NORMAL FRONTAL PERFUSION IN PATIENTS WITH FROZEN GAIT

We have studied the frontal perfusion in the resting condition of two groups of patients with frozen gait: 10 patients with the syndrome of ''isolated gait ignition failure'' (IGIF) and 8 patients with idiopath ic Parkinson's disease (PD) and severe ''off '' freezing. These patien ts were compared with two other groups: one including 20 age-matched v olunteers as normal control subjects and the other one including 12 pa tients with progressive supranuclear palsy (PSP) as a positive control with expected frontal hypoperfusion. Frontal perfusion was assessed u sing single photon emission computed tomography (SPECT) regional cereb ral blood flow measurement with intravenous (133)Xenon. A significant frontal hypoperfusion was only present in the PSP group but not in the three others. These results do not support the hypothesis that start hesitations and freezing when walking are related to a frontal lobe dy sfunction. However, it is possible that frontal neuronal dysfunction o ccurs without measurable cerebral blood flow changes in the resting co ndition.