THE INFLUENCE OF HEAD ROTATION ON THE VER TEBROBASILAR SYSTEM - A TRANSCRANIAL DOPPLER SONOGRAPHY STUDY

Examination of the vertebrobasilar system until a short time ago was p ossible only by invasive and therefore potentially harmful techniques. The results of these studies were also contradictory. The objective o f the present study was to determine how blood flow velocity differed in the vertebral arteries during head rotation in normal subjects. The origin of cervical vertigo essentially involves three components that are difficult to distinguish. There are the sensory proprioceptive, v ascular and sympathicotonic components. Use of transcranial Doppler so nography (TCD) has now made it possible to measure the flow velocity o f the vertebral arteries. In 17 normal probands without vertigo or cer vical nystagmus, the mean diameters of the vertebral arteries were mea sured by means of duplex scanning. TCD was used to determine the mean flow velocities of the vertebral arteries in a median position and aft er head rotations of 30-degrees and 60-degrees to the left and right. Blood flow velocities in both vertebral arteries were not altered by h ead rotation. This observation contrasted with that of other publicati ons, which were mainly based on cadaver findings. The results of this study form the basis for further investigations on symptomatic patient s with recurring cervical nystagmus and cervical vertigo.