Zur visuell-morphologischen Analyse des hirnelektrischen Verhaltens bei Patienten mit manisch-depressiven und schizoaffektiven Psychosen unter Lithiumprophylaxe

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Abstract
This study is a contribution to the still controversial problem of the long-term effects of lithium on the EEG. It is our aim to show, in particular by means of EEG-samples, that this controversy is mainly caused by the large interindividual range of variations of the EEG effects. As a rule, there hardly any connection between the methods of quantitative analysis on the one hand (conducted with considerable technical equipment, based on the observation of groups of patients pattern recognition, and analysis and on the other, which can be effected up to now on a purely visual-empirical basis only. Hence, in our opinion, this does away with the question of different types of reaction. The attempt at effecting a visual-morphological EEG analysis represents to some extent a rejection of the reductionistic-quantifying methods which are the order of the day. However, we believe that a sound basis for on-target analyses of a quantitative nature can be created only if the various types of reaction are classified according to heuristic-inductive principles, i.e. visually and morphologically. Due to their deductive character, quantitative methods cannot generate hypotheses. Their significance rests with their suitability to examine already existing hypotheses. In an attempt to classify the EEG's of 70 patients placed on long-term lithium therapy, according to visual-morphological criteria, we were able to define 8 reactive types, all of which can be interpreted as an expression of a more or less pronounced reduction of the vigilance level. The wide range of variations is probably due to the interaction of certain formative tendencies which must be classified as belonging to the sub-vigilant ,,A" stage, i.e. slowing down, synchronisation, increase of voltage, anterior spread of alpha-activity and counterregulatory beta-activation with an individually specific disposition depending upon age and constitutional factors. Particular attention was given to the problem of differential hemispheric effects. Helmchen and Kanowski (1971) reported of a highly significant increase in dysrhythmical groupings of a focal character above the left anterior temporal region in lithium treated patients. We were able to confirm these findings in principle. Whereas Helmchen and Kanowski found ,,foci" in the left hemisphere in 62% of the patients and in the right hemisphere in 14%, the relation established by us was 28.7% : 8.6%. Such predominance of changes in the left temporo-anterior region often in the form of grouped sub-alpha elements, but also as irregular 4-7/s theta and a few 3/s delta waves, appeared to be more or less regularly connected with an enhancement and anterior spread of alpha activity on the side of the left hemisphere. This suggests an uniform basis of interpretation. Basing on detailed analyses we interpret the left-hemispherical enhancement of alpha-activity and anteriorisation as well as the simultaneously intermittently manifested left temporo-anterior accentuation of slow waves as EEG correlates of a protraction and fixation of the subvigilant ,,A" stage preferentially concerning the left hemisphere. Such neurodynamic interpretation represents an approach for the generation of hypotheses which can be subjected to examination, regarding the neuropsychological and hence possibly also the mechanism of prophylactic action of lithium. One could, for example, assume that an impairment of function mainly of the left hemisphere would become manifest in a specific manner in the pattern of behaviour. Considering certain neuropsychological syndromes which become manifest subsequent to lesions of the left hemisphere, one could primarily think of a dynamic impairment of actions directed at the patient's environment and based on volition and intention. This hypothesis appears to be compatible with psychoexperimental studies conducted so far. Die Studie stellt einen Beitrag zur nach wie vor kontroversen Frage des Langzeiteffekts von Lithium auf das EEG dar. Wie wir, insbesondere auch mit Kurvenbeispielen, zu dokumentieren versuchen, dürfte diese Problematik im wesentlichen in der großen interindividuellen Variationsbreite der EEG-Effekte begründet sein. Den heute mit großem technischen Aufwand betriebenen, gruppenbezogenen und im Bestreben nach exakten Aussagen allein als allgemeinverbindlich erachteten quantitativen Analyseverfahren fehlt in der Regel jeder Bezug zu der allein visuell-empirisch vollziehbaren Mustererfassung und damit auch -analyse. Damit wird die u.E. zentrale Frage nach unterschiedlichen Reaktionstypen gar nicht erst aufgeworfen. Wir sind uns der Tatsache voll bewußt, daß der hier unternommene Versuch einer visuell-morphologischen EEG-Analyse in gewisser Weise eine Abkehr von den, derzeit noch immer das Feld beherrschenden, reduktionistisch-quantifizierenden Verfahren darstellt und dementsprechend hier und da mit Skepsis aufgenommen werden dürfte. Demgegenüber bekennen wir uns zu der Auffassung, daß erst eine nach heuristisch-induktiven Prinzipien erfolgende, d.h. visuellmorphologische Ordnung der verschiedenartigen Reaktionsformen eirie tragfähige Basis für gezielte Analysen quantitativer Art zu schaffen vermag. Quantitative Verfahren können aufgrund ihres logisch-deduktiven Charakters niemals hypothesengenerierend sein. Ihre Bedeutung liegt vielmehr in der Überprüfung von Hypothesen. Bei einem nach visuell-morphologischen Kriterien erfolgenden Klassifizierungsversuch der EEGs von 70 Patienten unter Lithium-Dauertherapie ließen sich 8 Reaktionstypen abgrenzen, die sich aus einem vigilanztheoretischen Blickwinkel trotz erheblicher deskriptiver Unterschiede sämtlich als Ausdruck einer mehr oder weniger deutlichen Absenkung des Vigilanzniveaus interpretieren lassen. Die vorgefundene große interindividuelle Variationsbreite dürfte aus der Interaktion von gewissen lithiuminduzierten, dem...

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