More Similar than Different: Memory, Executive Functions, Cortical Thickness, and Glucose Metabolism in Biomarker-Positive Alzheimer's Disease and Behavioral Variant Frontotemporal Dementia

Background

Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) are typically associated with very different clinical and neuroanatomical presentations; however, there is increasing recognition of similarities.

Objective

To examine memory and executive functions, as well as cortical thickness, and glucose metabolism in AD and bvFTD signature brain regions.

Methods

We compared differences in a group of biomarker-defined participants with Alzheimer's disease and a group of clinically diagnosed participants with bvFTD. These groups were also contrasted with healthy controls (HC).

Results

As expected, memory functions were generally more impaired in AD, followed by bvFTD, and both clinical groups performed more poorly than the HC group. Executive function measures were similar in AD compared to bvFTD for motor sequencing and go/no-go, but bvFTD had more difficulty with a set shifting task. Participants with AD showed thinner cortex and lower glucose metabolism in the angular gyrus compared to bvFTD. Participants with bvFTD had thinner cortex in the insula and temporal pole relative to AD and healthy controls, but otherwise the two clinical groups were similar for other frontal and temporal signature regions.

Conclusions

Overall, the results of this study highlight more similarities than differences between AD and bvFTD in terms of cognitive functions, cortical thickness, and glucose metabolism. Further research is needed to better understand the mechanisms mediating this overlap and how these relationships evolve longitudinally.

Ultrasound Blood-Brain Barrier Opening and Aducanumab in Alzheimer's Disease

Antiamyloid antibodies have been used to reduce cerebral amyloid-beta (Aβ) load in patients with Alzheimer's disease. We applied focused ultrasound with each of six monthly aducanumab infusions to temporarily open the blood-brain barrier with the goal of enhancing amyloid removal in selected brain regions in three participants over a period of 6 months. The reduction in the level of Aβ was numerically greater in regions treated with focused ultrasound than in the homologous regions in the contralateral hemisphere that were not treated with focused ultrasound, as measured by fluorine-18 florbetaben positron-emission tomography. Cognitive tests and safety evaluations were conducted over a period of 30 to 180 days after treatment. (Funded by the Harry T. Mangurian, Jr. Foundation and the West Virginia University Rockefeller Neuroscience Institute.).

Developing, implementing, and evaluating the visiting Neighbors' program in rural Appalachia: A quality improvement protocol

INTRODUCTION

Older adults living alone in rural areas frequently experience health declines, social isolation, and limited access to services. To address these challenges, our medical academic university supported a quality improvement project for developing and evaluating the Visiting Neighbors program in two rural Appalachian counties. Our Visiting Neighbors program trained local volunteers to visit and guide rural older adults in healthy activities. These age-appropriate activities (Mingle, Manage, and Move- 3M's) were designed to improve the functional health of older adults. The program includes four in-home visits and four follow-up telephone calls across three months.

PURPOSE

The purpose of this paper was to describe the 3M's Visiting Neighbors protocol steps guiding the quality improvement procedures relating to program development, implementation, and evaluation.

METHODS AND MATERIALS

This Visiting Neighbors study used a single-group exploratory quality improvement design. This program was tested using quality improvement standards, including collecting participant questionnaires and visit observations.

RESULTS

Older adults (> 65 years) living alone (N = 30) participants were female (79%) with a mean age of 82.96 (SD = 7.87) years. Volunteer visitor participants (N = 10) were older adult females. Two volunteer visitors implemented each visit, guided by the 3M's activities manual. All visits were verified as being consistently delivered (fidelity). Enrollment and retention data found the program was feasible to conduct. The older adult participants' total program helpfulness ratings (1 to 5) were high (M = 51.27, SD = 3.77). All volunteer visitor's program helpfulness ratings were also high (M = 51.78, SD = 3.73).

DISCUSSION

The Visiting Neighbors program consistently engaged older Appalachian adults living alone in the 3M's activities. The feasibility and fidelity of the 3M's home visits were verified. The quality improvement processes included engaging the expert advisory committee and rural county stakeholders to ensure the quality of the program development, implementation, and evaluation.

Safety and feasibility clinical trial of nucleus accumbens deep brain stimulation for treatment-refractory opioid use disorder

OBJECTIVE

There were more than 107,000 drug overdose deaths in the US in 2021, the most ever recorded. Despite advances in behavioral and pharmacological treatments, over 50% of those receiving treatment for opioid use disorder (OUD) experience drug use recurrence (relapse). Given the prevalence of OUD and other substance use disorders (SUDs), the high rate of drug use recurrence, and the number of drug overdose deaths, novel treatment strategies are desperately needed. The objective of this study was to evaluate the safety and feasibility of deep brain stimulation (DBS) targeting the nucleus accumbens (NAc)/ventral capsule (VC) and potential impact on outcomes in individuals with treatment-refractory OUD.

METHODS

A prospective, open-label, single-arm study was conducted among participants with longstanding treatment-refractory OUD (along with other co-occurring SUDs) who underwent DBS in the NAc/VC. The primary study endpoint was safety; secondary/exploratory outcomes included opioid and other substance use, substance craving, and emotional symptoms throughout follow-up and 18FDG-PET neuroimaging.

RESULTS

Four male participants were enrolled and all tolerated DBS surgery well with no serious adverse events (AEs) and no device- or stimulation-related AEs. Two participants sustained complete substance abstinence for > 1150 and > 520 days, respectively, with significant post-DBS reductions in substance craving, anxiety, and depression. One participant experienced post-DBS drug use recurrences with reduced frequency and severity. The DBS system was explanted in one participant due to noncompliance with treatment requirements and the study protocol. 18FDG-PET neuroimaging revealed increased glucose metabolism in the frontal regions for the participants with sustained abstinence only.

CONCLUSIONS

DBS of the NAc/VC was safe, feasible, and can potentially reduce substance use, craving, and emotional symptoms in those with treatment-refractory OUD. A randomized, sham-controlled trial in a larger cohort of patients is being initiated.

Low-intensity focused ultrasound targeting the nucleus accumbens as a potential treatment for substance use disorder: safety and feasibility clinical trial

Introduction

While current treatments for substance use disorder (SUD) are beneficial, success rates remain low and treatment outcomes are complicated by co-occurring SUDs, many of which are without available medication treatments. Research involving neuromodulation for SUD has recently gained momentum. This study evaluated two doses (60 and 90 W) of Low Intensity Focused Ultrasound (LIFU), targeting the bilateral nucleus accumbens (NAc), in individuals with SUD.

Methods

Four participants (three male), who were receiving comprehensive outpatient treatment for opioid use disorder at the time of enrollment and who also had a history of excessive non-opioid substance use, completed this pilot study. After confirming eligibility, these participants received 10 min sham LIFU followed by 20 min active LIFU (10 min to left then right NAc). Outcomes were the safety, tolerability, and feasibility during the LIFU procedure and throughout the 90-day follow-up. Outcomes also included the impact of LIFU on cue-induced substance craving, assessed via Visual Analog Scale (VAS), both acutely (pre-, during and post-procedure) and during the 90-day follow-up. Daily craving ratings (without cues) were also obtained for one-week prior to and one-week following LIFU.

Results

Both LIFU doses were safe and well-tolerated based on reported adverse events and MRI scans revealed no structural changes (0 min, 24 h, and 1-week post-procedure). For the two participants receiving "enhanced" (90 W) LIFU, VAS craving ratings revealed active LIFU attenuated craving for participants' primary substances of choice relative to sham sonication. For these participants, reductions were also noted in daily VAS craving ratings (0 = no craving; 10 = most craving ever) across the week following LIFU relative to pre-LIFU; Participant #3 pre- vs. post-LIFU: opioids (3.6 ± 0.6 vs. 1.9 ± 0.4), heroin (4.2 ± 0.8 vs. 1.9 ± 0.4), methamphetamine (3.2 ± 0.4 vs. 0.0 ± 0.0), cocaine (2.4 ± 0.6 vs. 0.0 ± 0.0), benzodiazepines (2.8 ± 0.5 vs. 0.0 ± 0.0), alcohol (6.0 ± 0.7 vs. 2.7 ± 0.8), and nicotine (5.6 ± 1.5 vs. 3.1 ± 0.7); Participant #4: alcohol (3.5 ± 1.3 vs. 0.0 ± 0.0) and nicotine (5.0 ± 1.8 vs. 1.2 ± 0.8) (all p's < 0.05). Furthermore, relative to screening, longitudinal reductions in cue-induced craving for several substances persisted during the 90-day post-LIFU follow-up evaluation for all participants.

Discussion

In conclusion, LIFU targeting the NAc was safe and acutely reduced substance craving during the LIFU procedure, and potentially had longer-term impact on craving reductions. While early observations are promising, NAc LIFU requires further investigation in a controlled trial to assess the impact on substance craving and ultimately substance use and relapse.

Surface-based correlates of cognition along the Alzheimer's continuum in a memory clinic population

Composite cognitive measures in large-scale studies with biomarker data for amyloid and tau have been widely used to characterize Alzheimer's disease (AD). However, little is known about how the findings from these studies translate to memory clinic populations without biomarker data, using single measures of cognition. Additionally, most studies have utilized voxel-based morphometry or limited surface-based morphometry such as cortical thickness, to measure the neurodegeneration associated with cognitive deficits. In this study, we aimed to replicate and extend the biomarker, composite study relationships using expanded surface-based morphometry and single measures of cognition in a memory clinic population. We examined 271 clinically diagnosed symptomatic individuals with mild cognitive impairment (N = 93) and Alzheimer's disease dementia (N = 178), as well as healthy controls (N = 29). Surface-based morphometry measures included cortical thickness, sulcal depth, and gyrification index within the "signature areas" of Alzheimer's disease. The cognitive variables pertained to hallmark features of Alzheimer's disease including verbal learning, verbal memory retention, and language, as well as executive function. The results demonstrated that verbal learning, language, and executive function correlated with the cortical thickness of the temporal, frontal, and parietal areas. Verbal memory retention was correlated to the thickness of temporal regions and gyrification of the inferior temporal gyrus. Language was related to the temporal regions and the supramarginal gyrus' sulcal depth and gyrification index. Executive function was correlated with the medial temporal gyrus and supramarginal gyrus sulcal depth, and the gyrification index of temporal regions and supramarginal gyrus, but not with the frontal areas. Predictions of each of these cognitive measures were dependent on a combination of structures and each of the morphometry measurements, and often included medial temporal gyrus thickness and sulcal depth. Overall, the results demonstrated that the relationships between cortical thinning and cognition are widespread and can be observed using single measures of cognition in a clinically diagnosed AD population. The utility of sulcal depth and gyrification index measures may be more focal to certain brain areas and cognitive measures. The relative importance of temporal, frontal, and parietal regions in verbal learning, language, and executive function, but not verbal memory retention, was replicated in this clinic cohort.

Procedural learning and retention relative to explicit learning and retention in mild cognitive impairment and Alzheimer's disease using a modification of the trail making test

Amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) dementia are characterized by pathological changes to the medial temporal lobes, resulting in explicit learning and retention reductions. Studies demonstrate that implicit/procedural memory processes are relatively intact in these populations, supporting different anatomical substrates for differing memory systems. This study examined differences between explicit and procedural learning and retention in individuals with aMCI and AD dementia relative to matched healthy controls. We also examined anatomical substrates using volumetric MRI. Results revealed expected difficulties with explicit learning and retention in individuals with aMCI and AD with relatively preserved procedural memory. Explicit verbal retention was associated with medial temporal cortex volumes. However, procedural retention was not related to medial temporal or basal ganglia volumes. Overall, this study confirms the dissociation between explicit relative to procedural learning and retention in aMCI and AD dementia and supports differing anatomical substrates.

Frontal and temporal lobe correlates of verbal learning and memory in aMCI and suspected Alzheimer's disease dementia

Alzheimer's disease is primarily known for deficits in learning and retaining new information. This has long been associated with pathological changes in the mesial temporal lobes. The role of the frontal lobes in memory in Alzheimer's disease is less well understood. In this study, we examined the role of the frontal lobes in learning, recognition, and retention of new verbal information, as well as the presence of specific errors (i.e., intrusions and false-positive errors). Participants included one hundred sixty-seven patients clinically diagnosed with amnestic mild cognitive impairment or suspected Alzheimer's disease dementia who were administered the California Verbal Learning Test and completed high-resolution MRI. We confirmed the role of the mesial temporal lobes in learning and retention, including the volumes of the hippocampus, entorhinal cortex, and parahippocampal gyrus. In addition, false-positive errors were associated with all volumes of the mesial temporal lobes and widespread areas within the frontal lobes. Errors of intrusion were related to the supplementary motor cortex and hippocampus. Most importantly, the mesial temporal lobes interacted with the frontal lobes for learning, recognition, and memory errors. Lower volumes in both regions explained more performance variance than any single structure. This study supports the interaction of the frontal lobes with the temporal lobes in many aspects of memory in Alzheimer's disease.

Ultrasound-mediated blood-brain barrier opening uncovers an intracerebral perivenous fluid network in persons with Alzheimer's disease

BACKGROUND

Focused ultrasound (FUS)-mediated blood-brain barrier (BBB) opening is under investigation as a therapeutic modality for neurodegeneration, yet its effects in humans are incompletely understood. Here, we assessed physiologic responses to FUS administered in multifocal brain sites of persons with Alzheimer's disease (AD).

METHODS

At a tertiary neuroscience institute, eight participants with AD (mean age 65, 38% F) enrolled in a phase 2 clinical trial underwent three successive targeted BBB opening procedures at 2 week intervals using a 220 kHz FUS transducer in combination with systemically administered microbubbles. In all, 77 treatment sites were evaluated and encompassed hippocampal, frontal, and parietal brain regions. Post-FUS imaging changes, including susceptibility effects and spatiotemporal gadolinium-based contrast agent enhancement patterns, were analyzed using serial 3.0-Tesla MRI.

RESULTS

Post-FUS MRI revealed expected intraparenchymal contrast extravasation due to BBB opening at all targeted brain sites. Immediately upon BBB opening, hyperconcentration of intravenously-administered contrast tracer was consistently observed around intracerebral veins. Following BBB closure, within 24-48 h of FUS intervention, permeabilization of intraparenchymal veins was observed and persisted for up to one week. Notably, extraparenchymal meningeal venous permeabilization and associated CSF effusions were also elicited and persisted up to 11 days post FUS treatment, prior to complete spontaneous resolution in all participants. Mild susceptibility effects were detected, however no overt intracranial hemorrhage or other serious adverse effects occurred in any participant.

CONCLUSIONS

FUS-mediated BBB opening is safely and reproducibly achieved in multifocal brain regions of persons with AD. Post-FUS tracer enhancement phenomena suggest the existence of a brain-wide perivenous fluid efflux pathway in humans and demonstrate reactive physiological changes involving these conduit spaces in the delayed, subacute phase following BBB disruption. The delayed reactive venous and perivenous changes are consistent with a dynamic, zonal exudative response to upstream capillary manipulation. Further preclinical and clinical investigations of these FUS-related imaging phenomena and of intracerebral perivenous compartment changes are needed to elucidate physiology of this pathway as well as biological effects of FUS administered with and without adjuvant neurotherapeutics.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03671889, registered 9/14/2018.

Stroke Lesion Volume and Injury to Motor Cortex Output Determines Extent of Contralesional Motor Cortex Reorganization

BACKGROUND

After stroke, increases in contralesional primary motor cortex (M1_CL) activity and excitability have been reported. In pre-clinical studies, M1_CL reorganization is related to the extent of ipsilesional M1 (M1_IL) injury, but this has yet to be tested clinically.

OBJECTIVES

We tested the hypothesis that the extent of damage to the ipsilesional M1 and/or its corticospinal tract (CST) determines the magnitude of M1_CL reorganization and its relationship to affected hand function in humans recovering from stroke.

METHODS

Thirty-five participants with a single subacute ischemic stroke affecting M1 or CST and hand paresis underwent MRI scans of the brain to measure lesion volume and CST lesion load. Transcranial magnetic stimulation (TMS) of M1_IL was used to determine the presence of an electromyographic response (motor evoked potential (MEP+ and MEP-)). M1_CL reorganization was determined by TMS applied to M1_CL at increasing intensities. Hand function was quantified with the Jebsen Taylor Hand Function Test.

RESULTS

The extent of M1_CL reorganization was related to greater lesion volume in the MEP- group, but not in the MEP+ group. Greater M1_CL reorganization was associated with more impaired hand function in MEP- but not MEP+ participants. Absence of an MEP (MEP-), larger lesion volumes and higher lesion loads in CST, particularly in CST fibers originating in M1 were associated with greater impairment of hand function.

CONCLUSIONS

In the subacute post-stroke period, stroke volume and M1_IL output determine the extent of M1_CL reorganization and its relationship to affected hand function, consistent with pre-clinical evidence.ClinicalTrials.gov Identifier: NCT02544503.

Focused ultrasound–mediated blood-brain barrier opening in Alzheimer’s disease: long-term safety, imaging, and cognitive outcomes

OBJECTIVE

MRI-guided low-intensity focused ultrasound (FUS) has been shown to reversibly open the blood-brain barrier (BBB), with the potential to deliver therapeutic agents noninvasively to target brain regions in patients with Alzheimer’s disease (AD) and other neurodegenerative conditions. Previously, the authors reported the short-term safety and feasibility of FUS BBB opening of the hippocampus and entorhinal cortex (EC) in patients with AD. Given the need to treat larger brain regions beyond the hippocampus and EC, brain volumes and locations treated with FUS have now expanded. To evaluate any potential adverse consequences of BBB opening on disease progression, the authors report safety, imaging, and clinical outcomes among participants with mild AD at 6–12 months after FUS treatment targeted to the hippocampus, frontal lobe, and parietal lobe.

METHODS

In this open-label trial, participants with mild AD underwent MRI-guided FUS sonication to open the BBB in β-amyloid positive regions of the hippocampus, EC, frontal lobe, and parietal lobe. Participants underwent 3 separate FUS treatment sessions performed 2 weeks apart. Outcome assessments included safety, imaging, neurological, cognitive, and florbetaben β-amyloid PET.

RESULTS

Ten participants (range 55–76 years old) completed 30 separate FUS treatments at 2 participating institutions, with 6–12 months of follow-up. All participants had immediate BBB opening after FUS and BBB closure within 24–48 hours. All FUS treatments were well tolerated, with no serious adverse events related to the procedure. All 10 participants had a minimum of 6 months of follow-up, and 7 participants had a follow-up out to 1 year. Changes in the Alzheimer’s Disease Assessment Scale–cognitive and Mini-Mental State Examination scores were comparable to those in controls from the Alzheimer’s Disease Neuroimaging Initiative. PET scans demonstrated an average β-amyloid plaque of 14% in the Centiloid scale in the FUS-treated regions.

CONCLUSIONS

This study is the largest cohort of participants with mild AD who received FUS treatment, and has the longest follow-up to date. Safety was demonstrated in conjunction with reversible and repeated BBB opening in multiple cortical and deep brain locations, with a concomitant reduction of β-amyloid. There was no apparent cognitive worsening beyond expectations up to 1 year after FUS treatment, suggesting that the BBB opening treatment in multiple brain regions did not adversely influence AD progression. Further studies are needed to determine the clinical significance of these findings. FUS offers a unique opportunity to decrease amyloid plaque burden as well as the potential to deliver targeted therapeutics to multiple brain regions in patients with neurodegenerative disorders.

The Appalachia Mind Health Initiative (AMHI): a pragmatic randomized clinical trial of adjunctive internet-based cognitive behavior therapy for treating major depressive disorder among primary care patients

BACKGROUND

Major depressive disorder (MDD) is a leading cause of disease morbidity. Combined treatment with antidepressant medication (ADM) plus psychotherapy yields a much higher MDD remission rate than ADM only. But 77% of US MDD patients are nonetheless treated with ADM only despite strong patient preferences for psychotherapy. This mismatch is due at least in part to a combination of cost considerations and limited availability of psychotherapists, although stigma and reluctance of PCPs to refer patients for psychotherapy are also involved. Internet-based cognitive behaviorial therapy (i-CBT) addresses all of these problems.

METHODS

Enrolled patients (n = 3360) will be those who are beginning ADM-only treatment of MDD in primary care facilities throughout West Virginia, one of the poorest and most rural states in the country. Participating treatment providers and study staff at West Virginia University School of Medicine (WVU) will recruit patients and, after obtaining informed consent, administer a baseline self-report questionnaire (SRQ) and then randomize patients to 1 of 3 treatment arms with equal allocation: ADM only, ADM + self-guided i-CBT, and ADM + guided i-CBT. Follow-up SRQs will be administered 2, 4, 8, 13, 16, 26, 39, and 52 weeks after randomization. The trial has two primary objectives: to evaluate aggregate comparative treatment effects across the 3 arms and to estimate heterogeneity of treatment effects (HTE). The primary outcome will be episode remission based on a modified version of the patient-centered Remission from Depression Questionnaire (RDQ). The sample was powered to detect predictors of HTE that would increase the proportional remission rate by 20% by optimally assigning individuals as opposed to randomly assigning them into three treatment groups of equal size. Aggregate comparative treatment effects will be estimated using intent-to-treat analysis methods. Cumulative inverse probability weights will be used to deal with loss to follow-up. A wide range of self-report predictors of MDD heterogeneity of treatment effects based on previous studies will be included in the baseline SRQ. A state-of-the-art ensemble machine learning method will be used to estimate HTE.

DISCUSSION

The study is innovative in using a rich baseline assessment and in having a sample large enough to carry out a well-powered analysis of heterogeneity of treatment effects. We anticipate finding that self-guided and guided i-CBT will both improve outcomes compared to ADM only. We also anticipate finding that the comparative advantages of adding i-CBT to ADM will vary significantly across patients. We hope to develop a stable individualized treatment rule that will allow patients and treatment providers to improve aggregate treatment outcomes by deciding collaboratively when ADM treatment should be augmented with i-CBT.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04120285 . Registered on October 19, 2019.

Evaluating the Abnormality of Bilateral Motor Cortex Activity in Subacute Stroke Patients Executing a Unimanual Motor Task With Increasing Demand on Precision

Abnormal contralesional M1 activity is consistently reported in patients with compromised upper limb and hand function after stroke. The underlying mechanisms and functional implications of this activity are not clear, which hampers the development of treatment strategies targeting this brain area. The goal of the present study was to determine the extent to which contralesional M1 activity can be explained by the demand of a motor task, given recent evidence for increasing ipsilateral M1 activity with increasing demand in healthy age-matched controls. We hypothesized that higher activity in contralesional M1 is related to greater demand on precision in a hand motor task. fMRI data were collected from 19 patients with ischemic stroke affecting hand function in the subacute recovery phase and 31 healthy, right-handed, age-matched controls. The hand motor task was designed to parametrically modulate the demand on movement precision. Electromyography data confirmed strictly unilateral task performance by all participants. Patients showed significant impairment relative to controls in their ability to perform the task in the fMRI scanner. However, patients and controls responded similarly to an increase in demand for precision, with better performance for larger targets and poorer performance for smaller targets. Patients did not show evidence of elevated ipsilesional or contralesional M1 blood oxygenation level-dependent (BOLD) activation relative to healthy controls and mean BOLD activation levels were not elevated for patients with poorer performance relative to patients with better task performance. While both patients and healthy controls showed demand-dependent increases in BOLD activation in both ipsilesional/contralateral and contralesional/ipsilateral hemispheres, patients with stroke were less likely to show evidence of a linear relationship between the demand on precision and BOLD activation in contralesional M1 than healthy controls. Taken together, the findings suggest that task demand affects the BOLD response in contralesional M1 in patients with stroke, though perhaps less strongly than in healthy controls. This has implications for the interpretation of reported abnormal bilateral M1 activation in patients with stroke because in addition to contralesional M1 reorganization processes it could be partially related to a response to the relatively higher demand of a motor task when completed by patients rather than by healthy controls.

Deep brain stimulation of the nucleus accumbens/ventral capsule for severe and intractable opioid and benzodiazepine use disorder

Given high relapse rates and the prevalence of overdose deaths, novel treatments for substance use disorder (SUD) are desperately needed for those who are treatment refractory. The objective of this study was to evaluate the safety of deep brain stimulation (DBS) for SUD and the effects of DBS on substance use, substance craving, emotional symptoms, and frontal/executive functions. DBS electrodes were implanted bilaterally within the Nucleus Accumbens/Ventral anterior internal capsule (NAc/VC) of a man in his early 30s with >10-year history of severe treatment refractory opioid and benzodiazepine use disorders. DBS of the NAc/VC was found to be safe with no serious adverse events noted and the participant remained abstinent and engaged in comprehensive treatment at the 12-week endpoint (and 12-month extended follow-up). Using a 0-100 visual analog scale, substance cravings decreased post-DBS implantation; most substantially in benzodiazepine craving following the final DBS titration (1.0 ± 2.2) compared to baseline (53.4 ± 29.5; p < .001). A trend toward improvement in frontal/executive function was observed on the balloon analog risk task performance following the final titration (217.7 ± 76.2) compared to baseline (131.3 ± 28.1, p = .066). FDG PET demonstrated an increase in glucose metabolism in the dorsolateral prefrontal and medial premotor cortices at the 12-week endpoint compared to post-surgery/pre-DBS titration. Heart Rate Variability (HRV) improved following the final titration (rMSSD = 56.0 ± 11.7) compared to baseline (19.2 ± 8.2; p < .001). In a participant with severe, treatment refractory opioid and benzodiazepine use disorder, DBS of the NAc/VC was safe, reduced substance use and craving, and improved frontal and executive functions. Confirmation of these findings with future studies is needed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

High prevalence of co-occurring substance use in individuals with opioid use disorder

OBJECTIVE

Funding to address the current opioid epidemic has focused on treatment of opioid use disorder (OUD); however, rates of other substance use disorders (SUDs) remain high and non-opioid related overdoses account for nearly 30% of overdoses. This study assesses the prevalence of co-occurring substance use in West Virginia (WV) to inform treatment strategies. The objective of this study was to assess the prevalence of, and demographic and clinical characteristics (including age, gender, hepatitis C virus (HCV) status) associated with, co-occurring substance use among patients with OUD in WV.

METHODS

This retrospective study utilized the West Virginia Clinical and Translation Science Institute Integrated Data Repository, comprised of Electronic Medical Record (EMR) data from West Virginia University Medicine. Deidentified data were extracted from inpatient psychiatric admissions and emergency department (ED) healthcare encounters between 2009 and 2018. Eligible patients were those with OUD who had a positive urine toxicology screen for opioids at the time of their initial encounter with the healthcare system. Extracted data included results of comprehensive urine toxicology testing during the study timeframe.

RESULTS

3,127 patients met the inclusion criteria of whom 72.8% had co-occurring substance use. Of those who were positive for opioids and at least one additional substance, benzodiazepines were the most common co-occurring substances (57.4% of patients yielded a positive urine toxicology screen for both substances), followed by cannabis (53.1%), cocaine (24.5%) and amphetamine (21.6%). Individuals who used co-occurring substances were younger than those who were positive for opioids alone (P < 0.001). There was a higher prevalence of individuals who used co-occurring substances that were HCV positive in comparison to those who used opioids alone (P < 0.001). There were limited gender differences noted between individuals who used co-occurring substances and those who used opioids alone. Among ED admissions who were positive for opioids, 264 were diagnosed with substance toxicity/overdose, 78.4% of whom had co-occurring substance use (benzodiazepines: 65.2%; cannabis: 44.4%; cocaine: 28.5%; amphetamine: 15.5%). Across the 10-year timespan, the greatest increase for the entire sample was in the rate of co-occurring amphetamine and opioid use (from 12.6% in 2014 to 47.8% in 2018).

CONCLUSIONS

These data demonstrate that the current substance use epidemic extends well beyond opioids, suggesting that comprehensive SUD prevention and treatment strategies are needed, especially for those substances which do not yet have any evidence-based and/or medication treatments available.

Blood-Brain Barrier Opening with MRI-guided Focused Ultrasound Elicits Meningeal Venous Permeability in Humans with Early Alzheimer Disease

Background Opening of the blood-brain barrier (BBB) induced with MRI-guided focused ultrasound has been shown in experimental animal models to reduce amyloid-β plaque burden, improve memory performance, and facilitate delivery of therapeutic agents to the brain. However, physiologic effects of this procedure in humans with Alzheimer disease (AD) require further investigation. Purpose To assess imaging effects of focused ultrasound-induced BBB opening in the hippocampus of human participants with early AD and to evaluate fluid flow patterns after BBB opening by using serial contrast-enhanced MRI. Materials and Methods Study participants with early AD recruited to a Health Insurance Portability and Accountability Act-compliant, prospective, ongoing phase II clinical trial (ClinicalTrials.gov identifier, NCT03671889) underwent three separate focused ultrasound-induced BBB opening procedures that used a 220-kHz transducer with a concomitant intravenous microbubble contrast agent administered at 2-week intervals targeting the hippocampus and entorhinal cortex between October 2018 and May 2019. Posttreatment effects and gadolinium-based contrast agent enhancement patterns were evaluated by using 3.0-T MRI. Results Three women (aged 61, 72, and 73 years) consecutively enrolled in the trial successfully completed repeated focused ultrasound-induced BBB opening of the hippocampus and entorhinal cortex. Postprocedure contrast enhancement was clearly identified within the targeted brain volumes, indicating immediate spatially precise BBB opening. Parenchymal enhancement resolved within 24 hours after all treatments, confirming BBB closure. Transient perivenous enhancement was consistently observed during the acute phase after BBB opening. Notably, contrast enhancement reappeared in the perivenular regions after BBB closure. This imaging marker is consistent with blood-meningeal barrier permeability and persisted for 24-48 hours before spontaneous resolution. No evidence of intracranial hemorrhage or other adverse effect was identified. Conclusion MRI-guided focused ultrasound-induced blood-brain barrier opening was safely performed in the hippocampi of three participants with Alzheimer disease without any adverse effects. Posttreatment MRI reveals a unique spatiotemporal contrast enhancement pattern that suggests a perivenular immunologic healing response downstream from targeted sites. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Klibanov in this issue.

β-Amyloid Plaque Reduction in the Hippocampus After Focused Ultrasound-Induced Blood-Brain Barrier Opening in Alzheimer's Disease

The blood–brain barrier (BBB) limits therapeutic delivery in Alzheimer’s disease (AD) and other neurological disorders. Animal models have demonstrated safe BBB opening and reduction in β-amyloid plaque with focused ultrasound (FUS). We recently demonstrated the feasibility, safety, and reversibility of FUS-induced BBB opening in the hippocampus and entorhinal cortex in six participants with early AD. We now report the effect of BBB opening with FUS treatment on β-amyloid plaque. Six participants underwent ¹⁸F-Florbetaben PET scan at baseline and 1 week after the completion of the third FUS treatment (60 days interval). PET analysis comparing the hippocampus and entorhinal cortex in the treated and untreated hemispheres revealed a decrease in the ratio of ¹⁸F-Florbetaben ligand binding. The standard uptake value ratios (SUVr) reduction ranged from 2.7% to 10% with an average of 5.05% (±2.76) suggesting a decrease in β-amyloid plaque.

Something to despair: Gender differences in adverse childhood experiences among rural patients

Existing research has demonstrated that patients in treatment for an opioid use disorder (OUD) have high rates of adverse childhood experiences (ACE) compared to community-based samples. While research has documented important gender differences in ACEs in patients with OUD receiving treatment in urban areas, research has not shown whether these findings would generalize to rural and Appalachian areas, which are known to have lower ACE scores. We conducted a secondary analysis of existing clinical data, utilizing intake assessment data from a rural Appalachian outpatient buprenorphine program. We restricted the sample to patients with an OUD who presented for treatment between June 2018 and June 2019 (n = 173). The clinical intake assessment included a modified 17-item ACE instrument that patients self-administered. More than half (54.3%) of patients reported having experienced 4+ categories of adverse childhood experiences. On average, females endorsed 4.5 categories of adverse experiences, whereas males endorsed 3.3 (p < 0.00); female patients were significantly more likely to have experienced sexual abuse (42.4% versus 10.6%, p < 0.00). Alarmingly, 25.9% of females and 8.2% of males reported being forced to have sex before age 18. Disproportionately high rates of childhood adversities, particularly among females, may partially explain despair in rural Appalachian areas. OUD treatment programs should conduct clinical assessments of trauma and integrate trauma-informed care into drug treatment, especially for female patients residing in rural Appalachia.

A case report illustrating the effects of repetitive transcranial magnetic stimulation on cue-induced craving in an individual with opioid and cocaine use disorder

Nationally, it was estimated that 11.4 million people misused opioids in 2017 with more than 47,000 opioid-related deaths. Although medication-assisted treatment (MAT) has been effective in enhancing treatment retention and decreasing frequency of opioid use, relapse rates for opioids and other substances remain high, emphasizing the importance of investigating novel interventions to augment MAT. One potential treatment approach is repetitive transcranial magnetic stimulation (rTMS)-a noninvasive, electrophysiological method of neuromodulation. Recently published studies of rTMS in individuals with alcohol, nicotine, and cocaine use disorder have suggested that this treatment shows promise in reducing cravings and substance use. The literature specific to rTMS and opioid use disorder (OUD) is limited to a single published study in heroin users, which showed that a single session of rTMS to the left dorsolateral prefrontal cortex (DLPFC) reduced cue-induced craving, with a further reduction following 5 consecutive days of rTMS. The following case report involved a 25-year-old Caucasian male diagnosed with OUD and cocaine use disorder. This subject continued to demonstrate ongoing substance use despite participating in comprehensive MAT with buprenorphine/naloxone in combination with psychosocial interventions. He was administered 7 separate sessions of rTMS targeting the left DLPFC. Substance-related cues were presented prior to, during, and following these rTMS administration sessions and the subject rated his substance cravings via a 100-point Visual Analog Scale. When compared with his cue-induced craving ratings, there was a mean reduction in craving for heroin and cocaine by ∼60% to 82% following the 7 administration sessions. Although this is a single case, further investigation of rTMS as an augmentation strategy for OUD and polysubstance use is warranted. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Hebbian-Type Primary Motor Cortex Stimulation: A Potential Treatment of Impaired Hand Function in Chronic Stroke Patients

Background. Stroke often involves primary motor cortex (M1) and its corticospinal (CST) projections. As hand function is critically dependent on these structures, its recovery is often incomplete. Objective. To determine whether impaired hand function in patients with chronic ischemic stroke involving M1 or CST benefits from the enhancing effect of Hebbian-type stimulation (pairing M1 afferent stimulation and M1 activity in a specific temporal relationship) on M1 plasticity and hand function. Methods. In a double-blind, randomized, sham-controlled design, 20 patients with chronic ischemic stroke affecting M1 or CST were randomly assigned to 5 days of hand motor training that was combined with either Hebbian-type (training_Hebb) or sham stimulation (training_sham) of the lesioned M1. Measures of hand function and task-based M1 functional magnetic resonance imaging (fMRI) activity were collected prior to, immediately following, and 4 weeks after the intervention. Results. Both interventions were effective in improving affected hand function at the completion of training, but only participants in the training_Hebb group maintained functional gains. Changes in hand function and fMRI activity were positively correlated in both ipsilesional and contralesional M1. Compared with training_sham, participants in the training_Hebb group showed a stronger relationship between improved hand function and changes in M1 functional activity. Conclusions. Only when motor training was combined with Hebbian-type stimulation were functional gains maintained over time and correlated with measures of M1 functional plasticity. As hand dexterity is critically dependent on M1 function, these results suggest that functional reorganization in M1 is facilitated by Hebbian-type stimulation. ClinicalTrials.gov Identifier: NCT01569607.

Four single nucleotide polymorphisms in genes involved in neuronal signaling are associated with Opioid Use Disorder in West Virginia

Objective

Pilot study to assess utility in opioid use disorder (OUD) of a panel of single nucleotide polymorphisms in genes previously related to substance use disorder (SUD) and/or phenotypes that predispose individuals to OUD/SUD.

Design

Genetic association study.

Setting

West Virginia University's Chestnut Ridge Center Comprehensive Opioid Abuse Treatment (COAT) clinic for individuals diagnosed with OUD.

Patients

Sixty patients 18 years of age or older with OUD undergoing medication (buprenorphine/naloxone)-assisted treatment (MAT); all sixty patients recruited contributed samples for genetic analysis.

Outcome Measures

Minor allele frequencies for single nucleotide polymorphisms.

Results

Four of the fourteen single nucleotide polymorphisms examined were present at frequencies that are statistically significantly different than in a demographically-matched general population.

Conclusions

For the purposes of testing WV individuals via genetic means for predisposition to OUD, at least four single nucleotide polymorphisms in three genes are likely to have utility in predicting susceptibility. Additional studies with larger populations will need to be conducted to confirm these results before use in a clinical setting.

West Virginia's model of buprenorphine expansion: Preliminary results

West Virginia (WV) is situated at the epicenter of the opioid epidemic with the highest rates of overdose deaths and some of the lowest rates of access to life saving evidence-based medication assisted treatment (MAT) for patients with opioid use disorder (OUD). WV used a modified hub-and-spoke model to build organizational capacity for facilities to use buprenorphine to treat patients with OUD and to provide ongoing case consultation. The purpose of this study is to 1) describe the group-base model of buprenorphine treatment and the model used to build organizational capacity, 2) to describe the preliminary results of buprenorphine expansion in WV and 3) to report preliminary data describing and comparing the characteristics of the patients served across five hubs. A single Coordinating Center uses video conferencing to train hubs and provide ongoing case consultation, as well as clinical support. Hubs were trained to deliver a buprenorphine treatment model that is multi-disciplinary and includes group-based medication management and psychosocial therapy. Five regional hubs independently treat patients and are leading MAT expansion in their local areas by training and mentoring spokes (n = 13). As a result of the WV STR funding, 14 health care facilities have started to use buprenorphine, 56 health professionals were trained and 196 patients with OUD have been treated. There were few sociodemographic characteristic differences across patients treated at the five hubs, while there were differences in self-reported alcohol and drug use in the 30 days prior to intake. Additional research is needed to determine whether the WV modified hub-and-spoke model resulted in statistically significant improvements in buprenorphine treatment capacity; there is a need to address MAT stigma and regulatory barriers in order to ensure the long-term sustainability of the buprenorphine expansion.

Abnormally reduced primary motor cortex output is related to impaired hand function in chronic stroke

Stroke often involves primary motor cortex (M1) and its corticospinal projections (CST). As hand function is critically dependent on these structures, its recovery is often incomplete. The neuronal substrate supporting affected hand function is not well understood but likely involves reorganized M1 and CST of the lesioned hemisphere (M1_IL and CST_IL). We hypothesized that affected hand function in chronic stroke is related to structural and functional reorganization of M1_IL and CST_IL. We tested 18 patients with chronic ischemic stroke involving M1 or CST. Their hand function was compared with 18 age-matched healthy subjects. M1_IL thickness and CST_IL fractional anisotropy (FA) were determined with MRI and compared with measures of the other hemisphere. Transcranial magnetic stimulation (TMS) was applied to M1_IL to determine its input-output function [stimulus response curve (SRC)]. The plateau of the SRC (MEPmax), inflection point, and slope parameters of the curve were extracted. Results were compared with measures in 12 age-matched healthy controls. MEPmax of M1_IL was significantly smaller ( P = 0.02) in the patients, indicating reduced CST_IL motor output, and was correlated with impaired hand function ( P = 0.02). M1_IL thickness ( P < 0.01) and CST_IL-FA ( P < 0.01) were reduced but did not correlate with hand function. The results indicate that employed M1_IL or CST_IL structural measures do not explain the extent of impairment in hand function once M1 and CST are sufficiently functional for TMS to evoke a motor potential. Instead, impairment of hand function is best explained by the abnormally low output from M1_IL. NEW & NOTEWORTHY Hand function often remains impaired after stroke. While the critical role of the primary motor cortex (M1) and its corticospinal output (CST) for hand function has been described in the nonhuman primate stroke model, their structure and function have not been systematically evaluated for patients after stroke. We report that in chronic stroke patients with injury to M1 and/or CST an abnormally reduced M1 output is related to impaired hand function.

Completed suicide in an autopsy-confirmed case of early onset Alzheimer's disease

We report a case of a 57-year-old male with clinically diagnosed and autopsy-confirmed early onset Alzheimer's disease who completed suicide by gunshot wound to the chest. This case has several unique aspects that have not been discussed in previous case reports of completed suicide in Alzheimer's disease. In particular, our patient's death was highly planned with successful compensation for his cognitive deficits. After all firearms had been removed from the home as a safety precaution, he obtained a new weapon, hid it and left himself cues to find and use it. The case is discussed in the context of literature differentiating the neural circuitry propagating impulsive versus planned suicidal acts.

Effects of monoaminergic drugs on training-induced motor cortex plasticity in older adults

Primary motor cortex (M1) plasticity is involved in motor learning and stroke motor recovery, and enhanced by increasing monoaminergic transmission. Age impacts these processes but there is a paucity of systematic studies on the effects of monoaminergic drugs in older adults. Here, in ten older adults (age 61+4years, 4 males), we determine the effects of a single oral dose of carbidopa/levodopa (DOPA), d-amphetamine (AMPH), methylphenidate (MEPH) and placebo (PLAC) on M1 excitability and motor training-induced M1 plasticity. M1 plasticity is defined as training related long lasting changes in M1 excitability and kinematics of the trained movement. At peak plasma level of the drugs, subjects trained wrist extension movements for 30min. Outcome measures were motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation at increasing intensity (stimulus response curve, SRC) and peak acceleration of the trained wrist extension movements. Measures were obtained before and after completion of training. The curve parameters plateau (MEPmax), inflection point, and slope were extracted from SRC. At baseline drugs had a differential effect on curve parameters, while kinematics remained unchanged. Training alone (PLAC) increased MEPmax but did not improve kinematics. Drugs affected training-related changes of the curve parameters differently, but did not enhance them or kinematics when compared to PLAC. The results demonstrate that in the older adults, MEPH, DOPA, or AMPH have differential effects on baseline M1 excitability and training-related M1 plasticity but fail to enhance them above the naïve level.

Amnesia Associated with Bilateral Hippocampal and Bilateral Basal Ganglia Lesions in Anoxia with Stimulant Use

We report a case of a 55-year-old man with ischemic lesions of the bilateral hippocampus and bilateral basal ganglia following a myocardial infarction during an episode of multiple drug use with subsequent anoxia requiring resuscitation. He presented for a neuropsychological evaluation with an anterograde amnesia for both explicit and procedural memory. There are two main points to this case, the unique aspects of the bilateral multifocal lesions and the functional, cognitive impact of these lesions. We hypothesize that his rare focal bilateral lesions of both the hippocampus and basal ganglia are a result of anoxia acting in synergy with his stimulant drug use (cocaine and/or 3,4-methylenedioxy-methamphetamine). Second, his unique lesions produced an explicit and implicit/procedural anterograde amnesia.

Demand on skillfulness modulates interhemispheric inhibition of motor cortices

The role of primary motor cortex (M1) in the control of hand movements is still unclear. Functional magnetic resonance imaging (fMRI) studies of unimanual performance reported a relationship between level of precision of a motor task and additional ipsilateral M1 (iM1) activation. In the present study, we determined whether the demand on accuracy of a movement influences the magnitude of the inhibitory effect between primary motor cortices (IHI). We used transcranial magnetic stimulation (TMS) to measure active IHI (aIHI) of the iM1 on the contralateral M1 (cM1) in the premovement period of a left-hand motor task. Ten healthy participants manipulated a joystick to point to targets of two different sizes. For aIHI, the conditioning stimulus (CS) was applied to iM1, and the test stimulus (TS) to cM1, with an interstimulus interval of 10 ms. The amount of the inhibitory effect of the CS on the motor-evoked potential (MEP) of the subsequent TS was expressed as percentage of the mean MEP amplitude evoked by the single TS. Across different time points of aIHI measurements in the premovement period, there was a significant effect for target size on aIHI. Preparing to point to small targets was associated with weaker aIHI compared with pointing to large targets. The present findings suggest that, during the premovement period, aIHI from iM1 on cM1 is modulated by the demand on accuracy of the motor task. This is consistent with task fMRI findings showing bilateral M1 activation during high-precision movements but only unilateral M1 activity during low-precision movements.

Completed suicide in a case of clinically diagnosed progressive supranuclear palsy

We present the clinical history and the cognitive and behavioral presentations of a male patient with suspected progressive supranuclear palsy (PSP) who fatally shot himself in the head. We believe his act of suicide was the consequence of impulsivity, rather than primary depression or mood disturbance. In cases of suspected PSP and other atypical parkinsonisms, health professionals must be aware of neurobehavioral risk factors for suicide attempts and completions to promote patient safety; however, the literature on this topic is sparse. Our case highlights the potentially lethal consequences of impulsivity and other neuropsychiatric symptoms in PSP and related syndromes.

Conditions for enhancing the encoding of an elementary motor memory by rTMS

OBJECTIVE

Motor learning results in changes of movement representation in primary motor cortex (M1) a process involving long-term potentiation (LTP). Pairing motor training with repetitive transcranial magnetic stimulation (rTMS) of M1 enhances the formation of a motor memory. Here we determined the effect of pairing M1 stimulation and the execution of training movements at different times and frequencies on the formation of a motor memory.

METHODS

Formation of a motor memory was defined as increases in motor evoked potentials (MEP) of the training agonist (extensor carpi ulnaris muscle, ECU) and increases in peak acceleration of the trained movements that last more than 60min. Training consisted of auditory-paced ballistic wrist extension movements (30min, 0.5Hz) paired with 0.1, 0.25 or 0.5Hz subthreshold rTMS. The rTMS pulse was applied at either the onset, 100ms prior to or 300ms after the onset of training movement related increases in electromyographic (EMG) activity of ECU. This was compared to a Sham condition.

RESULTS

Only 0.1Hz rTMS applied at the onset of the training related increase in ECU-EMG activity resulted in increases in MEP amplitudes and peak acceleration when compared to the Sham.

CONCLUSIONS

The formation of motor memory is enhanced above the naïve level by co-administration of low frequency rTMS at the time of execution of training movements.

SIGNIFICANCE

These results indicate the importance of time and frequency of rTMS in these settings and should be considered in the design of rehabilitation treatment strategies using rTMS.

Differences in brain structure and function in older adults with self-reported disabling and nondisabling chronic low back pain

OBJECTIVE

The primary aim of this pilot study was to identify structural and functional brain differences in older adults with self-reported disabling chronic low back pain (CLBP) compared with those who reported nondisabling CLBP.

DESIGN

Cross-sectional.

PARTICIPANTS

Sixteen cognitively intact older adults, eight with disabling CLBP and eight with nondisabling CLBP. Exclusions were psychiatric or neurological disorders, substance abuse, opioid use, or diabetes mellitus.

METHODS

Participants underwent: structural and functional brain MRI; neuropsychological assessment using the Repeatable Battery for the Assessment of Neuropsychological Status, Trail Making Tests A and B; and physical performance assessment using the Short Physical Performance Battery.

RESULTS

In the disabled group, there was significantly lower white matter (WM) integrity (P < 0.05) of the splenium of the corpus callosum. This group also demonstrated activation of the right medial prefrontal cortex at rest whereas the nondisabled demonstrated activation of the left lateral prefrontal cortex. Combined groups analysis revealed a strong positive correlation (r(s) = 0.80, P < 0.0002) between WM integrity of the left centrum semiovale with gait-speed. Secondary analysis revealed a strong negative correlation between total months of CLBP and WM integrity of the SCC (r(s) = -0.59, P < 0.02).

CONCLUSIONS

Brain structure and function is different in older adults with disabling CLBP compared with those with nondisabling CLBP. Deficits in brain morphology combining groups are associated with pain duration and poor physical function. Our findings suggest brain structure and function may play a key role in chronic pain related disability and may be important treatment targets.

Adjuvant chemotherapy for breast cancer: effects on cerebral white matter seen in diffusion tensor imaging

PURPOSE

The purpose of this study was to examine the effect of adjuvant chemotherapy on normal-appearing white matter in women with breast cancer.

PATIENTS AND METHODS

Ten patients with early-stage breast cancer who were treated with adjuvant chemotherapy and 9 age-, education-, and IQ-matched healthy controls were studied with magnetic resonance imaging. Diffusion tensor imaging was used to calculate fractional anisotropy (FA), a measure of white matter integrity. Measurements were made in the genu and splenium of the corpus callosum. Participants also completed measures of processing speed, depression, and anxiety.

RESULTS

Relative to controls, patients had slower processing speed and lower FA in the genu. Processing speed was positively correlated with FA in the genu.

CONCLUSION

The results of this pilot study suggest that adjuvant chemotherapy affects normal-appearing white matter in the genu of the corpus callosum and that this is related to the cognitive deficits experienced by patients.

Reduced frontal white matter volume in long-term childhood leukemia survivors: a voxel-based morphometry study

BACKGROUND AND PURPOSE

To our knowledge, no published studies have examined whole-brain regional differences to identify more discrete volumetric changes in the brains of childhood leukemia survivors. We used voxel-based morphometry (VBM) to examine regional gray and white matter differences in a group of long-term survivors of acute lymphoblastic leukemia (ALL) compared with a group of healthy controls. Differences in regional white matter volume were expected, given previous reports of white matter changes during treatment for ALL and reduced brain white matter volumes in long-term survivors. Follow-up analyses examined the relationship of regional brain volumes to cognitive function.

MATERIALS AND METHODS

We compared 9 long-term survivors of ALL with 14 healthy controls. Survivors of ALL were treated with systemic and intrathecal chemotherapy only. T1-weighted axial 3D spoiled gradient high-resolution images collected on a 1.5T MR imaging scanner were used for the VBM analysis. Neuropsychological evaluations were conducted within 2 months of the MR imaging to assess cognitive function.

RESULTS

VBM analysis revealed 2 specific regions of reduced white matter in the right frontal lobes of survivors of ALL compared with healthy controls. Survivors of ALL had lower performances on tests of attention, visual-constructional skills, mental flexibility, and math achievement compared with healthy individuals. Decreased performance on neuropsychological measures was associated with decreased regional white matter volumes. No differences were found between the groups with respect to gray matter regions.

CONCLUSION

These findings are consistent with previous literature describing the long-term cognitive, academic, and imaging findings of survivors of ALL and suggest that right frontal white matter is particularly vulnerable to disruption following intensive chemotherapy for ALL. Future studies should focus on further clarifying the white matter changes observed.

Corpus Callosum Volume in Railroad Workers With Chronic Exposure to Solvents

OBJECTIVE

Changes to cognition and behavior have been reported after long-term exposure to solvents. Solvents are hypothesized to affect brain white matter. To test this, we examined the volume of the corpus callosum in workers with a history of exposure to solvents.

METHODS

We manually traced (blind to group membership) the volume of the corpus callosum in 31 railroad workers and 31 matched controls.

RESULTS

There was a decrease in the genu of the corpus callosum in the solvent-exposed workers compared with controls. A smaller volume of the genu of the corpus callosum was associated with greater exposure and worse performance on cognitive tasks.

CONCLUSIONS

This study supports the hypothesis that occupational exposure to solvents affects the anterior white matter of the brain and is related to extent of exposure and degree of cognitive change.

Anterior medial temporal lobe activation during encoding of words: FMRI methods to optimize sensitivity

The existence of a rostrocaudal gradient of medial temporal lobe (MTL) activation during memory encoding has historically received support from positron emission tomography studies, but less so from functional MRI (FMRI) studies. More recently, FMRI studies have demonstrated that characteristics of the stimuli can affect the location of activation seen in the MTL when those stimuli are encoded. The current study tested the hypothesis that MTL activation during memory encoding is related to the modality of stimulus presentation. Subjects encoded auditorily or visually presented words in an FMRI novelty paradigm. Imaging and analysis parameters were optimized to minimize susceptibility artifact in the anterior MTL. Greater activation was observed in the anterior than posterior MTL for both modalities of stimulus presentation. The results indicate that anterior MTL activation occurred during encoding, independent of stimulus modality and provide support for the hypothesis that verbal-semantic memory processing occurs in anterior MTL. The authors suggest that technical factors are critical for observing the rostrocaudal gradient in MTL memory activation.

Neural activation during frequency-memory performance

Lesion studies have demonstrated that frequency memory, or memory for the frequency of occurrence, is associated with prefrontal and not temporal lobe lesions. This study examined neural activation during performance on a frequency-memory-judgment task and a recognition-memory task, both using words. Relative to a control task, the authors observed peaks of activation during frequency-memory performance in the left ventrolateral prefrontal cortex (BA 45) and other areas typically associated with working memory (dorsolateral prefrontal cortex, posterior parietal cortex). Recognition performance was associated with activation in the same left ventrolateral prefrontal location as was observed with frequency memory. When comparing activation during frequency memory with activation during recognition memory, the authors found a suppression of activation in the hippocampus bilaterally during frequency memory. This study supports a neuroanatomical distinction between frequency and recognition memory.

Neural activation during frequency-memory performance

Lesion studies have demonstrated that frequency memory, or memory for the frequency of occurrence, is associated with prefrontal and not temporal lobe lesions. This study examined neural activation during performance on a frequency-memory-judgment task and a recognition-memory task, both using words. Relative to a control task, the authors observed peaks of activation during frequency-memory performance in the left ventrolateral prefrontal cortex (BA 45) and other areas typically associated with working memory (dorsolateral prefrontal cortex, posterior parietal cortex). Recognition performance was associated with activation in the same left ventrolateral prefrontal location as was observed with frequency memory. When comparing activation during frequency memory with activation during recognition memory, the authors found a suppression of activation in the hippocampus bilaterally during frequency memory. This study supports a neuroanatomical distinction between frequency and recognition memory.

Neural activation during performance of number-letter sequencing

Recent advances in neuroimaging have enabled researchers to establish relatively specific areas of the brain that are involved in working memory. In this positron emission tomography study we examined the pattern of neural activation associated with performance on number-letter sequencing, a purported measure of working memory included in the new Wechsler scales for memory and intelligence. After controlling for basic audition, verbalization, and attention, areas of activation were observed in the orbital frontal lobe, dorsolateral prefrontal cortex, and posterior parietal cortex. This is highly consistent with reports from the literature on activation patterns associated with working memory. More activation peaks were observed in the right hemisphere, suggesting the participants utilized visualization of the verbal information. Consistent with task conceptualization, this study provides support for number-letter sequencing as a task involving working memory.

Verbal working memory and solvent exposure: a positron emission tomography study

Neuropsychological studies have documented frontal dysfunction in patients with a history of exposure to organic solvents. The deficits typically observed in these patients appear to be related to working memory (WM). This study used [15O] water positron emission tomography (PET) to examine the pattern of neural activation during verbal working memory in patients with a history of exposure to solvents. Six individuals with solvent exposure were compared with 6 age- and education-matched controls. On the 2 WM tasks examined with PET, with equivalent task performance, participants with solvent exposure demonstrated frontal peaks that were atypical for the tasks, whereas the posterior peaks were typical for the tasks. The results support frontal dysfunction and compensatory use within anterior regions of the WM system in patients with solvent exposure.