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Functional Elements of the Explorer Mini's Saddle Seat


Part 11 in our series about developmental milestones in early childhood focusing on mobility. 


The saddle seat was designed intentionally to facilitate an upright posture through developmentally appropriate supports. Research regarding the use of either flat seats or saddle-like seating has been conducted over the years. The work of DT Reid (1996) tells us that children with Cerebral Palsy displayed better seat alignment and postural control of the upper body resulting in a more efficient reaching path in a saddle seat making it easier to reach desired item. In 2006, Stavness reviewed the literature on the effect of positioning for children with cerebral palsy and upper extremity function. Evidence supports that an upright position, versus sitting back in a chair, improves reaching and hand manipulation. Additionally, the optimal position is a cutout tray, a sloped seat forward of 0-15 degrees and that the line of gravity be in front of the “sit bones”, otherwise known as the ischial tuberosities.

Recommendations for Seating

Sunny Hill Health Centre for Children provide very specific parameters of optimal seating for children with Cerebral Palsy (CP) based on extensive research. Their aim in creating these recommendations was to develop symmetry of the pelvis, trunk, neck and head in all positions. They suggest:

  • Change positions to encourage motor development and movement
  • Introduce sitting at around 5 months gradually bringing them into a more upright posture to encourage head control
  • If needed provide lateral supports and a thigh guide to encourage hip abduction and external rotation and aligned foot position
  • Aim for hip abduction of 15-30 degrees and external rotation of 5-15 degrees.

The shape of the saddle seat is designed to provide this hip abduction and external rotation while weight bearing through the feet. While it is not essential that your young child always be in this position, it is optimal for hip bone growth and development. For children who are not crawling or walking this helps develop the hip joint and head of the femur (thigh bone). The weight bearing in this position helps build a cup like structure around the hip joint for stability.

These recommendations are not just for children with CP, they are developmentally aligned for all children with mobility impairments. 

Incorporating the research findings regarding the development of young child sitting skills, the Explorer Mini saddle seat is designed to optimize weight bearing on the ITs by not including padded seating. The Explorer Mini is not designed for children to use continuously, therefore padding is not necessary. As always, each child is different and skin care checks should be routine when altering a young child’s position.

You may wonder why the seat does not offer a seat belt. The seat and tray table as well as the foot support are designed to allow for dynamic movement. If movement is not encouraged the muscle fibers and nerve endings become static and do not communicate the messages of movement to the brain. By placing a seat belt on the device, we would restrict movement and not facilitate an upright posture. If your child cannot sit upright at first, do not give up.

Work with the therapist to find the best seat height to encourage this level of support. Remember your child is learning. When a child is learning to crawl, we let them struggle and fail before they finally achieve the skill. The same is true for upright sitting in the Explorer Mini. They may not be instantly successfully. But be assured we have worked with great intention to know how to assist in development of posture, environmental exploration and movement.

What is Success? 

The picture below show Davis when he was originally put in the device. Initially he was not putting weight through the seat and his abnormal reflexes had him leaning to one side.

The temptation was to go and straighten him out, provide supports to keep him upright. But we didn’t do that. Davis struggled and worked at getting his trunk more upright and saw the joystick that he wanted to reach. Over time during this session of 1 hour, Davis was successful at bringing his body to a more upright position. Is this position perfect? No, but neither was that first crawl attempt of a child without mobility impairments!

The Explorer Mini is a tool that can be used over time to allow very young children to get into developmentally appropriate positions to achieve a more upright posture, and as a result promote visual, sensory, and motor integration, and provide the opportunity for independent mobility. Success in the Explorer Mini may initially be measured by showing small gains or improvements in ability to maintain midline positioning for longer periods of time while visually locating or reaching for the joystick to help promote development of postural control, strength, and endurance required for self-initiated mobility. 


Reid, D. T. (1996). The effects of the saddle seat on seated postural control and upper-extremity movement in children with cerebral palsy. Developmental Medicine and Child Neurology, 38, 805–815.

Stavness, C., (2006). The effect of positioning for children with Cerebral Palsy on upper-extremity function: A review of the evidence. PT and OT in Pediatrics, 26,39-52

Sunny Hills Health Centre for Children. (2014). Positioning for children with GMFCS Levels IV-V: Focus on Hip Health. Retrieved from sunny-hill-clinical-tool-for-hip-health-gmfcs-iv-v-2014.pdf 


Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS
Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology. She is a member of the International Society of Wheelchair  Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has presented internationally, nationally and regionally particularly in the area of pediatric power mobility. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

Conventions of Functional Seating in the Explorer Mini   


Part 10 in our series about developmental milestones in early childhood focusing on mobility.


We can find all sorts of ways to sit, usually not always the most optimal but we change our positions based on the task we are performing. Reading a book, maybe our legs are propped on the couch, or we sit cross legged. If engaged in writing or typing we are probably resting our feet on the floor, leaning slightly forward and resting our hands on the desk or chair supports. A young child with delayed milestones or mobility impairments cannot access those alternative positions. They are dominated by gravity. If they have not had opportunities to meet the developmental milestones in incremental order, their posture will be affected, therefore the task they perform will be altered.

If you think about how a young child develops trunk and head control, it’s logical to think about ways to correct that. If the child is unable to do so themselves, they will need postural support. In order for a young child to begin using their arms and hands they need first to control their core muscles. This is why a pre-crawling infant will spend a lot of time rocking back and forth when on all fours. This movement around the joint strengthens the joint capsule—where the muscles attach—to help build muscle strength and endurance.  

How does the Explorer Mini provide functional seating? 

The Explorer Mini is designed for the non-ambulatory and the emerging ambulator. It provides the developmentally appropriate supports to establish an upright trunk. We call this sequence of movements and postures the “conventions of functional seating”. In this case function means whatever that young child would be doing at that stage of their development.  

The elements of functional seating: One must have a stable base of support on the buttocks and thighs. In order to prevent a slumping posture, the pelvis needs to be tilted forward. 

When we typically visualize a child with mobility impairments in “functional seating”, we think of them in a wheelchair with a cushion, back support, head support, and maybe even lateral trunk supports. It’s easy to assume that all these supports are required to provide stability for function. This may be true, but the supports don’t encourage the strengthening of core muscles or activation of the trunk muscles for posture, head control, and ultimately functional use of the hands.

There is now an option with the Explorer Mini to put young children in a posture of functional seating that will place the pelvis in a forward position for stability, with feet directly underneath. The forearms provide added stability by weightbearing on the tray, triggering the trunk muscles to activate and extend, which encourages an upright head. By allowing freedom of movement through intentionally not using straps or belts, young children can safely work to bring themselves into a functional seating posture. Although the Explorer Mini is not intended for full time use, it is a device that can be used intermittently and help a very young child develop a functional upright posture, with the reward being intentional, self-initiated movement to explore their environment. 


 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS
Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology. She is a member of the International Society of Wheelchair  Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has presented internationally, nationally and regionally particularly in the area of pediatric power mobility. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

 

 

The Importance of the Explorer Mini's Midline Joystick for Development


Part 9 in our series about developmental milestones in early childhood focusing on mobility. Read our previous blog entries below.


Upper extremity function, such as reaching, grasping, and manipulating objects requires dynamic stability of the shoulder girdle on a stable trunk. The Explorer Mini tray provides this support to the upper extremities to allow for midline access to the joystick. The design of the midline joystick allows for the two hands to come together to support hand manipulation which contributes to handedness and haptic perception development. 

What is Handedness Development?

Handedness or hand dominance typically occurs in children between the ages of 2-3 years of age. For children who are immobile and use a power mobility device with a joystick, hand dominance may be affected by the joystick placement to the right or to the left. Having a joystick in midline encourages bimanual exploration and allows hand dominance to be determined naturally. Additionally, having a joystick placement on the right or left may lead to scoliosis because the trunk may be hypotonic while the extremities may be hypertonic for example for children with cerebral palsy. 

 

What is Haptic Perception?

Haptic perception is the recognition of objects and object properties by the hand without the use of vision. The hands and mouth are the primary sources of haptic information for an infant. “As the infant develops, the hands become a perceptual system that increasingly participates in the infant’s construction of knowledge” (2). Infants will first learn about their environment through haptic perception and as mobility develops their ability to interact with their environment allows for greater exploration. 

“Vision appears to guide the development of haptic manipulation strategies. It is not until later in life that vision and somatosensory sensations appear to take on separate but supportive roles in object identification and use" (2). For this reason, it is a strategic part of development that the young child may “play” with the joystick, manipulating it, feeling the texture and even mouthing the joystick. Once he has an opportunity to develop the haptic perception and realize that what he is seeing is the same as what he is feeling, he may then come to realize that the joystick actually moves the device. Therefore, as part of training and exploration it is essential that the young child have adequate opportunities to explore the Explorer Mini before understanding that movement is part of the package. 

How does posture affect upper extremity function?

Evidence supports that an upright posture versus a reclined posture improves upper extremity function such as reaching and manipulation (5). The posture that a child is put in with the design of the Explorer Mini is a forward posture, using weight bearing of the upper extremities. 


1.Hagert, E., Persson, J., Werner, M., & Ljung, B-O. (2009). Evidence of wrist proprioceptive reflexes elicited after stimulation of the scapholunate interosseous ligament. American Society for Surgery of the Hand, 34A. 642-651. 

2.Henderson, A., & Pehoski, C., (2006). Hand Functions in the Child: Foundations for Remediation, 2nd edition. Mosby, Elsevier. St. Louis, Missouri.

3.Michelson, JD, & Hutchins, C., (1995), Mechanoreceptors in human ankle ligaments. The Journal of Bone and Joint Surgery. British vol. 77-B

4.Rosenblum, S., & Josman, N. (2003). The relationship between postural control and fine  manual dexterity. Physical and Occupational Therapy in Pediatrics, 23,(4). 47-60. 

5.Stavness, C., (2006). The effect of positioning for children with Cerebral Palsy on upper-extremity function: A review of the evidence. PT and OT in Pediatrics, 26,39-52 

6.Westcott, S., & Burtner, P. (2004). Postural control in children: Implications for pediatric practice. PT and OT in Pediatrics, 24, 5-55. 

7.Scheiman, M. (2011). Understanding and managing vision deficits: A guide for occupational therapists. Thorofare, NJ: SLACK Incorporated.  


 

P, CEAS, CAPS
Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology. She is a member of the International Society of Wheelchair  Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has presented internationally, nationally and regionally particularly in the area of pediatric power mobility. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

 

Could your child benefit from the Explorer Mini ? - Part 2

 


Part 8 in our series about developmental milestones in early childhood focusing on mobility. Read our previous blog entries below.


 

Functional Groups Examples
Children who may never ambulate
  • Children with severe cerebral palsy, spinal muscle atrophy types I and II.
Children with inefficient mobility
  • Those who ambulate but are unable to do so at a reasonable rate of speed or with acceptable endurance.
  • This includes children with milder forms of cerebral palsy and myelomeningocele with upper extremity involvement.
Children who lose the ability to walk or to walk efficiently
  • Children with progressive neuromuscular disorders.
  • Children who experienced a traumatic brain or spinal event.
  • Developmental delay of this group would depend upon when their mobility and structures impaired.
Children who need mobility assistance in early childhood
  • Often progress to independent mobility with age
  • Children with conditions such as osteogenesis imperfecta and arthrogryposis
  • Considerations for this group are both developmental and functional

  


There are hundreds of pediatric medical diagnoses that may warrant the consideration of a power mobility device (PMD). However, there are some limitations of associating the use of a device solely with a specific diagnosis. One consideration is that many children are not diagnosed with a medical diagnosis as no etiology can be pinpointed for the cause of the deficits. In this common situation, a child may demonstrate delays in development but there is no known cause. In these cases, it is not unusual to wait until a child is 24-48 months to deem that this is a delay in development. And we know from our previous blog what happens when a child is unable to perform self-initiated movement. Rather than relying on diagnosis to determine the use of a PMD, it may be prudent to use the Hays (1) categories to determine the need.

A diagnosis such as spinal muscular atrophy impairs a body structure and consequently a function such as sitting and walking. Whereas a diagnosis like developmental delay is not associated with a body structure deficit but rather functional deficits ranging from the inability to reach developmental milestones such as fine motor dexterity to severe deficits in all motor tasks. Some children may have visual problems and some may not. Each case is different.

One may also consider the International Classification of Functioning, Disability and Health (ICF) as a framework for establishing a nomenclature for describing a mobility impairment. The level of impairment can be at the level of health condition, body structure and function, activities, participation, environmental or personal factors. Any one or all of these can lead to a child not having access to mobility and thereby participation (15).

The ICF conceptualizes a person's level of functioning as a dynamic interaction between her or his health conditions, environmental factors, and personal factors. It is a biopsychosocial model of disability, based on an integration of the social and medical models of disability. Disability is multidimensional and interactive. All components of disability are important and any one may interact with another. By way of illustration a graphic depiction may include any of all of the following levels of impairment that may warrant consideration for a power mobility device such as the Explorer Mini (15).

Without an opportunity to participate in life’s activities a child may develop additional impairments and delays. Exploration provides an infant with new perspectives and reveals new information that drive changes in a host of different psychological phenomena (3). For young children with disabilities such as CP, Spina Bifida, and other developmental disabilities, studies have shown that cognitive, social, and language development can be advanced through powered-mobility interventions (10, 13). Whereby a lack of environmental exploration leads to delays in cognition, vision, language and social skills (3). The World Health Organization has recognized that children who experience reduced mobility are at an increased risk of being denied educational opportunities, with the resulting impact on future employment and poverty (4). Therefore, it is imperative that we consider young children with mobility impairments as candidates for the Explorer Mini. 


1. Rosen, L., Plummer, T., Sabet, A., Lange, M., & Livingstone, R. (2017). RESNA Position on the Application of Power Mobility Devices for Pediatric Users-Update 201. Rehabilitation Engineering And Assistive Technology Society Of North America

2. Acredolo, L.P., Adams, A., & Goddwyn, SW., (1984) The role of self-produced movement and visual tracking in infant spatial orientation. Journal of Experimental Psychology, 38, 312-327. Doi: 10.1016/0022-0965(84)90128-0

3. Anderson, D. I., Campos, J. J., Witherington, D. C., Dahl, A., Rivera, M., He, M.,… Barbu-Roth, M. (2013). The role of locomotion in psychologicaldevelopment. Frontiers in Psychology, 4(July), 440. https://doi.org/10.3389/fpsyg.2013.00440

4. Armstrong, W., Borg, J., Krizack, M., Lindsley, A., Mines, K., Pearlman, J., . . . Sheldon, S. (2008). Guidelines on the provision of manual wheelchairs in less resourced settings. Geneva, Switzerland: World Health Organization, WHO Press.

5. Butler, P. (1988). High tech tots: Technology for mobility, manipulation, communication, and learning in early childhood.Technology, Infants Young Children, 1, 66-73

6. Butler, P.B. (1998) A preliminary report on the effectiveness of trunk targeting in achieving independent sitting balance in children with cerebral palsy. Clinical Rehabilitation, 12, 281-293.

7. Butler C, Okamoto G and McKay T. Powered mobility for very young disabled children. Dev Med Child Neurology. 1983;25(4):472–474.

8. Butler C, Okamoto G and McKay T. Motorized wheelchair driving by disabled children. Arch Phys Med Rehabilitation 1984;65(2):95–97.

9. Higgins, C. I., Campos, J. J., and Kermoian, R. (1996). Effect of self-produced locomotion on infant postural compensation to optic flow. Dev. Psychol. 32, 836–841. doi: 10.1037/0012-1649.32.5.836

10. Lynch A, Ryu J, Agrawal S, Galloway JC. (2009) Power mobility training for a 7-month-old infant with spina bifida. Pediatric Physical Therapy.;21:362–368.

11. Mancini, M. C., Coster, W. J., Trombly, C. a, & Heeren, T. C. (2000). Predicting elementary school participation in children with disabilities. Archives of Physical Medicine and Rehabilitation, 81(3), 339–347. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10724080

12. Paulsson K Christofferson M - 1986 - Psychosocial aspects of technical aids How does independent mobility affect the psychosocial and intellectual development of children with physical disabilities.pdf.

13. Ragonesi CB, Chen X, Agrawal S, Galloway JC. Power mobility and socialization in preschool: a case study of a child with cerebral palsy. Pediatric Physical Therapy. 2010; 22:322–329.

14. Stanton, D., Wilson, P.N., and Foreman, N. (2002). Effects of early mobility on shortcut performance in a simulated maze. Behavior Brain,136, 61-66. doi:10.1016/SO166-4328 (02)00097-9

15. World Health Organization. (2001) The ICF: An overview. Retrieved from https://www.wcpt.org/sites/wcpt.org/files/files/GH-ICF_overview_FINAL_for_WHO.pdf

16. Weisz JR (1979) Perceived control and learned helplessness among mentally retarded and nonretarded children: a developmental analysis. Developmental Psychology 15(3): 311–9470 


Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS
Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology. She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has presented internationally, nationally and regionally particularly in the area of pediatric power mobility. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.


 

 

 

Could your child benefit from the Explorer Mini ? Part 1 

  


Welcome to Part 7 of our series about developmental milestones in early childhood focusing on mobility! Read our previous blog entries below.


The Explorer Mini is designed to be used by a wide variety of young children with mobility impairments. Children with physical disabilities who have difficulty achieving independent motor control are often deprived of opportunities for self-initiated or self-produced mobility. Mobility impaired toddlers who cannot move across a room to reach out and touch an object or interact with a person are at a great disadvantage.

They can’t experience the sensorimotor and developmental activities of their peers who have achieved upright mobility, such as pushing and pulling toys, opening and closing drawers, or moving around and under objects.

Self-initiated mobility also affects motor functioning and the ability to develop mature grasp and postural control. Researchers who have studied the impact of early exploration on a child’s development have also suggested that self-produced locomotion and active choice are important for the development of perception and cognition (1).

Because self-produced, self-initiated mobility is intertwined—skills in concert with visual, cognitive, psychosocial, language and coordination—it is not possible to state that there is any pre-requisite skill that would predict a young child’s readiness to be successful or ready for the training in use of the Explorer Mini or any other power mobility device (PMD). 


We can only look at typical developmental patterns and skills and suggest that the skills necessary for joystick interaction are a stable base of support, either by means of postural control or an external postural control seating surface. The joystick interaction is the means by which the device is designed to move. The child’s response to movement will prompt interaction with the device and with the act of mobility. It is the response to movement that contributes to the related aspects of language, postural response, and cognitive skills. 

Therefore, the skill set necessary to engage in self-initiated mobility by means of the Explorer Mini have not been established as no device has allowed us to investigate this.

Our best understanding is predicated on the work of conceptual thinkers and researchers who have demonstrated that mobility prompts the sensorimotor system to respond to the enhanced environmental exploration. Indeed, we know when a child is immobile for a period of time they lapse into a state of “visual idle”, wherein the visual system not being stimulated fails to orient or respond to the all too familiar and non-novel environment (8).

Regarding the gross and fine motor skills necessary for safe use of the EM, we would highlight that these skills are developed as a result of mobility and not foundational skills that are necessary for interacting/ interfacing with the joystick or the movement of the device. To suggest that there are pre-requisites skills necessary to operate the EM would be presumptuous until such a device is available for clinical testing and ongoing use by children with mobility impairments.

Evaluation of children has traditionally focused on the achievement of developmental milestones. Underlying impairments such as motor control deficits cannot fully explain the extent and form of functional difficulties seen in children with disabilities. The tasks that are most relevant for daily independence in mobility function have not been well defined in traditional developmental milestone tests (10).

We do have reliable and valid tools to assess posture of the infant (8). But as noted above, posture or motor skills alone does not predict the infant’s ability to activate a joystick and begin the cascade of development that one would see in an infant capable of self-produced mobility.


If there are no pre-requisites, how can I know if it’s appropriate?

In light of the fact that there are no developmental tests that can predict a young child’s ability to operate the Explorer Mini, it’s important to understand that this does not negate the value of trialling a child in the device. Of the 34 children under the age of 36 months who participated in human factor validation studies of the Explorer Mini, 94% were able to move the device using the midline joystick control while 88% demonstrated cause and effect learning through grasping and releasing the joystick.

Keep in mind, developing children typically don’t learn to sit unsupported or crawl without struggling through some initial failures to reach success. The same is true with the Explorer Mini. The key is to allow young children to try, and even struggle a bit to experience the success of self-initiated movement. 


1. Acredolo, L.P., Adams, A., & Goddwyn, SW., (1984) The role of self-produced movement and visual tracking in infant spatial orientation. Journal of Experimental Psychology, 38, 312-327. Doi: 10.1016/0022-0965(84)90128-0

2. Anderson, D. I., Campos, J. J., Witherington, D. C., Dahl, A., Rivera, M., He, M.,… Barbu-Roth, M. (2013). The role of locomotion in psychologicaldevelopment. Frontiers in Psychology, 4(July), 440. https://doi.org/10.3389/fpsyg.2013.00440

3. Armstrong, W., Borg, J., Krizack, M., Lindsley, A., Mines, K., Pearlman, J., . . . Sheldon, S. (2008). Guidelines on the provision of manual wheelchairs in less resourced settings. Geneva, Switzerland: World Health Organization, WHO Press.

4. Butler, P. (1988). High tech tots: Technology for mobility, manipulation, communication, and learning in early childhood.Technology, Infants Young Children, 1, 66-73

5. Butler, P.B. (1998) A preliminary report on the effectiveness of trunk targeting in achieving independent sitting balance in children with cerebral palsy. Clinical Rehabilitation, 12, 281-293.

6. Butler C, Okamoto G and McKay T. Powered mobility for very young disabled children. Dev Med Child Neurology. 1983;25(4):472–474.

7. Butler C, Okamoto G and McKay T. Motorized wheelchair driving by disabled children. Arch Phys Med Rehabilitation 1984;65(2):95–97.

8. Higgins, C. I., Campos, J. J., and Kermoian, R. (1996). Effect of self-produced locomotion on infant postural compensation to optic flow. Dev. Psychol. 32, 836–841. doi: 10.1037/0012-1649.32.5.836

9. Lynch A, Ryu J, Agrawal S, Galloway JC. (2009) Power mobility training for a 7-month-old infant with spina bifida. Pediatric Physical Therapy.;21:362–368.

10. Mancini, M. C., Coster, W. J., Trombly, C. a, & Heeren, T. C. (2000). Predicting elementary school participation in children with disabilities. Archives of Physical Medicine and Rehabilitation, 81(3), 339–347. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10724080

11. Paulsson K Christofferson M – 1986 – Psychosocial aspects of technical aids How does independent mobility affect the psychosocial and intellectual development of children with physical disabilities. pdf.

12. Ragonesi CB, Chen X, Agrawal S, Galloway JC. Power mobility and socialization in preschool: a case study of a child with cerebral palsy. Pediatric Physical Therapy. 2010; 22:322–329.

13. Stanton, D., Wilson, P.N., and Foreman, N. (2002). Effects of early mobility on shortcut performance in a simulated maze. Behavior Brain,136, 61-66. doi:10.1016/SO166-4328 (02)00097-9

14. World Health Organization. (2001) The ICF: An overview. Retrieved from https://www.wcpt.org/sites/wcpt.org/files/files/GH-ICF_overview_FINAL_for_WHO.pdf

15. Weisz JR (1979) Perceived control and learned helplessness among mentally retarded and nonretarded children: a developmental analysis. Developmental Psychology 15(3): 311–9470

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology. 

Dr Teresa is a member of the International Society of Wheelchair  Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has presented internationally, nationally and regionally particularly in the area of pediatric power mobility. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

Why is freedom of movement important in early childhood development?

 

   


Welcome to Part 6 in our series about developmental milestones in early childhood focusing on mobility. Be sure to read our previous entries below in case you missed them! 


Proximal stability creates distal stability and mobility

The development of posture begins in utero. As the fetus moves against the uterine wall and encounters resistance and moves through amniotic fluid against gravity, muscle strength and tone develop. The baby finds a sense of self and stability due to proprioceptive input. Proprioceptive input is the pressure to the joints, muscles, and connective tissues that tells us where our body is in space, and this is happening even in the womb.

Fetal movement is spontaneously generated and modifiable based on environmental stimuli. Gibson (1988) uses the term “perception-action” supporting the concept that sensory input elicits motor output in a continual cycle rather than a start stop action. Sensory information, movement variability, and postural control are structural and occur during gestation, after birth and throughout the life span.


Why movement is important

Proprioception is the sense that tells us where the body is in space. Proprioceptive input is a sensation at a joint, muscle or connective tissue that is obtained by weight-bearing, lifting, pushing, or pulling objects. When a child is unable to independently move, this proprioception is impacted which can affect body awareness, self-regulation, posture, and coordination to name a few. This is why the position or posture that we put a young child in is so important. We want to promote postures that will provide proprioceptive input at the joints and allow movement to provide stimuli that will trigger muscle function. It’s important to note that providing static or constant stimuli such as constant pressure to a joint capsule results in adaptation. This means the mechanoreceptors embedded in ligaments and joints adapt to a constant stimulus and stop transmitting information about that joint and muscles will not be activated. 

This is one reason movement should not be limited by excessive or undue restraints

Most early mobility devices include postural supports such as pelvic belts, chest harnesses, head supports. These make sense for a full-time mobility device, to provide appropriate support to facilitate an upright and functional posture. But the Explorer Mini was designed with another objective in mind. This device is not meant to be used full time and was designed to promote developmental milestones through movement—not only movement of the device, but movement of an unrestricted yet safely supported posture.

What does this look like?

You can see below when Davis was first placed in the device he was severely leaning but was not in danger of falling due to the inherent support of the tray and back. The temptation was to “fix” his posture right away and not watch him struggle. Yet we are used to watching typically developing children struggle through their milestones with crawling, sitting, standing, and walking. We watched Davis struggle and he was persistent and moved himself into an upright seated posture where he could eventually have success achieving midline in the device! 

The Explorer Mini was designed to promote proprioceptive input to the upper extremities with the tray and joystick, and to the lower extremities with the saddle seat and adjustable seat height.

Upper Extremity Weight-Bearing: Weight-bearing through the forearms and hands contributes to weight-bearing at the shoulder joint which translates stability into the upper trunk leading to greater control of the upper trunk and head. This synergistic (combined ) weight-bearing aids in the development of oculomotor stability and vestibular stimuli.

Lower Extremity Weight-Bearing: The saddle seat specifically promotes proprioceptive input and hip development by positioning hips in abduction with lower extremity weight-bearing. The seat height can be adjusted to alter joint angles and encourage forward weight shift. Additionally, the shape of the saddle seat coupled with the tray for upper extremity weight-bearing bring the pelvis into an anterior pelvic tilt which encourages trunk extension.

There are intentionally no postural restraints on the Explorer Mini to allow movement and proprioceptive input to the joints and encourage muscle activation. 

The body needs frequent opportunities to move around a stable surface, that being the pelvis and/or lower body support. One consideration in using a device like the Explorer Mini is to alter the positions and height of the tray and seat support to provide a variety of joint angles and maximise proprioceptive input.  

The following picture depicts how the table and seat surface of the Explorer Mini facilitates postural support through the multiple weight-bearing surfaces. 

Remember, the Explorer Mini is not intended to be a child’s full-time device. It is meant to be a tool that will promotes self-initiated mobility and allow freedom of movement to develop trunk extension and stability, head control, and functional use of the upper extremities.  


1. Hagert, E., Persson, J., Werner, M., & Ljung, B-O. (2009). Evidence of wrist proprioceptive reflexes elicited after stimulation of the scapholunate interosseous ligament. American Society for Surgery of the Hand, 34A. 642-651.

2. Henderson, A., & Pehoski, C., (2006). Hand Functions in the Child: Foundations for Remediation, 2nd edition. Mosby, Elsevier. St. Louis, Missouri.

3. Michelson, JD, & Hutchins, C., (1995), Mechanoreceptors in human ankle ligaments. The Journal of Bone and Joint Surgery. British vol. 77-B

4. Rosenblum, S., & Josman, N. (2003). The relationship between postural control and fine manual          dexterity. Physical and Occupational Therapy in Pediatrics, 23,(4). 47-60.

5. Stavness, C., (2006). The effect of positioning for children with Cerebral Palsy on upper-extremity      function: A review of the evidence. PT and OT in Pediatrics, 26,39-52

6. Westcott, S., & Burtner, P. (2004). Postural control in children: Implications for pediatric practice. PT and OT in Pediatrics, 24, 5-55.

7. Scheiman, M. (2011). Understanding and managing vision deficits: A guide for occupational                therapists. Thorofare, NJ: SLACK Incorporated. 


 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology.

She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

Fostering Independence for Children with Limited Mobility

 

  


Welcome to Part 5 in our series about developmental milestones in early childhood focusing on mobility. 


“When development along any line is restricted, delayed, or distorted, other lines of development are adversely affected as well.” (1)

Restricted experiences and mobility during early childhood can have a diffuse and lasting influence. Long term physical restrictions during infancy or early childhood can significantly alter and disrupt the entire subsequent course of emotional or psychological development in the involved child (2).

Breeding Dependence

Such deprivation of physical and social contingencies can lead to secondary developmental problems, including limiting motivation to explore the environment. This motivation effect is termed learned helplessness, a condition in which the child gives up trying to control his or her own world because of motor disability and diminished expectations of caregivers (3).

Butler (1998) also found that children whose mobility is limited during early childhood develop a pattern of apathetic behaviors—specifically a lack of curiosity and initiative. In essence, being deprived of the experience of self-initiated mobility may keep these children dependent.

Fostering Independence

Sound empirical evidence demonstrates that children with disabilities using mobility devices became less dependent on controlling their environment using verbal commands, more interested in the environment and peer interaction (4). By providing a means for self-initiated mobility we are fostering a sense of independence and curiosity. The longer a child is without self-initiated mobility the more profoundly cognitive, social, language and motor skills will be delayed.

In other words, if we provide mobility to a young child we may prevent the range of deficits that come with the lack of mobility experience noted above. But if we are considering a 2-year-old that has not had self-initiated mobility we will see a greater array of challenges and difficulties since their lack of control and independence may have led to apathy. Based on this alone, we understand that a trial of the device should start as early as 12 months of age.

Prerequisites

Since the evidence supports that children are less dependent when provided with self-initiated mobility, what are the pre-requisite skills for a young child to trial the Explorer Mini? We know that this device was designed for children who have limited, or no mobility and the device has incorporated the postural support required not only for safety, but to promote freedom of movement, trunk and head control and hands coming to midline.

Since the Explorer Mini is the only device of its kind, we don’t have the data to provide specific pre-requisites for use. But we do know what happens with extended periods of immobility for these children. Allowing infants as young as 12 months to trial the Explorer Mini may prevent the learned helplessness and loss of curiosity that can occur with children who have been immobile. Be proactive in providing every opportunity for an infant to achieve self-initiated mobility and contact us here for a trial.  


1. Butler, P.B. (1998) A preliminary report on the effectiveness of trunk targeting in achieving independent sitting balance in children with cerebral palsy. Clinical Rehabilitation, 12, 281-293.

2. Butler, P. (1988). High tech tots: Technology for mobility, manipulation, communication, and learning in early childhood. Technology, Infants Young Children, 1, 66-73

3. Weisz JR (1979) Perceived control and learned helplessness among mentally retarded and nonretarded children: a developmental analysis. Developmental Psychology 15(3): 311–9470

4. Paulsson K Christofferson M – 1986 – Psychosocial aspects of technical aids How does independent mobility affect the psychosocial and intellectual development of children with physical disabilities.pdf.

 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology.

She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

Early Milestones: Developing Proximal Stability

 


Welcome to Part 4 in our series about developmental milestones in early childhood focusing on mobility. See Part 1, Part 2, and Part 3 below in case you missed them earlier!


A young infant begins by weight bearing through hands, knees and toes. This proximal stability is what allows him to hold his head against gravity. This is a critical part of development. At two months of age this action is what facilitates head control and is linked to oculomotor control which is the foundation of visual skills.

At this point the infant begins to develop visual fixations and is able to bring both eyes (controlled by six oculomotor muscles) together to stabilise his gaze. Infants who have not developed this trunk control lack the ability to gain full head and eye control. Without proximal control of the trunk and the development of eye gaze, a child’s development will be greatly altered.  

The seat surface and opportunity for weight bearing in the Explorer Mini aims to mimic this posture to augment the non-mobile infant.

So while a young child may not yet have full head control, the use of the Explorer Mini provides a supportive seat and weight bearing surface to encourage further development of the trunk, visual and vestibular system while providing proprioceptive input which stimulates co-contraction at the weight bearing joints, to help promote improved head control. 

How sitting typically develops:

3-5 Months: Pre-sitting period, single postural muscles are activated. For an infant at this age they need postural support and opportunities for supportive sitting.

5-6 Months: A young child can sit with arm support.

7-10 Months: The leg, trunk and neck muscles are activated and cooperate in sitting and reaching activities.

9 Months to 3 Years: The young child has good modulation of pelvic muscles for a stable base of support.

3 Years and Beyond: The child needs less co-contraction and the use of neck muscles for postural control (6). 

 

How does the Explorer Mini provide postures to mimic the stages a young child goes through for sitting?

For the non-ambulatory child, a stable base of support is realised in the Explorer Mini by many contact points and a wide base of support, as is provided in a variety of positions by the adjustable seat and tray surfaces. In contrast to a device that positions the child in a non-active sitting position, a child will typically assume a slumped posture with weight bearing behind the ischial tuberosities and no mechanoreceptors are activated. 

The saddle seat surface of the Explorer Mini places the weight bearing in front of the ITs to facilitate weight bearing through the upper extremities, while the pelvis is positioned in a forward/anterior tilt, with the hip position signaling the erector spinal muscles (or back muscles) to activate.

This device not only allows a young child to independently move, but it also promotes postures that may help them reach developmental milestones over time. Rather than limiting non-mobile young children to lay in a stroller or bed, we can use the Explorer Mini to help trigger muscle activation in postures that are safe and stable. 


1.Hagert, E., Persson, J., Werner, M., & Ljung, B-O. (2009). Evidence of wrist proprioceptive reflexes elicited after stimulation of the scapholunate interosseous ligament. American Society for Surgery of the Hand, 34A. 642-651.

2.Henderson, A., & Pehoski, C., (2006). Hand Functions in the Child: Foundations for Remediation, 2nd edition. Mosby, Elsevier. St. Louis, Missouri.

3.Michelson, JD, & Hutchins, C., (1995), Mechanoreceptors in human ankle ligaments. The Journal of Bone and Joint Surgery. British vol. 77-B

4.Rosenblum, S., & Josman, N. (2003). The relationship between postural control and fine manual dexterity. Physical and Occupational Therapy in Pediatrics, 23,(4). 47-60.

5.Stavness, C., (2006). The effect of positioning for children with Cerebral Palsy on upper-extremity function: A review of the evidence. PT and OT in Pediatrics, 26,39-52

6.Westcott, S., & Burtner, P. (2004). Postural control in children: Implications for pediatric practice. PT and OT in Pediatrics, 24, 5-55.

7.Scheiman, M. (2011). Understanding and managing vision deficits: A guide for occupational therapists. Thorofare, NJ: SLACK Incorporated.

 

 Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology.

She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

At what age can a child use the Explorer Mini?

 


Part 3 in our series about developmental milestones in early childhood focusing on mobility. 


The characteristics of the Explorer Mini take into consideration developmental milestones and the hierarchical nature of these achievements.

The 3-5-month-old child begins pre-sitting skills activating the postural support muscles. He draws on earlier achieved skills such as visual fixation, which occurs at 2 months of age, consistent with the onset of propping prone on forearms. The weight bearing that occurs in prone on forearm elicits co-contraction of the gleno-humeral (shoulder) joint muscles which provides the proprioceptive input for joint stability. This promotes upper trunk girdle activation by facilitating the thoracic extensor muscles to engage which in turn encourages head and neck extension. 

It is this co-integration of trunk extension with head extension and the visual vestibular interplay that promotes proximal stability

A young child who is able to hold his head upright, or recover head control if temporarily lost, and make postural corrections in a supported sitting position may benefit from use of the Explorer Mini to help promote further development of proximal stability. This allows the other sensory motor skills to gradually integrate. The device is designed for upper extremity weight bearing, like propping up on forearms, that would be a necessary foundation for upper body control. The Explorer Mini provides trunk, pelvis and upper body support to help an infant progress with sitting skills. The infant will be in a position to put weight through the forearms which will promote shoulder joint stability and encourage trunk extension and head control.

While the Explorer Mini is designed for 12-36 month old children, the pre-requisite motor skills are compensated for by the inherent support in the design of the sitting and trunk support surfaces (1,2,4,6). In fact, the device is designed to promote sitting by providing a wide base of support and many points of weight bearing including the feet, the pelvis and the forearms.

Proximal Support and Distal Mobility

Regarding the efficient control of the joystick, the infant with a supported seating posture begins commanding distal motor control once the support or sitting skills are initiated. In other words, one needs proximal support or control to command distal mobility. They are inextricably linked and codependent. You can see this in infants who have mastered independent sitting and are able to manipulate toys with their hands.  

Essentially, the postural activation transmits “action plans” to the motor cortex of the brain to control movement of the arms, hands and fingers (4). The multifaceted, multisensory input facilitates motor output. The sensory input mechanisms include somatosensory and proprioceptive systems, weight bearing, kinesthesia (the feeling of movement) and visual cues to align the head and the vestibular system to respond to gravity.

The Explorer Mini is designed to promote the proximal support by providing a wide base of support and many points of weight bearing, including the feet, the pelvis, and the forearms. This support and points of weight bearing promote joint stability, and in the case of the upper extremities, can allow for successful distal mobility and use of the joystick.

The Explorer Mini is designed to provide on-time mobility that supports development. As the goal is not simply getting from point A to point B, the proportional joystick and multiple weight bearing surfaces work in concert to bring about postural control and upper extremity stability required for self-initiated movement. 


1. Hadders-Algra, M., Brogren, E., & Forssberg, H. (1996). Training affects the development of postural adjustments in sitting infants. In Journal of Physiology

2. Hadders-Algra, M. (2010) Variation and variability: Key words in human motor development. Physcial Therapy (Vol. 90), Issue 12. https://doi. /10.2522/ptj.20100006

3. Rosen, L., Plummer, T., Sabet, A., Lange, M. L., & Livingstone, R. (2018). RESNA position on the application of power mobility devices for pediatric users. Assistive Technology. https://doi.org/10.1080/10400435.2017.1415575

4. Rosenblum, S., & Josman, N. (2003). The relationship between postural control and fine manual dexterity. Physical and Occupational Therapy in Pediatrics, 23,(4). 47-60.

5. Scheiman, M. (2011). Understanding and managing vision deficits: A guide for occupational therapists (3rd ed.) Thorofare, NJ:SLACK Incorporated.

6. Westcott, S., & Burtner, P. (2004). Postural control in children: Implications for pediatric practice. PT and OT in Pediatrics, 24, 5-55.

 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology.

She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.

Benefits of Self-Initiated Mobility in Early Childhood

 


 Part 2 in our series on early childhood developmental milestones related to mobility.  


Several therapists present courses on the benefits of early self-initiated mobility. We are among them. In this blog series, we are going to begin examining how self-initiated independent movement happens and the developmental milestones that promote independent movement. Self-initiated mobility is defined as movement that is controlled by an individual and may include:

  • Ambulation (e.g., walking, crawling),
  • Use of non-powered technology such as prosthetics, walking aids and manual wheelchairs
  • Use of powered technology such as motorized wheelchairs and battery-operated ride-on toy cars (Logan, Hospodar, Feldner, Huang, & Galloway, 2018).

Powered technology is usually considered when other means of movement have not been successful. The problem with most power mobility devices is they were not truly designed for EARLY. In fact, they are designed for “its really late-but let’s see if we can catch up” and compensate for what has been lost or never gained. Until now we have not been able to observe or examine the full benefits of early self-initiated mobility for young children with disabilities as there has not been a truly appropriate mobility device.

But we do know this, in order to learn, children need SELF-INITIATED exploration:

  • If they cannot bring objects to their mouth, their language may be delayed because the oral muscles are not adequately stimulated.
  • If they cannot bring an object from one hand to the other and manipulate it around their hand, they do not learn size, shape or texture.
  • If they do not crawl or walk or have access to EARLY mobility, they do not learn that their world is a 3-dimensional universe with walls, doors, toys, siblings or parents.
  • If they always have to wait until an adult brings them an object curiosity is not fostered.
  • Crawling (or self-initiated mobility) provides children opportunities to learn about the environment and social relationships, as well as developing their own self-awareness. (Butler, 1991).
  • If children cannot move independently, their visual skills related to spatial relations are delayed.
  • If they do not have self-initiated mobility many aspects of development are delayed.

But if we could explore the true sense of early access to self-initiated mobility, we could better understand the potential to impact development and perhaps change the growth and developmental milestones trajectory for young children with mobility impairments. 

 


 

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS

Associate Professor in the School of Occupational Therapy at Belmont University

Dr Teresa Plummer, PhD, OTR/L, ATP, CEAS, CAPS is an Associate Professor in the School of Occupational Therapy at Belmont University in Nashville, TN. She has over 40 yrs of OT experience and 20 in the area of Assistive Technology.

She is a member of the International Society of Wheelchair Providers, and the Clinicians Task Force. She is a reviewer for American Journal of OT and guest reviewer for many other journals. She has authored journal articles and textbook chapters in the area of OT and pediatric mobility and access.