IADR Abstract Archives
Frequency of Referred Sensations Evoked by Glutamate and Mechanical Stimulation
Objectives: The aims of this study were to assess whether participants who experienced referred sensations (RS) in the trigeminal region would experience it at the same frequency for both glutamate and mechanical stimulation. Secondary aims were to assess if increased pain ratings would increase the chances of eliciting RS and if RS location overlaps between different sessions for each participant.
Methods: The present randomized, double-blind, controlled, crossover study recruited 60 healthy participants who were assessed in two sessions at least 2 days apart. In both sessions, pressure was applied to the masseter muscle with four different forces (0.5, 1, 2 and 4 kg), and glutamate (1 mol/L or 0.25mol/L) was injected into the same area. Participants were asked to rate their perceived masseter sensations and rate and draw any RS they experienced.
Results: No difference in number of participants that reported RS following glutamate injection when compared to mechanical-stimulation was found. More participants reported RS when the stimulus was painful compared to a non-painful stimulus. Furthermore, it was shown the more intense the stimulus, the higher the frequency of RS. Finally, RS center-of-gravity location was very similar between the 2 sessions.
Conclusions: In summary, RS was elicited in healthy individuals through both modalities and no differences in frequency of RS were observed. Hence, RS does not seem to be modality dependent and only the painfulness of the stimulus caused an increase in frequency of RS. Finally, RS location for each participant was similar in both sessions possibly indicating a preferred location of referral. These findings may have implications for our understanding of RS in clinical pain conditions.
Methods: The present randomized, double-blind, controlled, crossover study recruited 60 healthy participants who were assessed in two sessions at least 2 days apart. In both sessions, pressure was applied to the masseter muscle with four different forces (0.5, 1, 2 and 4 kg), and glutamate (1 mol/L or 0.25mol/L) was injected into the same area. Participants were asked to rate their perceived masseter sensations and rate and draw any RS they experienced.
Results: No difference in number of participants that reported RS following glutamate injection when compared to mechanical-stimulation was found. More participants reported RS when the stimulus was painful compared to a non-painful stimulus. Furthermore, it was shown the more intense the stimulus, the higher the frequency of RS. Finally, RS center-of-gravity location was very similar between the 2 sessions.
Conclusions: In summary, RS was elicited in healthy individuals through both modalities and no differences in frequency of RS were observed. Hence, RS does not seem to be modality dependent and only the painfulness of the stimulus caused an increase in frequency of RS. Finally, RS location for each participant was similar in both sessions possibly indicating a preferred location of referral. These findings may have implications for our understanding of RS in clinical pain conditions.