engleski

TRANSCRANIAL DOPPLER SONOGRAPHY DURING VISUAL STIMULATION

Posterior cerebral artery (PCA) provides arterial blood supply for most parts of the occipital lobe and thus for primary and associative visual areas located in the occipital lobe. In this paper, changes of mean blood flow velocities (MBFV) in the posterior cerebral arteries recorded during visual stimulation in a group of 51 healthy right-handed volunteers are presented. There were 27 (52.9%) males and 24 (47.1%) females aged from 20 to 59 years. The mean age of the group was 36.98 years, with a standard deviation (SD) of 10.43 years. Measurements were performed with a hand-held 2 MHz probe using a Transscan 3D EME transcranial Doppler (TCD) device. PCA was identified and insonated through temporal window using a standard technique, while the subjects had their eyes wide open and closed when looking at white light. In a half of the subjects, the measurements were first performed on the right side and then on the left side, while in the other half a reverse procedure was used. Statistical analysis was made using Wilcoxon's matched-pair signed-rank test. Mean MBFV value in the left PCA was 41.2ą8.6 cm/s (mean ą SD) with eyes wide open, 27.8ą8.5 cm/s with eyes closed, and 42.3ą9.1 cm/s while looking at white light. Mean MBFV value in the right PCA was 41.7ą8.9 cm/ s with eyes wide open, 28.2ą9.1 cm/s with eyes closed, and 42.4ą8.8 cm/s while looking at white light. Differences between eyes open and eyes closed, and between eyes open and white light in the left PCA were statistically significant (p<0.001, z=-6.2146, and p<0.001, z=-3.4836, respectively). In the right PCA, a difference between eyes open and eyes closed in the right PCA was statistically significant (p<0.001, z=-6.2146), but there was no significance between eyes open and white light (p=0.03, z=2.1693). The results showed that simple visual stimulation had an effect on blood tlow velocities in PCA that could be measured with TCD.

posterior cerebral artery; visual stimulation; TCD

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