A general principle of EEG measurements is that each recorded channel represents the difference in activity between two electrodes on the head. Use of different reference schemes between studies may contribute, among other factors, to inconsistencies of findings (Hagemann, 1998). This study investigates the effect of choice of reference on the CAEPs to auditory and audiovisual stimuli in normal hearing adults. The CAEPs were recorded to natural speech tokens presented as auditory, visual and audiovisual stimuli. The CAEPs were recorded with FCz as a reference and re-referenced offline to right mastoid, left mastoid, mean mastoids and an average reference respectively. The amplitude of the average reference waveforms were significantly smaller compared to the other references. Three of the four references (right, left and mean mastoids) showed a temporal facilitation with shorter latencies for N1 in the audiovisual condition. No latency differences were found for the average reference. All references showed a modality effect with audiovisual stimuli resulting in significantly enhanced N1/P2 amplitudes compared to auditory. The results suggest that the choice of reference has a significant effect on the temporal analysis of CAEPs and emphasise the importance of indication and justification of any choice of reference.
|Number of pages||1|
|Journal||Clinical EEG and neuroscience|
|Publication status||Published - 2012|
|Event||Australasian Cognitive Neurosciences Conference (21st : 2011) - Sydney|
Duration: 9 Dec 2011 → 12 Dec 2011