Sensorimotor development

Question 1

what age is the sensorimotor stage according to piaget?

Answer 1

0-2 years

Question 2

what happens in the sensorimotor stage according to Piaget?

Answer 2

• The infant explores the world through direct sensory and motor contact.
• Object permanence and separation anxiety develop

Question 3

what are sensorimotor skills?

Answer 3

integrating the sensory aspects of your environment around you into movement

Question 4

what are some examples of sensorimotor skills?

Answer 4

• walking
• ‘clumsiness’
• hand/eye coordination
• reading
• writing
• coordinating eye contact with speech and gesture during a conversation

Question 5

How does the sensorimotor system work?

Answer 5

1. sensory inputs from the visual system and the proprioceptive system provides essential information about the task i.e. image of the mug on table and sense of your hand in space
2. sensory inputs are integrated into second step the state estimation. This specifies where the mug is, how big it is, where your hand is and other relevant information
3. the current state of the world must then be compared to the desired state. Motor system plans how to move hand efficiently from current location to the mug. This planning processes is called the inverse model. Turns goal into a sequence of motor commands
4. during execution errors might occur e.g. noise in the system, planning failure etc. sensory feedback is too allow sufficient error correction and rapid hand movements. to reduce this problem the brain uses a forward model (predictor) takes a copy of the outgoing motor compound called the efference copy and it generates a prediction of the expected sensory input. So as the movement develops the actual sensory movement is compared to the predicted to allow rapid detections and correction of errors
5. motor execution

Question 6

what is sensorimotor integration?

Answer 6

the integration of the forward model output with the state estimates, as well as the use of the state estimate by the inverse model to create a motor plan

Question 6

what can go wrong in the sensorimotor system?

Answer 6

• precise motor performance requires accurate sensory inputs concerning the body and the world so wouldn’t create a precise state estimation
• during movement execution its essential to check that the executed action is proceeding as planned and to check for errors if needed. so deficits in forward model would create difficulty in making rapid corrections to movement
• motor planning impairments could result in much longer reaction times before a movement is performed

Question 7

How does the sensorimotor system explain learning?

Answer 7

• motor control systems aren’t fixed at birth, but rapidly learn new information and adapt to the environment
• The motor learning takes place on all timescales and all components of the motor circuit
• must update the forward model to take into account the extra weight and pay more attention to proprioceptive information from the limbs until they become accustomed to them
• this process also happens for more abstract learning such as using tools and sequencing actions
• deficits in any of these aspects could also affect motor learning

Question 8

what skills are affected in ASD due to disorder of sensorimotor development?

Answer 8

pronounced difficulties in:
- communication
- socialisation
- narrow circumscribed interests
- repetitive behaviours
- sensory hypersensitivity

Question 9

what skills are affected in developmental coordination disorder (DCD)/dysoraxia due to disorder of sensorimotor development?

Answer 9

pronounced difficulties in:
- selection, timing and spatial organisation of purposeful movement and coordination
- social anxiety, social and communication skills

Question 10

Is DCD?dyspraxia more prevalent in autism then the general population?
Is DCD/Dyspraxia associated with significantly higher autistic traits? cassidy et al (2016)

Answer 10

• used self report questionnaire which captured difficulties usually associated with autism
• The AQ traits are usually experienced in people with autism and people without autism
• but having high autistic traits doesn’t mean you will necessarily meet the autism diagnosis criteria
• found that autistic adults were significantly more likely to be diagnosed with dyspraxia compared to the normal population
• suggesting autistic adults are more likely to experience sensorimotor motor issues
• adults with autism significantly more likley yo have DCD/dyspraxia (6.9%) than the general population (0.8%)
• adults with DCD/dyspraxia have significantly higher autistic traits and lower empathy than controls
• sensorimotor skills important for social skills and empathy

Question 11

what is the impact of motor difficulties?

Answer 11

• imitation (Mostofsky et al., 2006)
• speech sound production (Page and Boucher, 1998)
• emotion recognition (cummins et al. 2005)
• anxiety in response to social interaction (Batt et al. 2011)

Question 12

what are the sensory difficulties in autism?

Answer 12

• now part of the current diagnostic criteria for autism in DSM-V
• early clinical reports described “sensory intrusions” (Kanner and Asperger)
  corroborated by research
• high prevalence in autism (65-95%) (Caminha and Lampreia, 2012; Tomcheck and Dunn, 2007)
• proprioceptive impairment (determining where body is in space)(Blanche et al. 2012)
• Increased rates of synaesthesia (where one sensory modality triggers another) (baron-Cohen et al., 2013)

Question 13

how is the evidence inconsistent with sensory difficulties in autism?

Answer 13

• weak central coherence (or strong local coherence)
• Embedded figures test
• ASD significantly faster than matched controls
• Evidence of superior visual processing of details

Question 14

How does sensory differences impact higher order skills such as motion in autism

Answer 14

• coherent motion - snow flakes blowing in the wind
• biological motion - characteristic human and animal body movements
• distinguish coherent/biological at 3 months old (Pavlova et al., 2001) - however autistic children struggles with this
• difficulties in processing biological traits are associated with autistic traits and maybe result in the higher-order deficits in social cognition and dynamic attention

Question 15

what are the impacts of sensory difficulties in people with autism?

Answer 15

• sonsory reactivity associated with difficulties in social and communication skills (Matsushima and Kato, 2013)
• autistic traits associated with sensory reactivity (Tavissoli et al., 2013)
• many studies not with autistic people
• sensory processing important for social development
• sensory difficulties a core feature of autism and associated with restricted repetitive behaviours (RRB) and anxiety
• RRBS = insistence in sameness and repetitive motor movements e.g. autistic people asking what time is it or asking whats coming next

Question 16

study to determine pathways between sensory abnormalities and our RRBsand the role that anxiety and uncertainity may have in this (Wigham et al., 2015)

Answer 16

• gathered caregiver report data for 53 autistic people aged 8-16
• found that sensory under responsiveness and sensory over responsiveness was significantly associated with repetitive motor movements and insistence on sameness behaviours
• these relationships were mediated by intolerance of uncertainty and anxiety
• the results suggest a pathway where sensory differences are associated with RRBs particularly for those children experiencing anxiety and uncertainity
• RBs restricted behaviours appear to be a functional coping mechanism to cope with overwhelming sensory environment and anxiety

Question 17

what impact does autistic people’s coping mechanisms have on families

Answer 17

• insisting on taking the same route to school
• not wanting to try anything new
• struggle to cope with change

Question 18

how can you help autistic children cope with uncertainty?

Answer 18

• use of social stories of what will happen in a new situation and reduce anxiety and uncertainty
• visual timetables of the day to reduce uncertainty about what will happen
• clear instructions throughout the day like how long things will take

Question 19

sensorimotor difficulties study (Hannant et al., 2016)

Answer 19

• Autistic children have marked sensory and motor difficulties compared to those without autism
• sensorimotor skills, such as catching a ball, most strongly associated with a number of autism symptoms acriss measures in both groups
• sensorimotor skills (as opposed to sensory or motor alone) more strongly predict social and communication skills regardless of autism diagnosis
• suggests that integrating sensory information into motor movement is the most important skill for the development of social and communication skills in autistic and non autistic people

Question 20

eye movements as a way of sensorimotor integration in autism

Answer 20

• less accurate moving eyes to a new target (Scmitt et al., 2013)
• slower to initiate an eye movement to the target
• difficulties coordinating hand and eye movement such as catching a ball (Glazebrook et al., 2009)
• could explain why delay in looking pertinent social cues with downstream effects on social and communication ability (Hannant et al., 2016; Klin et al., 2002)

Question 21

rubber hand illusion as a way of sensorimotor integration in autistic people (Cascio et al., 2012)

Answer 21

• perceived hand ownership is transferred to the rubber hand
  autistic children less susceptible than typically developing controls
• delayed susceptibility to the illusion (6 minutes)
• reduced empathy = less susceptible to the illusion
• reduced ability to integrate visual and tactile information

Question 22

rubber hand illusion as a way of sensorimotor integration in autistic people (Paton et al., 2012)

Answer 22

• autistic people did experience the rubber hand illusion, but were less sensitive to visual-tactile discrepancies
• less proprioceptive drift to the rubber hand controls

Question 23

mirror drawing

Answer 23

• need to adapt motor mobvements in response to senory information from a mirror to trace a shape such as a star, square or rectangel
• comapred performance in autistic and non autistic children
• if autistic children rely on proprioceptive feedback and therefore fail to integrate visual feedback into their motor movements they might find this task difficult to complete and make more errors
• found autistic and non autistic children perform similarly withe few errors for direct drawing
• however when viewing the hand of the mirrors the magnitudes if errors in the autistic group were largely outside the distribution of errors made by the typical control group
• some autistic children performed between than the typical control group whereas others performed much worse
• mirror drawing with correlated with difficulties imitating another persons hand orientation and hand shape and movement
• visual spatial processing deficits may contribute to functional motor coordination deficits in autistic people

Question 23

difficulties in incorporating visual information in motor learning in autism

Answer 23

• presence of a visual distractor did not impact performance of children with autism like with typical controls (Dowd et al., 2012)
• significantly less able to correct movements from visual compared to proprioceptive feedback (Gepner and Mestre, 2002)
• specific difficulties with motor movements which require visual cues or other sensory signals (Gowen et al., 2008)

Question 24

where and how does sensorimotor integration occur?

Answer 24

• in the purkinje cells in the cerebellum
• this region contains large GABAergic inhibitory neurons
• the inhibitory neurotransmitter GABA, and the main excitatory neurotransmitter glutamate are also released by these neurones
• glutamate is known to increase the firing of neurons, thereby increasing sensory feedback
• GABA is known to decrease the firing of neurons therefore reducing and inhibiting sensory feedback

Question 24

Biological basis of sensorimotor difficulties

Answer 24

cerebellum could play a role:
- saccadic accuracy has been connected to error-reducing function of the cerebellum (Schmitt et al., 2014)
- cerebellum volume associated with difficulties incorporating visual cues in motor learning
- cerebellum contains pathways that link sensory and motor pathways in the brain (Glickstein, 1998)
- abnormalities found in autistic people (McAlonan et al., 2002)
- Decreased activation in cerebellum during motor tasks in autism (Allen et al., 2004)

Question 25

GABA synthesis in neurotypical individuals

Answer 25

• sufficient synthesis of GABA and sufficient GABA receptors
• therefore no imbalance in these neurotransmitters and no hypo or hyper sensory feedback

Question 26

GABA synthesis in autistic individuals

Answer 26

• inefficient synthesis of GABA and limited receptors for GABA
• this means there is an imbalance in these neurotransmitters with increased excitatory neurotransmitter glutamate present so hypersensitive feedback occurs in the brain
• could explain why more autistic people experience hyper sensitivity