Effect of a Home-Based Exercise Program on Indices of Physical Function and Quality of Life in Elderly Maintenance Hemodialysis Patients.

Background: Patients on maintenance hemodialysis (MHD) exhibit muscle wasting and impaired physical function which can be reversed with regular exercise, but accessibility to exercise programs for this unique population is lacking. We assessed the efficacy of a home-based exercise program on a broad range of indices of physical function, quality of life (QoL), and cognitive decline in patients with MHD. Design and Methods: Twenty-eight MHD patients, mean age 66 ± 7 years, were randomized to a 12-week home-based, case-managed aerobic and resistance exercise program or to usual care (13 exercise and 15 usual care). Comparisons were made for peak VO2, ventilatory inefficiency, 6-min walk test (6MWT), 1-min sit-to-stand (1STS), muscle strength, body composition, QoL, and cognitive measures. Results: Peak VO2 improved significantly in the exercise group (p = 0.01 between groups); exercise time improved by 41 and 36% at the ventilatory threshold and peak exercise, respectively (p < 0.01 between groups), but there were no differences in ventilatory efficiency. Trends for improvements in 6MWT and 1STS in the exercise group were observed, but no differences were observed in strength or body composition. Among measures of QoL, general health determined by the SF-36 improved in the exercise group, but there were no differences between groups in cognitive function. Conclusions: MHD patients improved exercise capacity and some indices of QoL following a 12-week home-based exercise program. Home-based exercise is feasible for patients undergoing MHD and may help to obviate accessibility barriers to regular exercise

Diffusion tensor tractography of brainstem fibers and its application in pain.

Evaluation of brainstem pathways with diffusion tensor imaging (DTI) and tractography may provide insights into pathophysiologies associated with dysfunction of key brainstem circuits. However, identification of these tracts has been elusive, with relatively few in vivo human studies to date. In this paper we proposed an automated approach for reconstructing nine brainstem fiber trajectories of pathways that might be involved in pain modulation. We first performed native-space manual tractography of these fiber tracts in a small normative cohort of participants and confirmed the anatomical precision of the results using existing anatomical literature. Second, region-of-interest pairs were manually defined at each extracted fiber's termini and nonlinearly warped to a standard anatomical brain template to create an atlas of the region-of-interest pairs. The resulting atlas was then transformed non-linearly into the native space of 17 veteran patients' brains for automated brainstem tractography. Lastly, we assessed the relationships between the integrity levels of the obtained fiber bundles and pain severity levels. Fractional anisotropy (FA) measures derived using automated tractography reflected the respective tracts' FA levels obtained via manual tractography. A significant inverse relationship between FA and pain levels was detected within the automatically derived dorsal and medial longitudinal fasciculi of the brainstem. This study demonstrates the feasibility of DTI in exploring brainstem circuitries involved in pain processing. In this context, the described automated approach is a viable alternative to the time-consuming manual tractography. The physiological and functional relevance of the measures derived from automated tractography is evidenced by their relationships with individual pain severities