VASOMOTOR REACTIVITY IS EXHAUSTED IN TRANSIENT ISCHEMIC ATTACKS WITH LIMB SHAKING

Objectives-To investigate cerebral vasomotor reactivity in five patien ts with limb shaking transient ischaemic attacks by using transcranial Doppler sonography. Method-Attacks with transient limb shaking were u nilateral in four patients and bilateral in one. Internal carotid arte ries on the side opposite tbe abnormal limb movements showed three 90- 95% stenoses and three occlusions as assessed by cerebral angiography in three and magnetic resonance angiography and ultrasound in one case each. Reactivity of cerebral resistance vessels was studied by measur ing peak mean velocities in the middle cerebral artery (MCA) before an d after the application of CO2 enriched air. Reference values were obt ained from 25 normal subjects. Results-During hypercapnia peak mean ve locities slightly decreased in five MCAs (steal phenomenon) and remain ed unchanged in one MCA opposite the abnormal movements, whereas the o ther MCAs showed normal reactivities. Conclusion-The delineation of an exhausted cerebral vasoreactivity in all hemispheres opposite the inv oluntary limb movements suggests that haemodynamic failure is the caus e of transient ischaemic attacks with limb shaking.