The clinical significance of incidental white-matter foci seen on MRI is controversial. Mainly using a computer-assisted neuropsychological test battery, we tested the hypothesis that there is a clinical correlate of these foci. We studied 41 individuals aged 45-65 years with no history of neurological or psychiatric disorder, in whom no indication of central nervous system abnormalities was found on standardised neurological examination. A computer-assisted neuropsychological test battery, with the advantage of precise measuring of both time and deviation (e.g. in position memory tests), and rating scales for emotional dysfunction were administered; selected soft neurological signs were assessed. In 16 subjects (39%) MRI showed high-signal foci in the white matter on spin-echo sequences. White-matter foci not adjacent to the lateral ventricles were found to be related to performance on immediate visual memory/visuoperceptual skills, visuomotor tracking/psychomotor speed and, to a lesser degree, learning capacity and abstract and conceptual reasoning skills. Subtle cognitive dysfunction would appear to be a clinical correlate of punctate white-matter foci on MRI of otherwise "healty" individuals.

(1) EMG investigations in 17 female manic-depressive patients under longterm treatment with lithium salts showed a reduction of the maximal motor nerve conduction velocity (NCV) and of the duration of isolated potentials (IPs) in six cases. These changes, however, were not clearly due to the influence of lithium only. Psychopathology, additional medication, and other variables may have been also responsible for these findings. (2) NCV and IPs as well as the concentration of electrolytes in serum and RBC were determined in seven healthy volunteers before, during, and after lithium administration. NCV was significantly decreased and the duration of IPs slightly increased after l week of lithium intake. The magnesium serum concentration increased steadily during the experimental period. (3) Thus, the possibility cannot be excluded that symptoms of fatigue and muscular weakness in lithium-treated patients might be caused at least partially by changes of the peripheral nervous-muscular function.

Topographical information provided by brainstem auditory evoked potentials (BAEPs) was investigated in 43 patients by comparison with cerebral nuclear magnetic resonance imaging (NMR). Lesions in the region of the brainstem auditory pathways were demonstrated by BAEPs in 44.2%, and in 39.5% by NMR. As regards brainstem levels, in 15/21 (71.4%) with abnormal findings at least one lesion was verified by NMR-matched BAEP results. The study confirms the topographical information provided by the BAEPs on the different levels of the brainstem, but not the assumption that generation of the BAEPs is predominantly ipsilateral. BAEPs retain their importance for the detection of disseminated lesions in the diagnosis of multiple sclerosis (MS) in the era of expensive imaging methods.

Subtle changes of adaptive behaviour under lithium treatment may possess interest not only as side-effects, but also as a possible explanation for the mechanism of action of lithium salts. - In 18 patients under long-term lithium treatment and 10 normal volunteers before and after one week of lithium application the EEG was recorded and performance as well as psychophysiological tests were carried out. The results, particularly of the d-2-test point to a considerably reduced performance in patients and normal volunteers. The EEG data in both groups suggest reduced vigilance until stage B3 or C (in the sense of Head of Bente); CFF was significantly elevated only during the first days of lithium application in the normal volunteers. Whereas EEG changes persist, other symptoms as CFF reduction, fine hand tremor, or reduced performance resolved at least partially 7 days after lithium withdrawal in the normal volunteers.