8 research outputs found
Transcranial Doppler Sonography As A Diagnostic-tool In Vascular Dementia
Transcranial Doppler monitoring of the flow velocity at the level of the middle
cerebral artery was performed in 40 demented patients, 20 with multi-infarct
dementia (MID) and 20 with senile dementia of the Alzheimer type (SDAT), and in
25 age-matched controls. The following conditions were evaluated: (1) rest; (2)
60 s hyperventilation; (3) longest possible apnea, and (4) 5 min closed-circuit
air rebreathing. We also measured: PaCO2 levels at rest and under stimulus
conditions; mean flow velocity and pulsatility index (PI) at rest, and percentage
velocity variations. The PIs were higher and the velocity decrease during
hyperventilation was lower in all demented patients than in the healthy group; no
side-related asymmetry in rest values or in vasomotor responses to CO2 changes
was regularly detected in any group. On the contrary, rest flow velocities and
vasomotor responses to hypercapnia induced by both apnea and rebreathing tests
proved to be lower in MID patients than in SDAT and healthy groups. These
alterations were neither exclusive to MID patients nor homogeneous, therefore
some caution should be taken when evaluating single cases