Sensitivity of functional tympanic membrane thermometry (fTMT) as an index of hemispheric activation in cognition

The measure of hemispheric activation in cognitive and clinical studies remains out of reach of many scientists due to cost, analysis complexity, and practical consideration of the techniques available such as fMRI, EEG, or EMG. The present study was conducted to determine whether infrared functional tympanic membrane thermometry (fTMT) is a measure of lateralised activation sensitive enough to be used in typical cognitive and clinical experiments. A total of 24 participants had their tympanic membrane temperature measured while performing a letter-matching task. Activation in the two hemispheres was manipulated by changing the proportion of matches occurring in the left and right visual fields and by varying the task complexity. Changes in fTMT due to the greater proportion of matches presented in one visual field and due to the modulation in task complexity were detected. These findings suggest that fTMT is a measure of broad lateralised cerebral activation sensitive enough for use in typical psychological studies.