Visual tests, touch responses: Computer-based neuropsychological tools.

Objective: Investigate three new computer tests of visual abilities relative to traditional paper-and-pencil (P&P) tests on groups with and without cerebral neurological impairment (CNI, Non-CNI) based on MRI and EEG criteria. The new tests employ an intuitive interface with audio instructions, touch responses, non-response prompts, and videography of test behavior. The Presidents Test was designed as an achievement-related measure of visual knowledge; the Railroad Test - visual perception and delayed recognition; and the Swamp Test - visual attention. Attitudes toward testing were assessed with an original Testing Experience Questionnaire (TEQ). Method: Of the 129 participants, 84 were women, 73 identified as non-White, average age 45.5 and education 14.3 years. Procedures included the new computer tests and a selection of standard neuropsychological measures including performance validity tests (PVT). Participants who failed two or three PVTs or had missing PVT data were excluded from main analyses, resulting in N = 115. Results: The new computer tests demonstrated adequate reliability. Correlations and factor analyses confirmed the computer tests as functioning in accordance with design. The Presidents Test was associated with academic achievement. The Railroad and Swamp Tests were linked to visual perception and visual attention. Correlations between computer total test duration time and traditional speed of processing tasks were modest. Computer and traditional tests demonstrated similar discriminability between CNI and Non-CNI groups. TEQ indicated positive attitudes toward testing in general, and computer testing in particular. Conclusions: The new computer tests evaluated in this study were found to be reliable, functioned to assess the designed cognitive domains, and discriminated between CNI and Non-CNI participants similarly to the traditional neuropsychological measures. Attitudes toward computer testing were favorable.

Guardians of memory: The urgency of early dementia screening in an aging society.

The global aging population has led to a significant rise in the prevalence of age-related non-communicable diseases such as dementia and other cognitive disorders. In 2019, there were 57.4 million people with dementia worldwide, and this number is projected to triple by 2050. Intervening in and managing 12 potentially modifiable dementia risk factors can prevent or delay the onset and progression of about 40% of dementia cases. Neuroimaging, biomarkers, and advanced neuropsychological testing offer promising pathways for the early detection of dementia. Emphasis should be placed on educating the public about the importance of brain health and the early signs of cognitive impairment, as well as promoting dementia prevention measures. Adopting a healthy lifestyle - including a balanced diet, regular physical exercise, active social engagement, cognitive activities, and avoiding smoking and excessive alcohol consumption - can help reduce the risk of cognitive decline and prevent cognitive disorders. Government policies on dementia prevention and health care, along with early and regular dementia screening programs, can enhance the early identification and management of individuals at risk. In addition, integrating cognitive health assessments into routine medical check-ups is essential for the early screening and management of dementia.

Self-reported hearing loss is associated with faster cognitive and functional decline but not diagnostic conversion in the ADNI cohort.

INTRODUCTION: Hearing loss is identified as one of the largest modifiable risk factors for cognitive impairment and dementia. Studies evaluating this relationship have yielded mixed results. METHODS: We investigated the longitudinal relationship between self-reported hearing loss and cognitive/functional performance in 695 cognitively normal (CN) and 941 participants with mild cognitive impairment (MCI) enrolled in the Alzheimer's Disease Neuroimaging Initiative. RESULTS: Within CN participants with hearing loss, there was a significantly greater rate of cognitive decline per modified preclinical Alzheimer's cognitive composite. Within both CN and MCI participants with hearing loss, there was a significantly greater rate of functional decline per the functional activities questionnaire (FAQ). In CN and MCI participants, hearing loss did not significantly contribute to the risk of progression to a more impaired diagnosis. DISCUSSION: These results confirm previous studies demonstrating a significant longitudinal association between self-reported hearing loss and cognition/function but do not demonstrate an increased risk of conversion to a more impaired diagnosis. CLINICAL TRIAL REGISTRATION INFORMATION: NCT00106899 (ADNI: Alzheimer's Disease Neuroimaging Initiative, clinicaltrials.gov), NCT01078636 (ADNI-GO: Alzheimer's Disease Neuroimaging Initiative Grand Opportunity, clinicaltrials.gov), NCT01231971 (ADNI2: Alzheimer's Disease Neuroimaging Initiative 2, clinicaltrials.gov), NCT02854033 (ADNI3: Alzheimer's Disease Neuroimaging Initiative 3, clinicaltrials.gov). HIGHLIGHTS: Hearing loss is a potential modifiable risk factor for dementia. We assessed the effect of self-reported hearing loss on cognition and function in the ADNI cohort. Hearing loss contributes to significantly faster cognitive and functional decline. Hearing loss was not associated with conversion to a more impaired diagnosis.

Monitoring cognitive functions during deep brain stimulation (DBS) interventions by Real Time Neuropsychological Testing (DBS-RTNT).

Objective: We monitored cognition during Deep brain stimulation (DBS) surgery, when the electrode is positioned at the target subthalamic nucleus (i.e., STN motor area) in 14 PD patients. Methods: We present the Real Time Neuropsychological Testing (DBS-RTNT) protocol, our preliminary experience, along with patients' performance comparing intraoperative results with baseline data. Results: Compared to baseline, DBS-RTNT in the target area showed a significantly decreased performance at some tasks belonging to memory and executive functions domains. Significantly decreased short-term memory and sequencing scores were found for right (vs. left) hemisphere DBS-RTNT. Conclusions: PD patients' performance should be monitored during DBS surgery as STN-DBS may induce changes in cognitive performance. These preliminary data contribute to improve, during DBS-surgery the anatomo-functional topography of the STN in order to identify, in future approaches, in the individual patient the best site producing positive motor effects, without causing negative cognitive and/or emotional changes. Medications (i.e., the patients underwent surgery in a levodopa off state) could in principle have influenced our results therefore future studies are needed to address possible confounding effect of levodopa use.

Impact of postoperative cerebral hyperperfusion on 2-year cognitive outcomes of patients undergoing carotid endarterectomy.

OBJECTIVE: In 10% of patients undergoing carotid endarterectomy (CEA), the cognitive function declines postoperatively, primarily in association with postoperative cerebral hyperperfusion. In contrast, in the majority of patients undergoing CEA, long-term cognitive outcomes remain unclear. Furthermore, it is not known whether the decline in cognition due to cerebral hyperperfusion recovers on a long-term basis. This study aimed to understand how postoperative cerebral hyperperfusion affects the cognitive outcomes of patients who undergo CEA. METHODS: The participants in this prospective observational study were patients with internal carotid artery stenosis who underwent CEA. Cerebral hyperperfusion syndrome or asymptomatic cerebral hyperperfusion following CEA was determined based on brain perfusion SPECT scans and symptomatology before and after surgery. Neuropsychological testing was performed preoperatively, at 1-2 months postoperatively, and at 2 years postoperatively to investigate cognitive decline. RESULTS: A logistic regression analysis revealed that asymptomatic cerebral hyperperfusion (95% CI 13.0-84.5, p < 0.0001) and cerebral hyperperfusion syndrome (95% CI 449.7-14,237.4, p < 0.0001) were significantly associated with cognitive decline at 1-2 months postoperatively. The incidence of cognitive decline was significantly decreased at 2 years postoperatively (7%) in comparison to 1-2 months postoperatively (11%) (p = 0.0461). A logistic regression analysis also revealed that asymptomatic cerebral hyperperfusion (95% CI 3.7-36.7, p < 0.0001), cerebral hyperperfusion syndrome (95% CI 128.0-6183.6, p < 0.0001), and further strokes during the 2-year follow-up period (95% CI 1.5-78.7, p = 0.0167) were significantly associated with cognitive decline at 2 years postoperatively. The incidence of cognitive decline at 1-2 months postoperatively was significantly higher in patients with cerebral hyperperfusion syndrome (100%) than in those with asymptomatic cerebral hyperperfusion (44%) (p < 0.0001). No significant difference in incidence was observed in the former patients at 2 years postoperatively (88%), but significant reduction was found in patients with asymptomatic cerebral hyperperfusion and cognitive decline between the timepoints of 1-2 months postoperatively (100%) and 2 years postoperatively (39%) (p = 0.0001). CONCLUSIONS: Postoperative cerebral hyperperfusion causes prolonged cognitive decline at 2 years postoperatively in patients undergoing CEA.

The minimal computational substrate of fluid intelligence.

The quantification of cognitive powers rests on identifying a behavioural task that depends on them. Such dependence cannot be assured, for the powers a task invokes cannot be experimentally controlled or constrained a priori, resulting in unknown vulnerability to failure of specificity and generalisability. Evaluating a compact version of Raven's Advanced Progressive Matrices (RAPM), a widely used clinical test of fluid intelligence, we show that LaMa, a self-supervised artificial neural network trained solely on the completion of partially masked images of natural environmental scenes, achieves representative human-level test scores a prima vista, without any task-specific inductive bias or training. Compared with cohorts of healthy and focally lesioned participants, LaMa exhibits human-like variation with item difficulty, and produces errors characteristic of right frontal lobe damage under degradation of its ability to integrate global spatial patterns. LaMa's narrow training and limited capacity suggest matrix-style tests may be open to computationally simple solutions that need not necessarily invoke the substrates of reasoning.

Patterns of cognitive domain abnormalities enhance discrimination of dementia risk prediction: The ARIC study.

INTRODUCTION: The contribution of neuropsychological assessments to risk assessment for incident dementia is underappreciated. METHODS: We analyzed neuropsychological testing results in dementia-free participants in the Atherosclerosis Risk in Communities (ARIC) study. We examined associations of index domain-specific neuropsychological test performance with incident dementia using cumulative incidence curves and Cox proportional hazards models. RESULTS: Among 5296 initially dementia-free participants (mean [standard deviation] age of 75.8 [5.1] years; 60.1% women, 22.2% Black) over a median follow-up of 7.9 years, the covariate-adjusted hazard ratio varied substantially depending on the pattern of domain-specific performance and age, in an orderly manner from single domain language abnormalities (lowest risk) to single domain executive or memory abnormalities, to multidomain abnormalities including memory (highest risk). DISCUSSION: By identifying normatively defined cognitive abnormalities by domains based on neuropsychological test performance, there is a conceptually orderly and age-sensitive spectrum of risk for incident dementia that provides valuable information about the likelihood of progression. HIGHLIGHTS: Domain-specific cognitive profiles carry enhanced prognostic value compared to mild cognitive impairment. Single-domain non-amnestic cognitive abnormalities have the most favorable prognosis. Multidomain amnestic abnormalities have the greatest risk for incident dementia. Patterns of domain-specific risks are similar by sex and race.

Long-term neurological and neurocognitive impairments after tick-borne encephalitis in Lithuania - a prospective study.

BACKGROUND: The aim of this study was to characterise long-term neurological and neurocognitive sequelae after tick-borne encephalitis (TBE) in adults. METHODS: 98 prospective consecutive TBE patients, classified by disease severity, were included. Immediate outcomes were evaluated with Glasgow Outcome Scale (GOS) and Rankin Scale (RS). After 6 and 18 months, long-term disability was evaluated using Modified Rankin Scale (MRS) and neurocognitive assessment was performed with Matrics Consensus Cognitive Battery (MCCB), measuring processing speed, attention/vigilance, working memory, verbal learning, visual learning, reasoning/problem solving and social cognition. The MCCB results were compared to healthy age, gender and education-matched controls. RESULTS: Mild, moderate, and severe TBE was diagnosed in 53.1%, 38.8%, and 8.2% of cases, respectively. At discharge, 25.5% of the patients had major or moderate impairments (GOS) and various levels of disability in 34.7% (RS). Up to 18 months from the onset of TBE, over 20% remained with slight to moderate disability (MRS). GOS, RS and MRS scores correlated with disease severity. At 6 months after the onset, TBE patients scored significantly lower than controls in processing speed, verbal, and visual learning. Two latter domains were significantly more impaired in patients with mild TBE. Patients aged 18-39 performed significantly worse in attention/vigilance and working memory, whereas aged 60+ in verbal learning. A year later, significant improvement was observed in six of seven cognitive domains. CONCLUSIONS: Long-term neurological sequelae persist in a substantial proportion of TBE patients with significant impairment in several cognitive domains, especially in younger patients and even after mild TBE.

[Impairment of attention and executive functions in chronic cerebrovascular disease and Alzheimer's disease]. / Narushenie vnimaniya i upravlyayushchikh funktsii pri sosudistykh kognitivnykh narusheniyakh i bolezni Al'tsgeimera.

OBJECTIVE: To establish specific features of executive functions (EF) impairment and attention in vascular cognitive impairment (VCI) and Alzheimer's disease (AD). MATERIAL AND METHODS: Eighty people (over the age of 50) diagnosed with cerebrovascular disease (CVD) and AD, as well as 29 healthy volunteers (control group), were examined. The following neuropsychological methods were used to study the quantitative and qualitative characteristics of cognitive impairments: Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), EXIT-25, Frontal Assessment Battery (FAB), Clock Drawing Test, «12 Words¼ test, verbal associations (literal and categorical) method, Trail Making Test A and B, Symbol-Digit Modalities Test (SDMT), Stroop Test, and Benton Visual Retention Test. Mandatory inclusion criteria in the study included having a completed magnetic resonance imaging (MRI) of the brain (in T1, T2, FLAIR, DWI, SWI modes) within 1 year before enrollment in one of the groups. RESULTS: No significant differences in age, sex, and level of education were found between the groups. Groups AD and CVD were also comparable in the severity of cognitive impairment overall. Attention and working memory deficits were observed in both CVD and AD, with slightly more pronounced deficits in the AD group. Qualitative analysis of individual components of working memory revealed that both CVD and AD groups had comparable cognitive control impairment compared to the control group, while AD was characterized by a more significant decrease in intellectual flexibility compared to CVD. Sustained attention was equally impaired among patients in the CVD and AD groups, with a significant difference from the control group (p<0.05). In terms of memory, it was found that auditory-verbal memory and semantic memory were significantly more affected in AD, while visual memory was impaired in both conditions. CONCLUSION: Attention and EF impairments are not specific to the «subcortical¼ type of cognitive disorders. Already in the early stages, AD is characterized by a significant impairment of attention and EF, and such a component of EF as intellectual flexibility suffers at the onset of AD to a greater extent than in VCI. Memory impairments are not specific to AD; already at the onset of VCI, visual memory impairment comparable to AD is noted. The obtained data can be used for early neuropsychological diagnosis and differential diagnosis of dementing cerebral diseases.

Corrigendum: Remote assessment of cognition in Parkinson's disease and cerebellar ataxia: the MoCA test in English and Hebrew.

[This corrects the article DOI: 10.3389/fnhum.2023.1325215.].

An Interdisciplinary Protocol for Ventriculoperitoneal Shunt Patient Selection in Normal Pressure Hydrocephalus.

BACKGROUND: Normal pressure hydrocephalus can be treated with ventriculoperitoneal shunt (VPS) placement, but no broadly implemented indication for VPS exists. METHODS: Our protocol consists of physical therapy and occupational therapy practitioners administering validated tests of gait, balance, and cognition before and after lumbar drain placement. Specific tests include: Timed "Up & Go", Tinetti Gait and Balance Assessment, Berg Balance Scale, Mini Mental Status Exam, Trail Making Test Part B, and the Rey Auditory and Visual Learning Test. Minimal clinically important difference values for each test were determined from literature review. A retrospective review of patients treated under this protocol was performed. The primary outcomes were candidacy for VPS based on the protocol and patient-reported symptomatic improvement after VPS placement. RESULTS: A total of 48/75 (64%) patients received VPS. A total of 43/48 (89.6%) of those shunted reported improved symptoms at 6-week follow-up. However, 10/22 (45.5%) reported worsening symptoms at 1-year follow-up. The mean Tinetti score significantly increased after lumbar drain in patients who improved with VPS compared to the no shunt group (4.27 vs. -0.48, P < 0.001). A total of 6/33 (18%) patients with postoperative imaging had a subdural fluid collection identified and 3/49 (6%) had other complications, including 1 seizure, 1 intracerebral hemorrhage, and 1 stroke. CONCLUSIONS: Standardized assessment of gait, balance, and cognition before and after temporary cerebrospinal fluid diversion identifies patients with normal pressure hydrocephalus likely to benefit from VPS placement with a low complication rate. One year after VPS, approximately one half of patients had symptoms recurrence.

Short-Term Practice Effects on Cognitive Tests Across the Late Life Cognitive Spectrum and How They Compare to Biomarkers of Alzheimer's Disease.

Background: Practice effects on cognitive testing in mild cognitive impairment (MCI) and Alzheimer's disease (AD) remain understudied, especially with how they compare to biomarkers of AD. Objective: The current study sought to add to this growing literature. Methods: Cognitively intact older adults (n = 68), those with amnestic MCI (n = 52), and those with mild AD (n = 45) completed a brief battery of cognitive tests at baseline and again after one week, and they also completed a baseline amyloid PET scan, a baseline MRI, and a baseline blood draw to obtain APOE ɛ4 status. Results: The intact participants showed significantly larger baseline cognitive scores and practice effects than the other two groups on overall composite measures. Those with MCI showed significantly larger baseline scores and practice effects than AD participants on the composite. For amyloid deposition, the intact participants had significantly less tracer uptake, whereas MCI and AD participants were comparable. For total hippocampal volumes, all three groups were significantly different in the expected direction (intact > MCI > AD). For APOE ɛ4, the intact had significantly fewer copies of ɛ4 than MCI and AD. The effect sizes of the baseline cognitive scores and practice effects were comparable, and they were significantly larger than effect sizes of biomarkers in 7 of the 9 comparisons. Conclusion: Baseline cognition and short-term practice effects appear to be sensitive markers in late life cognitive disorders, as they separated groups better than commonly-used biomarkers in AD. Further development of baseline cognition and short-term practice effects as tools for clinical diagnosis, prognostic indication, and enrichment of clinical trials seems warranted.

Emotional processing impairments in patients with insula lesions following stroke.

Functional imaging has helped to understand the role of the human insula as a major processing network for integrating input with the current state of the body. However, these studies remain at a correlative level. Studies that have examined insula damage show lesion-specific performance deficits. Case reports have provided anecdotal evidence for deficits following insula damage, but group lesion studies offer a number of advances in providing evidence for functional representation of the insula. We conducted a systematic literature search to review group studies of patients with insula damage after stroke and identified 23 studies that tested emotional processing performance in these patients. Eight of these studies assessed emotional processing of visual (most commonly IAPS), auditory (e.g., prosody), somatosensory (emotional touch) and autonomic function (heart rate variability). Fifteen other studies looked at social processing, including emotional face recognition, gaming tasks and tests of empathy. Overall, there was a bias towards testing only patients with right-hemispheric lesions, making it difficult to consider hemisphere specificity. Although many studies included an overlay of lesion maps to characterise their patients, most did not differentiate lesion statistics between insula subunits and/or applied voxel-based associations between lesion location and impairment. This is probably due to small group sizes, which limit statistical comparisons. We conclude that multicentre analyses of lesion studies with comparable patients and performance tests are needed to definitively test the specific function of parts of the insula in emotional processing and social interaction.

Change in Neuropsychological Test Performance Seen in a Longitudinal Study of Patients With Post-acute Sequelae of COVID-19: A 6-Month Follow-up Study.

BACKGROUND: Post-acute sequelae of COVID-19 may include physical, psychiatric, and neurocognitive symptoms. Few studies of cognitive symptoms have been longitudinal, with many following participants briefly after infection and relying on subjective complaints, screening instruments, or computerized testing. This group previously reported diminished neuropsychological (NP) test performance in over half of 60 individuals tested in-person 7 months post-COVID-19, particularly those seeking care for cognitive complaints. The current study describes the initial and 6-month follow-up results of an expanded cohort of 75 participants. OBJECTIVE: To measure longitudinal changes in neuropsychological test performance, as well as medical and psychiatric changes, post-COVID-19. METHODS: Participants underwent NP, psychiatric, and medical assessments approximately 7 months after acute COVID-19 infection. Sixty-three (84%) returned approximately 6 months later for repeat evaluation. RESULTS: At the initial visit, 29 (38.7%) met criteria for low NP performance, and 16 (21.3%) met criteria for extremely low NP performance. At 6-month follow-up, several NP domains that were significantly below normative values at the initial visit were no longer abnormal, with the exception of language. Only measures of delayed memory and fatigue showed significant improvements between the 2 time points. CONCLUSIONS: A substantial proportion of individuals recovered from acute COVID-19 infection have persistent neuropsychiatric symptoms over 1 year after infection. While the overall sample in this study showed some improvement in NP test performance relative to norms, only fatigue and delayed memory improved significantly between times 1 and 2. No individual declined in NP test performance, though relatively few individuals made significant clinical improvement, indicating the need for serial neuropsychiatric assessment and treatment supports. Longitudinal follow-up of this cohort is in progress.

A systematic review of cognition in idiopathic intracranial hypertension.

Background: Cognitive disturbance is not pathognomonic of idiopathic intracranial hypertension (IIH), and therefore is not routinely assessed unless it presents as a major complaint. Consequently, cognition has been slow to gain substantial traction in IIH-related research, despite its notable impact on a subset of patients. We completed a systematic review of the literature examining the neurocognitive profile of patients with IIH. Methods: A PRISMA compliant literature search was conducted in Ovid Medline, PubMed, PsycInfo, Embase, Web of Science, Cochrane, Cinahl, and Scopus databases. The initial query yielded 1376 unique articles. These articles were narrowed to those including empirical analyses of cognitive assessment in adult patients with IIH. Results: A final cohort of nine articles resulted, comprising the findings from 309 patients with IIH and 153 healthy control subjects. Although there was considerable variability in methodology particularly with respect to cognitive assessment, fairly consistent deficits were observed across studies in the domains of processing speed, working memory, sustained and complex attention, set-shifting, and confrontation naming. Body mass index and body weight were not associated with cognitive performance. Pertinent limitations of the literature were identified, most notably failure to report trial-level cognitive testing data, the need for more comprehensive testing batteries with less reliance on screening tools, and not controlling for variables that may impact cognition. Conclusions: A more complete understanding of the cognitive profile in patients with idiopathic intracranial hypertension could lead to the increased -relevance of cognitive screening in disease management, and therefore more appropriate neuropsychological referral, earlier identification of functional limitations, and targeted neurorehabilitation.

Differences Between Consistent and Inconsistent Handedness Remain Consistently Interesting: Ten Years of Research on the Consistency of Handedness With the Edinburgh Handedness Inventory.

Almost 10 years ago Prichard et al. (2013) published a literature review on consistency of handedness. They described how consistency of handedness, typically measured by the Edinburgh Handedness Inventory (EHI), predicted outcomes in memory and decision-making paradigms better than direction of handedness. In the last 10 years, new research has extended these findings and added new theoretical perspectives. The goal of this short form review is to highlight and summarize some of these more intriguing findings and to encourage researchers in the fields of memory and decision making to incorporate handedness as a variable in future research.

Cognition and post-concussive symptom status after pediatric mild traumatic brain injury.

Cognitive impairment and post-concussive symptoms (PCS) represent hallmark sequelae of pediatric mild traumatic brain injury (pmTBI). Few studies have directly compared cognition as a function of PCS status longitudinally. Cognitive outcomes were therefore compared for asymptomatic pmTBI, symptomatic pmTBI, and healthy controls (HC) during sub-acute (SA; 1-11 days) and early chronic (EC; approximately 4 months) post-injury phases. We predicted worse cognitive performance for both pmTBI groups relative to HC at the SA visit. At the EC visit, we predicted continued impairment from the symptomatic group, but no difference between asymptomatic pmTBI and HCs. A battery of clinical (semi-structured interviews and self-report questionnaires) and neuropsychological measures were administered to 203 pmTBI and 139 HC participants, with greater than 80% retention at the EC visit. A standardized change method classified pmTBI into binary categories of asymptomatic or symptomatic based on PCS scores. Symptomatic pmTBI performed significantly worse than HCs on processing speed, attention, and verbal memory at SA visit, whereas lower performance was only present for verbal memory for asymptomatic pmTBI. Lower performance in verbal memory persisted for both pmTBI groups at the EC visit. Surprisingly, a minority (16%) of pmTBI switched from asymptomatic to symptomatic status at the EC visit. Current findings suggest that PCS and cognition are more closely coupled during the first week of injury but become decoupled several months post-injury. Evidence of lower performance in verbal memory for both asymptomatic and symptomatic pmTBI suggests that cognitive recovery may be a process separate from the resolution of subjective symptomology.

Performance on complex memory tests is associated with ß-amyloid in individuals at risk of developing Alzheimer's disease.

The pathophysiological development of Alzheimer's disease (AD) begins in the brain years before the onset of clinical symptoms. The accumulation of beta-amyloid (Aß) is thought to be the first cortical pathology to occur. Carrying one apolipoprotein E (APOE) ε4 allele increases the risk of developing AD at least 2-3 times and is associated with earlier Aß accumulation. Although it is difficult to identify Aß-related cognitive impairment in early AD with standard cognitive tests, more sensitive memory tests may be able to do this. We sought to examine associations between Aß and performance on three tests within three subdomains of memory, verbal, visual, and associative memory, to elucidate which of these tests were sensitive to Aß-related cognitive impairment in at-risk subjects. 55 APOE ε4 carriers underwent MRI, 11 C-Pittsburgh Compound B (PiB) PET, and cognitive testing. A composite cortical PiB SUVR cut-off score of 1.5 was used to categorise subjects as either APOE ε4 Aß+ or APOE ε4 Aß-. Correlations were carried out using cortical surface analysis. In the whole APOE ε4 group, we found significant correlations between Aß load and performance on verbal, visual, and associative memory tests in widespread cortical areas, the strongest association being with performance on associative memory tests. In the APOE ε4 Aß+ group, we found significant correlations between Aß load and performance of verbal and associative, but not visual, memory in localised cortical areas. Performance on verbal and associative memory tests provides sensitive markers of early Aß-related cognitive impairment in at-risk subjects.

Investigating the Latent Structure of Executive Function in the Delis-Kaplan Executive Function System Using Cattell-Horn-Carroll Theory.

OBJECTIVE: To replicate a seven-factor model previously reported for the Delis-Kaplan Executive Function System (D-KEFS). METHOD: This study used the D-KEFS standardization sample including 1,750 non-clinical participants. Several seven-factor models previously reported for the D-KEFS were re-evaluated using confirmatory factor analysis (CFA). Previously published bi-factor models were also tested. These models were compared with a three-factor a priori model based on Cattell-Horn-Carroll (CHC) theory. Measurement invariance was examined across three age cohorts. RESULTS: All previously reported models failed to converge when tested with CFA. None of the bi-factor models converged after large numbers of iterations, suggesting that bi-factor models are ill-suited to represent the D-KEFS scores as reported in the test manual. Although poor fit was initially observed for the three-factor CHC model, inspection of modification indices showed potential for improvement by including method effects via correlated residuals for scores derived from similar tests. The final CHC model showed good to excellent fit and strong metric measurement invariance across the three age cohorts with minor exceptions for a subset of Fluency parameters. CONCLUSIONS: CHC theory extends to the D-KEFS, supporting findings from previous studies that executive functions can be integrated into CHC theory.