Non-linear age effects in tactile perception from early childhood to adulthood

Abstract

Tactile perception plays a pivotal role in the early stages of human development; however, little is known about tactile function in young children. A better understanding of how tactile function improves with age from early childhood to adulthood is fundamental in understanding atypical tactile experiences in childhood-onset neurodevelopmental disorders, including autism spectrum disorder. In this study, one hundred and forty-two children and adults aged 3–23 years completed a vibrotactile testing battery consisting of five tasks, which rely on different cortical mechanisms. The battery was designed to be suitable for testing in young children and was used to investigate tactile perception from early childhood to adulthood. Our results show a general pattern of rapid, age-related improvements in tactile perception (lower discrimination threshold = greater sensitivity) across early childhood (ages 3–6 years). However, differences in the rate of change across tasks were observed, with tactile performance reaching adult-like levels earlier on same tasks than others. These findings highlight that early childhood is a period of rapid changes in tactile perception, and that the different underlying cortical, physical and cognitive development processes likely develop at different rates. Further, we are the first to show the feasibility of vibrotactile testing in an early childhood sample, which has important clinical implications for examining developmental disorders with altered tactile function and our results can be used as a reference.

Atypical Tactile Perception in Early Childhood Autism

“…However, we did not observe a significant worsening of the amplitude discrimination ability in the simultaneous condition for either cohorts and the difference between sequential and simultaneous amplitude discrimination did not reveal an effect of diagnosis. While it appears that autistic children have inhibitory levels that are categorically different from neurotypical children, as discussed, it could be speculated that, irrespective of diagnosis, an immature inhibitory system in early childhood (Gaetz W. et al, 2014;Port et al, 2017;Saleh et al, 2020) results in worse discrimination ability, as shown in previous behavioural findings (Kaur et al, 2021), and that modulation of the relative timing of stimuli does not further change the threshold. Alternatively, this young age group is expected to show greater perceptual-motor processes.…”

“…TOJ: Temporal Order Judgement. DD: Duration Discrimination Using a customized testing battery that has previously been shown to be appropriate for use in young children (Kaur et al, 2021), our findings show altered tactile perception in early childhood autism on a number of vibrotactile tasks, which suggests reduced cortical inhibition in autism. Specifically, young children with autism showed poorer amplitude discrimination as well as poorer temporal order judgment (e.g., higher thresholds), but not duration discrimination, compared to neurotypical children.…”

“…Differences in tactile perception between neurotypical and autistic children were assessed using analysis of covariance (ANCOVA) for each task, with group as between-participant factor and age as a covariate given its influence on the tactile tasks (Kaur et al, 2021). Whenever group differences…”

“…Specifically, the ability to discriminate between two sequential stimuli requires comparison of both the remembered (first) and current (second) stimulus. While working memory and attentional capacity increase throughout childhood (Gathercole et al, 2004;Swanson 2017;Tamnes et al, 2013) and thus, are likely to account for some age-related improvements in tactile perception (Kaur et al, 2021), they are also likely to be impaired in autism (Ames tute. Infrastructure including the tactile stimulator was supported by the Canada Foundation for Innovation John R. Evans Leaders Fund (A.D.H).…”

“…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.…”