Influence of plantar cutaneous sensitivity on daily fluctuations of postural control and gait in institutionalized older adults: a hierarchical cluster analysis.

The aim of this study was to characterize daily fluctuations in postural control, gait and plantar cutaneous sensitivity in institutionalized older adults. Twenty-five older adults (>85 years old) living in a nursing home were recruited. Postural, gait and plantar cutaneous sensitivity parameters were collected at the following times: 8:00, 11:00, 14:00 and 17:00. Statistics were first calculated with the data from the whole group of the participants. A hierarchical cluster analysis was performed as a second step in order to determine if there was more than one pattern in the daily fluctuations of gait, postural control and plantar cutaneous sensitivity. When considering data from the whole group, results showed that postural control deteriorated from morning to the early afternoon and that gait improved from early to late morning. Daily fluctuations of plantar cutaneous sensitivity showed a decrease in tactile acuity in the afternoon. For most gait, postural control and plantar cutaneous sensitivity parameters, the hierarchical cluster analysis showed that there were three subgroups within the whole group of participants who had similar fluctuation patterns. Participants with the best tactile acuity, postural control and gait displayed relatively constant patterns without a period of increased risk of falling. By contrast, participants who presented a poor tactile acuity with a less efficient postural control and gait had greater daily fluctuations of plantar cutaneous sensitivity, with a marked decline of postural control and gait in the afternoon. In spite of a strong relationship between plantar cutaneous sensitivity and gait/postural control, the decline in postural control and gait observed in the afternoon could not be related to plantar sensation. It might rather relate to a cognitive function which is known to peak early in human circadian rhythms and to have a greater contribution in postural control regulation in the elderly than in young healthy subjects.