Catherine R Jutzeler, Lukas D Linde, Jan Rosner, Michele Hubli, Armin Curt, and John LK Kramer

Laser and contact heat evoked potentials (LEPs and CHEPs, respectively) provide an objective measure of pathways and processes involved in nociception. The majority of studies analyzing LEP or CHEP outcomes have done so based on conventional, across trial averaging. This approach is subject to considerable latency jitter and ignores potentially relevant information contained in single trials. The current study addressed the advantage of analyzing nociceptive evoked potentials based on individual responses to noxious stimulation. Single trial and conventional averaging were applied to data previously collected in 90 healthy subjects from 3 stimulation locations on the upper limb. The primary analysis focused on relationships between single and across trial averaged CHEP outcomes (i.e., N2P2 amplitude and latencies) and subject level independent variables (i.e., age, sex, height, and pain rating), which were examined by way of linear mixed model analysis. In fully adjusted models, age and pain ratings were the only significant subject level independent variables associated with CHEP outcomes that interacted with analysis method. The strength of relationships, measured by linear fit, were consistently increased for single trial compared to conventional across trial averaged CHEPs outcomes. Single trial averaging improved the biological interpretability of CHEPS and should be incorporated as a standard analytical technique in future studies.

Who should we contact?: Dr. Catherine Jutzeler or Prof. John Kramer