The present study evaluates the reproducibility of lateralised blood how ve
locity (BFV) changes measured with transcranial Doppler (TCD) ultrasonograp
hy during various cognitive paradigms. A total of 20 right-handed volunteer
s were confronted twice with 13 verbal and visuospatial tasks, with a time
interval of 23 to 71 days. No statistically significant differences were fo
und between the lateralisation indices (left BFV change minus right BFV cha
nge) on the first and second examinations. Lateralisation indices of eight
tasks showed a significant test-retest reliability (r = 0.61 to 0.83), The
reproducibility of cognitively induced lateralised BFV changes appears to b
e task-dependent. The possible influence from technical, physiological, and
psychological factors is discussed, We conclude that functional neuroimagi
ng studies based on blood flow data should preferably select cognitive para
digms that demonstrated sufficient test-retest reliability. (C) 2001 World
Federation for Ultrasound in Medicine & Biology.