Haptic Discrimination and Matching of Viscosity

In three experiments, viscosity perception of liquids using the sense of touch was studied. The first two were discrimination experiments in which Weber fractions were determined for a number of viscosities spanning the range of what is encountered in daily life, and for two ways of perceiving viscosity (stirring with a spatula or with the index finger). For high viscosities, Weber fractions were around 0.3, whereas they increased for lower viscosities. For low viscosities, discrimination performance was much worse with the finger than with the spatula. In the third experiment, subjects matched liquids perceived with these two methods, which resulted in biases of around 80 %. Control experiments and force measurements were performed to find an explanation for these results. It was concluded that the relationship between perceived and physical viscosity is steeper for stirring liquids with a spatula than stirring with the finger

Haptic perception of viscosity

Viscosity is a liquid's resistance against flow. Using a discrimination experiment, the human ability to distinguish between different viscosities was measured over the range of 200-20,000 mPa.s. Eight blindfolded subjects stirred pairs of different silicone oils using a wooden spatula and had to indicate the thicker of the two. The viscosity of the liquids was measured seperately using a rheometer. Weber fractions for discrimination ranged from 0.3 at high viscosities to almost 1 at the lowest viscosity. For the higher viscosities, discrimination could be described as Weber-like, but for the low viscosities, there seemed to be a floor effect for the absolute threshold. The characterisation of the discrimination threshold as a function of viscosity is of fundamental interest in perception research, but also of practical value for designers of haptic devices capable of displaying viscosity. Viscosity is a liquid’s resistance against flow. Using a discrimination experiment, the human ability to distinguish between different viscosities was measured over the range of 200–20,000 mPa.s. Eight blindfolded subjects stirred pairs of different silicone oils using a wooden spatula and had to indicate the “thicker” of the two. The viscosity of the liquids was measured seperately using a rheometer. Weber fractions for discrimination ranged from 0.3 at high viscosities to almost 1 at the lowest viscosity. For the higher viscosities, discrimination could be described as Weber-like, but for the low viscosities, there seemed to be a floor effect for the absolute threshold. The characterisation of the discrimination threshold as a function of viscosity is of fundamental interest in perception research, but also of practical value for designers of haptic devices capable of displaying viscosity

An extended 15 Hz ERG protocol (1): the contributions of primary and secondary rod pathways and the cone pathway

The minimum in the amplitude versus flash strength curve of dark-adapted 15 Hz electroretinograms (ERGs) has been attributed to interactions between the primary and secondary rod pathways. The 15 Hz ERGs can be used to examine the two rod pathways in patients. However, previous studies suggested that the cone-driven pathway also contributes to the 15 Hz ERGs for flash strengths just above that of the minimum. We investigated cone pathway contributions to improve upon the interpretation of (abnormal) 15 Hz ERGs measured in patients. We recorded 15 Hz ERGs in five healthy volunteers, using a range of flash strengths that we extended to high values. The stimuli were varied in both colour (blue, green, amber, and red) and flash duration (short flash and square wave) in order to stimulate rods and cones in various ways. The differences in the responses to the four colours could be fully explained by the spectral sensitivity of rods for flash strengths up to approximately 12.5 log quanta·deg−2. At higher flash strengths, higher-order harmonics appeared in the responses which could be attributed to cones being more sensitive than rods to higher frequencies. Furthermore, the amplitude curves of the blue and green responses showed a second minimum suggesting rod to cone interactions. We present a descriptive model of the contributions of the rod and cone pathways. In clinical application, we would advise using the short flash flicker instead of the square wave flicker, as the responses are of larger amplitude, and cone pathway contributions can be recognized from large higher-order harmonics

Replication Data for: “The development of the Screening of Visual Complaints questionnaire for patients with neurodegenerative disorders: evaluation of psychometric features in a community sample”

The total dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition) and responses of participants on the questionnaires Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter Defizite der Aufmerkzamkeit; FEDA), Depression Anxiety Stress Scale–21 (DASS-21) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment of the total sample. The test-retest dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition)and responses of participants on the questionnaires Screening Visual Complaints (SVC), the Behavior Rating Inventory of Executive Function-A (BRIEF-A) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment (time 1) and the second assessment (time 2). The study population consists of 1461 participants from the Dutch community of 18 years or older. Main variables: Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter

Replication Data for: “The development of the Screening of Visual Complaints questionnaire for patients with neurodegenerative disorders: evaluation of psychometric features in a community sample”

The total dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition) and responses of participants on the questionnaires Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter Defizite der Aufmerkzamkeit; FEDA), Depression Anxiety Stress Scale–21 (DASS-21) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment of the total sample. The test-retest dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition)and responses of participants on the questionnaires Screening Visual Complaints (SVC), the Behavior Rating Inventory of Executive Function-A (BRIEF-A) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment (time 1) and the second assessment (time 2). The study population consists of 1461 participants from the Dutch community of 18 years or older. Main variables: Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter

Replication Data for: “The development of the Screening of Visual Complaints questionnaire for patients with neurodegenerative disorders: evaluation of psychometric features in a community sample”

The total dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition) and responses of participants on the questionnaires Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter Defizite der Aufmerkzamkeit; FEDA), Depression Anxiety Stress Scale–21 (DASS-21) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment of the total sample. The test-retest dataset contains demographic information (age, sex, educational level), medical information (categorisation of neurological conditions, ophthalmologic conditions and psychiatric condition)and responses of participants on the questionnaires Screening Visual Complaints (SVC), the Behavior Rating Inventory of Executive Function-A (BRIEF-A) and the Structured Inventory for Malingered Symptomatology (SIMS) at the first assessment (time 1) and the second assessment (time 2). The study population consists of 1461 participants from the Dutch community of 18 years or older. Main variables: Screening Visual Complaints (SVC), Cerebral Visual Complaints questionnaire (CVC-q), National Eye Institute Visual Function Questionnaire–25 (NEI-VFQ-25), Behavior Rating Inventory of Executive Function-A (BRIEF-A), Questionnaire for Experiences of Attention Deficits (Fragebogen erlebter