[Postural stability after head-shaking in the healthy young individuals]

To investigate the postural stability after head-shaking in the normal young individuals.

Twenty-eight normal young individuals were taken the static posturography under 4 standing conditions including (T1) head center and eye open (EO), (T2) head center and eye closed, (T3) after head-shaking and EO, (T4) after head-shaking and EC. The sway velocity (SV) of center of pressure under feet in each testing condition was recorded as parameter and each test protocol was 30 s.

All examinee did not fall in each testing condition. (1) The SV increased (4.60 +/- 6.36) % after head-shaking in the EO condition, while the (8.86 +/- 8.27) % was demonstrated in the EC condition. There was significant difference between these two degrees of increase (t = 2.759, P < 0.01). (2) In static head orientation, the SV of EC (T2) increased (9.83 +/- 5.10)% compared with the SV of EO condition (T1). However, the SV of EC (T4) increased (14.05 +/- 6.89) % compared with the SV of EO condition (T3) after head-shaking. And there was significant difference between these two degrees of increase (t = 2.772, P < 0.01).

The stimuli of head-shaking that interrupted input from vestibular end organ can affect the function of vestibulospinal reflex in healthy young individual, especially when the visual input was interrupted simultaneously. In order to keeping balance after head-shaking, there was a complex mechanism sensory reorganization even in the normal young subject.