Changes in sensory and pain perception thresholds after linear polarized near-infrared light radiation in the trigeminal region.
Linearly polarized light in the near-infrared portion of the spectrum has recently been associated with a variety of musculoskeletal disorders including temporomandibular disorders. The purpose of this study was to determine whether short-term linearly polarized near-infrared light radiation in the trigeminal region affects sensory and pain perception thresholds in the trigeminally mediated region and in the cervically mediated region of normal subjects. Thirty-five normal female volunteers participated in this study. Each subject received an 8-minute course of irradiation in the right cheek, and sensory/nociceptive perception thresholds were compared before and immediately after the irradiation in the right cheek and the right forearm. As a result, this study demonstrated a significant elevation of the heat-induced pain threshold in both regions and a tendency for the warm sensation threshold to elevate in the cervical region. In addition, a significant increase in vibratory sensitivity was observed in the trigeminal region. In conclusion, our results provided additional evidence that the warming sensation has a negative feedback influence on heat pain intensity in humans, and provides a theoretical basis for the application of linear polarized near-infrared light radiation to the trigeminal region.
Kashima
Koji
K
Department of Oral and Maxillofacial Surgery, Miyazaki Medical College, Hyotake-cho, Miyazaki, Japan. kojikash@post.miyazaki-med.ac.jp
Watanabe
Naoshi
N
Higashinaka
Shuichi
S
Maeda
Sho
S
Shiba
Ryosuke
R
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D003080:Cold Temperature; D005246:Feedback; D005260:Female; D005542:Forearm / Q000294:innervation; D006358:Hot Temperature; D006801:Humans; D007259:Infrared Rays; D008406:Masseter Muscle / Q000294:innervation; D010101:Oxygen Consumption / Q000502:physiology; D010146:Pain / Q000503:physiopathology; D017288:Pain Threshold / Q000528:radiation effects*; D011674:Pulse; D012684:Sensory Thresholds / Q000528:radiation effects*; D014276:Trigeminal Nerve / Q000528:radiation effects*; D014732:Vibration