Clinical, neuropsychological and neuropsychophysiological data (Q-EEG, ERPs and CNV/RT activity) were obtained from 24 patients who had more or less severe presenile primary cognitive decline without depression, and compared with similar data from 10 age-matched healthy volunteers (mean age, 59.4 years). All of the patients (15 M and 9 F; mean age 59.6 years) were selected according to the DSM III-R, ICD-10 and NINCDS-ADRDA criteria and underwent CT and MRI scanning, in addition to a standard clinical examination, a battery of psychometric tests, spectral EEG, and bit-mapped CNV complex and RT to S2 analyses. Twelve of the 24 patients presented an initial presenile idiopathic cognitive decline (PICD) but did not wholly fulfil the clinical and neuropsychological criteria for primary dementia or for a diagnosis of probable AD; the remaining 12 patients showed characteristic clinical signs and symptoms of a very probable early stage of presenile Alzheimer-type dementia (PAD). ANOVA, correlational and discriminant analyses of the neuropsychological test scores, and the neurophysiological and RT to S2 data revealed 22 highest-ranked between-group discriminant factors (all with a significance level of p < 0.01). The conclusive discriminant analysis retained 13 of these factors as final canonical functions, and these showed a 97% grouping accuracy (33 of the 34 subjects examined); the same percentage of correct classifications was also achieved using only the 15 best indicators in the group of CNV/RT findings. Using both of these sets of highest-ranked discriminators, all of the normal subjects and all of the PAD patients were correctly classified; only 1 PICD patient was misclassified as normal when the first group of 13 factors was used, and another PICD patient was misclassified as PAD using the second group of 15 factors. Our findings suggest that, providing they are correctly performed and interpreted, these non-invasive techniques may be an important tool for identifying incipient stages of presenile Alzheimer-type dementia.

The aim of the present study was to assess the relationship between overt and covert orienting of attention in visual neglect patients with parietal and fronto-parietal lesions. Two stimuli were presented at eccentricities of 8° or 20° to the left (LVF) or right (RVF) visual fields and the patient was required to maintain fixation on the central mark and to respond only manually upon the appearance of the stimulus. Neglect patients with fronto-parietal lesion showed a lack of oculomotor control and the presence of leftward eye movements without corresponding attentional shifts. Neglect patients with parietal lesions did not show this phenomenon. They rarely responded ocularly and manually to LVF stimuli, whereas they were unable to inhibit an automatic ocular orienting reaction towards RVF stimuli. When a RVF stimuli triggered both ocular and attentional shifts, the pattern of responses revealed a retinal eccentricity effect. Patients were more accurate to respond to stimuli located at 8° than 20°. In contrast, when a RVF stimuli triggered only attentional shifts, the results showed the attentional gradient effect (Iiidavas, 1990). Patients were more accu- rate to respond to stimuli located at 20° than 8°. Therefore, the results of the present study seem to suggest a functional dissociation of the mechanisms subserving attentional and gaze orienting and a differential role played by the frontal and parietal lobes in overt visual orienting.

Although drug-resistant partial epilepsy is associated with a higher probability of developing vestibulo-cerebellar AEs, the risk for PGB toxicity does not differ across distinct disorders.

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