Antipredictable sequences: harder to predict than random sequences

For any discrete-state sequence prediction algorithm A, it is always possible, using an algorithm B no more complicated than A, to generate a sequence for which A's prediction is always wrong. For any prediction algorithm A and sequence x, there exists a sequence y no more complicated than x, such that if A performs better than random on x, then it will perform worse than random on y by the same margin. An example of a simple neural network predicting a bit sequence is used to illustrate this very general but not widely recognized phenomenon. This implies that any predictor with good performance must rely on some (usually implicitly) assumed prior distributions of the problem.

[Testing with the computer--the Diamed System]

The Diamed System has been developed to reduce the time-consuming testing routines involved in psychopathometric studies of disease course in the field of medicine. Test administration was to be relieved of those activities, in particular in repeat testing, examiners experienced as weary, unpleasant, repetitive, and uncreative. An important aim had been to permit data collection by as independent a dialogue as possible between the patient and the micro-computer, and extremely simple operations and instructions were considered of great importance. The opportunity has, however, also been utilized to implement promising performance testing procedures for measuring basic parameters of mental capability. Beside mental-amnestic capacity, the procedures cover subjective complaints because these, too, frequently are relevant in measuring the course of psychic disorders. The procedures incorporated in the Diamed System permit reliability verifications as to whether self-assessment and independent computerized testing might not be asking too much of the patients intellectually. Most of the procedures will be used for studying disease course in acute Organic Psychosyndromes and in all disorders that are associated with changes in mood and/or with subjective complaints. Diagnostic assistance moreover is offered for determining the presence of acute Organic Psychosyndromes. Under the name of "brain jogging", an economical programme is introduced for mental training, aimed at maintaining and improving basic central information processing capacities. Its effect on intelligence and memory has been demonstrated on in-patient populations, both with and without brain-organic disorders. Notably in the case of acute Organic Psychosyndromes, it has turned out to be an effective supplement to drug treatment.

Cross-sectional epidemiological study on neurotoxicity of solvents in paints and lacquers

In a multi-disciplinary retrospective study we examined 105 house painters employed for at least ten years (median 27 years, range 10-36 years). Fifty-three workers from various professions (non-painters), who were matched with regard to age, occupational training and socio-economic status served as the control group. In both groups no cases of a clinically manifest polyneuropathy or encephalopathy were found. The neurophysiological examinations (EEG and NCV-measurement) showed no differences in painters and controls that would indicate adverse effects of organic solvents. There were no cases with neuroradiological findings of a diffuse cerebral atrophy. Furthermore the evaluation of certain brain structures (ventricular diameter, cella media index) of the CAT films did not reveal any significant differences. In the neurobehavioral tests significant differences in the results were only found in the subtests "change of personality" and "short term memory capacity" in a subgroup of painters with repeated prenarcotic symptoms at the workplace. Ambient air monitoring measurements at 30 representative workplaces showed that the concentrations of the main components of the solvent-mixtures were well below the MAK-values. The results of the "Erlangen Painter Study" does not confirm former epidemiologic findings from other countries, mainly Denmark. However, there are some aspects, such as minor solvent exposure in German house painters, insufficient diagnostic and etiological procedures as well as misclassifications which may explain the different experiences.

[Short forms of a short psychopathological intelligence test (author's transl)]

Even short tests can still be materially shortened when they are intended to provide rough information. An example of a short intelligence test shows that considerable reductions are permissible when the procedure is intended to classify subjects into IQ groups of roughly "under 100" or "over 100". Also division into three as below average, average and above average level of intelligence is possible, and also division into four grades. If about 85% accuracy is satisfactory, a three-problem test is sufficient. For grading into three and four parts, six and nine problems, respectively may be adequate.

[Disturbances of orientation with functional psychoses (author's transl)]

It was supposed by clinical impressions that disturbances of orientation do not appear only in severe degrees of a transit-syndrome, but also in the light stadium of such a physically founded psychosis. In order to verify these impressions, a questionnaire was developed which permitted an objective scoring. This Q-Test consists of 37 questions (items), which measure the orientations of time, space, situation, and person. On the base of this questionnaire two samples were tested, the one consisting of 50 patients with functional psychoses (reversible physically founded psychoses), the other consisting of 50 patients with only neurological disturbances. The degree of the functional psychoses was determined by the "Syndrome-Test" (F. Bocker, 1959). The range of the scores corresponded with the clinical categories from a low degree of the transit-syndrome to a medium degree of disturbances of consciousness. The scoring was based on an standard system derived from the results of the control group (patients with only neurological disturbances). The clinical impressions could be verified by empirical and statistical methods. According to the test results, disturbances of orientation already appear during the light stadium of the transit-syndrome. Furthermore there is a high significant correlation (p. less than 001) between the degree of the functional psychoses and the degree of the disturbances of orientation. This applies to all categories of orientation. The orientation concerning time, space and situation proved to be more susceptible to disturbances than the orientation concerning the person. The very close correlation between the degrees of the functional psychoses and the degrees of the disturbances of orientation make it possible to determine the stadium of the functional psychoses promptly. The complete and very handy "short-time-test" will be published in a special paper.