Determination of cognitive hemispheric dominance by "stereo" transcranial Doppler sonography.
OBJECTIVE
Transcranial Doppler sonography (TCD) can assess blood flow velocity changes induced by focal brain activation. Therefore, TCD may have the potential to identify hemispheric dominance for cognitive tasks.


METHODS
Using a system with two TCD probes ("stereo" TCD), we monitored simultaneously both middle cerebral arteries (MCAs) of 14 healthy right-handed volunteers while they performed cognitive tasks. The averaged blood flow velocity ratio of the two MCAs and the hemispheric blood flow velocity shift induced by the cognitive task were calculated.


RESULTS
In every subject, language tasks resulted in blood flow velocity shift to the left compared with visuospatial tasks. Mean MCA blood flow velocity shift to the left was 1.67%, 2.01%, and 2.31% in three language tasks. Mean blood flow velocity shift to the right was 1.67% and 2.31% in two visuospatial tasks.


CONCLUSIONS
Bilateral simultaneous MCA blood flow velocity monitoring and averaging during cognitive tasks can help to identify hemispheric dominance for cognitive tasks in individuals.
Department of Neurology, University of Berne, Inselspital, Switzerland.
F
F
Rihs
K
K
Gutbrod
B
B
Gutbrod
H J
HJ
Steiger
M
M
Sturzenegger
H P
HP
Mattle
D000328:Adult; D002560:Cerebrovascular Circulation; D003071:Cognition / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D013037:Spatial Behavior; D013238:Stereotaxic Techniques; D017585:Ultrasonography, Doppler, Transcranial; D014796:Visual Perception