Periventricular lucencies on computed tomography in multiple cerebral infarcts: correlation with cerebral blood flow measurements

Memory in patients with subcortical infarction--an auditory event-related potential study

Event-related potentials (ERPs) were recorded from 21 patients with subcortical infarction (mean age, 62.1 years) and 14 normal control subjects (mean age, 62.7 years) as they listened to lists of words or pronounceable non-words. Some words were repeated immediately after initial presentation (lag 0), while others were repeated after five intervening words (lag 5), or after 2 to 4 min (lag 11-77). The subjects were asked to push a button upon hearing the occasional non-words. The Auditory-Verbal Learning Test (AVLT) also was administered to the patients to examine explicit memory. The mean N400 amplitude, appearing between 300 and 800 ms after the stimulus, was smaller in patients with subcortical infarction than in control subjects. The N400 in response to repeated words at lags 0, 5 and 11-77 was attenuated for both the patient and control groups. On the AVLT the total number of recalled words and number of words after interference were significantly decreased in patients relative to controls, while recognition was relatively preserved. The results suggest that lexical processing and retrieval mechanism of explicit memory are disturbed in patients with subcortical infarction, but implicit memory measured by this N400 paradigm is relatively preserved.

Central motor conduction time in patients with periventricular lucencies

Central motor conduction time and regional cerebral blood flow were measured before and 20 min after intravenous injection of 17 mg/kg acetazolamide in 10 patients with periventricular lucencies (PVL) and 10 age-matched healthy controls. Central motor conduction time was measured using a magnetic stimulator and regional cerebral blood flow was measured by stable xenon computed tomography method. The central motor conduction time was significantly longer in the patients with PVL than in the healthy controls and was shortened significantly by the intravenous injection of acetazolamide in the patients with PVL. The blood flow not only in the periventricular white matter but also in the cerebral cortex and the cerebral white matter was significantly lower in the patients with PVL than in the healthy controls. The intravenous injection of acetazolamide increased significantly the regional cerebral blood flow except in the PVL areas. The prolongation of the central motor conduction time may be at least partly related with decreased blood flow in the cerebral cortex and cerebral white matter.