Using high-resolution imaging to study the impact of the Kalogon wheelchair cushion on blood flow in the gluteal area.

AIM OF THE STUDY: This study investigated how the air-bladder offloading mode of the Orbiter by Kalogon wheelchair cushion (Orbiter) affected blood flow in the gluteal region of non-disabled subjects. The hypothesis was that the cushion's offloading mode would improve blood flow, resulting in reduced reactive hyperemia when compared to the static setting, or Loaded Control (LC). Furthermore, the study proposed a technique using a high-resolution image laser speckle contrast system to measure blood flow in the gluteal area. METHODS: Two procedures were carried out, one with the participant sitting on a cushion in LC, and the second, the cushion was set to offloading mode. Blood flow was measured through data imaging after each procedure. Three trials were performed, starting and ending in different cushion bladders. Customized algorithms were used to select regions of interest on the images for calculations. The Wilcoxon Signed-Rank Test was conducted to compare the offloads and loaded control values of each region of interest. Results were considered significant at α = 0.05. RESULTS: Ten healthy, non-disabled adults participated in the study, seven females and three males. There were no significant differences among the participants. However, results showed that seven subjects tended to decrease reactive hyperemia in the offload sequence of trial when the last two bladders offloaded were the sacrum followed by the right ischial tuberosity. CONCLUSIONS: The high-resolution imager showed that the Orbiter Offloads helped reduce reactive hyperemia in seven subjects, potentially improving blood flow. More research is necessary to comprehend the mechanisms of these effects fully.

Cortical hemodynamic responses induced by low-intensity transcranial ultrasound stimulation of mouse cortex.

Ultrasound-mediated neuromodulation is emerging as a key technology for targeted noninvasive brain stimulation, but key insights into its effects and dose-response characteristics are still missing. The purpose of this study is to systematically evaluate the effect of low-intensity transcranial ultrasound stimulation (TUS) on complementary aspects of cerebral hemodynamic. We simultaneously record the EMG signal, local field potential (LFP) and cortical blood flow (CBF) using electrophysiological recording and laser speckle contrast imaging under ultrasound stimulation to simultaneously monitor motor responses, neural activities and hemodynamic changes during the application of low-intensity TUS in mouse motor cortex, using excitation pulses which caused whisker and tail movement. Our experimental results demonstrate interdependent TUS-induced motor, neural activity and hemodynamic responses that peak approximately 0.55s, 1.05s and 2.5s after TUS onset, respectively, and show a linear coupling relationship between their respective varying response amplitudes to repeated stimuli. We also found monotonic dose-response parametric relations of the CBF peak value increase as a function of stimulation intensity and duration, while stimulus duty-cycle had only a weak effect on peak responses. These findings demonstrate that TUS induces a change in cortical hemodynamics and LSCI provide a high temporal resolution view of these changes.