The psychometric equivalence of two alternate forms of the Controlled Oral Word Association Test

Utility of a Short-Form Phonemic Fluency Task

OBJECTIVE

to establish a proof-of-concept and ascertain the reliability of an abbreviated 30-second (30s) phonemic fluency measure as a cognitive screening tool in older adults.

METHODS

in all, 201 English-speaking individuals with normal cognition (NC; n = 119) or cognitive impairment (CI; mild CI or dementia; n = 82) were administered a standard 60s phonemic fluency task (FAS/CFL) with discrete 30s intervals denoted.

RESULTS

for all letters, 30s trial scores significantly predicted 60s scores for the same letter, R2 = .7-.9, F(1, 200) = 850-915, p < .001. As with 60s total scores, 30s cumulative scores (for all three trials) were significantly different between NC and CI groups (p < .001). Receiver operating characteristic analyses showed that 30s total scores distinguished NC and CI groups as effectively (AUC = .675) as 60s total scores (AUC = .658).

CONCLUSIONS

these findings support the utility and reliability of a short-form phonemic fluency paradigm, as 30s performance reliably predicted 60s/trial totals and was equally accurate in distinguishing impaired/non-impaired groups.

Normative Data for Single-Letter Controlled Oral Word Association Test in Older White Australians and Americans, African-Americans, and Hispanic/Latinos

Background

The Controlled Oral Word Association Test (COWAT) is a commonly used measure of verbal fluency. While a normal decline in verbal fluency occurs in late adulthood, significant impairments may indicate brain injury or diseases such as Alzheimer's disease. Normative data is essential to identify when test performance falls below expected levels based on age, gender, and education level.

Objective

This study aimed to establish normative performance data on single-letter COWAT for older community-dwelling adults.

Methods

Over 19,000 healthy men and women, without a diagnosis of dementia or a Modified Mini-Mental State Examination score below 77/100, were recruited for the ASPREE trial. Neuropsychological assessments, including the COWAT with letter F, were administered at study entry.

Results

Median participant age was 75 years (range 65-98), with 56.5% being women. The majority of participants had 9-11 years of education in Australia and over 12 years in the U.S. The COWAT performance varied across ethno-racial groups and normative data were thus presented separately for 16,335 white Australians, 1,084 white Americans, 896 African-Americans, and 316 Hispanic/Latinos. Women generally outperformed men in the COWAT, except for Hispanic/Latinos. Higher education levels consistently correlated with better COWAT performance across all groups, while the negative association with age was weaker.

Conclusions

This study provides comprehensive normative data for the COWAT stratified by ethno-racial groups in Australia and the U.S., considering age, gender, and education level. These norms can serve as reference standards for screening cognitive impairments in older adults in both clinical and research settings.

Switching from Sugar- to Artificially-Sweetened Beverages: A 12-Week Trial

BACKGROUND

Consumption of sugar-sweetened beverages (SSBs) forms the primary source of added sugar intake and can increase the risk of metabolic disease. Evidence from studies in humans and rodents also indicates that consumption of SSBs can impair performance on cognitive tests, but that removing SSB access can ameliorate these effects.

METHODS

The present study used an unblinded 3-group parallel design to assess the effects of a 12-week intervention in which young healthy adults (mean age = 22.85, SD = 3.89; mean BMI: 23.2, SD = 3.6) who regularly consumed SSBs were instructed to replace SSB intake with artificially-sweetened beverages (n = 28) or water (n = 25), or (c) to continue SSB intake (n = 27).

RESULTS

No significant group differences were observed in short-term verbal memory on the Logical Memory test or the ratio of waist circumference to height (primary outcomes), nor in secondary measures of effect, impulsivity, adiposity, or glucose tolerance. One notable change was a significant reduction in liking for strong sucrose solutions in participants who switched to water. Switching from SSBs to 'diet' drinks or water had no detectable impact on cognitive or metabolic health over the relatively short time frame studied here. This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615001004550; Universal Trial Number: U1111-1170-4543).

Effects of Repeated Administration and Comparability of Alternate Forms for the Global Neuropsychological Assessment (GNA)

The Global Neuropsychological Assessment (GNA) is an extremely brief battery of cognitive tasks assessing episodic memory, processing speed, working memory, verbal fluency, executive function, and mood. It can be given in under 15 minutes, has five alternate forms, and does not require an examinee to be literate. The purpose of this study was to quantify practice effects over repeated administrations and assess comparability of the GNA's five alternate forms, preparing the battery for repeated administration in research and clinical settings. Forty participants each completed all five GNA forms at weekly intervals following a Latin square design (i.e., each form was administered at every position in the sequence an equal number of times). In a cognitively intact population, practice effects of 0.56 to 1.06 SD were observed across GNA measures when comparing the first and fifth administration. Most GNA tests showed nonsignificant interform differences with cross-form means differing by 0.35 SD or less, with the exception of modest but statistically significant interform differences for the GNA Story Memory subtest across all five forms. However, post hoc analysis identified clusters of two and three Story Memory alternate forms that were equivalent.

Assessment of language impairment and function

This chapter is written for the qualified neurologist or related professional working with persons who have had a stroke or other sudden brain injury. It is critical that the presence of aphasia is detected, no matter how mild the presentation, and to support that assertion, this chapter highlights the plight of persons with latent aphasia. At the individual level, the impact of aphasia is devastating, with overwhelming evidence that aphasia negatively impacts psychosocial outcomes. At the global level, sensitive detection and accurate diagnosis of aphasia are critical for accurate characterization and quantification of the global burden of aphasia. The word "LANGUAGE" is leveraged as an acronym to create a useful and memorable checklist to guide navigation of aphasia screening and assessment: it begins with the definition of language (L), followed by the definition and diagnostic criteria for aphasia (A). Then language abilities and characteristics to be considered in assessment are presented: naming (N); grammar and syntax (G); unintelligible words, jargon, and paraphasias (U); auditory comprehension and repetition (A); graphemic abilities-reading and writing (G); and everyday communication and discourse (E). Recommendations for improving procedural adherence are provided, and a list of potential brief assessment measures are introduced.

The Reliability and Validity of the Action Fluency Test in Healthy College Students

Objective

This study examined the test–retest reliability and construct validity of the Action Fluency Test (AFT) as a measure of executive functioning.

Method

Using a correlational design, 128 healthy college students (M Age = 19.24, SD = 2.01; M education = 13.29 years, SD = 0.81) completed the AFT, and measures of verbal and figural fluency, executive functioning and other relevant constructs (e.g., vocabulary, working memory, and attention).

Results

Coefficients of stability were acceptable for AFT correct words (r = .76; p &lt; .01), but not for errors (r = .41) or perseverations (r = .14). No practice effects were observed upon repeat testing (M interval = 39.21 days). Divergent validity evidence was mixed. AFT scores were unrelated to working memory and perceptual-reasoning abilities; however, correlations with vocabulary (r = .32; p &lt; .01) and information-processing speed (r = .30; p &lt; .01) were greater than associations between AFT scores and executive measures. Regarding convergent validity, AFT scores correlated with other fluency tasks (r = .4 range), but correlations with measures of executive functioning were absent or small. Action and letter fluency correlated with measures of attentional control and inhibition; however, these associations were no longer significant after controlling for shared variance with information-processing speed.

Conclusions

Findings are consistent with previous research suggesting vocabulary and information-processing speed underlie effective fluency performance to a greater extent than executive functioning. The AFT measures unique variance not accounted for by semantic and letter fluency tasks, and therefore may be used for a variety of research and clinical purposes.

Duration of Posttraumatic Amnesia Predicts Neuropsychological and Global Outcome in Complicated Mild Traumatic Brain Injury

OBJECTIVES

Examine the effects of posttraumatic amnesia (PTA) duration on neuropsychological and global recovery from 1 to 6 months after complicated mild traumatic brain injury (cmTBI).

PARTICIPANTS

A total of 330 persons with cmTBI defined as Glasgow Coma Scale score of 13 to 15 in emergency department, with well-defined abnormalities on neuroimaging.

METHODS

Enrollment within 24 hours of injury with follow-up at 1, 3, and 6 months.

MEASURES

Glasgow Outcome Scale-Extended, California Verbal Learning Test II, and Controlled Oral Word Association Test. Duration of PTA was retrospectively measured with structured interview at 30 days postinjury.

RESULTS

Despite all having a Glasgow Coma Scale Score of 13 to 15, a quarter of the sample had a PTA duration of greater than 7 days; half had PTA duration of 1 of 7 days. Both cognitive performance and Extended Glasgow Outcome Scale outcomes were strongly associated with time since injury and PTA duration, with those with PTA duration of greater than 1 week showing residual moderate disability at 6-month assessment.

CONCLUSIONS

Findings reinforce importance of careful measurement of duration of PTA to refine outcome prediction and allocation of resources to those with cmTBI. Future research would benefit from standardization in computed tomographic criteria and use of severity indices beyond Glasgow Coma Scale to characterize cmTBI.

Moderate alcohol use and apolipoprotein E-4 (ApoE-4): Independent effects on cognitive outcomes in later life

OBJECTIVES

Substantive past research suggests that moderate alcohol use confers beneficial health outcomes. The study of moderate alcohol use and cognition has produced variable findings. The primary goal was to examine the relationship between alcohol use and cognitive aging over time (Experiment 1), in a demographically representative, longitudinal survey of older adults. Experiment 2 examined the hypothesis that apolipoprotein E-4 (ApoE-4) would moderate the relationship between moderate drinking and performance on cognitive domains.

METHOD

The sample was drawn from the Aging, Demographics, and Memory Study (ADAMS) supplement of the Health and Retirement Study (HRS) and included 856 participants over age 65 in 2001. Follow-up data were from 2002, 2006, and 2008. Alcohol use was measured via self-report. Control variables included gender, age, race, number of years of education, medical burden (total number of medical diseases), and marital status.

RESULTS

Results of Experiment 1 indicated that moderate alcohol use was significantly associated with better baseline functioning across cognitive measures (p ≤ .05), but had no significant effect on rate of change over time across cognitive domains. Results of Experiment 2 indicated that while ApoE-4 carriage did not moderate the relationship between alcohol use and cognitive performance, generally, both ApoE-4 and moderate alcohol use were significant predictors of cognitive performance.

CONCLUSIONS

Overall, findings from this study support past findings that moderate alcohol use is associated with better cognitive functioning among community-dwelling older adults, and these relative benefits appear to persist throughout later life. However, the role of individual differences on manifestation of benefit remain very poorly understood. Future research should further examine the respective roles of demographic differences associated with cognitive aging, genetic moderators, and the influence of social interaction.

From Perception to Metacognition: Auditory and Olfactory Functions in Early Blind, Late Blind, and Sighted Individuals

Although evidence is mixed, studies have shown that blind individuals perform better than sighted at specific auditory, tactile, and chemosensory tasks. However, few studies have assessed blind and sighted individuals across different sensory modalities in the same study. We tested early blind (n = 15), late blind (n = 15), and sighted (n = 30) participants with analogous olfactory and auditory tests in absolute threshold, discrimination, identification, episodic recognition, and metacognitive ability. Although the multivariate analysis of variance (MANOVA) showed no overall effect of blindness and no interaction with modality, follow-up between-group contrasts indicated a blind-over-sighted advantage in auditory episodic recognition, that was most pronounced in early blind individuals. In contrast to the auditory modality, there was no empirical support for compensatory effects in any of the olfactory tasks. There was no conclusive evidence for group differences in metacognitive ability to predict episodic recognition performance. Taken together, the results showed no evidence of an overall superior performance in blind relative sighted individuals across olfactory and auditory functions, although early blind individuals exceled in episodic auditory recognition memory. This observation may be related to an experience-induced increase in auditory attentional capacity.

Targeting alertness to improve cognition in older adults: A preliminary report of benefits in executive function and skill acquisition

Efficient self-regulation of alertness declines with age exacerbating normal declines in performance across multiple cognitive domains, including learning and skill acquisition. Previous cognitive intervention studies have shown that it is possible to enhance alertness in patients with acquired brain injury and marked attention impairments, and that this benefit generalizes to improvements in more global cognitive functions. In the current preliminary studies, we sought to test whether this approach, that targets both tonic (over a period of minutes) and phasic (moment-to-moment) alertness, can improve key executive functioning declines in older adults, and enhance the rate of skill acquisition. The results of both Experiments 1 and 2 demonstrate that, compared to active control (AC) training, alertness training significantly enhanced performance in several validated executive function measures. In Experiment 2, alertness training significantly improved skill acquisition compared to AC training in a well-characterized speed of processing (SOP) task, with the largest benefits shown in the most challenging SOP blocks. The results of the current study suggest that targeting intrinsic alertness through cognitive training provides a novel approach to improve executive functions in older adults and may be a useful adjunct treatment to enhance benefits gained in other clinically validated treatments.

Word Retrieval Ability on Phonemic Fluency in Typically Developing Children

Verbal fluency tasks are simple behavioral measures useful in assessing word retrieval abilities. Among the verbal fluency tasks, the utility of the Phonemic Fluency Task in children has received less attention. As the task is dependent on phonemic characteristics of each language, there is a great need for understanding its developmental trend. The present study, therefore, aims to delineate the performance on phonemic fluency in typically developing Malayalam-speaking children. Verbal fluency performance on 2 tasks of phonemic fluency was tested using a cross-sectional study design among 1,015 school-going Malayalam-speaking typically developing children aged 5 to 15 years old. Performance with respect to word productivity and clustering-switching measures was analyzed. The effect of age, gender, and tasks on the outcome measures were investigated in the present study. Study findings revealed a positive influence of age with no statistically significant gender effects. Children employed both task-discrepant and task-consistent organizational strategies during tasks of phonemic fluency, dependent purely on the Malayalam language. Future research focusing on developmental trends across different languages is vital for enhancing the task's clinical sensitivity and specificity among childhood disorders.

Impact of Short- and Long-term Tai Chi Mind-Body Exercise Training on Cognitive Function in Healthy Adults: Results From a Hybrid Observational Study and Randomized Trial

BACKGROUND

Cognitive decline amongst older adults is a significant public health concern. There is growing interest in behavioral interventions, including exercise, for improving cognition. Studies to date suggest tai chi (TC) may be a safe and potentially effective exercise for preserving cognitive function with aging; however, its short-term and potential long-term impact on physically active, healthy adults is unclear.

OBJECTIVE

To compare differences in cognitive function among long-term TC expert practitioners and age-matched and gender-matched TC-naïve adults and to determine the effects of short-term TC training on measures of cognitive function in healthy, nonsedentary adults.

DESIGN

A hybrid design including an observational comparison and a 2-arm randomized clinical trial (RCT).

PARTICIPANTS

Healthy, nonsedentary, TC-naive adults (50 y-79 y) and age-matched and gender-matched long-term TC experts.

METHODS

A cross-sectional comparison of cognitive function in healthy TC-naïve (n=60) and TC expert (24.5 y ÷ 12 y experience; n=27) adults: TC-naïve adults then completed a 6-month, 2-arm, wait-list randomized clinical trial of TC training. Six measures of cognitive function were assessed for both cross-sectional and longitudinal comparisons.

RESULTS

TC experts exhibited trends towards better scores on all cognitive measures, significantly so for category fluency (P=.01), as well as a composite z score summarizing all 6 cognitive assessments (P=.03). In contrast, random assignment to 6 months of TC training in TC-naïve adults did not significantly improve any measures of cognitive function.

CONCLUSIONS

In healthy nonsedentary adults, long-term TC training may help preserve cognitive function; however, the effect of short-term TC training in healthy adults remains unclear.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01340365.

Change in cognitive function over 12 months among patients with an implantable cardioverter-defibrillator

BACKGROUND

Patients with implantable cardioverter-defibrillators (ICDs) have decreased cognitive function associated with arrhythmic and/or cardiac disorders, such as ischemic cardiomyopathy. Little is known about changes in cognitive function over time among ICD patients.

AIMS

The aim of this study was to evaluate baseline-to-12-month changes in cognitive function in memory (total recall and delayed recall), psychomotor speed, and executive function among ICD patients.

METHODS

In this prospective study, 115 (mean [SD] age, 64.83 [9.06] years, 75% mean) and 77 ICD patients completed baseline and 12-month face-to-face interviews, respectively, which included neuropsychological tests to evaluate cognitive function.

RESULTS

Patients who completed baseline and 12-month testing had decreased total and delayed recall memory (all P < .05). No significant changes from baseline to 12 months were observed in psychomotor speed (t = 0.33; P = .74) and executive function (t = -1.12; P = .27). Using 1.0 standard deviation or below the mean as a cutoff criterion, 12% to 22% of ICD patients had poor cognitive function over time. Particularly, at baseline, 17 (15%) and 15 (13%) of the 115 patients had poor memory in total and delayed recall, respectively. At 12 months, 12 (16%) and 9 (12%) of the 77 patients had poor memory in total and delayed recall, respectively.

CONCLUSIONS

In this sample of patients with ICDs, memory was poor at baseline and decreased over 12 months. Future studies are indicated to determine how this change in memory influences outcomes such as medication adherence.

A systems biology approach to studying Tai Chi, physiological complexity and healthy aging: design and rationale of a pragmatic randomized controlled trial

INTRODUCTION

Aging is typically associated with progressive multi-system impairment that leads to decreased physical and cognitive function and reduced adaptability to stress. Due to its capacity to characterize complex dynamics within and between physiological systems, the emerging field of complex systems biology and its array of quantitative tools show great promise for improving our understanding of aging, monitoring senescence, and providing biomarkers for evaluating novel interventions, including promising mind-body exercises, that treat age-related disease and promote healthy aging.

MATERIAL AND METHODS

An ongoing, two-arm randomized clinical trial is evaluating the potential of Tai Chi mind-body exercise to attenuate age-related loss of complexity. A total of 60 Tai Chi-naïve healthy older adults (aged 50-79) are being randomized to either six months of Tai Chi training (n=30), or to a waitlist control receiving unaltered usual medical care (n=30). Our primary outcomes are complexity-based measures of heart rate, standing postural sway and gait stride interval dynamics assessed at 3 and 6months. Multiscale entropy and detrended fluctuation analysis are used as entropy- and fractal-based measures of complexity, respectively. Secondary outcomes include measures of physical and psychological function and tests of physiological adaptability also assessed at 3 and 6months.

DISCUSSION

Results of this study may lead to novel biomarkers that help us monitor and understand the physiological processes of aging and explore the potential benefits of Tai Chi and related mind-body exercises for healthy aging.

The cerebellum and its role in word generation: a cTBS study

The purpose of this study was to investigate the role of the cerebellum in the executive control of word generation using a phonemic and semantic fluency task. Phonemic fluency tasks require novel strategy to organize verbal output, and are more effortful than semantic fluency tasks. The number of category switches made between subcategories of words is a measure of mental flexibility, and is greatest during the early phase of the task (first 15sec). Both tasks were tested on healthy participants, before and after the application of transcranial magnetic stimulation using continuous theta burst stimulation (cTBS) applied over the left or the right posterior/lateral cerebellar cortex in separate groups. We hypothesized that the number of category switches and number of words produced within the first 15sec would be reduced after cTBS to the right, posterior-lateral cerebellum during phonemic fluency tasks. The results from the study were consistent with the hypothesis. Within the first 15sec of each trial, right cTBS participants displayed significantly lower switching scores (p=.05) after stimulation. Previous studies have illustrated similar impairments in switching between categories during phonemic fluency performance in patients with damage to the left frontal cortex. Our findings support the general hypothesis of cerebellar involvement in executive control through connections to the frontal cortex.

Effects of sleep deprivation on dissociated components of executive functioning

STUDY OBJECTIVES

We studied the effects of sleep deprivation on executive functions using a task battery which included a modified Sternberg task, a probed recall task, and a phonemic verbal fluency task. These tasks were selected because they allow dissociation of some important executive processes from non-executive components of cognition.

DESIGN

Subjects were randomized to a total sleep deprivation condition or a control condition. Performance on the executive functions task battery was assessed at baseline, after 51 h of total sleep deprivation (or no sleep deprivation in the control group), and following 2 nights of recovery sleep, at fixed time of day (11:00). Performance was also measured repeatedly throughout the experiment on a control task battery, for which the effects of total sleep deprivation had been documented in previously published studies.

SETTING

Six consecutive days and nights in a controlled laboratory environment with continuous behavioral monitoring.

PARTICIPANTS

Twenty-three healthy adults (age range 22-38 y; 11 women). Twelve subjects were randomized to the sleep deprivation condition; the others were controls.

RESULTS

Performance on the control task battery was considerably degraded during sleep deprivation. Overall performance on the modified Sternberg task also showed impairment during sleep deprivation, as compared to baseline and recovery and compared to controls. However, two dissociated components of executive functioning on this task--working memory scanning efficiency and resistance to proactive interference--were maintained at levels equivalent to baseline. On the probed recall task, resistance to proactive interference was also preserved. Executive aspects of performance on the phonemic verbal fluency task showed improvement during sleep deprivation, as did overall performance on this task.

CONCLUSION

Sleep deprivation affected distinct components of cognitive processing differentially. Dissociated non-executive components of cognition in executive functions tasks were degraded by sleep deprivation, as was control task performance. However, the executive functions of working memory scanning efficiency and resistance to proactive interference were not significantly affected by sleep deprivation, nor were dissociated executive processes of phonemic verbal fluency performance. These results challenge the prevailing view that executive functions are especially vulnerable to sleep loss. Our findings also question the idea that impairment due to sleep deprivation is generic to cognitive processes subserved by attention.