Aim: Semont liberatory manoeuvre is used in the treatment of posterior semicircular canal in patients with benign paroxysmal positional vertigo. The aim of the study was to determine the inter-individual and intra-individual variability in the processing of the manoeuvre and to define the parameters that affect it the most.
Methods: Three experienced therapists applied the manoeuvre bilaterally in 10 healthy probands. Inertial measurement unit consisting of the accelerometer and gyroscope recorded the trajectory and speed.
Angle changes were placed in the coordinate reference system. Accuracy of the manoeuvre was evaluated based on the deviations from the projected sensory plane.
Results: Parameters affecting the accuracy of the manoeuvre included height of a proband (p = 0.0252), phase of the movement (p < 0.0001), therapist and the side of the movement. The effect of these factors is the most pronounced when combined.
We assessed interactions of the phase of the movement and the height of the probands (p = 0.0130), the therapist and the phase of movement (p = 0.0001), the therapist and the height of the probands (p < 0.0252). The largest magnitude of deviation from the sensory plane was in the range of -37.17 degrees to 31 degrees with a standard deviation of 16.6 degrees.
Conclusions: The data highlight high variability in the implementation of the Semont liberatory manoeuvre, whether measurements by a single therapist or inter-individually between the therapists are compared. Analysis of the impact of these deviations on therapeutic efficacy in patients with benign paroxysmal positional vertigo and detailed analysis of influencing parameters should be the subject of further research.