Absolute reliability of tongue pressure measurement in young healthy adults and elderly patients with certification of needing long-term care or support

Aim We aimed to determine systematic bias and the range of random error in tongue pressure measurements among young healthy adults and elderly patients with certification of requiring long-term care or support, considering sex, and to establish a measurement method. Methods Subjects were 226 adults (88 young healthy adults and 138 elderly patients with certification of requiring long-term care or support). Tongue pressure was measured thrice. Bland-Altman analysis was performed for the first and second trials, and second and third trials. Results Fixed bias was revealed for the first and second trials among young healthy adults. Systematic bias was not found for the second and third trials. Fixed bias was revealed for the first and second trials among elderly patients, with a proportional bias with a negative slope for the second and third trials. For young healthy adults, the minimal detectable change was 6.0 and 5.4 kPa in males and females, respectively. For elderly patients, the limit of agreement ranged from -5.9 to 8.6 and from -5.4 to 8.8 kPa in males and females, respectively. Conclusions There was a difference in systematic bias in tongue pressure measurement between young healthy adults and elderly patients with certification of needing long-term care or support. In young healthy adults, the third trial results showed stability, whereas they decreased in elderly patients. In elderly patients, it was suggested that the number of measurements reduced from three to two when a maximum value was adopted. No differences were observed among sexes in either young or elderly patients. Geriatr Gerontol Int 2020; center dot center dot: center dot center dot-center dot center dot.