Mental demand, asymmetries, and tympanic membrane temperature (TMT)

Previous research has indicated that tympanic membrane temperature (TMT) is inversely correlated with cerebral blood flow and change in cerebral blood flow is a neurological measure of mental workload. We investigated whether TMT changed as a function of time on task and type of picture exposure (nature vs. urban) when participants performed two sessions of the original Sustained Attention to Response Task (SART: Robertson et al., 1997) that were separated by exposure to the pictures. Tympanic membrane temperature was recorded for both ears before and after each SART. We found a trend for declining temperature with time in the left ear and not the right ear. This finding is inconsistent with previous research that associated right-hemisphere dominance for vigilance tasks and suggested that SART is not a vigilance task. Further, the temperature asymmetries correlated with SART performance, which is in accordance with research by Helton (2010).