%0 Journal Article %J J Alzheimers Dis %D 2023 %T Serotonin Degeneration and Amyloid-β Deposition in Mild Cognitive Impairment: Relationship to Cognitive Deficits. %A Smith, Gwenn S %A Kuwabara, Hiroto %A Yan, Haijuan %A Nassery, Najlla %A Yoon, Mark %A Kamath, Vidya %A Kraut, Michael %A Gould, Neda F %A Savonenko, Alena %A Coughlin, Jennifer M %A Lodge, Martin %A Pomper, Martin G %A Nandi, Ayon %A Holt, Daniel %A Dannals, Robert F %A Leoutsakos, Jeannie M %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K Cognition %K Cognition Disorders %K Cognitive Dysfunction %K Humans %K Mice %K Positron-Emission Tomography %K Serotonin %X

BACKGROUND: Neuropathological and neuroimaging studies have demonstrated degeneration of the serotonin system in Alzheimer's disease (AD). Neuroimaging studies have extended these observations to the preclinical stages of AD, mild cognitive impairment (MCI). Serotonin degeneration has been observed also in transgenic amyloid mouse models, prior to widespread cortical distribution of amyloid-β (Aβ).

OBJECTIVE: The present study evaluated the regional distribution of the serotonin transporter (5-HTT) and of Aβ in individuals with MCI and healthy older controls, as well as the contribution of 5-HTT and Aβ to cognitive deficits.

METHODS: Forty-nine MCI participants and 45 healthy older controls underwent positron emission tomography (PET) imaging of 5-HTT and Aβ, structural magnetic resonance imaging and neuropsychological assessments.

RESULTS: Lower cortical, striatal, and limbic 5-HTT and higher cortical Aβ was observed in MCIs relative to healthy controls. Lower 5-HTT, mainly in limbic regions, was correlated with greater deficits in auditory-verbal and visual-spatial memory and semantic, not phonemic fluency. Higher cortical A β was associated with greater deficits in auditory-verbal and visual-spatial memory and in semantic, not phonemic fluency. When modeling the association between cognition, gray matter volumes and Aβ, inclusion of 5-HTT in limbic and in select cortical regions significantly improved model fit for auditory-verbal and visual-spatial memory and semantic, but not phonemic fluency.

CONCLUSIONS: These results support the role of serotonin degeneration in the memory and semantic fluency deficits observed in MCI.

%B J Alzheimers Dis %V 96 %P 215-227 %8 2023 %G eng %N 1 %R 10.3233/JAD-230570 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Deep Brain Stimulation Targeting the Fornix for Mild Alzheimer Dementia (the ADvance Trial): A Two Year Follow-up Including Results of Delayed Activation. %A Leoutsakos, Jeannie-Marie S %A Yan, Haijuan %A Anderson, William S %A Asaad, Wael F %A Baltuch, Gordon %A Burke, Anna %A Chakravarty, M Mallar %A Drake, Kristen E %A Foote, Kelly D %A Fosdick, Lisa %A Giacobbe, Peter %A Mari, Zoltan %A McAndrews, Mary Pat %A Munro, Cynthia A %A Oh, Esther S %A Okun, Michael S %A Pendergrass, Jo Cara %A Ponce, Francisco A %A Rosenberg, Paul B %A Sabbagh, Marwan N %A Salloway, Stephen %A Tang-Wai, David F %A Targum, Steven D %A Wolk, David %A Lozano, Andres M %A Smith, Gwenn S %A Lyketsos, Constantine G %X

BACKGROUND: Given recent challenges in developing new treatments for Alzheimer dementia (AD), it is vital to explore alternate treatment targets, such as neuromodulation for circuit dysfunction. We previously reported an exploratory Phase IIb double-blind trial of deep brain stimulation targeting the fornix (DBS-f) in mild AD (the ADvance trial). We reported safety but no clinical benefits of DBS-f versus the delayed-on (sham) treatment in 42 participants after one year. However, secondary post hoc analyses of the one-year data suggested a possible DBS-f benefit for participants≥65 years.

OBJECTIVE: To examine the long-term safety and clinical effects of sustained and delayed-on DBS-f treatment of mild AD after two years.

METHODS: 42 participants underwent implantation of DBS-f electrodes, with half randomized to active DBS-f stimulation (early on) for two years and half to delayed-on (sham) stimulation after 1 year to provide 1 year of active DBS-f stimulation (delayed on). We evaluated safety and clinical outcomes over the two years of the trial.

RESULTS: DBS-f had a favorable safety profile with similar rates of adverse events across both trial phases (years 1 and 2) and between treatment arms. There were no differences between treatment arms on any primary clinical outcomes. However, post-hoc age group analyses suggested a possible benefit among older (>65) participants.

CONCLUSION: DBS-f was safe. Additional study of mechanisms of action and methods for titrating stimulation parameters will be needed to determine if DBS has potential as an AD treatment. Future efficacy studies should focus on patients over age 65.

%B J Alzheimers Dis %V 64 %P 597-606 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29914028?dopt=Abstract %R 10.3233/JAD-180121 %0 Journal Article %J J Alzheimers Dis %D 2017 %T The Mild Behavioral Impairment Checklist (MBI-C): A Rating Scale for Neuropsychiatric Symptoms in Pre-Dementia Populations. %A Ismail, Zahinoor %A Agüera-Ortiz, Luis %A Brodaty, Henry %A Cieslak, Alicja %A Cummings, Jeffrey %A Fischer, Corinne E %A Gauthier, Serge %A Geda, Yonas E %A Herrmann, Nathan %A Kanji, Jamila %A Lanctôt, Krista L %A Miller, David S %A Mortby, Moyra E %A Onyike, Chiadi U %A Rosenberg, Paul B %A Smith, Eric E %A Smith, Gwenn S %A Sultzer, David L %A Lyketsos, Constantine %X

BACKGROUND: Mild behavioral impairment (MBI) is a construct that describes the emergence at ≥50 years of age of sustained and impactful neuropsychiatric symptoms (NPS), as a precursor to cognitive decline and dementia. MBI describes NPS of any severity, which are not captured by traditional psychiatric nosology, persist for at least 6 months, and occur in advance of or in concert with mild cognitive impairment. While the detection and description of MBI has been operationalized in the International Society to Advance Alzheimer's Research and Treatment - Alzheimer's Association (ISTAART-AA) research diagnostic criteria, there is no instrument that accurately reflects MBI as described.

OBJECTIVE: To develop an instrument based on ISTAART-AA MBI criteria.

METHODS: Eighteen subject matter experts participated in development using a modified Delphi process. An iterative process ensured items reflected the five MBI domains of 1) decreased motivation; 2) emotional dysregulation; 3) impulse dyscontrol; 4) social inappropriateness; and 5) abnormal perception or thought content. Instrument language was developed a priori to pertain to non-demented functionally independent older adults.

RESULTS: We present the Mild Behavioral Impairment Checklist (MBI-C), a 34-item instrument, which can easily be completed by a patient, close informant, or clinician.

CONCLUSION: The MBI-C provides the first measure specifically developed to assess the MBI construct as explicitly described in the criteria. Its utility lies in MBI case detection, and monitoring the emergence of MBI symptoms and domains over time. Studies are required to determine the prognostic value of MBI for dementia development, and for predicting different dementia subtypes.

%B J Alzheimers Dis %V 56 %P 929-938 %8 2017 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/28059789?dopt=Abstract %R 10.3233/JAD-160979 %0 Journal Article %J J Alzheimers Dis %D 2016 %T A Phase II Study of Fornix Deep Brain Stimulation in Mild Alzheimer's Disease. %A Lozano, Andres M %A Fosdick, Lisa %A Chakravarty, M Mallar %A Leoutsakos, Jeannie-Marie %A Munro, Cynthia %A Oh, Esther %A Drake, Kristen E %A Lyman, Christopher H %A Rosenberg, Paul B %A Anderson, William S %A Tang-Wai, David F %A Pendergrass, Jo Cara %A Salloway, Stephen %A Asaad, Wael F %A Ponce, Francisco A %A Burke, Anna %A Sabbagh, Marwan %A Wolk, David A %A Baltuch, Gordon %A Okun, Michael S %A Foote, Kelly D %A McAndrews, Mary Pat %A Giacobbe, Peter %A Targum, Steven D %A Lyketsos, Constantine G %A Smith, Gwenn S %X

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 patients 

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.

%B J Alzheimers Dis %V 54 %P 777-87 %8 2016 Sep 06 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/27567810?dopt=Abstract %R 10.3233/JAD-160017