The assessment of modality effect on the p300-event related potential elicited by auditory and visual oddball paradigm in healthy elderly people aged 50 and older

OBJECTIVE: The aim of the study is the assessment of differences generated by sensory modality on peak amplitude, peak latency, and mean amplitude of P300 event related potential component elicited by auditory, and visual two stimuli oddball paradigm in healthy elderly individuals aged 50 and over. METHOD: In this study presence of order effect was investigated firstly. For this purpose, 30 healthy participants aged 50 and over were separated into two demographically matched groups in equal numbers; one of the groups experienced auditory two stimuli oddball paradigm first and then the visual paradigm and the other group experienced them in reversed order. Modality analysis included data from 105 healthy individuals aged 50 and over. Electroencephalography data were recorded during auditory, and visual two stimuli oddball paradigms and peak amplitude, peak latency, and mean amplitude were measured on Fz, Cz, Pz and in the time window after the stimulus 250-550ms. RESULTS: There were no order effect for the auditory oddball paradigm on the peak amplitude [F(2,56)=.738,p=.440], peak latency [F(2,56)=.028,p=.903], and mean amplitude [F(2,56)=.669,p=.190] and for the visual oddball paradigm on the peak amplitude [F(2,56)=2,324,p=.118], peak latency [F(2,56)=3,309,p=.058], and mean amplitude [F(2,56)=.779,p=.414]. In the modality analysis, there were significant effects on peak amplitude [F(2,208)=47,317,p<.001] and mean amplitude [F(2,208)=64.793,p<.001]. In the post-hoc analysis auditory responses were lower than visual responses (all, p<.015). There were no significant modality effect on peak latency [F(2,208)=2.610, p=.092]. CONCLUSION: This study showed some differences generated by sensory modality effect on the P300 responses elicited by auditory and visual oddball paradigm. Keywords: Event related potential, Modality, P300, Auditory, Visual