title: Effects of occlusal disharmony on working memory performance and prefrontal cortex activity induced by working memory tasks measured by NIRS.
abstract: The effects of artificial occlusal disharmony (AOD) on working memory function and prefrontal cortex (PFC) activity in the elderly were examined. We evaluated working memory function using the modified Sternberg test (ST). We measured activity in the bilateral PFC during ST using near-infrared spectroscopy (NIRS) before and after AOD: the mandibular position was displaced by a splint for 10 min. AOD caused a gradual increase of oxyhemoglobin (oxy-Hb) in the bilateral PFC. The response time of ST (six digits) after AOD was longer than that before AOD. The oxy-Hb increase during ST after AOD was smaller than that before AOD. These results indicate that short-term physical stress caused by AOD decreased working memory function in elderly subjects, associated with a decrease of the evoked PFC activity during working memory function.
authors.affiliation: Division of Optical Brain Engineering, Nihon University School of Medicine, 30-1 Oyaguchi-uemachi, Itabasi-ku, Tokyo, 173-0032, Japan. sakatani@med.nihon-u.ac.jp.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
authors.affiliation: Division of Optical Brain Engineering, Nihon University School of Medicine, 30-1 Oyaguchi-uemachi, Itabasi-ku, Tokyo, 173-0032, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Tsujii
authors.affiliation: Division of Neurosurgery, Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Teruyasu
authors.initials: T
authors.lastname: Hirayama
authors.affiliation: Division of Neurosurgery, Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Katayama
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College, Chiba, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College, Chiba, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Amemiya
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College, Chiba, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
mesh_terms: D000368:Aged; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000503:physiopathology*; D008570:Memory, Short-Term; D010108:Oxyhemoglobins / Q000032:analysis; D017397:Prefrontal Cortex / Q000098:blood supply / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D013647:Task Performance and Analysis
chemical_list: D010108:Oxyhemoglobins