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Purpose: There is some controversy whether or not saccades change with age. This cross-sectional study aims to clarify the characteristics of reflexive saccades at various ages to establish a normative cohort in a standardized set-up. Second objective is to investigate the feasibility of saccadometry in daily ophthalmological practice.
Methods: One hundred healthy participants aged between 6 and 76 years underwent an ophthalmologic examination and saccadometry, using an infrared video-oculography device, sampling at 220 Hz. The reflexive saccades were evoked in four directions and three target displacements each (5°/15°/30° horizontally and of 5°/10°/20° vertically). Saccadic peak velocity, gain (amplitude/target displacement) and latency were measured.
Results: Mean peak velocity of saccades was 213°/s (± 29°/s), 352°/s (± 50°/s) and 455°/s (± 67°/s) to a target position 5°, 15°and 30° horizontally, respectively, and 208°/s (± 36°/s), 303°/s (± 50°/s) and 391°/s (± 71°/s) to a target position 5°, 10° and 20° vertically. The association between peak velocity and eccentricity proved to be present at any age in all four directions. We found no relevant effect of age on peak velocity, gain and latency in a fitted linear mixed model. However, latency becomes shorter during childhood and adolescence, while in adulthood it is relatively stable with a slight trend to increase in the elderly. Saccades are more precise when the target displacement is small. Isometric saccades are most common, followed by hypometric ones. All children and elderly were able to perform good quality saccadometry in a recording time of approximately 10 minutes.
Conclusion: The presented data may serve as normative control for further studies using such a video-oculography device for saccadometry. The means of peak velocity and the gain can be used independently from age respecting the target displacement. Latency is susceptible to age.
Perception of irony has been observed to be impaired in adults with autism spectrum disorder. In typically developed adults, the mismatch of verbal and nonverbal emotional cues can be perceived as an expression of irony even in the absence of any further contextual information. In this study, we evaluate to what extent high functioning autists perceive this incongruence as expressing irony. Our results show that incongruent verbal and nonverbal signals create an impression of irony significantly less often in participants with high-functioning autism than in typically developed control subjects. The extent of overall autistic symptomatology as measured with the autism-spectrum questionnaire (AQ), however, does not correlate with the reduced tendency to attribute incongruent stimuli as expressing irony. Therefore, the attenuation in irony attribution might rather be related to specific subdomains of autistic traits, such as a reduced tendency to interpret communicative signals in terms of complex intentional mental states. The observed differences in irony attribution support the assumption that a less pronounced tendency to engage in higher order mentalization processes might underlie the impairment of pragmatic language understanding in high functioning autism.
In 1957, Craig Mooney published a set of human face stimuli to study perceptual closure: the formation of a coherent percept on the basis of minimal visual information. Images of this type, now known as “Mooney faces”, are widely used in cognitive psychology and neuroscience because they offer a means of inducing variable perception with constant visuo-spatial characteristics (they are often not perceived as faces if viewed upside down). Mooney’s original set of 40 stimuli has been employed in several studies. However, it is often necessary to use a much larger stimulus set. We created a new set of over 500 Mooney faces and tested them on a cohort of human observers. We present the results of our tests here, and make the stimuli freely available via the internet. Our test results can be used to select subsets of the stimuli that are most suited for a given experimental purpose.