Exteroceptive suppression of masseter muscle: assessment of two methods for quantitating suppression periods.
OBJECTIVE
The late exteroceptive suppression period (ES2) of the masseter muscle is conventionally quantified by a combination of measures of duration, amplitude, or mean activity. The combination of measures makes it difficult to compare ES2s obtained from different set-ups. An unbiased method for quantitating ES2 is introduced allowing ranking of ES2s. The introduced method is utilized to evaluate stimulus and recording conditions under which ES2 is maximal.


METHODS
Fifteen male volunteers participated in 3 experiments designed to determine the effect of level of teeth clenching, stimulus intensity, and perceived pain intensity on the ES2.


RESULTS
Coefficients of variance (1 h/1 month) were: duration: 11%/43%, latency: 9%/12%, and magnitude of suppression: 11%/12%. A level of teeth clenching of 66% of maximal voluntary bite force, and a stimulus intensity below pain detection threshold was associated with maximal magnitude of suppression of ES2.


CONCLUSIONS
The introduced method is reproducible and allows ranking and stimulus-response estimations of ES2. It is suggested that ES2 does not reflect activity along the nociceptive pathways in the trigeminal region.
Hansen
P O
PO
Danish Pain Research Center and Dept of Neurology, Aarhus University Hospital.
Svensson
P
P
Nielsen
J
J
Arendt-Nielsen
L
L
Jensen
T S
TS
D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods / Q000592:standards*; D005069:Evaluation Studies as Topic; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000294:innervation / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology; D011930:Reaction Time; D012016:Reference Values; D012018:Reflex / Q000502:physiology; D015203:Reproducibility of Results; D014276:Trigeminal Nerve / Q000502:physiology*; D014836:Volition / Q000502:physiology