Abstract
<title>Abstract</title> <p>Maintaining independence in self-care is a major objective in geriatric long-term care; however, commonly used assessment tools may have limited sensitivity in individuals with severe mobility impairment. Although the Barthel Index is widely applied in clinical practice, its ability to differentiate among older adults with substantial functional decline remains uncertain. This cross-sectional study examined the diagnostic performance of the de Morton Mobility Index (DEMMI) and the Barthel Index in 83 residents of long-term care facilities, using the Katz Index as the reference standard for self-care dependency. Receiver operating characteristic analysis identified optimal cut-off values of 38.5 for the DEMMI and 52.5 for the Barthel Index for distinguishing between independent older adults and those requiring moderate or substantial assistance in self-care. Both instruments demonstrated good-to-excellent discriminative ability, although the DEMMI showed a slightly higher area under the curve (90.9%) than the Barthel Index (86.8%). A floor effect was observed only for the Barthel Index, whereas the DEMMI demonstrated a broader distribution of scores at lower mobility levels. These findings suggest that, despite comparable overall discriminative performance, the DEMMI may provide advantages in assessing older adults with severe mobility limitation, thereby supporting more precise individualized care planning and interdisciplinary decision-making in long-term care settings.</p>