Interhemispheric transfer time correlates with white matter integrity of the corpus callosum in healthy older adults.

The corpus callosum (CC) has been identified as an important structure in the context of cognitive aging (Fling et al., 2011). Interhemispheric transfer time (IHTT) is regularly used in order to estimate interhemispheric integration enabled by the CC (Marzi, 2010; Nowicka and Tacikowski, 2011). However, only little is known with regards to the relationship between IHTT and the structural properties of the CC with only few studies with specific samples and methods available (Whitford et al., 2011). Thus, the present study aimed at investigating this relationship applying an event-related potentials (ERP) based approach of estimating IHTT as well as diffusion weighted imaging (DWI) with fractional anisotropy (FA) as an indicator of white matter integrity (WMI) of the genu, corpus and splenium of the CC. 56 healthy older adults performed a Dimond Task while ERPs were recorded and underwent DWI scanning. IHTT derived from posterior electrode sites correlated significantly with FA of the splenium (r = -0.286*, p = .03) but not the corpus (r = -0.187, p = .08) or genu (r = -0.189, p = .18). The present results support the notion that IHTT is related to WMI of the posterior CC. It may be concluded that ERP based IHTT is a suitable indicator of CC structure and function, however, likely specific to the interhemispheric transfer of visual information. Future studies may wish to confirm these findings in a more divers sample further exploring the precise interrelation between IHTT and structural or functional properties of the CC.

The impact of aging on interhemispheric transfer time and respective sex differences.

Age-related cognitive decline has been attributed to degeneration of the corpus callosum (CC), which allows for interhemispheric integration and information processing [22,69]. Along with decreased structural integrity, altered functional properties of the CC may cause impaired cognitive performance in older adults, yet this aspect of age-related decline remains insufficiently researched [59]. In this context, potential sex-related differences have been proposed [31,58]. A promising parameter, which has been suggested to estimate functional properties of the CC is the interhemispheric transfer time (IHTT), which is ideally obtained from event-related potentials (ERP) evoked by lateralized stimuli [45]. To examine the possible functional consequences of aging with regards to the CC, the present study investigated the IHTT of 107 older (67.69 ±â€¯5.18y) as well as of 23 younger participants (25.09 ±â€¯2.59y). IHTT was obtained using an established letter matching task and targeting early N170 ERP components at posterior electrode sites. The results revealed significantly elongated IHTT in older compared to younger participants, but no significant sex differences. Furthermore, there was a significant positive correlation between IHTT and age, predominantly driven by the female participants. The present findings add support to the notion, that IHTT is subject to age-related elongation reflecting impaired interhemispheric transmission. Age-related decline in women appears to occur at a different age range compared to men.

Cluster Randomized Controlled Trial on the Effects of 12 Months of Combined Exercise Training during Hemodialysis in Patients with Chronic Kidney Disease-Study Protocol of the Dialysis Training Therapy (DiaTT) Trial.

Patients with chronic kidney disease (CKD) on hemodialysis (HD) experience treatment-related immobility and physical deconditioning, which is responsible for an increased risk of frailty and a high burden of multi-morbidity. Exercise has been shown to counteract this vicious cycle; however, its effectiveness has only been investigated in small cohorts. Therefore, the objective of the Dialysis Training Therapy (DiaTT) trial will be to assess the effects of a 12-month intradialytic exercise program on physical functioning, frailty and health economics in a large cohort of HD patients in a real-world setting. DiaTT will be a prospective, cluster-randomized (1:1), controlled, multi-center, interventional clinical trial across 28 dialysis units, aiming at the recruitment of >1100 CKD patients on HD. The intervention group will receive 12 months' intradialytic exercise (combined aerobic and resistance training), whereas the usual care group will not receive intervention. The primary endpoint will be a change on the sit-to-stand test (STS60) result between baseline and 12 months. Secondary endpoints will include physical functioning, frailty, quality of life, 3-point MACE, hospitalizations, survival, quality of HD, health literacy and health care costs. By including almost as many patients as previously investigated in smaller trials, DiaTT will be the largest randomized, controlled trial assessing frailty, quality of life and mortality in the field of nephrology.