<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Hi Piers,</div><div><br></div><div>Were your subjects regular hearing aid device users? If so, which ear was commonly used for this?</div><div><br></div><div>I hope this helps.</div><div>Best,</div><div><br></div><div>Javier Lopez-Calderon</div><div><br></div><div><br></div><div><br></div><div><br></div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span style="font-family: Helvetica; font-size: medium; color: rgb(127, 127, 127); "><b>From: </b></span><span style="font-family: Helvetica; font-size: medium; ">Piers Dawes <<a href="mailto:Piers.Dawes@manchester.ac.uk" style="color: blue; text-decoration: underline; ">Piers.Dawes@manchester.ac.uk</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span style="font-family: Helvetica; font-size: medium; color: rgb(127, 127, 127); "><b>Subject: </b></span><span style="font-family: Helvetica; font-size: medium; "><b>[Eeglablist] Auditory ERP asymmetry</b><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span style="font-family: Helvetica; font-size: medium; color: rgb(127, 127, 127); "><b>Date: </b></span><span style="font-family: Helvetica; font-size: medium; ">July 12, 2012 3:47:39 AM PDT<br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span style="font-family: Helvetica; font-size: medium; color: rgb(127, 127, 127); "><b>To: </b></span><span style="font-family: Helvetica; font-size: medium; ">"<a href="mailto:eeglablist@sccn.ucsd.edu" style="color: blue; text-decoration: underline; ">eeglablist@sccn.ucsd.edu</a>" <<a href="mailto:eeglablist@sccn.ucsd.edu" style="color: blue; text-decoration: underline; ">eeglablist@sccn.ucsd.edu</a>><br></span></div><br><br><div class="WordSection1" style="page: WordSection1; "><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Dear list<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">We have obtained an odd asymmetric auditory ERP. Does anyone have an explanation? Any suggestions would be welcome.<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">We recorded ERPs to pure tone beeps of 500 and 3000 Hz at 3 intensity levels. Tones were randomised and played separately to left and right ears, with responses recorded at Cz with a nose tip reference using a Neuroscan system. Insert headphones were calibrated before testing and re-checked after; left and right headphones provide identical levels of output. Participants were 58 older people (mean age 70 years) with age-related hearing loss (Mean HL of 45 dB at 2kHz). Selection criteria included symmetrical hearing (not greater than 15dB difference at any frequency), and overall mean HL is symmetrical.<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Grand mean ERPs are higher in amplitude for tones played to left ear compared to right ear (by about ~1uV for N1 and ~.5uV for P2), and this is a consistent pattern among participants. Latencies are similar. I would have thought amplitudes should also be very similar between left and right ear. What is happening here?<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Thanks for your help<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">Piers Dawes PhD<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">Audiology and Deafness Research Group<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">School of Psychological Sciences<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">Ellen Wilkinson Building<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">University of Manchester<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">Manchester M13 9PL<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-size: 10pt; font-family: Arial, sans-serif; color: navy; ">Tel: +44 (0)161 30 61758H</span></div></div></div></body></html>