•ASL MRI is a noninvasive method to quantitatively measure cerebral blood flow.•Technical advances and multivariate statistical analysis improve ASL investigations.•Cerebral blood flow changes in ...aging vary depending on vascular and AD risk factors.•ASL is promising to use in early diagnosis and monitoring disease progression in AD.
Arterial spin labeling (ASL) magnetic resonance imaging uses arterial blood water as an endogenous tracer to measure cerebral blood flow (CBF). In this review, based on ASL studies in the resting state, we discuss state-of-the-art technical and data processing improvements in ASL, and ASL CBF changes in normal aging, mild cognitive impairment (MCI), Alzheimer’s disease (AD), and other types of dementia. We propose that vascular and AD risk factors should be considered when evaluating CBF changes in aging, and that other validated biomarkers should be used as inclusion criteria or covariates when evaluating CBF changes in MCI and AD. With improvements in hardware and experimental design, ASL is proving to be an increasingly promising tool for exploring pathogenetic mechanisms, early detection, monitoring disease progression and pharmacological response, and differential diagnosis of AD.
The apolipoprotein E (APOE) gene contains both the major common risk variant for late onset Alzheimer's disease (AD), e4, and the major neuroprotective variant, e2. Here we examine the association of ...APOE e2 with multiple neurodegenerative pathologies, leveraging the NACC v. 10 database of 1557 brains that included 130 e2 carriers and 679 e4 carriers in order to examine potential neuroprotective effects. For AD-related pathologies of amyloid plaques and Braak stage, e2 had large and highly significant protective effects contrasted with e3/e3 and e4 carriers with odds ratios of about 0.50 for e3 contrasts and 0.10 for e4 contrasts. When we separately examined e2/e4 carriers, risk for AD pathologies was similar to that of e4 carriers, not e2 carriers. For multiple fronto-temporal lobar pathologies and tauopathies, e2 was not significantly associated with pathology. In sum, we found that e2 was associated with large but circumscribed protective effects.
Up to 70% of patients with treatment-resistant schizophrenia do not respond to clozapine. Pharmacological augmentation to clozapine has been studied with unimpressive results. The authors examined ...the use of ECT as an augmentation to clozapine for treatment-refractory schizophrenia.
In a randomized single-blind 8-week study, patients with clozapine-resistant schizophrenia were assigned to treatment as usual (clozapine group) or a course of bilateral ECT plus clozapine (ECT plus clozapine group). Nonresponders from the clozapine group received an 8-week open trial of ECT (crossover phase). ECT was performed three times per week for the first 4 weeks and twice weekly for the last 4 weeks. Clozapine dosages remained constant. Response was defined as ≥40% reduction in symptoms based on the psychotic symptom subscale of the Brief Psychiatric Rating Scale, a Clinical Global Impressions (CGI)-severity rating <3, and a CGI-improvement rating ≤2.
The intent-to-treat sample included 39 participants (ECT plus clozapine group, N=20; clozapine group, N=19). All 19 patients from the clozapine group received ECT in the crossover phase. Fifty percent of the ECT plus clozapine patients met the response criterion. None of the patients in the clozapine group met the criterion. In the crossover phase, response was 47%. There were no discernible differences between groups on global cognition. Two patients required the postponement of an ECT session because of mild confusion.
The augmentation of clozapine with ECT is a safe and effective treatment option. Further research is required to determine the persistence of the improvement and the potential need for maintenance treatments.
Understanding associations of Alzheimer disease (AD) and related dementias (ADRD) pathologies with common neuropsychiatric symptoms (NPS) may have implications for diagnosis and management.
To ...evaluate ADRD neuropathological diagnoses and NPS without consideration of clinical diagnosis.
This retrospective cohort study evaluated 1808 brains from 39 sites in the US National Alzheimer Coordinating Center v. 10 collection for participants among whom the Neuropsychiatric Inventory Questionnaire (NPIQ) was administered annually. Brain autopsy diagnoses of AD, Lewy body disease (LBD), cerebral amyloid angiopathy, frontotemporal lobar degeneration, cerebrovascular disease, hippocampal sclerosis, and no known pathology were examined. Autopsy data collected from January 2012 to January 2018 were deidentified and compiled into the publicly available v. 10 database. Data were analyzed from February 2021 to August 2021.
The primary outcome was NPIQ domain score, if present at any time point, and mean NPIQ domain score during follow-up was secondary. Associations of ADRD diagnoses with 12 NPIQ symptom domains were examined in regression analyses, correcting for multiple comparisons.
The study sample of 1808 adults had a mean (SD) age of 80.0 (11.0) years, and 987 participants (54.6%) were male. Apathy was the most prevalent NPS, reaching 80% (203 of 254 individuals) in those with hippocampal sclerosis. Cerebrovascular disease showed few NPS associations. Frontotemporal lobar degeneration was associated with increased apathy, increased disinhibition, and decreased psychosis and agitation compared with AD. Hippocampal sclerosis was associated with increased apathy (odds ratio, 2.60; 95% CI; 1.86-3.66, false discovery rate controlled P < .001) and disinhibition (odds ratio, 2.15; 95% CI, 1.63-2.84; false discovery rate controlled P < .001). In multiple regression analyses that included concomitant neuropathologies, the main findings remained. More severe pathology was consistently associated with increased NPS (eg, LBD was associated with an increase in hallucinations from brain stem β, 0.23; 95% CI, 0.07-0.76; P = .02 to limbic β, 1.69; 95% CI, 1.27-2.27; P < .001 to neocortical β, 4.49; 95% CI, 3.27-6.16; P < .001 pathology). Hallucinations were more common in participants with AD and LBD (168 of 534 31.5%) compared with those with AD without LBD (152 of 704 21.6%) and those with LBD without AD (23 of 119 19.6%).
In this cohort study of 1808 brains from the US National Alzheimer Coordinating Center, patients with LBD and AD showed a higher prevalence of hallucinations compared with those with LBD without AD. Neuropsychiatric symptom criteria of apathy and disinhibition in behavioral variant frontotemporal lobar degeneration were supported in this study. In hippocampal sclerosis, the findings of increased apathy and disinhibition merit further investigation. Severity of neuropathology was associated with NPS severity, indicating that NPS may reflect underlying ADRD pathology and highlighting the importance of diagnosing and treating NPS.
A major public health concern associated with schizophrenia and psychotic disorders is the long-term disability that involves impaired cognition, lack of social support, and an inability to function ...independently in the community. A critical goal of early detection and intervention studies in psychosis is therefore to understand the factors leading to this often profound impairment.
To develop a predictive model of functional (social and role) outcome in a clinical high-risk sample for psychosis.
Prospective, naturalistic, longitudinal 3- to 5-year follow-up study.
The Recognition and Prevention Program in New York, a research clinic located in the Zucker Hillside Hospital in New York.
One hundred one treatment-seeking patients at clinical high risk for psychosis. Ninety-two (91%) were followed up prospectively for a mean (SD) of 3 (1.6) years.
Neurocognitive and clinical assessment.
The primary outcome variables were social and role functioning at the last follow-up visit.
Poor social outcome was predicted by reduced processing speed (odds ratio OR, 1.38; 95% CI, 1.050-1.823; P = .02), impaired social functioning at baseline (OR, 1.85; 95% CI, 1.258-2.732; P = .002), and total disorganized symptoms (OR, 5.06; 95% CI, 1.548-16.527; P = .007). Reduced performance on tests for verbal memory (OR, 1.74; 95% CI, 1.169-2.594; P = .006), role functioning at baseline (OR, 1.34; 95% CI, 1.053-1.711; P = .02), and motor disturbances (OR, 1.77; 95% CI, 1.060-2.969; P = .03) predicted role outcome. The areas under the curve for the social and role prediction models were 0.824 (95% CI, 0.736-0.913; P < .001) and 0.77 (95% CI, 0.68-0.87; P < .001), respectively, demonstrating a high discriminative ability. In addition, poor functional outcomes were not entirely dependent on the development of psychosis, because 40.3% and 45.5% of nonconverters at clinical high risk had poor social and role outcomes, respectively.
Results from this study support the increasing emphasis on functional decline as a critically important outcome that parallels conversion to psychosis and suggest that both psychosis and long-term functional disability are equally important targets for prevention. Reduced neurocognitive performance, functional impairments, and nonpositive attenuated symptoms at baseline were associated with an increased risk of poor functional outcomes in our sample. Poor functional outcomes were not entirely dependent on positive symptoms and the development of psychosis, further highlighting the need for intervention at this early stage of development for those who do and do not convert to a full-blown psychotic disorder.
Extreme phenotype sequencing has led to the identification of high-impact rare genetic variants for many complex disorders but has not been applied to studies of severe schizophrenia. We sequenced ...112 individuals with severe, extremely treatment-resistant schizophrenia, 218 individuals with typical schizophrenia, and 4,929 controls. We compared the burden of rare, damaging missense and loss-of-function variants between severe, extremely treatment-resistant schizophrenia, typical schizophrenia, and controls across mutation intolerant genes. Individuals with severe, extremely treatment-resistant schizophrenia had a high burden of rare loss-of-function (odds ratio, 1.91; 95% CI, 1.39 to 2.63;
= 7.8 × 10
) and damaging missense variants in intolerant genes (odds ratio, 2.90; 95% CI, 2.02 to 4.15;
= 3.2 × 10
). A total of 48.2% of individuals with severe, extremely treatment-resistant schizophrenia carried at least one rare, damaging missense or loss-of-function variant in intolerant genes compared to 29.8% of typical schizophrenia individuals (odds ratio, 2.18; 95% CI, 1.33 to 3.60;
= 1.6 × 10
) and 25.4% of controls (odds ratio, 2.74; 95% CI, 1.85 to 4.06;
= 2.9 × 10
). Restricting to genes previously associated with schizophrenia risk strengthened the enrichment with 8.9% of individuals with severe, extremely treatment-resistant schizophrenia carrying a damaging missense or loss-of-function variant compared to 2.3% of typical schizophrenia (odds ratio, 5.48; 95% CI, 1.52 to 19.74;
= 0.02) and 1.6% of controls (odds ratio, 5.82; 95% CI, 3.00 to 11.28;
= 2.6 × 10
). These results demonstrate the power of extreme phenotype case selection in psychiatric genetics and an approach to augment schizophrenia gene discovery efforts.
Whether exposure to a single general anaesthetic (GA) in early childhood causes long-term neurodevelopmental problems remains unclear.
PubMed/MEDLINE, Embase, CINAHL, Web of Science, and the Cochrane ...Library were searched from inception to October 2019. Studies evaluating neurodevelopmental outcomes and prospectively enrolling children exposed to a single GA procedure compared with unexposed children were identified. Outcomes common to at least three studies were evaluated using random-effects meta-analyses.
Full-scale intelligence quotient (FSIQ); the parentally reported Child Behavior Checklist (CBCL) total, externalising, and internalising problems scores; and Behavior Rating Inventory of Executive Function (BRIEF) scores were assessed. Of 1644 children identified, 841 who had a single exposure to GA were evaluated. The CBCL problem scores were significantly higher (i.e. worse) in exposed children: mean score difference (CBCL total: 2.3 95% confidence interval {CI}: 1.0–3.7, P=0.001; CBCL externalising: 1.9 95% CI: 0.7–3.1, P=0.003; and CBCL internalising problems: 2.2 95% CI: 0.9–3.5, P=0.001). Differences in BRIEF were not significant after multiple comparison adjustment. Full-scale intelligence quotient was not affected by GA exposure. Secondary analyses evaluating the risk of these scores exceeding predetermined clinical thresholds found that GA exposure was associated with increased risk of CBCL internalising behavioural deficit (risk ratio RR: 1.47; 95% CI: 1.08–2.02; P=0.016) and impaired BRIEF executive function (RR: 1.68; 95% CI: 1.23–2.30; P=0.001).
Combining results of studies utilising prospectively collected outcomes showed that a single GA exposure was associated with statistically significant increases in parent reports of behavioural problems with no difference in general intelligence.
Introduction
Composite scales have been advanced as primary outcomes in early stage Alzheimer's disease trials, and endorsed by the U.S. Food and Drug Administration (FDA) for pivotal trials. They ...are generally composed of several neurocognitive subscales and may include clinical and functional activity scales.
Methods
We summarized the development of 12 composite scales intended as outcomes for clinical trials and assessed their characteristics.
Results
Composite scales have been constructed from past observational and clinical trial databases by selecting components of individual neuropsychological tests previously used in clinical trials. The atheoretical approaches to combining scales into a composite scale that have often been used risk omitting clinically important measures and so may include redundant, irrelevant, or noncontributory tests. The deliberate combining of neurocognitive scales with functional activity scales provides arbitrary weightings that also may be clinically irrelevant or obscure change in a particular domain. Basic psychometric information is lacking for most of the composites.
Discussion
Although composite scales are desirable for pivotal clinical trials because they, in principle, provide for a single, primary outcome combining neurocognitive and/or functional domains, they have substantial limitations, including their common derivations, inattention to basic psychometric principles, redundancy, absence of alternate forms, and, arguably, the inclusion of functional measures in some. In effect, any currently used composite is undergoing validation through its use in a trial. The assumption that a composite, by its construction alone, is more likely than an individual measure to detect an effect from any particular drug and that the effect is more clinically relevant or valid has not been demonstrated.
To describe the presence of practice effects in persons with Alzheimer disease (AD) or mild cognitive impairment (MCI) and to evaluate how practice effects affect cognitive progression and the ...outcome of clinical trials.
Using data from a meta-database consisting of 18 studies including participants from the Alzheimer disease Cooperative Study (ADCS) and the Alzheimer Disease Neuroimaging Initiative (ADNI) with ADAS-Cog11 as the primary outcome, we defined practice effects based on the improvement in the first two ADAS-Cog11 scores and then estimated the presence of practice effects and compared the cognitive progression between participants with and without practice effects. The robustness of practice effects was investigated using CDR SB, an outcome independent the definition itself. Furthermore, we evaluated how practice effects can affect sample size estimation.
The overall percent of practice effects for AD participants was 39.0% and 53.3% for MCI participants. For AD studies, the mean change from baseline to 2 years was 12.8 points for the non-practice effects group vs 7.4 for the practice effects group; whereas for MCI studies, it was 4.1 for non-practice effects group vs 0.2 for the practice effects group. AD participants without practice effects progressed 0.9 points faster than those with practice effects over a period of 2 years in CDR-SB; whereas for MCI participants, the difference is 0.7 points. The sample sizes can be different by over 35% when estimated based on participants with/without practice effects.
Practice effects were prevalent and robust in persons with AD or MCI and affected the cognitive progression and sample size estimation. Planning of future AD or MCI clinical trials should account for practice effects to avoid underpower or considers target trials or stratification analysis based on practice effects.
PDF
