Quantitative evaluation of stepping test data of patients with whiplash through digital CranioCorpoGraphy
The study of equilibrium disorders due to whiplash trauma is becoming more and more important to evaluate the injury itself and identify useful therapies. A few peculiar features of this disease have been shown through postural evaluations. We aimed at overcoming this lack of information by using the Digital CranioCorpoGraphy (dCCG) instrumentation to study both the motor strategy adopted by patients during the Stepping test and to obtain quantitative parameters which evaluate functional alterations due to whiplash trauma.
dCCG: a CCD camera (sample rate 50 Hz) acquires the position of a set of passive markers placed on the subject (two on a helmet, placed on the head of the subject and two on rigid shoulder supports). This data are transferred to a computer and processed to evaluate a set of parameters (coordination, lateral and longitudinal speed, indexes of rotation) useful to provide a quantitative analysis.
The experimental protocol: the subject is blindfolded to eliminate visual information and performs the Stepping Test (walking on the spot with raised knees) barefoot on a moquette floor to exclude somato-sensorial contributions.
Subjects: a control group (25 young healthy people: 9 males and 16 females, age 23 ± 3,4 years) and 33 people who suffer from whiplash trauma together with other disorders, dizziness or vertigo (13 males, 20 females; age 28 ± 6 years) were selected. The last group was divided into recent (<6 months) and chronic (>6 months) patients.
Quantitative investigations have been combined with qualitative evaluations of Stepping pattern of movement to find out the existence of significant differences in test execution modalities. Generally healthy people move forward during the test and present also limited sways and almost no head/trunk rotation . Moreover they show higher levels of coordination and lower speed with respect to pathological subjects both recent and chronic patients (Kruskal- Wallis, p<0.05).
In addition three different strategies have been observed in whiplash people. A small group of “recent” patients have shown a pattern similar to normal. In particular they seem to have a better coordination and stability of the head as shown by meaningful decrease of lateral speed (-35%) and higher coordination values (+18%) with respect to healthy people: this is probably due to stiffness caused by recent trauma that have not been recovered yet (collar effect). Pathological subjects who show a pattern of motion like fig. 1B present a decreasing coordination and increasing speed, whereas whiplash subjects, who rotate around their body axes , have deficits in head and head-to-trunk stability control, as described by meaningful increase of rotation parameters (for instance +215% in shoulders rotation).
dCCG has shown different motor strategies adopted by affected people. Moreover the dCCG is able to reveal the whiplash trauma through the quantitatively evaluation of performance parameters. Finally it could also be used as a follow-up investigation to verify the effects of therapy.