Cannabis use, oral dysbiosis, and neurological disorders.

Cannabis (marijuana) is a leafy plant that has medical, recreational, and other uses. Cannabis is socially accepted and widely used throughout the United States. Though cannabis use is increasingly gaining popularity, studies detail the deleterious effects of chronic cannabis smoking on mental health, as well as the immunosuppressive properties of cannabinoids.

The memory binding test in a longitudinal study of cognitive aging and preclinical disease.

Objective: The Memory Binding Test (MBT) shows promise in detecting early cognitive changes associated with Alzheimer's disease (AD). This study assesses the psychometric properties (i.e.

PyDesigner v1.0: A Pythonic Implementation of the DESIGNER Pipeline for Diffusion Magnetic Resonance Imaging.

PyDesigner is a Python-based software package based on the original Diffusion parameter EStImation with Gibbs and NoisE Removal (DESIGNER) pipeline (Dv1) for dMRI preprocessing and tensor estimation. This software is openly provided for non-commercial research and may not be used for clinical care. PyDesigner combines tools from FSL and MRtrix3 to perform denoising, Gibbs ringing correction, eddy current motion correction, brain masking, image smoothing, and Rician bias correction to optimize the estimation of multiple diffusion measures.

A phase I trial of accelerated intermittent theta burst rTMS for amnestic MCI.

Background: Emerging evidence suggests that repetitive transcranial magnetic stimulation (rTMS) enhances cognition in mild cognitive impairment (MCI). Accelerated intermittent theta burst stimulation (iTBS) rTMS protocols are promising as they substantially reduce burden by shortening the treatment course, but the safety, feasibility, and acceptability of iTBS have not been established in MCI.

Methods: 24 older adults with amnestic MCI (aMCI) due to possible Alzheimer's disease enrolled in a phase I trial of open-label accelerated iTBS to the left dorsolateral prefrontal cortex (8 stimulation sessions of 600 pulses of iTBS/day for 3 days).

Cannabis Perceptions and Patterns of Use Among Older Adult Cancer Survivors.

To descriptively assess cannabis perceptions and patterns of use among older adult cancer survivors in a state without a legal cannabis marketplace. This study used weighted prevalence estimates to cross-sectionally describe cannabis perceptions and patterns of use among older (65+) adults ( = 524) in a National Cancer Institute-designated center in a state without legal cannabis access. Half (46) had ever used cannabis (18% following diagnosis and 10 currently).

Gray matter and episodic memory associations with olfaction in middle-aged to older adults.

Background: Age-related declines in olfaction contribute to low quality of life and appear to occur with declines in cognitive function, including diminished episodic memory. We tested the hypothesis that low gray matter volume within cortical regions that support olfaction and episodic memory can explain age-related differences in olfactory and episodic memory functions.

Methods: T1-weighted images, Sniffin' Sticks olfactory measures, and the NIH Toolbox-Cognition Battery were administered to 131 middle-aged to older adults (50-86 years; 66% female).

Functional Network Alterations Associated with Cognition in Pre-Clinical Alzheimer's Disease.

Accumulation of cerebral amyloid-β (Aβ) is a risk factor for cognitive decline and defining feature of Alzheimer's disease (AD). Aβ is implicated in brain network disruption, but the extent to which these changes correspond with observable cognitive deficits in pre-clinical AD has not been tested. This study utilized individual-specific functional parcellations to sensitively evaluate the relationship between network connectivity and cognition in adults with and without Aβ deposition.

Optimized rectification of fiber orientation density function with background threshold.

Purpose: To describe an optimized fiber orientation density function (fODF) rectification procedure that removes negative values and absorbs all features below a specified threshold into a constant background.

Theory And Methods: The fODF for a white matter imaging voxel describes the angular density of axons. Because of signal noise and Gibbs ringing, fODFs estimated with diffusion MRI may take on unphysical negative values in some directions and contain spurious peaks.

Fiber Ball White Matter Modeling Reveals Microstructural Alterations in Healthy Brain Aging.

Age-related white matter degeneration is characterized by myelin breakdown and neuronal fiber loss that preferentially occur in regions that myelinate later in development. Conventional diffusion MRI (dMRI) has demonstrated age-related increases in diffusivity but provide limited information regarding the tissue-specific changes driving these effects. A recently developed dMRI biophysical modeling technique, Fiber Ball White Matter (FBWM) modeling, offers enhanced biological interpretability by estimating microstructural properties specific to the intra-axonal and extra-axonal spaces.

Unsupervised Clustering of Olfactory Phenotypes.

Background: Current clinical classifications of olfactory function are based primarily upon a percentage of correct answers in olfactory identification testing. This simple classification provides little insight into etiologies of olfactory loss, associated comorbidities, or impact on the quality of life (QOL).

Methods: Community-based subjects underwent olfactory psychophysical testing using Sniffin Sticks to measure threshold (T), discrimination (D), and identification (I).

Neurodegeneration of the Globus Pallidus Internus as a Neural Correlate to Dopa-Response in Freezing of Gait.

Background: Background: Parkinson's disease (PD) patients who develop freezing of gait (FOG) have reduced mobility and independence. While some patients experience improvement in their FOG symptoms with dopaminergic therapies, a subset of patients have little to no response. To date, it is unknown what changes in brain structure underlie dopa-response and whether this can be measured using neuroimaging approaches.

Greater Diffusion Restriction in White Matter in Preclinical Alzheimer Disease.

Objective: The Alzheimer's continuum is biologically defined by beta-amyloid deposition, which at the earliest stages is superimposed upon white matter degeneration in aging. However, the extent to which these co-occurring changes is characterized is relatively underexplored. The goal of this study was to use diffusional kurtosis imaging (DKI) and biophysical modeling to detect and describe amyloid-related white matter changes in preclinical Alzheimer disease.

Comparison of conventional and actuarial neuropsychological criteria for mild cognitive impairment in a clinical setting.

Introduction: Evidence-based practice in neuropsychology involves the use of validated tests, cutoff scores, and interpretive algorithms to identify clinically significant cognitive deficits. Recently, actuarial neuropsychological criteria (ANP) for identifying mild cognitive impairment were developed, demonstrating improved criterion validity and temporal stability compared to conventional criteria (CNP). However, benefits of the ANP criteria have not been investigated in non-research, clinical settings with varied etiologies, severities, and comorbidities.

A Bayesian hierarchical change point model with parameter constraints.

Alzheimer's disease is the leading cause of dementia among adults aged 65 or above. Alzheimer's disease is characterized by a change point signaling a sudden and prolonged acceleration in cognitive decline. The timing of this change point is of clinical interest because it can be used to establish optimal treatment regimens and schedules.

Brain Reserve in a Case of Cognitive Resilience to Severe Leukoaraiosis.

Objective: Leukoaraiosis, or white matter rarefaction, is a common imaging finding in aging and is presumed to reflect vascular disease. When severe in presentation, potential congenital or acquired etiologies are investigated, prompting referral for neuropsychological evaluation in addition to neuroimaging. T2-weighted imaging is the most common magnetic resonance imaging (MRI) approach to identifying white matter disease.

A Systematic Review of the Neurocognitive Effects of Cannabis Use in Older Adults.

Purpose Of Review: Older adults currently represent the fastest growing demographic of cannabis users, yet few studies have investigated the effects of cannabis use on cognitive functioning in aging. We conducted a systematic review of the recent literature examining cognitive outcomes associated with cannabis use in older adults, with and without neurocognitive disorders, to clarify the potential neuroprotective benefits and risks of cognitive decline in this population.

Recent Findings: We identified 26 studies examining cognitive outcomes associated with medical and recreational use of cannabis in healthy aging, dementia, Parkinson's disease, multiple sclerosis, HIV, and pain populations.

Self-reported cognition and marijuana use in older adults: Results from the national epidemiologic survey on alcohol and related conditions-III.

Marijuana use among older adults is on an unprecedented rise, yet little is known about its effects on cognition in this population where, due to advanced age, risk for cognitive decline is high. Thus, we investigated whether marijuana use and use characteristics were associated with self-reported cognition among older adults ages ≥ 50 years using the National Epidemiologic Survey on Alcohol and Related Conditions-III. Respondents either had never used marijuana ("never": n = 10,976), used but not in the past 12 months ("former": n = 2990), or used in the past 12 months ("current": n = 712).

Psychometric Properties of the NIH Toolbox Cognition Battery in Healthy Older Adults: Reliability, Validity, and Agreement with Standard Neuropsychological Tests.

Objective: Few independent studies have examined the psychometric properties of the NIH Toolbox Cognition Battery (NIHTB-CB) in older adults, despite growing interest in its use for clinical purposes. In this paper we report the test-retest reliability and construct validity of the NIHTB-CB, as well as its agreement or concordance with traditional neuropsychological tests of the same construct to determine whether tests could be used interchangeably.

Methods: Sixty-one cognitively healthy adults ages 60-80 completed "gold standard" (GS) neuropsychological tests, NIHTB-CB, and brain MRI.

Modeling white matter tract integrity in aging with diffusional kurtosis imaging.

Myelin breakdown and neural fiber loss occur in aging. This study used white matter tract integrity metrics derived from biophysical modeling using Diffusional Kurtosis Imaging to assess loss of myelin (i.e.

Voices of leadership: wisdom from women leaders in neuropsychology.

Objective: Inspired by panel discussions at various neuropsychology conferences, the aim of this paper is to share wisdom that women in neuropsychology acquired from their leadership experiences.

Method: We identified 46 women leaders in governance and academic research through reviews of organizational websites and journal editorial boards, and requested their response to brief questions via email. Twenty-one leaders provided responses to three questions formulated by the authors.

Women's leadership in neuropsychology: historical perspectives, present trends, and future directions.

Objective: Although psychology has become a female-dominated field, this pattern of gender representation has not held true within the specialty of neuropsychology. In recent years more women have been pursuing careers in neuropsychology, and while the balance of male and female neuropsychologists as a whole has shifted, it is unclear whether the gender composition of leadership has also changed. Our goal was to survey various neuropsychological organizations, training programs, editorial boards, and organizations granting board certification to determine the current gender composition of leadership positions within neuropsychology.

Association between Cholesterol Exposure and Neuropathological Findings: The ACT Study.

We characterized the relationship between late life cholesterol exposure and neuropathological outcomes in a community-based, older adult cohort. Adult Changes in Thought (ACT) is a cohort study that enrolls consenting, randomly selected, non-demented people aged ≥65 from a healthcare delivery system. We used late life HDL and total cholesterol lab values from Group Health computerized records, and calculated HDL and non-HDL levels.

Jump, Hop, or Skip: Modeling Practice Effects in Studies of Determinants of Cognitive Change in Older Adults.

Improvements in cognitive test scores upon repeated assessment due to practice effects (PEs) are well documented, but there is no empirical evidence on whether alternative specifications of PEs result in different estimated associations between exposure and rate of cognitive change. If alternative PE specifications produce different estimates of association between an exposure and rate of cognitive change, this would be a challenge for nearly all longitudinal research on determinants of cognitive aging. Using data from 3 cohort studies-the Three-City Study-Dijon (Dijon, France, 1999-2010), the Normative Aging Study (Greater Boston, Massachusetts, 1993-2007), and the Washington Heights-Inwood Community Aging Project (New York, New York, 1999-2012)-for 2 exposures (diabetes and depression) and 3 cognitive outcomes, we compared results from longitudinal models using alternative PE specifications: no PEs; use of an indicator for the first cognitive visit; number of prior testing occasions; and square root of the number of prior testing occasions.

Predictors of Retest Effects in a Longitudinal Study of Cognitive Aging in a Diverse Community-Based Sample.

Better performance due to repeated testing can bias long-term trajectories of cognitive aging and correlates of change. We examined whether retest effects differ as a function of individual differences pertinent to cognitive aging: race/ethnicity, age, sex, language, years of education, literacy, and dementia risk factors including apolipoprotein E ε4 status, baseline cognitive performance, and cardiovascular risk. We used data from the Washington Heights-Inwood Columbia Aging Project, a community-based cohort of older adults (n=4073).