Impact of Order of Movement on Nerve Root Function: A Neurophysiological Study With Implications for Neurodynamic Test Sequencing

Neurodynamic concept is used clinically to normalize nerve mobility. It has been manifested in previous studies that neurodynamics have increased mobility by floss like movement of the nerve. Whereas in other studies it has been concluded that neurodynamic techniques has an effect in decreasing fibrous and adhesions between neural tissues and the surrounding tissues therefore giving an outcome of improved infrafasicular gliding.

The upper limb neurodynamic test has an effect to alter the mechanical loads on the nerve by changing its dimensions. For neurodynamic to be more effective, it requires a certain sequence.

The different order of movements will induce different duration of tension in which it will influence the nerve root function, which is needed to be investigated to check for the effectiveness. A previous study has found that the difference of sequence on median nerve, had caused a change on the distribution of the sensory response on the asymptomatic participants. The sensory responses were more prevalent during the neurodynamic of the median nerve when it was applied from a distal to proximal sequence . One of the main purposes of the order of sequences is to add more strain to the nerve segment to increase the sensitivity of the test.

Clinically it has been assumed that the different order of movements could possibly influence the level of strain on a certain nerve segment. When the standard sequence was compared with the distal-to-proximal sequence for the median nerve, there was no physiological difference obtained at the end of the test. In comparison, there was a larger strain in the distal-to-proximal sequence in comparison to the proximal-to-distal sequence observed. However, the longitudinal excursion collected data indicated that the start and end positions for all the three sequences were alike.

In terms of neurophysiological outcomes, in this study we will use the dermatomal somatosensory evoked potential as a primary outcome due to its reliability in comparison with other physiological outcomes. There is a literature gap in regard to the effect of the order of sequence on the median nerve on the nerve root function and this is what the study will focus on. We hypothesized that the order of movements of the median nerve neurodynamic will influence the peak-to-peak amplitude and the latency.