The influence of psychological state on the masseteric exteroceptive suppression reflex and somatosensory function

• Published in: Clinical Neurophysiology Vol. 119; no. 10; pp. 2321 - 2328
• Main Authors: Komiyama, Osamu, Wang, Kelun, Svensson, Peter, Arendt-Nielsen, Lars, Kawara, Misao, Laat, Antoon De
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.10.2008; Elsevier BV; Elsevier Science
• Subjects: Adult; Anxiety; Anxiety - physiopathology; Biological and medical sciences; Electrodiagnosis. Electric activity recording; Electromyography; Electromyography - methods; Exteroceptive suppression; Female; Fundamental and applied biological sciences. Psychology; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Masseter Muscle; Masseter Muscle - physiopathology; Medical sciences; Nervous system; Neural Inhibition; Neural Inhibition - physiology; Neurology; Pain; Pain - physiopathology; Pain - psychology; Pain detection threshold; Physical Stimulation; Physical Stimulation - methods; Psychological status; Reaction Time; Reaction Time - physiology; Reflex; Reflex - physiology; Reflex - radiation effects; Reflex threshold; Sensory Thresholds; Sensory Thresholds - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Tactile detection threshold; Touch; Vertebrates: nervous system and sense organs; Young Adult; Psychological status; Tactile detection threshold; Masseter muscle; Reflex threshold; Pain detection threshold; Exteroceptive suppression; Human; Nociception; Affect affectivity; Evaluation; Threshold detection; E reflex; Electrophysiology; Orofacial pain; Silent period; Habituation; Electrodiagnosis; Fear; Detection threshold; Anxiety; Electromyography
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2008.07.004

This study examined the somatosensory function in the trigeminal region and quantitative measures of the exteroceptive suppression (ES) period in the masseteric EMG, in relation to a psychological evaluation. The ES in the surface EMG was recorded from the left masseter muscle in 12 men and 12 women. The stimulation intensity at which the ES appeared first and the lowest intensity at which the subjects reported it to be painful were defined as the electrical reflex threshold and electrical pain threshold, respectively. Three experimental sessions were scheduled. The state and trait anxiety inventory was used to evaluate the psychological status. The electrical reflex threshold significantly decreased ( p < 0.01), and the electrical pain threshold significantly increased ( p < 0.01) over the sessions in line with the effect on the state anxiety inventory ( p < 0.05). The present results illustrate that reflex parameters and electrical pain thresholds are associated with state anxiety. Possibly, habituation or decreased fear from the experimental set-up may play a role. This is important when electrophysiology or quantitative sensory testing is used to assess trigeminal nociception, e.g., in orofacial pain conditions.