Cerebral dysfunction and intellectual impairment in old age

Mögliche Einflussvariablen auf die Flimmer- und Verschmelzungs-Frequenz:

Zusammenfassung. Die vorliegende Studie prüft an N = 65 gesunden, medikationsfreien Probanden, im Alter zwischen 20 und 30 Jahren, ob sich ein Einfluss der Art der Reaktionsneigung in bezug auf optische Reize, des aktuellen Befindens und der kognitiven Informationsverarbeitungsgeschwindigkeit auf die Werte der Flimmerfrequenz-Analyse nach der Grenzmethode nachweisen lässt. Die Ergebnisse zeigen auf, dass die Verschmelzungs- (VF) und Flimmer-Frequenz (FF) nicht präzise gemessen werden können. Für eine zuverlässige Ergebnisanalyse fehlt der Messmethode vor allem die Bestimmung grundlegender psychologischer Parameter.

Critical flicker frequency of mentally retarded and normal persons

Critical flicker frequency (CFF) of 40 men, 20 mentally retarded whose mean age was 22.0 yr. and 20 normal whose mean age was 21.5 yr., was measured under binocular viewing using the Lafayette Visual Perception Control with a display unit. Subjects had been previously tested for visual acuity and color blindness. Analysis showed a significant difference in CFF between mentally retarded persons and normal individuals, the former having lower CFF than the latter. This finding suggests lower perceptual sensitivity of the mentally retarded persons. Further research with provision for EEG recordings is suggested.

Flicker fusion thresholds and mental arousal

Investigated the finding of Busch and Wachholder that flicker fusion thresholds increase under conditions of mental activity and decrease during inactivity. Flicker fusion thresholds for each eye of 21 undergraduates were measured after 2-min. rests, then after the performance of a mathematical counting exercise, and then after another 2-min. rest. The average thresholds for both the right and left eyes were significantly higher following the counting exercise than after the rests. Features of the experiment included a training/screening session for the subjects to detect and correct “pseudothreshold” problems, and an automatic adjustment of the light frequency to minimize possible experimenter effects.

Critical flicker frequency (CFF) and psychotropic drugs in normal human subjects-a review

This literature review presents summary methodological and statistical data on 33 studies in which critical flicker frequency (CFF) thresholds were used to evaluate the effects of acute oral doses of single psychotropic drugs in normal human subjects. In all, 96 drug-dose-study combinations are represented. CFF was found to be altered to a statistically significant degree (P is less than 0.05) in 51 (65%) of the 79 instances in which inferential statistical methods were used to evaluate the results. As expected, stimulants increased CFF while hypnotics decreased it. There is also a discussion of important methodological considerations in the design of psychopharmacological studies employing CFF. While many studies have shown CFF to be sensitive to the effects of psychotropic drugs, there have not always been adequate controls for extraneous factors (especially, set and suggestion, changes in pupillary diameter, and the presence of other commonly used drugs). Finally, consideration is given to the attempts to increase the sensitivity of the CFF test to drug effects.

Flicker fusion bibliography, 1953-1968

A list of 1293 references brings up to date Landis' bibliography on flicker fusion. CODEN abbreviations, periodical titles and subject index are included.