional CDT) showed good internal consistency (Chronbach's alpha; both alpha = 0.82). Cultural-demographic variables had little effect on CLOX scores. Although language had a significant effect on CLOX1 failure rates, this was not mediated by age, education, acculturation or income.

CONCLUSIONS

These results suggest that the Spanish CLOX can be validly administered to community-based Hispanic elder samples regardless of education or acculturation.

The neuropsychological assessment of dementia

It has become standard practice to base the diagnosis of dementia on the combination of neuropsychological and non-behavioral findings. The present article provides a short, clinically oriented synopsis of the targets, investigational procedures, and difficulties of the modern neuropsychological approach to the diagnosis of dementia. Over the years, neuropsychology has developed assessment tools to evaluate the cognitive and behavioral abnormalities of many dementias. Validated tests of memory, language, executive, and other cognitive functions are used to screen for dementia and identifying certain dementia profiles. Behavioral assessment procedures are available for non-cognitive neurodegenerative alterations. At present, problems arise mainly with the behavioral heterogeneity of certain dementia syndromes. Especially problematic are discrimination of age-associated or mild cognitive impairments from incipient dementia and the impact of psychiatric symptoms on cognitive functions. It is concluded that neuropsychology offers a valuable contribution to the diagnosis and differential diagnosis of dementia.

Informed consent for medical research by the elderly

Much has been written about the possible lack of capacity of the elderly, especially certain vulnerable populations of older individuals, to give informed consent for medical research. Several small studies have shown a deficit for comprehension of consent material, by the elderly, especially those with less education, but this appears small in comparison to an overall deficit in the general population. A number of investigations have suggested that deficits in executive control functions (ECFs) may be related to lack of capacity to make clinical judgments, but these have yet to be applied to research. Many methods have been piloted to measure capacity and to improve comprehension, some of which may help, although none has been proved conclusively to do either. As the elderly experience significant morbidity and mortality from a vast array of illnesses, the use of the elderly as subjects of medical research is especially important. To prevent older individuals from being coerced into participating or potentially being harmed by scientific investigation, they must give informed consent to their involvement. However, there are many studies to suggest that they are not well informed. A discussion ensued in the 1970s and 1980s about whether or not the elderly deserved special protection as a class of individuals, based on their possible increased risk during medical experimentation, but it was ultimately decided that, because the majority of elderly are perceived to be cognitively intact, they need not receive additional safeguards (High & Doole, 1995, Behavioral Science and Law, 13, 319-335). The U.S. Department of Health and Human Services in 2000 (Federal Registrar Rules and Regulations, 46, 8366-8392) reviewed existing protections for subjects of human research and deemed they were inadequate, issuing new guidelines. This article reviews evidence that differences exist between the ability of young and old in their capacity to give consent. Alterations in methods of obtaining consent may help individuals to give a more informed consent, and even enable subjects who lack the capacity to consent, such as cognitively impaired individuals, to participate in research. However an ideal means of screening or altering the consent process has yet to be devised. Many of these methods are briefly considered.

Frontal MRI findings associated with impairment on the Executive Interview (EXIT25)

We examined the association between the Executive Interview (EXIT25), a bedside measure of executive control, and regional magnetic resonance imaging (MRI) pathology among 52 consecutive geriatric patients presenting to a university dementia assessment clinic. Left frontal (p < .002), left medial (p < .03), right frontal (p < .02), and right medial (p < .02) cortical lesions significantly worsened EXIT25 scores, even after adjusting for age, global cognitive impairment (on the Mini-Mental State Examination), and the severity of cortical dementia on the Qualitative Evaluation of Dementia [QED]. The EXIT25's associations with right hemisphere lesions did not persist after adjusting for left frontal lesions. Left posterior lesions did not significantly affect the EXIT25. Similarly, left frontal circuit pathology worsened EXIT25 scores (p < .05). Pathology in left anterior subcortical structures showed a trend (p = .052). EXIT25 scores were not affected by right subcortical pathology, nor by pathology in either hippocampus. We conclude that the EXIT25 is specifically affected by frontal system MRI lesions, particularly on the left. This conclusion is consistent with earlier functional neuroimaging studies associating EXIT25 performance with left mesiofrontal perfusion.

Assessment of suspected dementia

At the Second Canadian Consensus Conference on Dementia (CCCD) (February, 1998), a group of neurologists, geriatricians, and psychiatrists met to consider guidelines for evaluation of dementia in Canada. This review paper formed a background paper for their discussion of dementia diagnosis. These experts from across the country concluded that diagnosis of suspected dementia cases continued to rest on skilled clinical assessment. Mental status exam, preferably in some quantifiable form, has become an essential part of the assessment. Selected laboratory tests are advisable in all cases (CBC, TSH, electrolytes, calcium, and glucose), but the CCCD continued to advise that CT scanning was mandatory only in selected cases where clinical findings pointed to another possibility besides Alzheimer's disease. The growing list of other diagnostic measures with potential usefulness in diagnosis of Alzheimer's disease or dementia in general was reviewed, but the evidence was judged as insufficient to support routine use of these tests by physicians. As new treatments for Alzheimer's disease become available, neurologists face new diagnostic challenges--differentiating Mild Cognitive Impairment, Frontotemporal dementias and Mixed dementias, and Lewy Body Dementia. Guidelines to aid in differential diagnosis are presented.

Correlates of disability among elderly retirees with "subclinical" cognitive impairment

BACKGROUND

We assessed the effects of impaired Executive Control Function (ECF) on Instrumental Activities of Daily Living (IADL) and level of care among noninstitutionalized elderly retirees with "subclinical" cognitive impairment.

METHODS

Subjects (N = 561; age 78.2 +/- 5.0 years) were residents of a single, 1,500 bed, continuing care retirement community. Subjects were examined for cognitive impairment using the Executive Interview (EXIT25), Mini-Mental State Examination (MMSE), and an executive clock-drawing task (CLOX). The CLOX is divided into executively sensitive (CLOX 1) and simple constructional (CLOX2) subtests.

RESULTS

Residents in congregate high-rises (n = 301) differed significantly from those in independent-living apartments (n = 260) with respect to age, gender, percent living alone, EXIT25, CLOX1, MMSE, and CLOX2 scores (all p < .03). Only differences in ECF measures persisted after adjusting for age and living alone (p < .004). The EXIT25 (p < .006) and CLOX2 (p = .02) were associated with the use of prostheses. The differences in EXIT25 scores persisted after adjusting for level and living alone (p = .01). All instruments distinguished residents with impairment in IADLs. However, only CLOX2 (p < .001), EXIT25 (p < .001), and age (p < .001) made significant independent contributions.

CONCLUSIONS

ECF has statistically significant effects on level of care and IADL impairment, even among noninstitutionalized retirees. This emergent disability is not well detected by traditional global cognitive measures. Evaluation and treatment may be delayed unless ECF measures are employed.

Executive functioning and compliance in HIV patients

25 adult HIV patients were evaluated in a study of appointments, medication, and compliance with restrictions on sexual activity. The Executive Interview (EXIT) was useful in assessing these patients for cognitive difficulties; compliance with medication and countertransference issues were negatively correlated with EXIT scores.

Executive dyscontrol: an important factor affecting the level of care received by older retirees

OBJECTIVES

To examine the relative contributions of Executive Control Function (ECF), general cognition, mood, problem behavior, physical disability, demographic variables, and the number of prescribed medications to the level of care received by older retirees.

DESIGN

Multivariate regression and discriminant modeling.

SETTING

A single Continuing Care Retirement Community (CCRC) in San Antonio, Texas.

PARTICIPANTS

A total of 107 older retirees (mean age = 83.7+/-7.2 years), including 17 community-dwelling, well, older controls and 90 CCRC residents. CCRC subjects represented a convenience sample of consecutive referrals for geropsychiatric assessment. Sixty-one subjects resided at a noninstitutionalized level of care, and 46 were institutionalized.

MEASUREMENTS

Tests of ECF (the Executive Interview (EXIT25)), general cognition (the Mini-Mental State Examination (MMSE)), mood (the Geriatric Depression Scale short-form (sGDS)), problem behavior (the Nursing Home Behavior Problem Scale (NHBPS)), physical disability (the Cumulative Illness Rating Scale (CIRS)), age, gender, years of education, and the number of prescribed medications were studied.

RESULTS

All variables except gender and education varied significantly across level of care. Four variables made significant independent contributions; EXIT25 score (r2 = .48, P< .001), medication usage (partial r2 = .11, P<.001), sGDS score (partial r2 = .06, P = .001), and problem behavior (partial NHBPS r2 = .04, P<.04). These variables accounted for 69% of the total variance in level of care (R2 = .69; F (df 7,99) = 32.1, P<.001). A discriminant model based on the number of prescribed medications, EXIT25, sGDS, and NHBPS scores classified 83.2% of cases correctly (Wilke's lambda = .50, F(5,101) = 20.1; P<.001). The MMSE enters but fails to contribute significantly, independent of the other variables. Age and CIRS scores fail to enter.

CONCLUSIONS

Cognitive (particularly ECF) impairment contributes most to the observed variance in level of care received by older retirees in this CCRC. In contrast, markers of general cognition, depression, and physical illness contributed relatively little additional variance. ECF is not detected well by traditional cognitive measures and must be sought by specific tests. Further study is needed to replicate these findings in other populations.

CLOX: an executive clock drawing task

OBJECTIVE

To describe a clock drawing task (CLOX) designed to elicit executive impairment and discriminate it from non-executive constructional failure.

SUBJECTS

90 elderly subjects were studied (45 elderly and well persons from the independent living apartments of a continuing care retirement community and 45 patients with probable Alzheimer's disease). The clock drawing performance of elderly patients was compared with that of 62 young adult controls.

METHODS

Subjects received the CLOX, an executive test (EXIT25), and the mini mental state examination (MMSE). The CLOX is divided into an unprompted task that is sensitive to executive control (CLOX1) and a copied version that is not (CLOX2). Between rater reliability (27 subjects) was high for both subtests.

RESULTS

In elderly subjects, CLOX subscores correlated strongly with cognitive severity (CLOX1: r=-0.83 v the EXIT25; CLOX2: r=0.85 v the MMSE). EXIT25 and MMSE scores predicted CLOX1 scores independently of age or education (F(4,82)=50.7, p<0.001; R2=0.71). The EXIT25 accounted for 68% of CLOX1 variance. Only the MMSE significantly contributed to CLOX2 scores (F(4,72)= 57.2, p<0.001; R2=0.74). CLOX subscales discriminated between patients with Alzheimer's disease and elderly controls (83.1% of cases correctly classified; Wilkes' lambda=0.48, p<0.001), and between Alzheimer's disease subgroups with and without constructional impairment (91.9% of cases correctly classified; Wilkes' lambda=0.31, p<0.001).

CONCLUSIONS

The CLOX is an internally consistent measure that is easy to administer and displays good inter-rater reliability. It is strongly associated with cognitive test scores. The pattern of CLOX failures may discriminate clinical dementia subgroups.