The influence of different error estimates in the detection of postoperative cognitive dysfunction using reliable change indices with correction for practice effects

A School-Based Approach to Building Resilience and Mental Health Among Adolescents on the Autism Spectrum: A Longitudinal Mixed Methods Study

Tackling mental health difficulties in adolescents on the autism spectrum requires a comprehensive prevention approach. A 3-year multisite proof-of-concept longitudinal study implemented an evidence-based multilevel resilience intervention in schools to promote protective factors at the adolescent, parent, and school level. The intervention, consisting of the adolescent, parent and teacher components of the Resourceful Adolescent Program–Autism Spectrum Disorder (RAP-ASD) augmented with the Index for Inclusion, was implemented in 6 secondary schools with 30 adolescents with an autism diagnosis in Grades 7 and 8, 31 parents of 23 of the adolescents, and school staff. The intervention was implemented with good validity and acceptability. Quantitative data from adolescents and parents were analysed using the Reliable Change Index, and qualitative data were analysed using Consensual Qualitative Research. Triangulated quantitative and qualitative outcomes from the majority of adolescents and their parents showed some evidence for promoting resilience for adolescents with a diagnosis or traits of autism, as reflected in reliable improvements in coping self-efficacy and school connectedness, and a reduction in anxiety symptoms and emotional and behavioural difficulties. A reliable improvement in depressive symptoms was more modest and was only achieved by a small minority of adolescents. This multilevel, strength-focused, resilience-building approach represents a promising and sustainable school-based primary prevention program to improve the quality of life for adolescents on the spectrum by promoting their mental health and providing their families with much needed support.

A Comparison of Cross-Sectional and Longitudinal Methods of Defining Objective Subtle Cognitive Decline in Preclinical Alzheimer's Disease Based on Cogstate One Card Learning Accuracy Performance

BACKGROUND

Longitudinal, but not cross-sectional, cognitive testing is one option proposed to define transitional cognitive decline for individuals on the Alzheimer's disease continuum.

OBJECTIVE

Compare diagnostic accuracy of cross-sectional subtle objective cognitive impairment (sOBJ) and longitudinal objective decline (ΔOBJ) over 30 months for identifying 1) cognitively unimpaired participants with preclinical Alzheimer's disease defined by elevated brain amyloid and tau (A+T+) and 2) incident mild cognitive impairment (MCI) based on Cogstate One Card Learning (OCL) accuracy performance.

METHODS

Mayo Clinic Study of Aging cognitively unimpaired participants aged 50 + with amyloid and tau PET scans (n = 311) comprised the biomarker-defined sample. A case-control sample of participants aged 65 + remaining cognitively unimpaired for at least 30 months included 64 who subsequently developed MCI (incident MCI cases) and 184 controls, risk-set matched by age, sex, education, and visit number. sOBJ was assessed by OCL z-scores. ΔOBJ was assessed using within subjects' standard deviation and annualized change from linear regression or linear mixed effects (LME) models. Concordance measures Area Under the ROC Curve (AUC) or C-statistic and odds ratios (OR) from conditional logistic regression models were derived. sOBJ and ΔOBJ were modeled jointly to compare methods.

RESULTS

sOBJ and ΔOBJ-LME methods differentiated A+T+ from A-T- (AUC = 0.64, 0.69) and controls from incident MCI (C-statistic = 0.59, 0.69) better than chance; other ΔOBJ methods did not. ΔOBJ-LME improved prediction of future MCI over baseline sOBJ (p = 0.003) but not over 30-month sOBJ (p = 0.09).

CONCLUSION

Longitudinal decline did not offer substantial benefit over cross-sectional assessment in detecting preclinical Alzheimer's disease or incident MCI.

An examination of reliable change methods for measuring cognitive change with the Cogstate Computerized Battery: Research and clinical implications

Objective

To compare the performance of four reliable change (RC) methods with respect to measuring cognitive change on the Cogstate Computerized Battery (CCB).

Method

We assessed cognitive change in 57 healthy, urban, well-educated males on the CCB at baseline and 6 months (Median age = 50, 65% university-educated). The study CCB version comprised seven measures covering attention, processing speed, verbal learning, and memory. Raw scores were z-score transformed using age-corrected Cogstate norms (CN) or the sample mean and standard deviation (internal standardization [IS]), and then averaged to create composite z-scores. Composite scores were entered into four RC formulae. RC was defined based on a 90% two-tailed confidence interval. Change scores were compared as continuous (z-scores) and ordinal variables (RC outcomes).

Results

CCB composite score reliability (rXY = .78–.79) was replicated in an age- and sex-matched Cogstate database sample of similar size. There was good overall agreement between the four RC methods (Bland–Altman Mdiff = .00; 95% limits of agreement with the mean—CN: z = ± .90; IS: z = ± .93), with each model adhering closely to the 10% rate of RC expected by chance alone (largest χ2 = .86, p = .99). Initial norming strategy (CN or IS) did not affect these outcomes.

Conclusions

Norming strategy and RC method choice did not significantly impact cognitive change predictions on CCB composite scores. A series of example case data are provided to practically demonstrate the steps involved in applying the longitudinal norms generated in this study. Research in more diverse normative samples is warranted.

Longitudinal Comparison of in Clinic and at Home Administration of the Cogstate Brief Battery and Demonstrated Practice Effects in the Mayo Clinic Study of Aging

BACKGROUND

The Cogstate Brief Battery (CBB) is a computerized cognitive assessment that can be completed in clinic or at home. Design/Objective: This retrospective study investigated whether practice effects / performance trajectories of the CBB differ by location of administration.

PARTICIPANTS/SETTING

Participants included 1439 cognitively unimpaired individuals age 50-75 at baseline participating in the Mayo Clinic Study of Aging (MCSA), a population-based study of cognitive aging. Sixty three percent of participants completed the CBB in clinic only and 37% completed CBB both in clinic and at home.

MEASUREMENTS

The CBB consists of four subtests: Detection, Identification, One Card Learning, and One Back. Linear mixed effects models were used to evaluate performance trajectories in clinic and at home.

RESULTS

Results demonstrated significant practice effects between sessions 1 to 2 for most CBB measures. Practice effects continued over subsequent testing sessions, to a lesser degree. Average practice effects/trajectories were similar for each location (home vs. clinic). One Card Learning and One Back accuracy performances were lower at home than in clinic, and this difference was large in magnitude for One Card Learning accuracy. Participants performed faster at home on Detection reaction time, although this difference was small in magnitude.

CONCLUSIONS

Results suggest the location where the CBB is completed has an important impact on performance, particularly for One Card Learning accuracy, and there are practice effects across repeated sessions that are similar regardless of where testing is completed.

Comparison of PC and iPad administrations of the Cogstate Brief Battery in the Mayo Clinic Study of Aging: Assessing cross-modality equivalence of computerized neuropsychological tests

Objective: Computerized neuropsychological assessments are increasingly used in clinical practice, population studies of cognitive aging and clinical trial enrichment. Subtle, but significant, performance differences have been demonstrated across different modes of test administration and require further investigation. Method: Participants included cognitively unimpaired adults aged 50 and older from the Mayo Clinic Study of Aging who completed the Cogstate Brief Battery and Cogstate's Groton Maze Learning Test (GMLT) on an iPad or a personal computer (PC) in the clinic. Mode of administration differences and test-retest reliability coefficients were examined across 3 cohorts: a demographically matched test-retest cohort completing PC and iPad administrations the same day (N = 168); a test naïve cohort comparing baseline PC (n = 1820) and iPad (n =605) performance; and a demographically matched longitudinal cohort completing 3 Cogstate visits over 15 months on either the PC (n =63) or iPad (n =63). Results: Results showed a small but statistically significant and consistent finding for faster performance on PC relative to iPad for several Cogstate Brief Battery measures. Measures of accuracy generally did not differ or differences were very small. The GMLT showed faster performance and higher total errors on iPad. Most Cogstate variables showed no difference in the rate of change across PC and iPad administrations. Conclusions: There are small, but significant, differences in performance when giving the same cognitive tests on a PC or an iPad. Future studies are needed to better understand if these small differences impact the clinical interpretation of results and research outcomes.

Caudwell Xtreme Everest: A prospective study of the effects of environmental hypoxia on cognitive functioning

Background

The neuropsychological consequences of exposure to environmental hypobaric hypoxia (EHH) remain unclear. We thus investigated them in a large group of healthy volunteers who trekked to Mount Everest base camp (5,300 m).

Methods

A neuropsychological (NP) test battery assessing memory, language, attention, and executive function was administered to 198 participants (age 44.5±13.7 years; 60% male). These were studied at baseline (sea level), 3,500 m (Namche Bazaar), 5,300 m (Everest Base Camp) and on return to 1,300 m (Kathmandu) (attrition rate 23.7%). A comparable control group (n = 25; age 44.5±14.1 years; 60% male) for comparison with trekkers was tested at/or near sea level over an equivalent timeframe so as to account for learning effects associated with repeat testing. The Reliable Change Index (RCI) was used to calculate changes in cognition and neuropsychological function during and after exposure to EHH relative to controls.

Results

Overall, attention, verbal ability and executive function declined in those exposed to EHH when the performance of the control group was taken into account (RCI .05 to -.95) with decline persisting at descent. Memory and psychomotor function showed decline at highest ascent only (RCI -.08 to -.56). However, there was inter-individual variability in response: whilst NP performance declined in most, this improved in some trekkers. Cognitive decline was greater amongst older people (r = .42; p < .0001), but was otherwise not consistently associated with socio-demographic, mood, or physiological variables.

Conclusions

After correcting for learning effects, attention, verbal abilities and executive functioning declined with exposure to EHH. There was considerable individual variability in the response of brain function to sustained hypoxia with some participants not showing any effects of hypoxia. This might have implications for those facing sustained hypoxia as a result of any disease.

CogState computerized memory tests in patients with brain metastases: secondary endpoint results of NRG Oncology RTOG 0933

Whole brain radiotherapy (WBRT) is associated with memory dysfunction. As part of NRG Oncology RTOG 0933, a phase II study of WBRT for brain metastases that conformally avoided the hippocampal stem cell compartment (HA-WBRT), memory was assessed pre- and post-HA-WBRT using both traditional and computerized memory tests. We examined whether the computerized tests yielded similar findings and might serve as possible alternatives for assessment of memory in multi-institution clinical trials. Adult patients with brain metastases received HA-WBRT to 30 Gy in ten fractions and completed Hopkins Verbal Learning Test-Revised (HVLT-R), CogState International Shopping List Test (ISLT) and One Card Learning Test (OCLT), at baseline, 2 and 4 months. Tests' completion rates were 52-53 % at 2 months and 34-42 % at 4 months. All baseline correlations between HVLT-R and CogState tests were significant (p ≤ 0.003). At baseline, both CogState tests and one component of HVLT-R differentiated those who were alive at 6 months and those who had died (p ≤ 0.01). At 4 months, mean relative decline was 7.0 % for HVLT-R Delayed Recall and 18.0 % for ISLT Delayed Recall. OCLT showed an 8.0 % increase. A reliable change index found no significant changes from baseline to 2 and 4 months for ISLT Delayed Recall (z = -0.40, p = 0.34; z = -0.68, p = 0.25) or OCLT (z = 0.15, p = 0.56; z = 0.41, p = 0.66). Study findings support the possibility that hippocampal avoidance may be associated with preservation of memory test performance, and that these computerized tests also may be useful and valid memory assessments in multi-institution adult brain tumor trials.

Postoperative cognitive dysfunction in geriatric patients

Postoperative cognitive dysfunction (POCD) is a severe long-term complication after surgical procedures. POCD is mainly seen among geriatric patients. Hospitalization, extent of surgery, and systemic inflammatory response might contribute to POCD. The possible influence of the type of anesthesia is discussed. POCD is often not recognized; thus, incidence rates are likely to be underestimated (19-40%). POCD is associated with major consequences for the individual patient, e.g., delayed long-term recovery, reduced quality of life, and an increased mortality rate. Multiple risk factors have been identified over the last decade. However, the exact etiology is still unknown. This mini-review summarizes the recent developments concerning POCD prevention, diagnosis, and treatment.

Cognitive function testing in adult brain tumor trials: lessons from a comprehensive review

Neurocognitive function (NCF) impairment is an important component of primary and metastatic brain tumors and their therapeutic interventions. As a result, modern clinical trials of cranial irradiation for adult cancer patients have incorporated NCF testing as a primary or secondary end point. In doing so, these clinical trials have provided a novel insight into our understanding of the NCF effects of cranial irradiation and brain tumor progression. In this article, we review these clinical trials both in terms of the trial findings and in terms of the types of NCF tests used in these trials. We also provide an introduction to the strengths and limitations of these NCF tests, as well as expert commentary on the current status and future directions of NCF testing in brain tumor trials.

Intraindividual cognitive decline using a brief computerized cognitive screening test

BACKGROUND

Progressive intraindividual decline in memory and cognition is characteristic of dementia and may be useful in detecting very early Alzheimer's disease pathology.

METHODS

This study evaluated the slopes of cognitive performance over a 12-month period in 263 healthy, community-dwelling, adult volunteers aged ≥50 years. Participants completed a brief computerized battery of cognitive tests (CogState) at baseline and during 3-, 6-, 9-, and 12-month follow-up assessments. Linear mixed models were used to estimate age-adjusted mean slopes and 95% confidence intervals of change for each of the cognitive measures.

RESULTS

By defining age-adjusted mean slopes, and 95% confidence intervals for a measure of episodic memory, individuals with greater than expected decline (equal to or lower than the fifth percentile level of decline) were identified. From these, four individuals completed a full medical, neurologic, and neuropsychological evaluation, with none of them fulfilling criteria for mild cognitive impairment, but three (75%) having positive amyloid-positron emission tomographic scans.

CONCLUSIONS

Intraindividual decline in cognitive performance can be detected in otherwise healthy, community-dwelling, older persons, and this may deserve further study as a potential indicator of early Alzheimer's disease pathology.

The two errors of using the within-subject standard deviation (WSD) as the standard error of a reliable change index

In this Journal, Lewis and colleagues introduced a new Reliable Change Index (RCI(WSD)), which incorporated the within-subject standard deviation (WSD) of a repeated measurement design as the standard error. In this note, two opposite errors in using WSD this way are demonstrated. First, being the standard error of measurement of only a single assessment makes WSD too small when practice effects are absent. Then, too many individuals will be designated reliably changed. Second, WSD can grow unlimitedly to the extent that differential practice effects occur. This can even make RCI(WSD) unable to detect any reliable change.

MMP-9 levels in elderly patients with cognitive dysfunction after carotid surgery

Approximately 25% of elderly patients scheduled for carotid endarterectomy (CEA) develop post-operative cognitive dysfunction (CD). We tested the hypothesis that the plasma levels of matrix metalloproteinase 9 (MMP-9) are predictive of moderate to severe CD after CEA. A total of 73 patients were prospectively enrolled in this Institutional Review Board-approved study. Plasma samples were obtained at baseline and day 1 post-surgery. We measured the plasma concentrations of both MMP-9 and its inhibitor, tissue inhibitor of metalloproteinases 1 (TIMP-1). We estimated the MMP-9 activity by calculating the MMP-9:TIMP-1 ratio. The cognitive performance day 1 post-surgery was quantified with z-scores, using a control group who were undergoing spinal surgery. The criteria used to define CD was performance of >or=1.5 standard deviations worse than the control group; approximately 19% of eligible patients developed CD. Compared to patients without CD, this group had both higher total (81.66+/-12.25 ng/mL versus [vs.] 43.18+/-4.44 ng/mL, p=0.005) and activity (0.88+/-0.24 ng/mL vs. 0.54+/-0.06 ng/mL, p=0.003) MMP-9 levels at baseline. All of the results were adjusted for age, diabetes and neurovascular symptoms.

Postoperative cognitive decline

Memory loss and lack of concentration are symptoms that frequently occur in patients who have undergone a surgical procedure. Although cognitive function can be assessed using neuropsychological tests, reliable diagnosis of postoperative cognitive decline (POCD) appears to be difficult. Therefore, the true incidence of POCD is unknown. Severe POCD, which is apparent even without neuropsychological testing, is reported most frequently after cardiac and hip-replacement surgery. In these cases, POCD probably reflects microembolic brain injury. Apart from the nature of the surgical procedure, advanced age is the most important risk factor for POCD. The anesthetic technique is not a determinant of POCD: the risk of POCD appears to be similar after both general and regional anesthesia.