title: Comparison of memory fMRI response among normal, MCI, and Alzheimer's patients.
abstract: OBJECTIVE
  To determine whether an fMRI memory encoding task distinguishes among cognitively normal elderly individuals, patients with mild cognitive impairment (MCI), and patients with early Alzheimer's disease (AD).
  
  
  METHODS
  Twenty-nine subjects (11 normal, 9 MCI, 9 AD) were studied with an fMRI memory encoding task. A passive sensory task was also performed to assess potential intergroup differences in fMRI responsiveness. Activation in the medial temporal lobe for the memory task and in the anatomic rolandic area for the sensory task was studied. Intergroup comparisons were performed using receiver operating characteristic (ROC) analyses. The ROC method provides rigorous control of artifactual false-positive "activation." Subjects were tested for recall and recognition of the encoding task stimuli following the fMRI study.
  
  
  RESULTS
  Medial temporal lobe activation was greater in normal subjects than MCI and AD patients (p = 0.03 and p = 0.04). There was no difference between AD and MCI patients in fMRI memory performance [corrected]. There was an association between fMRI memory activation (area under the ROC curve) and post-fMRI performance on recognition and free recall. There was no difference among the three groups on the sensory task.
  
  
  CONCLUSIONS
  MCI and AD patients had less medial temporal lobe activation on the memory task than the normal subjects but similar activation as normal subjects on the sensory task. These findings suggest decreased medial temporal activation may be a specific marker of limbic dysfunction due to the neurodegenerative changes of AD. In addition, fMRI is sufficiently sensitive to detect changes in the prodromal, MCI, phase of the disease.
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Machulda
authors.forename: H A
authors.initials: HA
authors.lastname: Ward
authors.forename: B
authors.initials: B
authors.lastname: Borowski
authors.forename: J L
authors.initials: JL
authors.lastname: Gunter
authors.forename: R H
authors.initials: RH
authors.lastname: Cha
authors.forename: P C
authors.initials: PC
authors.lastname: O'Brien
authors.forename: R C
authors.initials: RC
authors.lastname: Petersen
authors.forename: B F
authors.initials: BF
authors.lastname: Boeve
authors.forename: D
authors.initials: D
authors.lastname: Knopman
authors.forename: D F
authors.initials: DF
authors.lastname: Tang-Wai
authors.forename: R J
authors.initials: RJ
authors.lastname: Ivnik
authors.forename: G E
authors.initials: GE
authors.lastname: Smith
authors.forename: E G
authors.initials: EG
authors.lastname: Tangalos
authors.forename: C R
authors.initials: CR
authors.lastname: Jack
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D001931:Brain Mapping; D003072:Cognition Disorders / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D011939:Mental Recall; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D012372:ROC Curve; D013003:Somatosensory Cortex / Q000473:pathology / Q000503:physiopathology*