The perceived tempi of coherent and streaming tone sequences

Previous research has demonstrated that a sequence of tones that is alternated between ears is stretched out in echoic memory, as compared with monaural sequences. Although the stimulus onset asynchronies (SOAs) were the same in the interaural and monaural conditions, the perceptual onset asynchronies (POAs) differed by 24 msec. The present study investigated whether an analogous perceptual phenomenon exists for frequency-alternating tone sequences. It turned out that the POAs of coherent and even of streaming tone sequences were precisely the same as with nonalternating tone sequences.     

The perceived tempi of coherent and streaming tone sequences: II

Previous research demonstrated, by means of a reaction time technique, that there is no difference between the perceptual onset asynchronies (POAs) of nonalternating tone sequences and of frequency-alternating tone sequences, even if the latter are streaming. This finding implies that listeners are capable of extracting the tempo of the total alternating sequence, even though successive tones belong to different streams. The present study investigated whether subjects are also capable of establishing the tempo of one stream. To this end, listeners were required to match the rate of one stream by adjusting the rate of a nonalternating comparison stream (a pulse sequence). In addition, they were required to match the total rate of the streaming sequence. It turned out that the total tempo could be matched precisely and that the tempo of one stream could be approximated very closely.     

Vibrotactual choice reaction time,tactile receptor systems and ideomotor compatibility

In most of the literature on human performance the results of an experiment by Leonard (1959) are quoted as the most outstanding example of perfect S-R-compatibility. In that experiment the fingertips were stimulated by a 50 Hz vibration; the vibrating armature had to be depressed and the reaction times of the right index finger were recorded. The reaction time was found not to increase with an increasing number of tactual choices. In experiment 1 of the present study, also applying 50 Hz vibrations, the reaction times of other fingers were also reported. In addition the response stimulus interval (RSI) was varied. Leonard's results were not replicated: reaction time increased with the number of tactual choices at all levels of RSI. In experiment 2 the frequency and amplitude of vibration were systematically varied and it turned out that these variables could account for the differences between the results found. An increase in reaction time with the number of tactual choices was found with weak vibrations, but not with strong vibrations. The differences in reaction time patterns appeared to be caused by differences in tactile receptor systems (i.e. the non-Pacini versus the Pacinian system). It was concluded that the concept of S-R-compatibility did not cover the pattern of results but that the concept of ideomotor compatibility did.     

Side effects of bilateral electroconvulsive therapy--comparative clinico-computer tomographic study

The side effects of a five-times bilateral electric shock therapy were clinically and computer-tomographically investigated. A connection exists between the number of electric shock treatments which are carried out and the expression of a transitory organic psychosyndrome. However, no significant differences in relation to the initial findings were established a week after the completion of the treatment series despite great interindividual differentiation. Neither cerebral oedema or other signs of disturbances were computer-tomographically detectable as results of treatment. CT and clinic findings do not correspond to each other.     

Neurophysiologic findings in chronic alcohol abuse

Neurophysiological examinations of 100 long term alcohol dependent patients who were having neuropsychiatric treatment, showed symptoms of polytopic damage of the peripheral and central nervous system. The results show that for recognition of the damage an extensive diagnostic programme must be used.