Reliability and validity of classification of senile postural deformity in mass examinations

Nakada (1988) divided senile postural deformities into four types by visual observation: an extended type, an S-shaped type, a flexed type, and a hand-on-the-lap type. The purpose of this study was to investigate the inter-rater reliability and the discriminant validity of assessing the elderly spinal posture using a posture-measuring device developed by us and dividing postural deformities into the four types of Nakada's classification. Seventy-seven elderly persons (52 women and 25 men) who lived independently participated in the study. The average age of the subjects was 73 years (range, 65 to 84 years). The type of the senile postural deformity was determined by three judges using our posture-measuring device in combination with Nakada's classification. The rate of agreement of the classification was 92.2%. This method had a significantly high rate of inter-rater reliability. The thoracic kyphotic angle was larger in the S-shaped type than in the normal, extended type, and flexed type. The lumbar lordotic angle was also larger in the S-shaped type than in the extended type, flexed type, and hand-on-the-lap type. In the hand-on-the-lap type, the mean of the lumbar lordotic angle was much smaller. The lumbosacral angle was smaller in the extended type than in the normal, S-shaped type, and flexed type. With the analysis of x-ray photographs, this method appeared to have discriminant validity as a measure of senile postural deformity. The combination of our posture-measuring device and Nakada's classification would be useful to classify senile postural deformities in mass examinations.