Shafer et al 2021

Shafer et al 2021

• Autistics show reduced ability to integrate somatosensory feedback for precision manual motor behavior 
• Disrupting somatosensory feedback through tendon vibration increased force variability in typically developing individuals only, indicating distinct sensory feedback mechanisms in autism
• Sensorimotor deficits in autism may normalize by adolescence, impacting cognitive and social development 
• Autistics rely predominantly on visual feedback, suggesting deficits in parietal-cerebellar networks for integrating sensory feedback 
• Autistics predominantly rely on visual feedback for precision manual motor control 
• Somatosensory feedback integration is reduced in individuals with autism, leading to challenges in guiding motor behavior 
• Sensorimotor deficits in autism impact the ability to integrate somatosensory feedback, potentially affecting motor coordination
• Autistics show deficits in processing sensory feedback to adjust ongoing motor behaviors, with atypical reliance on visual and somatosensory feedback during motor tasks 
• Autistics exhibit reduced ability to integrate somatosensory feedback, leading to challenges in guiding precision manual motor behavior 
• The reliance on visual feedback is predominant in autistm, indicating deficits in parietal-cerebellar networks for integrating sensory feedback 

 

Shafer, R. L., Wang, Z., Bartolotti, J., & Mosconi, M. W. (2021). Visual and somatosensory feedback mechanisms of precision manual motor control in autism spectrum disorder. Journal of neurodevelopmental disorders, 13, 1-17

Mosconi et al 2015

 Key Takeaways. 

• Autistics show disruptions in both feedforward and feedback motor control mechanisms, implicating anterior and posterior cerebellar circuits 
• The severity of visuomotor abnormalities in autism is dependent on the level of demand on the motor system, with increased reliance on slower feedback mechanisms observed.
• Autistics exhibit a profile of motor control abnormalities similar to those seen in patients with cerebellar lesions, suggesting intrinsic alterations in cerebellar circuits in autism.
• Disruptions in feedforward control of force output are observed in autism, even when joint-coordination functions are not required, indicating impairments in planning functions of the cerebellum.

Mosconi, M. W., Mohanty, S., Greene, R. K., Cook, E. H., Vaillancourt, D. E., & Sweeney, J. A. (2015). Feedforward and feedback motor control abnormalities implicate cerebellar dysfunctions in autism spectrum disorder. Journal of Neuroscience, 35(5)

Autistic traits in general adult population

I'm somewhat conflicted on this research paper. We have hardly gotten around to understanding and finding solutions for the vast heterogeneity that is autism today. Frankly its one hot mess right now

Are we adding to the confusion with studies like this which are going about investigating general population to see if they too have "autistic traits." Its almost like saying everyone has some autistic traits which is nice for a coffee discussion but is distracting us from focus on research basd solutions that many of the more impacted autistics desperately need.

Palmer CJ, Paton B, Enticott PG, Hohwy J. 2015. “Subtypes” in the presentation of autistic traits in the general adult population. J. Autism Dev. Disord. 45:1291–301 

Key Findings.

• The study examined the presentation of autistic traits in a large adult population sample using the Autism-Spectrum Quotient (AQ).
• Cluster analysis was used to identify two subgroups with distinguishable trait profiles related to autism.
• The first subgroup (n = 1,059) reported significantly higher scores on the AQ subscales related to social difficulties (Social Skills and Communication) and significantly lower scores on the Detail Orientation subscale.
• The second subgroup (n = 1,284) reported significantly higher scores on the Detail Orientation subscale and significantly lower scores on the Social Skills subscale.
• The study also found that the AQ had a three-factor solution, with two related social-themed factors (Sociability and Mentalising) and a third non-social factor that varied independently (Detail Orientation).
• These findings suggest that there is significant variability in the presentation of autistic traits in the general adult population, and that different profiles of autistic characteristics tend to occur in nonclinical populations.

The Landmark Task

[concepts in Sensorimotor research]

The landmark task is a commonly used experimental paradigm to investigate spatial perception and cognition, particularly in relation to spatial memory and navigation. It involves presenting participants with a specific location or object in an environment and assessing their ability to remember and use that information to orient themselves.

In the landmark task, participants are typically placed in an unfamiliar environment or VR simulation where they are exposed to various landmarks. These landmarks can be objects, distinct features, or specific locations within the environment. The participants' task is to remember the location or arrangement of the landmarks and use them as reference points for subsequent navigation or spatial judgments.

After the initial exposure to the landmarks, participants may be asked to perform various tasks, such as:

• Landmark Recognition: Participants are shown a set of landmarks, including both the ones they previously encountered and new ones, and are asked to identify the ones they remember.
• Landmark Recall: Participants are asked to verbally describe or draw a map of the environment, indicating the locations and features of the landmarks they remember.
• Landmark Localization: Participants are instructed to physically move or point to the location of specific landmarks within the environment.
• Landmark Navigation: Participants are required to navigate through the environment to reach a target location, using the remembered landmarks as a guide.

The landmark task provides researchers with insights into spatial memory, cognitive mapping, and the ability to use environmental cues for navigation. By examining participants' performance on tasks like landmark recognition, recall, localization, and navigation, researchers can evaluate their spatial perception, memory accuracy, and strategies for spatial orientation.

The landmark task has been used in various fields of research, including cognitive psychology, neuroscience, and spatial cognition. It has provided valuable insights into the mechanisms underlying spatial memory, the role of landmarks in navigation, and the differences in spatial abilities among individuals.

Pseudoneglect

Pseudoneglect refers to a phenomenon in which people exhibit a bias or tendency to allocate more attention or perceptual processing to the left side of space than the right side (or vice versa). Despite the term "neglect" in its name, pseudoneglect does not indicate an actual neglect of the opposite side but rather an asymmetry in attention allocation.

The term "pseudoneglect" was coined by Bowers and Heilman in 1980 when they observed a leftward bias in line bisection tasks, where participants were asked to mark the midpoint of a horizontal line. They found that most individuals tend to place the mark slightly to the left of the true center, indicating a bias toward the left side of the line.

This phenomenon has been attributed to the dominance of the right hemisphere in spatial attention and perception. The right hemisphere of the brain is generally considered to be more involved in processing spatial information, while the left hemisphere is typically associated with language and analytical functions. As a result, the right hemisphere's dominance may contribute to a leftward attentional bias, leading to pseudoneglect.

Pseudoneglect has been observed in various perceptual tasks, including line bisection, line length estimation, and visual search. It is thought to reflect a normal asymmetry in attentional processing rather than a pathological condition.

Understanding pseudoneglect can have implications for studying brain function and spatial cognition. Researchers have used this phenomenon to explore the mechanisms underlying spatial attention, hemispheric specialization, and disorders such as neglect syndrome, where there is a true deficit in attending to one side of space.

Rubber Hand Illusion

Body ownership, specifically arm ownership, can be experimentally manipulated using the Rubber Hand Illusion (RHI). 

RHI is a perceptual phenomenon that occurs when a person's brain is tricked into perceiving a rubber hand as part of their own body. 

In the RHI, a realistic looking rubber hand is placed next to a subject's own hand, and both hands are stroked in synchrony at the same location, with only the rubber hand being visible.

By simultaneously stroking both the rubber hand and the participant's real hand, it creates the illusion that the rubber hand is their own (attributed to their own body)

To integrate the new hand into the body representation, it is important that both the rubber hand and real hand are anatomically aligned, meaning they should be positioned in the same orientation and in parallel to each other or above one another.

Embodying the rubber hand as one's own changes the sense of location of one's own hand, and the perceived location of one's own hand typically "drifts" towards the rubber hand after inducing the illusion, which is known as proprioceptive drift.

The RHI illustrates the plasticity of our body representation, as it transiently changes how and where we perceive our hand.

RHI can also affect the foot and the entire body. RHI has been used in various research studies to investigate body perception, multisensory integration, and the brain's ability to update its body representation. It was first described by Ehrsson in 1998  paper.

Researchers have utilized the rubber hand illusion to explore various aspects of body ownership and self-perception. It has been employed in studies examining disorders like schizophrenia and body dysmorphic disorder, as well as in research related to pain perception, self-identification, and body image.

Regarding autism research, the rubber hand illusion has been employed to investigate differences in body representation and multisensory integration; whether autistics show alterations in the experience of body ownership and if their multisensory integration processes differ from NT  individuals (Casio et al, 2012)

Citation:

Ehrsson, H. H. (1998). Touching a rubber hand: feeling of body ownership is associated with the synchronous multisensory stimulation. Cognitive Brain Research, 67(2), 561-570.

Cascio, C. J., Foss-Feig, J. H., Heacock, J. L., & Newsom, C. R. (2012). Rubber Hand Illusion in Autism Spectrum Disorder: Self versus Externally Attributed Touch. Journal of Autism and Developmental Disorders, 42(11), 2420–2429. doi: 10.1007/s10803-012-1500-1

NASA-TLX - Task Load Index

 [See posts on other Screening/Assessment Tools, Psychological Measures]

The NASA-TLX (Task Load Index) questionnaire is a tool developed by NASA to assess the workload and subjective workload experienced by individuals performing a task. Though initially designed for pilots, it is widely used across various industries including autism research 

The questionnaire has 6 subscales/submeasures, that assess different dimensions of workload. 

• Mental Demand: mental effort and cognitive load required to perform the task.
• Physical Demand: physical effort and exertion involved in performing the task.
• Temporal Demand: perceived time pressure and the amount of time available to complete the task.
• Performance: individual's perception of their own performance during the task.
• Effort: perceived level of effort and energy expenditure required to complete the task.
• Frustration: degree of annoyance, stress, and dissatisfaction experienced during the task.

Scoring and Interpretation

Participants rate each submeasure on a scale of 0 to 100. Scoring and interpretation vary depending on the specific study or context. Generally, higher scores indicate a higher perceived workload in the respective submeasure. 

Researchers often analyze the individual submeasure scores and the overall workload score to gain insights into the specific dimensions of workload that are most significant in a given task or situation. The questionnaire can help identify areas where workload can be optimized or where additional support or resources may be required.

Examples of use in Autism Research in evaluating workload and cognitive demands 

Study: "Task load and verbal responses to questions in children with autism spectrum disorder"Citation: Nishida, T., Yuhi, T., Kaneoke, Y., Kurosawa, K., & Dan, I. (2014). Task load and verbal responses to questions in children with autism spectrum disorder. Frontiers in Human Neuroscience, 8, 937.
Link: https://doi.org/10.3389/fnhum.2014.00937

Study: "Measurement of cognitive workload in individuals with high-functioning autism spectrum disorder using a virtual reality task"Citation: Park, S. M., Chong, S. C., Lim, S. L., Kim, J. S., & Kim, J. S. (2020). Measurement of cognitive workload in individuals with high-functioning autism spectrum disorder using a virtual reality task. Applied Sciences, 10(2), 581.
Link: https://doi.org/10.3390/app10020581