title: Tongue pressure as a novel biomarker of spinal and bulbar muscular atrophy.
abstract: OBJECTIVE
  This study aimed to explore the reliability and validity of tongue pressure measurement as a quantitative evaluation of swallowing function in patients with spinal and bulbar muscular atrophy (SBMA).
  
  
  METHODS
  This study enrolled 47 genetically confirmed patients with SBMA and 38 age- and sex-matched healthy controls. In both groups we measured tongue pressure using an intraoral pressure probe and assessed questionnaires that evaluated swallowing functions. We then analyzed the relationship between tongue pressure, functional scales, and the muscle weakness of other regions.
  
  
  RESULTS
  Levels of tongue pressure were decreased in patients with SBMA within 3 years from the onset of the disease compared to healthy controls (SBMA 15.3 ± 6.4 kPa; healthy controls 37.3 ± 9.6 kPa; p < 0.001). Test-retest analysis showed a high reliability in patients with SBMA (intraclass correlation coefficient = 0.986). Tongue pressure showed a strong correlation with bulbar-related functional scales. Decrease of tongue pressure was detected in patients who reported no subjective dysphagia, and repetition of swallowing compensated for tongue weakness in such subjects. In patients with SBMA, tongue pressure more strongly correlates with the strength of pharyngeal, neck, and upper limb musculatures than with that of the lower limbs.
  
  
  CONCLUSIONS
  Tongue pressure measurement is reliable and reflects swallowing function in patients with SBMA. The muscle strength of the tongue appears to decrease in SBMA before the awareness of subjective dysphagia, suggesting that tongue pressure measurement is a novel biomarker of SBMA and is applicable to early-stage detection.
authors.affiliation: From the Department of Neurology (T.M., M.K., H.B., K.S., N.S., A.H., A.A., H.W., G.S.), Nagoya University Graduate School of Medicine; Institute for Advanced Research (H.B.), Nagoya University; and Department of Speech Pathology and Audiology (S.T., M.Y.), Aichi-Gakuin University School of Health Science, Nagoya, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Mano
authors.forename: Masahisa
authors.initials: M
authors.lastname: Katsuno
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Banno
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
authors.forename: Noriaki
authors.initials: N
authors.lastname: Suga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hashizume
authors.forename: Amane
authors.initials: A
authors.lastname: Araki
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Watanabe
authors.forename: Seiya
authors.initials: S
authors.lastname: Tanaka
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D055534:Bulbo-Spinal Atrophy, X-Linked / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D003679:Deglutition / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D053581:Muscle Strength Dynamometer / Q000706:statistics & numerical data; D011312:Pressure; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014059:Tongue / Q000503:physiopathology*
chemical_list: D015415:Biomarkers