Visualizing motor control using rehabilitative ultrasound
During his presentation at the international symposium on Rehabilitative Ultrasound Imaging (RUSI), which was held in Madrid June 2016, Paul Hodges discussed the utility of ultrasound in evaluating the function of muscles with a role in lumbopelvic control. Understanding physiology and biomechanics is necessary to study lumbopelvic dysfunctions. Trunk control depends on a complex integrated system model which includes pelvic floor function, breathing pattern and lumbopelvic control. Ultrasound is a valuable tool to understand muscle activation patterns and propose an individualized treatment.
To have an optimal motor control of the spine and the pelvis, a correct coordination of functions, including a modulation of muscle forces and the integrity of the fascial system, is needed. An example of the utility of ultrasounds in measuring integrity of fascial tissues is the measure of the linea alba: not only the inter-rectus distance, but also changes in linea alba with different muscle activation can be determined. The ability of the muscular system to create sufficient tension in fascial structures is necessary to assure optimal load transfers: transversus abdominis contraction can generate tension in linea alba, which could positively impact transfer mechanics in abdominal wall.
In optimal control there is a balance between movement and stiffness: segmental contraction of deep muscles helps to provide a stability while permitting the movement. Nevertheless, the use of superficial muscles to stabilize the pelvis creates a co-contraction which produces stiffness. Ultrasound provides a unique tool for both, assessment and training, to get optimal motor control. It can a be used: 1) as a feedback instrument for cognitive training; 2) to help in the first stage of motor learning; and 3) as a feedback of quality of performance. Speed of muscle contraction and ability for muscle relaxation are also key factors which can be evaluated using ultrasound.
There is an important contribution of respiratory and pelvic floor muscles to lumbopelvic control. Urinary continence and a correct breathing pattern are necessary to assure a correct lumbopelvic function. Ultrasound can help to evaluate pelvic floor muscles function using transabdominal and transperineal approaches. Furthermore, it can also be used to measure diaphragmatic excursion and thickness.
Summarizing, RUSI provides an efficient tool for assessment and training of motor control. Using ultrasound, we can visualize and quantify the changes of muscles and fascia. It can also be used as a biofeedback tool to restore optimal motor control.