XXXX in @entity191 : influence of age, disease severity, and disease duration.

@entity1 @entity2845 @entity2003 @entity191
The aim of this cross-sectional study was to compare the role of aging in measures reflecting diurnal activity and immobility in 60 @entity191 @entity1 with predominant features of @entity2845 and @entity2003 and 100 healthy subjects aged 50 to 98 years. In the @entity1 , we also studied the relation between disease duration and subjective and objective measures of disease severity. Motor activity was recorded during 5 successive days at home with a wrist-worn activity monitor. For each subject, two mean measures reflecting the diurnal activity level and the relative proportion of activity and immobility were calculated. Diurnal measures of activity revealed in both groups a prominent absolute reduction of activity and an increase of the time spent without movement ("immobility") with advancing age. @entity191 @entity1 showed significantly lower values for both motor-activity measures than did the healthy subjects. The rate of the age-related decline of both diurnal activity measures in both groups, however, is comparable. Disease duration showed no relation with subjective and objective measures reflecting disease severity. This study shows that if care is taken to control for disease severity, the rate of the age-related decline of measures reflecting diurnal activity and immobility is similar in both groups. The lack of relation between disease duration and subjective and objective measures of disease severity suggests that the rate of progression of @entity191 can be reliably studied only by means of longitudinal studies.
