RT  - Journal of Oral & Facial Pain and Headache
ID  - 10.11607/jofph.1976
T1  - Jaw Clenching Modulates Sensory Perception in High- But Not In Low-Hypnotizable Subjects
A1  - Michael Tal
A1  - Yair Sharav
K1  - heterotopic stimulation; hypnotic susceptibility; jaw clenching; pain modulation; sensory modulation
YR  - 2005
SP  - 76
AB  - <p><i><b>Aims:</b> To investigate the effect of jaw clenching on the sensations evoked at segmental and nonsegmental levels by painful and non-painful stimuli and in relation to hypnotic susceptibility. <b>Methods: </b>The effect of jaw clenching on painful and nonpainful sensations on the face and leg was studied in high-hypnotizable (HH) and low-hypnotizable (LH) subjects. Sixteen healthy subjects were selected and assigned to either the HH group (n = 8) or the LH group (n = 8). Painful and nonpainful electrical stimuli were deliv-ered in random order to the face and leg. The subjects rated the intensity of the evoked sensation on a visual analog scale (VAS) while clenching or not clenching their jaw. <b>Results: </b>Jaw clenching significantly attenuated the VAS sensory ratings of all the subjects under various conditions (F</i><span style="font-size: 12px; vertical-align: sub;">1-</span><span style="font-size: 12px; vertical-align: sub;">31</span><i> = 6.15, P &lt; .02). When the HH and LH subjects were analyzed separately, jaw clenching was found to be effective in reducing sensations only in the HH sub-jects (F</i><span style="font-size: 12px; vertical-align: sub;">1–15</span><i> = 8.30, P = .01), only those evoked in the face (segmen-tal level), and only those evoked by nonpainful stimuli (tied Z = 2.52, tied P &lt; .02). <b>Conclusion:</b> Sensory modulation produced by jaw clenching may be related to hypnotic susceptibility. On the whole, jaw clenching had a weak, local effect in modulating sensa-tion, in contrast to its known widespread effect on motor behav-ior. </i></p>