Background and purpose: Aim of our study was to evaluate cerebral hemodynamic changes during performance of attention tasks and to correlate them with reaction time (RT) and percentage of right answers.
Methods: Mean flow velocity (MFV) in middle cerebral arteries was monitored in 30 subjects by transcranial Doppler during tonic alertness, phasic alertness, focused and divided attention tasks.
Results: Mean flow velocity increase was significantly higher during divided attention with respect to other tasks (P < .001). MFV increase was higher in the right than in the left side (P < .001). Asymmetry during attention tasks resulted significantly higher than that observed in tonic alertness condition. RT was increased during focused attention tasks (P < .001 vs. both alert tasks), with further increase during divided attention tasks (P < .001 vs. focused attention task). RT was inversely related to MFV increase only during tonic alertness (P = 0.012 for left side; P = 0.008 for right side). During the divided attention tasks, an association was found between MFV increase and correct answers (r = 0.39, P = 0.033).
Conclusions: These data show a relationship between RT, correct answers and changes in blood flow velocity and suggest that this method of cerebral blood flow investigation could be a useful approach during assessment of patients with attention deficit.