Reproducibility of flutter-range vibrotactile detection and discrimination thresholds

Abstract

Somatosensory processing can be probed empirically through vibrotactile psychophysical experiments.Psychophysical approaches are valuable for investigating both normal and abnormal tactile function in healthy and clinical populations. To date, the test-retest reliability of vibrotactile detection and discrimination thresholds has yet to be established. This study sought to assess the reproducibility of vibrotactile detection and discrimination thresholds in human adults using an established vibrotactile psychophysical battery. Fifteen healthy adults underwent three repeat sessions of an eleven-task battery that measured a range of vibrotactile measures, including reaction time, detection threshold, amplitude and frequency discrimination, and temporal order judgement. Coefficients of variation and intraclass correlation coefficients (ICCs) were calculated for the measures in each task. Linear mixedeffects models were used to test for length and training effects and differences between tasks within the same domain. Reaction times were shown to be the most reproducible (ICC: ~0.9) followed by detection thresholds (ICC: ~0.7). Frequency discrimination thresholds were the least reproducible (ICC: ~0.3). As reported in prior studies, significant differences in measures between related tasks were also found, demonstrating the reproducibility of task-related effects. These findings show that vibrotactile detection and discrimination thresholds are reliable, further supporting the use of psychophysical experiments to probe tactile function.Psychophysical experiments can be used to probe somatosensory processing empirically. Quantitative measures of vibrotactile sensitivity, in particular, have been used to elucidate on the cortical mechanisms underlying such processing 1,2 . Such behavioural approaches have proven to be valuable and may reflect cortical mechanisms underlying somatosensory function. For example, GABAergic inhibition drives neuronal responses to sensory stimulation 3,4 linked to behavioural outcomes. Measuring such behavioural outcomes may, therefore, provide information about cortical inhibition. The targeting of specific neuronal mechanisms of tactile function through psychophysics allows for the investigation of individual differences in healthy brain function or of impairments in disorders hypothesized to be driven by inhibitory dysfunction. Early work established the neurophysiological basis of tactile function in both nonhuman and human primates 5-10 . Psychophysical testing of sensory processing in general also has a long history 11,12 upon which present-day research has been built.A behavioural battery of psychophysical paradigms for assessing vibrotactile function 13 was previously developed and shown to be successfully implementable in both adults and typically developing children. The vibrotactile stimuli used in the paradigms fall within the flutter range of touch (<50 Hz), which are processed by rapidly adapting (RA) I mechanoreceptors in the glabrous skin 7,9 . The neurophysiology of amplitude...

Nonlinear age effects in tactile processing from early childhood to adulthood

“…The sample size is small and thus this is a preliminary study of this tactile battery in young children. Additional validation and reliability studies in young children are needed as it is unknown whether the reliability as established in older groups (Mikkelsen et al., 2020 ) extends to childhood. A common limitation in studying pediatric cohorts is their compliance with task requirements.…”

“…Vibrotactile testing paradigms can quantitatively examine the function (or dysfunction) of somatosensory processing and can be designed to provide insight into multiple cortical functions (Mikkelsen et al., 2020 ; Nguyen et al., 2013 ; Puts et al., 2013 , 2014 ; Tommerdahl et al., 2016 ). The different metrics have been shown to be sensitive to specific neurosensory mechanisms in humans, and parallels in said assessments have been observed in animal models (Tommerdahl et al., 2021 ).…”

Atypical Tactile Perception in Early Childhood Autism

“…To this end, we have developed a customized testing battery appropriate for use in young children (Kaur et al, 2021) which uses previously validated vibrotactile tasks Mikkelsen et al, 2020;Puts et al, 2011;Puts N.A., Edden R.A., Wodka E.L., Mostofsky S.H., & Tommerdahl M., 2013;Puts et al, 2017). In this study, we have used this customized battery to assess different aspects of tactile perception in young autistic children aged 3-6 years as compared to young neurotypical children.…”

Adaptive Nonparametric Psychophysics

“…To address this issue, the standard approach is to independently measure absolute detection and discrimination thresholds, i.e. implicitly assume a piecewise linear model with k detection k discrimination (e.g Aguilar & Stiles, 1954;Foley & Legge, 1981;Legge, 1984;Mikkelsen et al, 2020).…”