Purpose: Cognitive tasks’ perfomance with simultaneous recording of flow velocities (FVs) consists the method of functional transcranial Doppler (fTCD). Changes of the regional cerebral blood flow (rCBF) influence the small arteries and arterioles and are reflected as changes of flow velocity of the central artery in the corresponding territory; in this way, fTCD can estimate indirectly the rCBF at a high temporal resolution. Α series of measurements are needed in order to estimate maximum and mean velocity values. Test-retest reliability of the repetitive measurements, which aims to assess the present study, is a crucial factor for the evaluation of the measurements’ accuracy.

Methods: Forty healthy adult volunteers (19 men; mean age of 30.1 ± 4.6 years) were examined with the method of fTCD twice. Laterality indices (LIs) were estimated on the basis of the flow velocities of the MCA for each test separately (LI1-LI6). The LIs were assessed by numerical value that was calculated based on the percentage change of the flow velocity of one hemisphere to the other.

Results: There was no significant difference between the 1st and 2nd measurements paired samples t test) in any of the LIs. Excellent intraclassand Pearsoncorrelation coefficients were obtained. The Bland-Altman plots showed that the vast majority of the differences between the 1st and 2nd measurements of LIs was within the limits of agreement.

Conclusions: The repetition of the recordings gave excellent test-retest reliability. The fTCD consists a noninvasive method, easy to be used and in combination with its excellent test-retest reliability which constitutes an important tool for the study of the cerebral functions during specific cognitive tasks.

test-retest reliability, functional transcranial Doppler, cerebral blood flow.