title: 18F-Fluorodeoxyglucose Positron Emission Tomography Cortical Metabolic Activity Associated with Distinct Agitation Behaviors in Alzheimer Disease.
abstract: OBJECTIVE
  This study aimed to investigate the neurobiologic correlates of two distinct clusters of agitation symptoms to identify the unique biologic substrates underlying agitated behaviors.
  
  
  METHODS
  Eighty-eight outpatients with mild to moderate Alzheimer disease (AD) were recruited from the VA Greater Los Angeles Healthcare System Geropsychiatry Outpatient Program. A cross-sectional investigation was conducted of the relationship between cerebral glucose metabolism measured via18F-fluorodeoxyglucose positron emission tomography and agitated symptoms from the Neuropsychiatric Inventory (NPI) in patients with AD. Two empirically derived clusters of agitation symptoms were investigated: an Agitation factor comprising agitation/aggression and irritability/lability items of the NPI, and a Behavioral Dyscontrol factor comprising elation/euphoria, disinhibition, aberrant motor behavior, sleep, and appetite items of the NPI. Mean cerebral metabolism for patients who scored positively on each of the two factors was compared with mean cerebral metabolism for those who did not.
  
  
  RESULTS
  Patients with AD who scored positively on the Agitation factor showed reduced glucose metabolism of the right temporal, right frontal, and bilateral cingulate cortex. In contrast, the Behavioral Dyscontrol factor did not show specific neurobiologic correlates.
  
  
  CONCLUSIONS
  Symptoms encompassed within the Agitation factor have distinct neurobiologic underpinnings. The precipitants, course, and outcomes related to these symptoms may be unique from other neuropsychiatric symptoms characteristic of AD. Special attention to treatment of agitated behaviors involving anger, aggressiveness, hostility, and irritability/emotional lability is warranted, because they appear to reflect a clinically relevant symptom cluster with unique underlying neurobiologic correlates.
authors.affiliation: Brain Behavior and Aging Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA; Geriatric Research Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA. Electronic address: gweissbe@gmail.com.
authors.forename: Gali H
authors.initials: GH
authors.lastname: Weissberger
authors.affiliation: Brain Behavior and Aging Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA; Geriatric Research Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Melrose
authors.affiliation: Brain Behavior and Aging Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA.
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Narvaez
authors.affiliation: Brain Behavior and Aging Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Dylan
authors.initials: D
authors.lastname: Harwood
authors.affiliation: Imaging Service, VA Greater Los Angeles Healthcare System, Los Angeles, CA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mandelkern
authors.affiliation: Brain Behavior and Aging Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: David L
authors.initials: DL
authors.lastname: Sultzer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D059907:Functional Neuroimaging; D006801:Humans; D007508:Irritable Mood; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011595:Psychomotor Agitation / Q000150:complications / Q000378:metabolism*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Alzheimer disease; FDG-PET; agitation; cerebral metabolism