Auditory speed processing in sighted and blind individuals

Multisensory experience is crucial for developing a coherent perception of the world. In this context, vision and audition are essential tools to scaffold spatial and temporal representations, respectively. Since speed encompasses both space and time, investigating this dimension in blindness allows deepening the relationship between sensory modalities and the two representation domains. In the present study, we hypothesized that visual deprivation influences the use of spatial and temporal cues underlying acoustic speed perception. To this end, ten early blind and ten blindfolded sighted participants performed a speed discrimination task in which spatial, temporal, or both cues were available to infer moving sounds’ velocity. The results indicated that both sighted and early blind participants preferentially relied on temporal cues to determine stimuli speed, by following an assumption that identified as faster those sounds with a shorter duration. However, in some cases, this temporal assumption produces a misperception of the stimulus speed that negatively affected participants’ performance. Interestingly, early blind participants were more influenced by this misleading temporal assumption than sighted controls, resulting in a stronger impairment in the speed discrimination performance. These findings demonstrate that the absence of visual experience in early life increases the auditory system’s preference for the time domain and, consequentially, affects the perception of speed through audition.

Motion sensitivity assessment based on an analysis of the spatio-temporal features of eye movements

Motion sensitivity refers to the individual’s ability to detect and perceive motion in the environment. It is a fundamental property of visual perception, crucial for orientation and navigation in the environment. Yet, its behavioral assessment is usually tedious and time-consuming, limiting assessment in clinical and rehabilitation contexts. Assessment of eye-movements may provide a more observer-friendly way to obtain the same information. For this reason, in this study, we evaluated the suitability of an eye-movement-based method to assess various aspects of motion sensitivity. To do so, we quantify the spatio-temporal features of eye-movements made during a smooth pursuit task at different velocities. We found that the temporal and spatial uncertainties robustly reflected the changes in stimulus speed. Furthermore, we measured motion sensitivity using a conventional random dot kinematogram-based direction discrimination task. We found that none of the spatio-temporal features computed from the tracking task were correlated with the psychophysical motion sensitivity measures (slope and threshold) obtained with the random dot kinematogram. We conclude that continuous visual tracking efficiently assesses specific aspects of motion processing in an observer-friendly manner. Moreover, the approach provides information that is complementary to that obtained through conventional psychophysical tests such as the random dot kinematogram.

Investigation of the Anticipation Time in Forehand and Backhand Strokes of Badminton Players

The purpose of this study was to examine if there was a difference between forehand and backhand coincidence-anticipation timing (CAT) performance of badminton players. Badminton players participating in the study are in the age range of 18-23 ( = 20.25, SS = 1.48) and 12 top athletes who regularly participated in Super League competitions in Turkey were selected (4 female and 8 male).Those athletes were determined by using the Purposive Sampling method. Participants were 12 elit badminton players (4 female and 8 male) whose ages ranged from 18 to 23 years ( = 20.25, SS = 1.48). CAT performances were measured with modified Bassin Anticipation Timer (BAT) device. Stimulus speed used for this study was set at 4 m / s. Participants were informed about the test protocol and they performed 3 trials with a racket to familiarize BAT device. Then, participants performed 20 trials for forehand and 20 trials for backhand strokes, 40 trials in total. Collected data were transformed to absolute error (AE) and variable error (VE) scores. Independent sample t-test was employed to calculate statistical data, and the significance level was set as 0.05. Results showed that there were significant differences between forehand and backhand strokes in terms of absolute and variable error scores of participants (p<0,05). As a conclusion, CAT performance of badminton players is effected during forehand and backhand strokes. CAT forehand stroke scores are better than the backhand stroke scores.

Coincidence Anticipation Timing Performance during an Acute Bout of Brisk Walking in Older Adults: Effect of Stimulus Speed

This study examined coincidence anticipation timing (CAT) performance at slow and fast stimulus speeds before, during, and after an acute bout of walking in adults aged 60–76 years. Results from a series of repeated measures ANOVAs indicated significant rest versus exercise × stimulus speed × time interactions for absolute and variable errors (bothP=0.0001) whereby absolute and variable error scores, when stimulus speed was slow, improved as the duration of exercise increased. When stimulus speed was fast there were significantly greater absolute and variable errors at 18 minutes of the walking bout. There was also greater error at 18 minutes during walking compared to rest. These results suggest that, in a task involving walking and CAT, stimulus speeds plays an important role; specifically walking (exercise) enhances CAT performance at slow stimulus speeds but reduces CAT performance at fast stimulus speeds. The implications are that in everyday situations, where events require dual-task responses to be made at different speeds, for example, walking on the pavement whilst avoiding a crowd, compared to crossing a busy road, an understanding of how different stimulus speeds influence dual-task performance is extremely important, particularly in the older adult population.