We investigated the subjective disability in actions of daily life by a self-registering questionnaire study on 102 patients (50 males and 52 females, mean age 67.7 years old), who visited our institutions without any vertiginous diseases. Multiple regression analysis demonstrated that subjective disability in daily actions depended on age, joint problems and employment, with age being the most significant factor among them. Age-dependent actions were walking in the dark, going up and down stairs, standing with the area of soles or the head position changed, sitting and standing up, standing upright in a moving vehicle. Going up and down stairs, sitting and standing up, standing upright in a moving vehicle were significantly influenced not only by age but also joint problems. We thought that subjective disability in the age-dependent actions were caused mainly by the deterioration of balance function. Discriminant functions showed that the borderline age for subjective disability in daily actions was around 70 years old. We suggest that the border of age can be applied to the subjective disability due to aging of balance function and also the subjective disability due to joint problems.
