Patients with mild cognitive impairment display reduced auditory event-related delta oscillatory responses.
BACKGROUND
Event-related oscillations (ERO) may provide a useful tool for the identification of cognitive deficits in mild cognitive impairment (MCI) and Alzheimer's disease (AD). In the present study, we investigate peak-to-peak amplitude of auditory event-related delta oscillations of MCI subjects.


METHODS
The study included twenty-two consecutive patients with MCI recruited in neurology clinic and 21 age- and education-matched normal elderly controls. A classical auditory oddball paradigm was used in the experiments. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz, and O2 locations. The maximum peak-to-peak amplitudes for each subject's averaged delta response (0.5-2.2 Hz) were measured.


RESULTS
The amplitudes between groups differed significantly at the frontal and mid-centroparietal locations. ANOVA on delta responses revealed a significant effect for groups (F(1.41) = 4.84, P = 0.033), indicating a larger delta response for healthy controls than MCI subjects. Post hoc comparisons revealed that peak-to-peak delta response was significantly larger for healthy controls than for MCI over electrode sites F3, Fz, F4, Cz, C4, and Pz.


CONCLUSIONS
Event-related delta frequency band seems to be the most affected oscillatory response in cognitive impairment due to AD. Therefore, it deserves to be investigated as a candidate electrophysiological biomarker in further studies.
Brain Dynamics and Multidisciplinary Research Center, Dokuz Eylul University, Balçova, 35340 Izmir, Turkey ; Department of Neurosciences, Dokuz Eylul University, 35340 Izmir, Turkey ; Department of Neurology, Dokuz Eylul University, 35340 Izmir, Turkey ; Department of Psychology, Istanbul Arel University, 34295 Istanbul, Turkey.
Pınar
P
Kurt
Brain Dynamics and Multidisciplinary Research Center, Dokuz Eylul University, Balçova, 35340 Izmir, Turkey ; Department of Neurosciences, Dokuz Eylul University, 35340 Izmir, Turkey ; Brain Dynamics, Cognition and Complex Systems Research Center Istanbul Kültür University, 35156 Istanbul, Turkey.
Derya Durusu
DD
Emek-Savaş
Department of Neurology, Maltepe University, 34844 Istanbul, Turkey.
Kübra
K
Batum
Brain Dynamics, Cognition and Complex Systems Research Center Istanbul Kültür University, 35156 Istanbul, Turkey.
Bilge
B
Turp
Brain Dynamics, Cognition and Complex Systems Research Center Istanbul Kültür University, 35156 Istanbul, Turkey.
Bahar
B
Güntekin
Department of Neurology, Maltepe University, 34844 Istanbul, Turkey.
Sibel
S
Karşıdağ
Brain Dynamics and Multidisciplinary Research Center, Dokuz Eylul University, Balçova, 35340 Izmir, Turkey ; Department of Neurosciences, Dokuz Eylul University, 35340 Izmir, Turkey ; Department of Neurology, Dokuz Eylul University, 35340 Izmir, Turkey ; Brain Dynamics, Cognition and Complex Systems Research Center Istanbul Kültür University, 35156 Istanbul, Turkey.
Görsev Gülmen
GG
Yener
D000368:Aged; D000369:Aged, 80 and over; D001303:Auditory Cortex / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D003700:Delta Rhythm / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged