Prevalence of disorders of executive cognitive functioning among the elderly: findings from the San Luis Valley Health and Aging Study

Circulating Plasma Metabolites and Cognitive Function in a Puerto Rican Cohort

BACKGROUND

Minorities, including mainland Puerto Ricans, are impacted disproportionally by Alzheimer's disease (AD), dementia, and cognitive decline. Studying blood metabolomics in this population has the potential to probe the biological underpinnings of this health disparity.

OBJECTIVE

We performed a comprehensive analysis of circulating plasma metabolites in relation to cognitive function in 736 participants from the Boston Puerto Rican Health Study (BPRHS) who underwent untargeted mass-spectrometry based metabolomics analysis and had undergone a battery of in-person cognitive testing at baseline.

METHODS

After relevant exclusions, 621 metabolites were examined. We used multivariable regression, adjusted for age, sex, education, apolipoprotein E genotype, smoking, and Mediterranean dietary pattern, to identify metabolites related to global cognitive function in our cohort. LASSO machine learning was used in a complementary analysis to identify metabolites that could discriminate good from poor extremes of cognition. We also conducted sensitivity analyses: restricted to participants without diabetes, and to participants with good adherence to Mediterranean diet.

RESULTS

Of 621 metabolites, FDR corrected (p < 0.05) multivariable linear regression identified 3 metabolites positively, and 10 negatively, associated with cognitive function in the BPRHS. In a combination of FDR-corrected linear regression, logistic regression regularized via LASSO, and sensitivity analyses restricted to participants without diabetes, and with good adherence to the Mediterranean diet, β-cryptoxanthin plasma concentration was consistently associated with better cognitive function and N-acetylisoleucine and tyramine O-sulfate concentrations were consistently associated with worse cognitive function.

CONCLUSION

This untargeted metabolomics study identified potential biomarkers for cognitive function in a cohort of Puerto Rican older adults.

Executive dysfunction and risk of suicide in older adults: a population-based prospective cohort study

OBJECTIVE

It is uncertain what factors increases the risk of suicide in older adults without depression, and it is unknown whether executive dysfunction (ED) is one of those factors. We aimed to examine the effect of ED on the risk of suicide in non-demented older adults without depression.

METHODS

In an ongoing population-based prospective cohort of Korean older adults, we identified suicide using the National Mortality Database and suicidal ideation or attempt (SIA) based on the Korean version of the Mini International Neuropsychiatric Interview. We defined ED as performing below -1.5 SD of age-adjusted, gender-adjusted and education-adjusted norms in any of following tests: Frontal Assessment Battery, Trail Making Test A, Digit Span Test or Verbal Fluency Test.

RESULTS

The mean age of the 4791 participants at baseline was 69.7 (SD 6.4) years, and 57.1% of them were women (mean follow-up duration=4.9 years). ED at baseline increased the risk of suicide by about seven times (HR 7.20, 95% CI 1.84 to 28.12, p=0.005) but did not change the risk of SIA. However, cognitive impairment without ED did not change the risks of suicide and SIA. In participants with ED, being aged 75 years or above, living alone, and having a low socioeconomic status were associated with the risk of suicide.

CONCLUSION

ED is a strong risk factor of late life suicide independent from depression, particularly in very old adults living in disadvantaged environments.

Verbal test of practical judgment (VPJ): a new test of judgment that predicts functional skills for older adults

OBJECTIVES

The clinical assessment of older adults' judgment is important for mitigating safety risks that often precipitate loss of independence. Our national survey of geriatric healthcare providers (N = 496; M years of experience = 17.11 ± 10.60) indicated that formal judgment tests are underutilized in clinical practice. We developed the Verbal Test of Practical Judgment (VPJ) as a new test of judgment for older adults intended to identify difficulty performing instrumental activities of daily living (IADL).

METHOD

In two prospective studies, participants were long-term care facility residents (age ≥ 50) in Maryland, USA (Study 1, N = 51; Study 2, N = 110) referred to licensed psychologists for neuro-cognitive and mood evaluation by facility attending physicians. Psychometric analyses were performed to examine the construct validity of the VPJ.

RESULTS

The VPJ evidenced adequate reliability and strong construct validity across both studies. Receiver operating characteristic analysis yielded an optimal VPJ cut score for identifying impaired judgment. The VPJ significantly predicted IADL performance beyond clinician and participant ratings.

CONCLUSION

The VPJ appears to be a valid tool for assessing judgment among older adults with suspected cognitive impairment. VPJ score inferences can inform clinicians on the odds of requiring assistance for specific IADLs.

Reduced gait and postural stability under challenging conditions in fallers with upper limb fracture

BACKGROUND

While most fractures are caused by falls, not all falls result in fractures. Risk factors for falls are well established, but only weak associations have been demonstrated for risk factors for fractures. Conflicting results on the implication of bone mineral density (BMD) suggest that other risk factors should be studied, such as gait and balance disorders.

AIMS

Gait and postural stability in challenging conditions were, therefore, compared between fallers with and without fracture.

METHODS

We enrolled 80 adults aged 55 and older who fell in the previous year. We compared gait and posture after obstacle crossing between fallers with an upper-limb fracture (n = 38), and fallers without fracture (n = 42). Data on BMD, body mass index, handgrip strength, fear of falling, number of comorbidities, number of falls, global cognition, executive functioning and education level were collected.

RESULTS

Compared to fallers without fracture, fallers with fracture had significant lower gait velocity (Likelihood-Ratio = 4.93; P = 0.03) and lower postural stability during stabilization after obstacle crossing (Likelihood-Ratio = 10.99; P < 0.001). In addition, fallers with fracture had lower handgrip strength (Likelihood-Ratio = 9.92; P = 0.002), lower education level (Likelihood-Ratio = 8.32; P = 0.004), poorer executive functions (Likelihood-Ratio = 5.81; P = 0.02, higher fear of falling (Likelihood-Ratio = 5.55; P = 0.02) and were more likely women (Likelihood-Ratio = 17.55; P < 0.001), compared to fallers without fracture.

DISCUSSION

This study demonstrated that the main difference between fallers with upper-limb fracture and fallers without fracture is mobility in dynamic condition. Poor executive function and low muscular strength could also be involved.

CONCLUSIONS

These factors should be taken into account when assessing risk factors for fracture and implementing preventive programs.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov. NCT02292316.

Prospective Associations of Erythrocyte Composition and Dietary Intake of n-3 and n-6 PUFA with Measures of Cognitive Function

Polyunsaturated fatty acid (PUFA) consumption is recommended as part of a healthy diet, but evidence of the impact of individual species and biological concentrations on cognitive function is limited. We examined prospective associations of PUFA erythrocyte composition and dietary intake with measures of cognitive function among participants of the Boston Puerto Rican Health Study (aged 57 years). Erythrocyte and dietary PUFA composition were ascertained at baseline and associated with 2-year scores on the Mini-Mental State Exam (MMSE) (n = 1032) and cognitive domain patterns derived from a battery of tests (n = 865), as well as with incidence of cognitive impairment. Erythrocyte and dietary n-3 PUFA were not significantly associated with MMSE score. However, total erythrocyte and dietary n-3 very-long-chain fatty acids (VLCFA), and intake of individual species, were associated with better executive function (P-trend < 0.05, for all). There was evidence that greater erythrocyte n-6 eicosadienoic acid concentration was associated with lower MMSE and executive function scores (P-trend = 0.02). Only erythrocyte arachidonic acid (ARA) concentration predicted cognitive impairment (Odds Ratio = 1.26; P = 0.01). Among Puerto Rican adults, we found that n-3 VLCFA consumption may beneficially impact executive function. Further, these findings provide some evidence that n-6 metabolism favoring greater ARA tissue incorporation, but not necessarily dietary intake, could increase the risk of cognitive impairment.

Neuropsychological state of the population living in the Aral Sea region (zone of ecological crisis)

Background The Aral Sea crisis has led to harmful effects on human habitat. In recent years, mild cognitive impairment is a growing problem. Objectives This article provides the results of studying the neuropsychological state of residents living in the crisis zone of the Aral Sea region in the case of Shalkar city. We have provided an assessment of the neuropsychological state of examined population and determined the leading pathology in this region. Methods The survey sample included 344 persons of reproductive age from 21 to 45 years. We have obtained results in biochemical studies, indicating perturbations of proteometabolism and lipid metabolism. Results A correlation analysis showed dependence between a decrease of albumin and high-density lipoproteins, an increase of low-density lipoproteins and parameters of cognitive function. Conclusions The research suggests a high prevalence of cerebrovascular pathology among the population, changes in cognitive function parameters, long-term and short-term memory problems and high levels of depression.

Association of psychological, cognitive, and functional variables with self-reported executive functioning in a sample of nondemented community-dwelling older adults

Subjective executive functioning (EF) measures provide valuable information about real-world difficulties, although it is unclear what variables actually associate with subjective EF scores. We investigated subjective EF in 245 nondemented, community-dwelling older adults (aged 70 and above) from the Einstein Aging Study. Partial correlational analyses controlling for age were performed between the nine Behavior Rating Inventory of Executive Function-Adult version (BRIEF-A) clinical scales and objective EF tests, self-reported mood and personality, and informant-reported activities of daily living. The significance level was set at p < .006 for all analyses (two-tailed). Most notably, higher worry/oversensitivity, physiological anxiety, and fear of aging were significantly associated with increased EF difficulties on all nine BRIEF-A scales. Additionally, increased EF difficulties on five or more BRIEF-A scales were significantly associated with lower conscientiousness, higher neuroticism, and higher depressive symptom scores. The only objective neuropsychological test that significantly correlated with increased EF difficulties (on four BRIEF-A scales) was a measure of practical judgment. Overall, results indicate that interpretation of subjective EF scores must account for self-report of mood and personality. Moreover, the BRIEF-A only minimally taps objective EF as measured by performance-based measures. We discuss the theoretical and practical implications of these findings.

White matter disease and cognitive impairment in FMR1 premutation carriers

OBJECTIVE

This cross-sectional, observational study examined the role of white matter involvement in the cognitive impairment of individuals with the fragile X mental retardation 1 (FMR1) premutation.

METHODS

Eight asymptomatic premutation carriers, 5 participants with fragile X tremor/ataxia syndrome (FXTAS), and 7 noncarrier controls were studied. The mean age of the asymptomatic premutation carriers, participants with FXTAS, and noncarrier controls was 60, 71, and 67 years, respectively. Magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) were used to examine the middle cerebellar peduncles (MCP) and the genu and splenium of the corpus callosum in relation to executive function and processing speed. MRS measures were N-acetyl aspartate/creatine (NAA/Cr) and choline/creatine, and fractional anisotropy (FA) was used for DTI. Executive function was assessed with the Behavioral Dyscontrol Scale and the Controlled Oral Word Association Test (COWAT), and processing speed with the Symbol Digit Modalities Test.

RESULTS

Among all 13 FMR1 premutation carriers, significant correlations were found between N-acetyl aspartate/creatine and choline/creatine in the MCP and COWAT scores, and between FA in the genu and performance on the Behavioral Dyscontrol Scale, COWAT, and Symbol Digit Modalities Test; a correlation was also found between FA in the splenium and COWAT performance. In all regions studied, participants with FXTAS had the lowest mean FA.

CONCLUSION

Microstructural white matter disease as determined by MRS and DTI correlated with executive dysfunction and slowed processing speed in these FMR1 premutation carriers. Neuroimaging abnormalities in the genu and MCP suggest that disruption of white matter within frontocerebellar networks has an important role in the cognitive impairment associated with the FMR1 premutation.

White matter disease and cognitive impairment in FMR1 premutation carriers

OBJECTIVE

This cross-sectional, observational study examined the role of white matter involvement in the cognitive impairment of individuals with the fragile X mental retardation 1 (FMR1) premutation.

METHODS

Eight asymptomatic premutation carriers, 5 participants with fragile X tremor/ataxia syndrome (FXTAS), and 7 noncarrier controls were studied. The mean age of the asymptomatic premutation carriers, participants with FXTAS, and noncarrier controls was 60, 71, and 67 years, respectively. Magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) were used to examine the middle cerebellar peduncles (MCP) and the genu and splenium of the corpus callosum in relation to executive function and processing speed. MRS measures were N-acetyl aspartate/creatine (NAA/Cr) and choline/creatine, and fractional anisotropy (FA) was used for DTI. Executive function was assessed with the Behavioral Dyscontrol Scale and the Controlled Oral Word Association Test (COWAT), and processing speed with the Symbol Digit Modalities Test.

RESULTS

Among all 13 FMR1 premutation carriers, significant correlations were found between N-acetyl aspartate/creatine and choline/creatine in the MCP and COWAT scores, and between FA in the genu and performance on the Behavioral Dyscontrol Scale, COWAT, and Symbol Digit Modalities Test; a correlation was also found between FA in the splenium and COWAT performance. In all regions studied, participants with FXTAS had the lowest mean FA.

CONCLUSION

Microstructural white matter disease as determined by MRS and DTI correlated with executive dysfunction and slowed processing speed in these FMR1 premutation carriers. Neuroimaging abnormalities in the genu and MCP suggest that disruption of white matter within frontocerebellar networks has an important role in the cognitive impairment associated with the FMR1 premutation.

Impairment of executive cognitive control in type 2 diabetes, and its effects on health-related behavior and use of health services

We evaluated whether, among persons with type 2 diabetes: (1) impaired executive cognitive functioning (ECF) is more common than among people without diabetes; (2) ECF is associated with the capacity to engage in instrumental health-related behaviors; and (3) worse ECF is associated with increased health services utilization. A population-based sample of 1,063 older people was interviewed regarding medical history and health services utilization; participants were administered the Mini Mental State Exam and the Behavioral Dyscontrol Scale, a measure of ECF. Participants with diabetes performed more poorly on cognitive measures than those without diabetes. Among those with diabetes, lower ECF was associated with more outpatient care and with ever having been in a nursing home. Impaired behavioral self-regulation may affect the capacity to engage in behaviors that could improve clinical status, resulting in greater health services use. The findings suggest the possibility of a positive feedback loop, with ECF deficits adversely affecting adherence, in turn leading to greater cognitive impairment-an issue for future research.

Antihypertensive therapy and cerebral hemodynamics in executive mild cognitive impairment: results of a pilot randomized clinical trial

OBJECTIVES

To compare the effects of three antihypertensive medications on cerebral hemodynamic and cognitive function in hypertensive individuals with executive dysfunction.

DESIGN

Double-blind randomized clinical trial.

SETTING

Community.

PARTICIPANTS

Fifty-three individuals aged 60 and older with hypertension and executive dysfunction.

INTERVENTION

Lisinopril, candesartan, or hydrochlorothiazide for 1 year.

MEASUREMENTS

Cerebral blood flow velocity (BFV; transcranial Doppler ultrasonography during rest, sitting, standing, hypercapnia, and hypocapnia), cognition, and blood pressure were measured at baseline and after 6 and 12 months. Linear mixed models were used to compare the three groups.

RESULTS

Of the 53 participants, 47 had successful insonation (mean age 72; 70% white; 57% women). There was a tendency toward an increase in BFV in the candesartan group and a decrease in the lisinopril and hydrochlorothiazide groups (between-group P = .57) that was significant in those with low BFV at baseline (<median 27.6 cm/s, between-group P = .03). The candesartan group also had the greatest improvement in executive function (Trail Making Test Part B improved by 17.1 seconds, vs hydrochlorothiazide improved by 4.2 seconds and lisinopril worsened by 14.4 seconds, P = .008). Carbon dioxide vasoreactivity and vasomotor range declined significantly in the lisinopril (within-group P = .001 for vasoreactivity and .02 for vasomotor range) and hydrochlorothiazide groups (within-group P = .10 and .009, respectively) but not in the candesartan group (within-group P = .25 and .38, respectively; between-group P = .30 and .46, respectively).

CONCLUSION

Angiotensin receptor blockers may preferentially preserve cerebral hemodynamics and executive function in individuals with executive dysfunction. These findings warrant further investigation in a larger trial.

Cognitive decline and cardiometabolic risk among Hispanic and non-Hispanic white adults in the San Luis Valley Health and Aging Study

Cardiometabolic risk factors, including hypertension, dyslipidemia, central obesity, insulin resistance and diabetes are linked to cognitive impairment. The Hispanic population appears to be differentially affected by both cardiometabolic risk factors and cognitive impairment. We sought to determine whether ethnic differences in cognitive impairment in long-resident southwestern US elders was explained by the presence of cardiometabolic risk factors, and to explore patterns of cognitive decline over time. We performed a secondary analysis of data collected on 378 Hispanic and 409 non-Hispanic white adult participants in a longitudinal study of community-dwelling elderly in southern Colorado. Measures of cardiometabolic risk included waist circumference, blood pressure, diagnosis of diabetes, and random blood glucose. Cognitive measures included the Mini-Mental State Exam (MMSE) and the behavioral dyscontrol scale (a measure of executive cognitive function), at baseline and after an average of 22 months. Subjects were also administered the Center for Epidemiologic Studies Depression Scale, and the Coronary Artery Risk Development in Young Adults 1-Year Activity Recall. At baseline, Hispanic elders had a greater number of cardiometabolic risk factors and lower MMSE and behavioral dyscontrol scale scores than non-Hispanic whites. Hispanic ethnicity was associated with a greater likelihood of decline in general cognitive function, but not executive cognitive function, after adjusting for age and education. This differential decline was not explained by either individual or total number of baseline cardiometabolic risk factors, depression, or physical activity. A borderline increased risk of decline in general cognitive function was seen in sedentary individuals (P = 0.05).

Neuropsychology and cognitive health in healthy older adults: a brief overview for psychiatric nurses

This article contains a brief synopsis on nonpathological aspects of the neuropsychology of aging and cognitive health. In nonpathological aging, normal subtle decline occurs in a number of cognitive domains such as executive functioning, speed of processing, memory, language, and psychomotor ability; however, some domains of cognitive functioning appear to increase with age, such as vocabulary and crystallized intelligence. In the neuropsychology and the cognitive aging literatures, several hypotheses for such age-related declines are proposed, including the diminished speed-of-processing hypothesis, the common cause hypothesis, and the frontal aging hypothesis. As these age-related changes diminish cognitive reserve, the decline in the related cognitive domains emerges. Ways to protect and improve cognitive health are suggested to encourage positive neuroplasticity and discourage negative neuroplasticity. Implications for nursing practice are provided.

Impaired design fluency is a marker of pathological cognitive aging; results from the Korean longitudinal study on health and aging

OBJECTIVE

We investigated neuropsychological markers that can be used to discriminate pathological cognitive aging from normal cognitive aging.

METHODS

We administered frontal lobe function tests including the Wisconsin Card Sorting Test (WCST), digit span test, lexical fluency test, fixed condition design fluency test, and Trail Making Test B (TMT-B) to 92 individuals with pathological cognitive aging (PCA) and 222 individuals with normal cognitive aging (NCA). We examined the main effects of participants' diagnoses (PCA, NCA) and age (65-69 years old, 70-74 years old and 75 years old or over) on their test performance using multivariate analysis of variance.

RESULTS

The main effects of both the diagnosis (F=2.860, p=0.002) and the age group (F=2.484, p<0.001) were significant. The PCA group showed lower performance on the backward digit span test (F=14.306, p<0.001), fixed condition design fluency test (F=8.347, p=0.004) and also exhibited perseverative errors in the WCST (F=4.19, p=0.042) compared with the NCA group. The main effect of the diagnosis on the backward digit span test and the fixed condition design fluency test remained significant after Bonferroni correction. The main effect of age remained significant in the TMT-B (F=8.737, p<0.001) after Bonferroni correction. Other test scores were not influenced by diagnosis or age.

CONCLUSION

The design fluency task may be a good neuropsychological marker to assess pathological cognitive aging.

The rationale and design of the antihypertensives and vascular, endothelial, and cognitive function (AVEC) trial in elderly hypertensives with early cognitive impairment: role of the renin angiotensin system inhibition

BACKGROUND

Prior evidence suggests that the renin angiotensin system and antihypertensives that inhibit this system play a role in cognitive, central vascular, and endothelial function. Our objective is to conduct a double-blind randomized controlled clinical trial, the antihypertensives and vascular, endothelial, and cognitive function (AVEC), to compare 1 year treatment of 3 antihypertensives (lisinopril, candesartan, or hydrochlorothiazide) in their effect on memory and executive function, cerebral blood flow, and central endothelial function of seniors with hypertension and early objective evidence of executive or memory impairments.

METHODS/DESIGN

The overall experimental design of the AVEC trial is a 3-arm double blind randomized controlled clinical trial. A total of 100 community eligible individuals (60 years or older) with hypertension and early cognitive impairment are being recruited from the greater Boston area and randomized to lisinopril, candesartan, or hydrochlorothiazide ("active control") for 12 months. The goal of the intervention is to achieve blood pressure control defined as SBP < 140 mm Hg and DBP < 90 mm Hg. Additional antihypertensives are added to achieve this goal if needed. Eligible participants are those with hypertension, defined as a blood pressure 140/90 mm Hg or greater, early cognitive impairment without dementia defined (10 or less out of 15 on the executive clock draw test or 1 standard deviation below the mean on the immediate memory subtest of the repeatable battery for the assessment of neuropsychological status and Mini-Mental-Status-exam >20 and without clinical diagnosis of dementia or Alzheimer's disease). Individuals who are currently receiving antihypertensives are eligible to participate if the participants and the primary care providers are willing to taper their antihypertensives. Participants undergo cognitive assessment, measurements of cerebral blood flow using Transcranial Doppler, and central endothelial function by measuring changes in cerebral blood flow in response to changes in end tidal carbon dioxide at baseline (off antihypertensives), 6, and 12 months. Our outcomes are change in cognitive function score (executive and memory), cerebral blood flow, and carbon dioxide cerebral vasoreactivity.

DISCUSSION

The AVEC trial is the first study to explore impact of antihypertensives in those who are showing early evidence of cognitive difficulties that did not reach the threshold of dementia. Success of this trial will offer new therapeutic application of antihypertensives that inhibit the renin angiotensin system and new insights in the role of this system in aging.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00605072.

Executive function (capacity for behavioral self-regulation) and decline predicted mortality in a longitudinal study in Southern Colorado

OBJECTIVE

To assess the relationship between mortality and impairment and decline in a specific executive cognitive function, the capacity for behavioral self-regulation.

STUDY DESIGN AND SETTING

This study examined the association between mortality and baseline and 22-month decline in the capacity for behavioral self-regulation, as measured by the Behavioral Dyscontrol Scale, among 1,293 participants of the San Luis Valley Health and Aging Study (SLVHAS), a population-based longitudinal study. The Behavioral Dyscontrol Scale and a measure of overall mental status, the Mini-Mental State Examination, were administered at baseline and follow-up interviews. Cox regression was used to examine baseline and decline in capacity for behavioral self-regulation as possible predictors of mortality.

RESULTS

Baseline Behavioral Dyscontrol Scale score was predictive of mortality, independent of demographics and comorbidity count (hazard ratio [HR]=1.07; 95% confidence interval [CI]: 1.04, 1.09). It remained a significant predictor with further adjustment for Mini-Mental State Examination score. Decline in this specific executive cognitive function was associated with mortality after adjustment for covariates and baseline cognitive scores (HR=1.09; 95% CI: 1.04, 1.13).

CONCLUSION

Thus, both baseline capacity for behavioral self-regulation and its decline over time predicted mortality in the SLVHAS cohort. These associations may partly be attributed to maintaining the ability for self-care. Understanding how specific forms of impairment contribute to mortality may help identify patients who could benefit from early intervention.

A review of fragile X premutation disorders: expanding the psychiatric perspective

CONTEXT

Fragile X premutation conditions are associated with a significant degree of psychopathology and thus are of interest to the psychiatrist. Remarkable advances at the molecular level have enhanced our understanding of fragile X premutation disorders.

OBJECTIVE

The authors review the genetic, molecular, neuroimaging, and clinical (systemic, neurologic, and psychiatric) manifestations of the premutation carrier state (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene.

DATA SOURCES

The search for the psychiatric clinical manifestations of fragile X-associated conditions was accomplished by PubMed for clinical papers published between 1970 and 2008 with the following search terms: Fragile X syndrome, depression, psychosis, anxiety, and dementia.

STUDY SELECTION

Articles addressing psychiatric symptoms in premutation carriers based on review of the abstracts were reviewed. As the majority of the literature on this topic is based on case reports and small case series, these were included in the database.

RESULTS

Reported clinical manifestations of psychiatric illness in premutation carriers include an apparently significant rate of cognitive, mood, anxiety, and other psychiatric disorders. Fragile X premutation-associated conditions are part of the clinical differential diagnosis of several psychiatric syndromes, particularly in pedigrees with known fragile X syndrome cases.

CONCLUSIONS

Fragile X-associated psychiatric manifestations serve as a useful model for a molecular genesis of neuropsychiatric illness. Because of the multigenerational expression of fragile X-associated neuropsychiatric illness, there is a prominent role for genetic testing and genetic counseling of patients and their relatives. Genetic testing is confirmatory of the FMR1 premutation and is an essential component of the clinical evaluation. Psychopharmacologic and psychotherapeutic treatment of fragile X-associated psychiatric illnesses may improve patient function and assist in adaptation to the burden of a genetic neuropsychiatric illness.

The primary cognitive deficit among males with fragile X-associated tremor/ataxia syndrome (FXTAS) is a dysexecutive syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder associated with a premutation trinucleotide repeat expansion in the fragile X mental retardation 1 gene. Symptoms include gait ataxia, action tremor, and cognitive impairment. The objectives of the study were to clarify the nature of the dysexecutive syndrome observed in FXTAS and to assess the contribution of executive impairment to deficits in nonexecutive cognitive functions. Compared to controls, men with FXTAS demonstrated significant executive impairment, which was found to mediate group differences in most other cognitive abilities. Asymptomatic premutation carriers performed similarly to controls on all but two measures of executive functioning. These findings suggest that the impairment of nonexecutive cognitive skills in FXTAS is in large part secondary to executive dysfunction.

The impact of executive cognitive functioning on rates of smoking cessation in the San Luis Valley Health and Aging Study

Cigarette smoking is one of the leading preventable causes of death. Previous research has shown that many common smoking cessation interventions are effective with older smokers; a few interventions have been tailored to this population. To our knowledge, however, no smoking cessation research or interventions targeted at older adults have addressed the influence of cognition on successful smoking cessation. We hypothesized that impairment of executive cognitive functioning (ECF), which is relatively prevalent among older adults, would negatively influence smoking cessation rates among older smokers. The relationship of ECF to smoking cessation was examined in a population-based sample of 1,338 community-dwelling older persons in Colorado's San Luis Valley, 204 of whom were current smokers. As predicted, current ECF did not predict early smoking behaviour, but was a significant predictor of successful smoking cessation. Older persons suffering from executive dysfunction were less likely to have quit smoking than were their cognitively intact counterparts (OR = 1.10, 95% CI 1.04-1.17, P < 0.01). Among those with normal ECF, 73.7% had quit smoking, compared with 65.1% of participants showing any level of ECF impairment. Limiting the sample to individuals who were active smokers at or after the age of 65, when executive impairment is relatively common, produced similar results. Individuals with better executive functioning were more likely to have quit smoking (OR = 1.12, 95% CI 1.02-1.23, P = 0.02).

Executive function, more than global cognition, predicts functional decline and mortality in elderly women

BACKGROUND

Functional impairment in community-dwelling older adults is common and is associated with poor outcomes. Our goal was to compare the contribution of impairment in executive function or global cognitive function to predicting functional decline and mortality.

METHODS

We studied 7717 elderly women enrolled in a prospective study (mean age 73.3 years) and identified women with poor baseline executive function (score > 1 standard deviation [SD] below the mean on the Trail Making Test B (Trails B; n = 957, 12.4%), poor global cognitive function (score > 1 SD below the mean on a modified Mini-Mental State Examination [mMMSE], n = 387, 5.0%), impairment in both (n = 249, 3.2%), or no impairment (n = 6124, 79.4%). We compared level of functional difficulty (Activities of Daily Living [ADLs] and Instrumental ADLs [IADLs]) at baseline and at 6-year follow-up and survival at follow-up. We also determined if the association was independent of age, education, depression, medical comorbidities, and baseline functional ability.

RESULTS

At baseline, women with Trails B impairment only or impairment on both tests reported the highest proportion of ADL and IADL dependence compared to the other groups. At the 6-year follow-up after adjusting for age, education, medical comorbidities, depression, and baseline ADL or IADL, women with only Trails B impairment were 1.3 times more likely to develop an incident ADL dependence (adjusted odds ratio [OR] = 1.34; 95% confidence interval [CI], 1.07-1.69) and 1.5 times more likely to develop a worsening of ADL dependence (adjusted OR = 1.48; 95% CI, 1.16-1.89) when compared to women with no impairment on either test. In addition, women with only Trails B impairment had a 1.5-fold increased risk of mortality (adjusted hazard ratio [HR] = 1.48; 95% CI, 1.21-1.81). In contrast, women with impairment on only mMMSE were not at increased risk to develop incident ADL or IADL dependence, a worsening of ADL or IADL dependence, or mortality.

CONCLUSION

Compared to women with no impairment, women with executive function impairment had significantly worse ADL and IADL function cross-sectionally and over 6 years. Individuals with executive dysfunction also had increased risk of mortality. These results suggest that screening of executive function can help to identify women who are at risk for functional decline and decreased survival.

The elusive nature of executive functions: a review of our current understanding

Executive functions include abilities of goal formation, planning, carrying out goal-directed plans, and effective performance. This article aims at reviewing some of the current knowledge surrounding executive functioning and presenting the contrasting views regarding this concept. The neural substrates of the executive system are examined as well as the evolution of executive functioning, from development to decline. There is clear evidence of the vulnerability of executive functions to the effects of age over lifespan. The first executive function to emerge in children is the ability to inhibit overlearned behavior and the last to appear is verbal fluency. Inhibition of irrelevant information seems to decline earlier than set shifting and verbal fluency during senescence. The sequential progression and decline of these functions has been paralleled with the anatomical changes of the frontal lobe and its connections with other brain areas. Generalization of the results presented here are limited due to methodological differences across studies. Analysis of these differences is presented and suggestions for future research are offered.

Neuropsychological test profile differences between young and old human immunodeficiency virus-positive individuals

Human immunodeficiency virus (HIV) dementia remains as an important cause of neurological morbidity among HIV-seropositive (HIV+) individuals. Differences in the neuropsychological profiles between older and younger HIV+ individuals have not been examined extensively. The objective of this study was to examine the neuropsychological test performance between old and young HIV+ individuals (a) with and without cognitive impairment (total cohort) and (b) with dementia. One hundred thirty-three older (age >or= 50 years) HIV+ individuals and 121 younger (age 20 to 39 years) HIV+ individuals were evaluated with a standardized neuropsychological test battery. Differences between age groups in the mean z score for each neuropsychological test were determined. The older HIV+ (total) cohort had greater impairment in tests of verbal memory (P = .006), visual memory (P < .002), verbal fluency (P = .001), and psychomotor speed (P < .001) compared to the young HIV+ (total) cohort. After adjusting for differences in education, older HIV+ patients with dementia (n = 31) had a greater deficit in the Trail Making test Part B (P = 0.02) compared to younger HIV+ patients with dementia (n = 15). Age was associated with lower performance in tests of memory, executive functioning, and motor performance in older HIV+ individuals with and without cognitive impairment (total cohort), compared to younger HIV+ individuals. Among HIV+ patients with dementia, age may be associated with greater impairment in a test of executive functioning. These differences could be a result of advanced age itself or age-associated comorbidities such as coexisting cerebrovascular or neurodegenerative disease.

Impairment in the cognitive functioning of men with fragile X-associated tremor/ataxia syndrome (FXTAS)

Disorders associated with fragile X syndrome involve a trinucleotide (CGG) repeat expansion in the FMR1 gene. Recently, a progressive movement disorder (fragile X-associated tremor/ataxia syndrome [FXTAS]) has been identified in premutation carriers, persons with 55 to 200 CGG repeats. In addition to ataxia, action tremor, and Parkinsonism, early case reports suggested that FXTAS involves impaired cognition, but the precise nature of the impairment has not been elucidated. In this first, preliminary study of the subject, circumscribed aspects of cognitive functioning were examined in 25 men with FXTAS. Subjects' performance on the cognitive tests was compared with normative data. Scores on two measures of executive cognitive functioning showed a high prevalence of substantial impairment. Capacity for inhibition was severely affected in one-quarter of this highly educated sample; information processing speed was profoundly impaired in most subjects. Although mean verbal and performance IQ scores were not significantly different from the general population, they were quite low given the sample's educational level. Cognitive and functional impairment was greater for men with more CGG repeats, although number of repeats was not associated with age of onset of either tremor or ataxia. The results provide evidence that FXTAS involves marked impairment of executive cognitive abilities.

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.

Misclassification Is Likely in the Assessment of Mild Cognitive Impairment

We estimated the relative frequency of isolated memory impairment versus isolated and comorbid impairment in executive control function (ECF). One hundred and ninety-three noninstitutionalized residents of a single Comprehensive Care Retirement Community (mean age 79.2 years) were investigated. The subjects were tested with multiple measures of memory and ECF. Test scores were standardized to minimize scaling effects. 'Impairment' was defined as performance < or =1.5 standard deviations below the mean for the entire sample (i.e., a z score < or =-1.5). Disability was estimated as the sum of self-reported activities of daily living and instrumental activities of daily living. The cognitive test performance was significantly associated with functional impairment, independently of age. ECF and memory measures were significantly intercorrelated. Both were significantly and independently associated with disability ratings. 6-10% of the subjects had memory impairment; 25-35% of the memory-impaired subjects had comorbid ECF impairments. An additional 4-7% of the subjects had isolated ECF impairment. A significant fraction of the cases otherwise meeting the criteria for 'mild cognitive impairment' may have comorbid ECF impairment. This raises the issue of whether they might be more properly classified as 'demented'. In addition, isolated ECF impairment may affect almost as many persons as isolated memory impairment. Isolated ECF impairment is not consistent with the natural history of preclinical Alzheimer's disease, suggests other conditions, and can be disabling, independently of age and/or memory loss.

Executive dyscontrol in normal aging: normative data, factor structure, and clinical correlates

Although there is ample evidence of frontal system dysfunction in old age, the clinical significance of these impairments has not been well studied. In this article, we examine the factor structure of putative executive measures in a sample of well elderly subjects. Three stable factors emerged, but only one was associated with measures of functional status. This factor was most strongly associated with relatively simple bedside executive measures that might prove useful in dementia screening. In contrast, a second factor, dominated by the Wisconsin Card Sorting Task, was weakly associated with disability. These data suggest that certain executive measures may be more relevant to functional outcomes, and hence dementia case finding, than others. Moreover, associations with functional status should not be casually extrapolated from regional frontal clinical correlations, particularly with the dorsolateral prefrontal cortex.

Subcortical ischaemic vascular dementia

Vascular dementia is the second most common type of dementia. The subcortical ischaemic form (SIVD) frequently causes cognitive impairment and dementia in elderly people. SIVD results from small-vessel disease, which produces either arteriolar occlusion and lacunes or widespread incomplete infarction of white matter due to critical stenosis of medullary arterioles and hypoperfusion (Binswanger's disease). Symptoms include motor and cognitive dysexecutive slowing, forgetfulness, dysarthria, mood changes, urinary symptoms, and short-stepped gait. These manifestations probably result from ischaemic interruption of parallel circuits from the prefrontal cortex to the basal ganglia and corresponding thalamocortical connections. Brain imaging (computed tomography and magnetic resonance imaging) is essential for correct diagnosis. The main risk factors are advanced age, hypertension, diabetes, smoking, hyperhomocysteinaemia, hyperfibrinogenaemia, and other conditions that can cause brain hypoperfusion such as obstructive sleep apnoea, congestive heart failure, cardiac arrhythmias, and orthostatic hypotension. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL)and some forms of cerebral amyloid angiopathy have a genetic basis. Treatment is symptomatic and prevention requires control of treatable risk factors.