title: Mismatch Negativity and Ear Laterality in Alzheimer's Disease and in Mild Cognitive Impairment.
abstract: Cortical auditory event-related potentials (ERPs) were studied in order to measure mismatch negativity (MMN). Three groups of subjects were studied: patients with Alzheimer's disease (AD, n = 32), mild cognitive impairment (MCI, n = 44), and subjective memory complaints without cognitive decline (SMC, n = 27). A bottom up strategy was applied, and the right and left ears were stimulated monaurally.
  
  
  
  To investigate MMN in AD and MCI, and in a clinical reference group.
  
  
  
  ERPs were carried out with 500 tone pulses at 80 dBnHL. Each sequence included 80% standard tones (500 Hz) (f), and 20% deviant tones (1000 Hz) (r). MMN measurements were carried out by comparing the amplitudes of (f) and (r) recordings and to calculate the amplitude difference in μV for each group. The right and the left ears were analyzed separately.
  
  
  
  A left ear advantage (LEA) of MMN amplitude was demonstrated in the two groups with better cognition (the MCI and the SMC groups), but not in the AD group.
  
  
  
  The absence of MMN asymmetry in the AD group is possibly caused by a dysfunction to apprehend changes of tonal stimuli.
authors.affiliation: Department of Audiology and Neurotology, Karolinska University Hospital, Stockholm, Sweden.|Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Esma
authors.initials: E
authors.lastname: Idrizbegovic
authors.affiliation: Department of Audiology and Neurotology, Karolinska University Hospital, Stockholm, Sweden.|Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Hederstierna
authors.affiliation: Department of Audiology and Neurotology, Karolinska University Hospital, Stockholm, Sweden.|Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Rosenhall
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D004423:Ear / Q000503:physiopathology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics
keywords: Central auditory processing disorders; cortical auditory event-related potentials; left ear advantage; right ear advantage; subjective memory complaints