Gwenn S. Smith

A phase I trial of deep brain stimulation of memory circuits in Alzheimer's disease.

Alzheimer disease (AD) is characterized by functional impairment in the neural elements and circuits underlying cognitive and memory functions. We hypothesized that fornix/hypothalamus deep brain stimulation (DBS) could modulate neurophysiological activity in these pathological circuits and possibly produce clinical benefits.

Subcallosal cingulate deep brain stimulation for treatment-refractory anorexia nervosa: a phase 1 pilot trial

BACKGROUNDnAnorexia nervosa is characterised by a chronic course that is refractory to treatment in many patients and has one of the highest mortality rates of any psychiatric disorder. Deep brain stimulation (DBS) has been applied to circuit-based neuropsychiatric diseases, such as Parkinsons disease and major depression, with promising results. We aimed to assess the safety of DBS to modulate the activity of limbic circuits and to examine how this might affect the clinical features of anorexia nervosa.nnnMETHODSnWe did a phase 1, prospective trial of subcallosal cingulate DBS in six patients with chronic, severe, and treatment-refractory anorexia nervosa. Eligible patients were aged 20-60 years, had been diagnosed with restricting or binge-purging anorexia nervosa, and showed evidence of chronicity or treatment resistance. Patients underwent medical optimisation preoperatively and had baseline body-mass index (BMI), psychometric, and neuroimaging investigations, followed by implantation of electrodes and pulse generators for continuous delivery of electrical stimulation. Patients were followed up for 9 months after DBS activation, and the primary outcome of adverse events associated with surgery or stimulation was monitored at every follow-up visit. Repeat psychometric assessments, BMI measurements, and neuroimaging investigations were also done at various intervals. This trial is registered with ClinicalTrials.gov, number NCT01476540.nnnFINDINGSnDBS was associated with several adverse events, only one of which (seizure during programming, roughly 2 weeks after surgery) was serious. Other related adverse events were panic attack during surgery, nausea, air embolus, and pain. After 9 months, three of the six patients had achieved and maintained a BMI greater than their historical baselines. DBS was associated with improvements in mood, anxiety, affective regulation, and anorexia nervosa-related obsessions and compulsions in four patients and with improvements in quality of life in three patients after 6 months of stimulation. These clinical benefits were accompanied by changes in cerebral glucose metabolism (seen in a comparison of composite PET scans at baseline and 6 months) that were consistent with a reversal of the abnormalities seen in the anterior cingulate, insula, and parietal lobe in the disorder.nnnINTERPRETATIONnSubcallosal cingulate DBS seems to be generally safe in this sample of patients with chronic and treatment-refractory anorexia nervosa.nnnFUNDINGnKlarman Family Foundation Grants Program in Eating Disorders Research and Canadian Institutes of Health Research.

Neuropsychiatric symptoms in Alzheimer's disease: Past progress and anticipation of the future

Neuropsychiatric symptoms (NPS) in Alzheimers disease (AD) are widespread and disabling. This has been known since Dr. Alois Alzheimers first case, Frau Auguste D., presented with emotional distress and delusions of infidelity/excessive jealousy, followed by cognitive symptoms. Being cognizant of this, in 2010 the Alzheimers Association convened a research roundtable on the topic of NPS in AD. A major outcome of the roundtable was the founding of a Professional Interest Area (PIA) within the International Society to Advance Alzheimers Research and Treatment (ISTAART). The NPS‐PIA has prepared a series of documents that are intended to summarize the literature and provide more detailed specific recommendations for NPS research. This overview paper is the first of these living documents that will be updated periodically as the science advances. The overview is followed by syndrome‐specific synthetic reviews and recommendations prepared by NPS‐PIA workgroups on depression, apathy, sleep, agitation, and psychosis.

Neuropsychiatric symptoms as early manifestations of emergent dementia: Provisional diagnostic criteria for mild behavioral impairment

Neuropsychiatric symptoms (NPS) are common in dementia and in predementia syndromes such as mild cognitive impairment (MCI). NPS in MCI confer a greater risk for conversion to dementia in comparison to MCI patients without NPS. NPS in older adults with normal cognition also confers a greater risk of cognitive decline in comparison to older adults without NPS. Mild behavioral impairment (MBI) has been proposed as a diagnostic construct aimed to identify patients with an increased risk of developing dementia, but who may or may not have cognitive symptoms. We propose criteria that include MCI in the MBI framework, in contrast to prior definitions of MBI. Although MBI and MCI can co‐occur, we suggest that they are different and that both portend a higher risk of dementia. These MBI criteria extend the previous literature in this area and will serve as a template for validation of the MBI construct from epidemiologic, neurobiological, treatment, and prevention perspectives.

Neuroinflammation and brain atrophy in former NFL players: An in vivo multimodal imaging pilot study

There are growing concerns about potential delayed, neuropsychiatric consequences (e.g, cognitive decline, mood or anxiety disorders) of sports-related traumatic brain injury (TBI). Autopsy studies of brains from a limited number of former athletes have described characteristic, pathologic changes of chronic traumatic encephalopathy (CTE) leading to questions about the relationship between these pathologic and the neuropsychiatric disturbances seen in former athletes. Research in this area will depend on in vivo methods that characterize molecular changes in the brain, linking CTE and other sports-related pathologies with delayed emergence of neuropsychiatric symptoms. In this pilot project we studied former National Football League (NFL) players using new neuroimaging techniques and clinical measures of cognitive functioning. We hypothesized that former NFL players would show molecular and structural changes in medial temporal and parietal lobe structures as well as specific cognitive deficits, namely those of verbal learning and memory. We observed a significant increase in binding of [(11)C]DPA-713 to the translocator protein (TSPO), a marker of brain injury and repair, in several brain regions, such as the supramarginal gyrus and right amygdala, in 9 former NFL players compared to 9 age-matched, healthy controls. We also observed significant atrophy of the right hippocampus. Finally, we report that these same former players had varied performance on a test of verbal learning and memory, suggesting that these molecular and pathologic changes may play a role in cognitive decline. These results suggest that localized brain injury and repair, indicated by increased [(11)C]DPA-713 binding to TSPO, may be linked to history of NFL play. [(11)C]DPA-713 PET is a promising new tool that can be used in future study design to examine further the relationship between TSPO expression in brain injury and repair, selective regional brain atrophy, and the potential link to deficits in verbal learning and memory after NFL play.

The Functional Neuroanatomy of Geriatric Depression

Positron Emission Tomography (PET) studies of cerebral glucose metabolism have demonstrated sensitivity in evaluating the functional neuroanatomy of treatment response variability in depression, as well as in the early detection of functional changes associated with incipient cognitive decline. The evaluation of cerebral glucose metabolism in late life depression may have implications for understanding treatment response variability, as well as evaluating the neurobiological basis of depression in late life as a risk factor for dementia.

Deep Brain Stimulation Influences Brain Structure in Alzheimer's Disease

BACKGROUNDnDeep Brain Stimulation (DBS) is thought to improve the symptoms of selected neurological disorders by modulating activity within dysfunctional brain circuits. To date, there is no evidence that DBS counteracts progressive neurodegeneration in any particular disorder.nnnOBJECTIVE/HYPOTHESISnWe hypothesized that DBS applied to the fornix in patients with Alzheimers Disease (AD) could have an effect on brain structure.nnnMETHODSnIn six AD patients receiving fornix DBS, we used structural MRI to assess one-year change in hippocampal, fornix, and mammillary body volume. We also used deformation-based morphometry to identify whole-brain structural changes. We correlated volumetric changes to hippocampal glucose metabolism. We also compared volumetric changes to those in an age-, sex-, and severity-matched group of AD patients (n = 25) not receiving DBS.nnnRESULTSnWe observed bilateral hippocampal volume increases in the two patients with the best clinical response to fornix DBS. In one patient, hippocampal volume was preserved three years after diagnosis. Overall, mean hippocampal atrophy was significantly slower in the DBS group compared to the matched AD group, and no matched AD patients demonstrated bilateral hippocampal enlargement. Across DBS patients, hippocampal volume change correlated strongly with hippocampal metabolism and with volume change in the fornix and mammillary bodies, suggesting a circuit-wide effect of stimulation. Deformation-based morphometry in DBS patients revealed local volume expansions in several regions typically atrophied in AD.nnnCONCLUSIONnWe present the first in-human evidence that, in addition to modulating neural circuit activity, DBS may influence the natural course of brain atrophy in a neurodegenerative disease.

A Phase II Study of Fornix Deep Brain Stimulation in Mild Alzheimer's Disease

Background: Deep brain stimulation (DBS) is used to modulate the activity of dysfunctional brain circuits. The safety and efficacy of DBS in dementia is unknown. Objective: To assess DBS of memory circuits as a treatment for patients with mild Alzheimer’s disease (AD). Methods: We evaluated active “on” versus sham “off” bilateral DBS directed at the fornix-a major fiber bundle in the brain’s memory circuit-in a randomized, double-blind trial (ClinicalTrials.gov NCT01608061) in 42 patients with mild AD. We measured cognitive function and cerebral glucose metabolism up to 12 months post-implantation. Results: Surgery and electrical stimulation were safe and well tolerated. There were no significant differences in the primary cognitive outcomes (ADAS-Cog 13, CDR-SB) in the “on” versus “off” stimulation group at 12 months for the whole cohort. Patients receiving stimulation showed increased metabolism at 6 months but this was not significant at 12 months. On post-hoc analysis, there was a significant interaction between age and treatment outcome: in contrast to patientsu200a<65 years old (nu200a=u200a12) whose results trended toward being worse with DBS ON versus OFF, in patients≥65 (nu200a=u200a30) DBS-f ON treatment was associated with a trend toward both benefit on clinical outcomes and a greater increase in cerebral glucose metabolism. Conclusion: DBS for AD was safe and associated with increased cerebral glucose metabolism. There were no differences in cognitive outcomes for participants as a whole, but participants aged≥65 years may have derived benefit while there was possible worsening in patients below age 65 years with stimulation.

Lack of association of the α2-macroglobulin locus on chromosome 12 in AD

Objective: Analysis of AD has revealed that the apolipoprotein E locus (APOE) cannot account for all of the genetic risk associated with AD. Whole genome scanning in AD families suggests that a chromosome 12 locus may contribute significantly to disease development. The α2-macroglobulin gene (A2M) has been suggested as a candidate locus for AD based on analysis of familial AD. Method: We determined, in 195 neuropathologically verified AD cases and 107 age-matched control subjects, the association of two common polymorphisms in A2M (a pentanucleotide deletion 5′ to the bait domain exon, and a valine-1000-isoleucine polymorphism in the thiolester site of the protein). Results: Evidence was observed for linkage disequilibrium between the deletion and Ile1000 polymorphisms. No evidence was observed for an association between the thiolester polymorphism and AD alone or when accounting for the APOE-ε4 allele. No alteration in the frequency of the bait domain deletion was observed, although a small excess (4%) of deletion homozygotes was found in the AD group, which were absent in the control population. Conclusions: The A2M deletion polymorphism at most accounts for a small fraction of the genetic contribution toward AD, and this is small compared with APOE. Furthermore, reverse transcriptase PCR of A2M RNA from the brains of patients homozygous for the deletion polymorphism showed that the bait domain exon still is present in the RNA. This suggests that the A2M deletion polymorphism may be nonfunctional and that the chromosome 12 AD locus is situated elsewhere.

Imaging of Glial Cell Activation and White Matter Integrity in Brains of Active and Recently Retired National Football League Players

Importance Microglia, the resident immune cells of the central nervous system, play an important role in the brain’s response to injury and neurodegenerative processes. It has been proposed that prolonged microglial activation occurs after single and repeated traumatic brain injury, possibly through sports-related concussive and subconcussive injuries. Limited in vivo brain imaging studies months to years after individuals experience a single moderate to severe traumatic brain injury suggest widespread persistent microglial activation, but there has been little study of persistent glial cell activity in brains of athletes with sports-related traumatic brain injury. Objective To measure translocator protein 18 kDa (TSPO), a marker of activated glial cell response, in a cohort of National Football League (NFL) players and control participants, and to report measures of white matter integrity. Design, Setting, and Participants This cross-sectional, case-control study included young active (nu2009=u20094) or former (nu2009=u200910) NFL players recruited from across the United States, and 16 age-, sex-, highest educational level–, and body mass index–matched control participants. This study was conducted at an academic research institution in Baltimore, Maryland, from January 29, 2015, to February 18, 2016. Main Outcomes and Measures Positron emission tomography–based regional measures of TSPO using [11C]DPA-713, diffusion tensor imaging measures of regional white matter integrity, regional volumes on structural magnetic resonance imaging, and neuropsychological performance. Results The mean (SD) ages of the 14 NFL participants and 16 control participants were 31.3 (6.1) years and 27.6 (4.9) years, respectively. Players reported a mean (SD) of 7.0 (6.4) years (range, 1-21 years) since the last self-reported concussion. Using [11C]DPA-713 positron emission tomographic data from 12 active or former NFL players and 11 matched control participants, the NFL players showed higher total distribution volume in 8 of the 12 brain regions examined (Pu2009<u2009.004). We also observed limited change in white matter fractional anisotropy and mean diffusivity in 13 players compared with 15 control participants. In contrast, these young players did not differ from control participants in regional brain volumes or in neuropsychological performance. Conclusions and Relevance The results suggest that localized brain injury and repair, indicated by higher TSPO signal and white matter changes, may be associated with NFL play. Further study is needed to confirm these findings and to determine whether TSPO signal and white matter changes in young NFL athletes are related to later onset of neuropsychiatric symptoms.