11/27/2017. Wheelchair Seating for Clients with Low Muscle Tone. Low muscle tone - definitions. Learning Objectives

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1 Tamara Kittelson-Aldred MS, OTR/L, ATP/SMS Missoula, Montana Wheelchair Seating for Clients with Low Muscle Tone Addressing Potential Orthopedic Challenges Posture 24/7 Eleanore s Project Occupational Therapist 42 years ATP/SMS (RESNA) Advanced Postural Care Certificates (Open College Network, UK) Friend of NRRTS Eleanore Tesia Clinician Task Force member Mother of three Learning Objectives Participants will be able to list 3 common pelvic, trunk and head postures seen in people with low muscle tone. Participants will be able to list 3 potential orthopedic complications impacted by wheelchair seating and configuration. Low muscle tone - definitions We know it when we see it what is really happening? Participants will be able to describe the interaction between tilt in space and recline when seating a person with low tone. 1

2 Muscle tone Normal muscle tone The natural tension in a resting muscle ability to contract in response to external stretch. Muscles feel firm but yielding Stability and motor control are supported Allows both activity and rest Hypertonia - high muscle tone Normal trunk and neck tone stabilizes upright sitting posture. Muscles feel tight or rigid Excessive resistance to passive stretch Range of movement is decreased Can occur with or without spasticity Spasticity is velocity dependent resistance to passive movement Example: Difficulty bending at the hips or other joints related to high tone Hypotonia - low muscle tone Muscles feel soft or mushy Reduced or no resistance to passive movement Can occur with spasticity Lax ligaments are common Leads to joint hypermobility Example: A person with low tone collapsing against a support surface. 2

3 Muscle strength The force generated in a single contraction against resistance. Evaluated through manual muscle testing and dynamometer (grip strength) Muscle endurance The ability of a muscle group to exert less than maximal force for extended periods of time Example: Efficient manual wheelchair propulsion for distances requires motor control, muscle strength and endurance. Hypotonia symptom, not diagnosis People with hypotonia have underlying conditions Central hypotonia most common 66-88% of children with low tone Central nervous system based Signals to the muscles are disrupted in brain or spinal cord E.g. CP, CVA, spinal cord injuries, chromosome disorders Hypotonia symptom, not diagnosis Peripheral more common in adults Peripheral nervous system interference between spinal cord and muscles Neuromuscular junction disorders Muscle disorders E.g. muscular dystrophies, SMA, Ehlers-Danlos Central and Peripheral combined E.g. ALS, gigantic axonal neuropathy (GAN) Why is understanding origin important? Understanding diagnosis and prognosis impacts seating and wheeled mobility decisions Will the person s condition improve or decline? Is it likely to remain the same? What co-morbidities might develop? 3

4 What does hypotonia look like? Other characteristics Diminished reach and grasp Shallow breathing Weak or quiet voice Flat affect open mouth Eating and swallowing difficulties Absent or slow postural reactions Joint hypermobility Poll Postural Tendencies They have consequences The Human Sandwich Noreen Hare The foundation - lying posture We lie, sit or stand on a support surface We are constantly influenced by gravity We are the sandwich filling! Moving and maintaining posture against gravity is a big deal for a person with low tone Our first human orientation is lying down Children with low tone have difficulty counteracting gravity in lying Habitual lying postures can be destructive - unless identified and corrected Well-aligned, supported lying posture helps preserve a symmetrical body Sets the stage for successful seating interventions Ability to lie in balance - foundation for balanced sitting 4

5 Lying and sitting are linked Impaired lying balance is associated with sitting challenges Sitting problems - more visible and extreme weight-bearing surface area is smaller challenge of gravity is greater Sitting is highly desirable physical, social, and psychological reasons plus mobility Sitting requires more support than lying to counteract forces of gravity and natural postural tendencies. Tendency - An inclination towards a particular characteristic or type of behavior. Oxford Dictionary We all have postural tendencies, but stakes are higher for people with tone problems Postural tendencies Seated postural tendencies Destructive allows distortion of body shape during activities and rest. This will limit function and health over time. Non-destructive preserves the natural symmetry of the body while allowing activities and rest. This will promote health and function over time. Posterior Anterior Lateral/Rotational 2017, Aspen Seating/Ride Designs 5

6 Anterior tendency low tone Lateral/rotational tendency low tone Trunk collapses forward Arm propping to stay upright Compensatory lumbar lordosis can become extreme Neck hyperextension to maintain visual field Unstable pelvis and trunk Arm propping to stay upright Head tilting to maintain visual field Compensatory spinal curve Rib cage/pelvis proximity health complications 2017, Aspen Seating/Ride Designs 2017, Aspen Seating/Ride Designs Posterior tendency low tone Posterior support for pelvis/trunk stability Allows well-aligned resting position Neck may hyperextend or flex With low tone - posterior tendency is good Promotes rest and activity options if done well But what about sliding out? May tend to slide out of seat 2017, Aspen Seating/Ride Designs Wheelchair frames and low tone Recline vs. tilt in space Recline Tilt in space Many people with low tone need both Tilt in space Relief from force of gravity Weight shifts Counteracts tendency to slide out Recline (can be just a few degrees) Assists with breathing and digestion Weight shifts and relief from force of gravity Counteracts tendency to slide out 6

7 Recline & tilt in space frame styles Recline & tilt in space frame styles Manual frames ultralight/lightweight adjustable Fixed tilt (seat slope adjustment) Recline (open seat/back angle) Frame configuration and/or seating Manual tilt and recline frames (dependent) Adjustable tilt/recline mechanisms Fixed tilt or recline Frame and/or seating configuration Recline & tilt in space frame styles Power wheelchairs Power seat functions Tilt Recline Both combined Seating configuration Poll Seating components Many seating products work well for people with low tone 1. Mat evaluation determines postural support & other needs 2. Select mobility base style 3. Select back and seat cushions for 1. Core stabilization pelvis, back, upper legs 2. Cushion and back material properties positioning, pressure relief, thermal regulation Secondary supports - All pelvic positioning belts are NOT created equal! For people with low tone: Attachment angle is key 4 point design can help 7

8 Secondary supports - All anterior trunk supports are NOT created equal! Secondary supports Head and extremities need support too! Select style carefully for folks with low tone Be aware of surface seeking Use with tilt/recline Head support Full-time? Only when tilted/reclined or fatigued? Upper extremity supports arm troughs/trays Prevent or reduce upper limb drag Support trunk/head posture Protect vulnerable joints Same day, same chair, never lasted Meet Henry A bed in a classroom fatigue as a factor Time for a new power chair - Henry s issues Fatigue sitting upright gets harder as Day goes on Weather gets warmer Comfort hips and chest expansion Henry fights too much hip flexion, likes stretching Pelvic stability two point belt - inadequate Slides under and out consistently Anterior trunk support Hangs forward on chest harness Head support Needs lateral support 8

9 11/27/2017 How did we get from before to after? Before After We added features and functions Power recline AND tilt in space Just enough recline to improve trunk posture We added features and functions Four point pelvic belt Carefully placed, could not slide under Our goal function, participation, quality of life Slightly open hip angle is more tolerable Power recline assists activities and resting (video) We added features and functions Head pad with posterior AND lateral support Arms of head support provide anterior cue No more hanging on a harness! References Arledge, S., Armstrong, W., Babinec, M., Dicianno, B. E., Digiovine, C., Dyson-Hudson, T. Plummer, T., Rosen, L., Schmeler, M., Shea, M., Stogner, J. (2011). RESNA Wheelchair Service Provision Guide. RESNA (NJ1). Bay, MJ and Johnston, MV. (2016) hypotonia. Accessed September Govender P, Joubert, RW. (2016) Toning up hypotonia assessment: A proposal and critique, African Journal of Disability 5(1), a231. htp://dx.doi.org/ /ajod. v5i1.231 Harrand, J., & Bannigan, K. (2016). Do tilt-in-space wheelchairs increase occupational engagement: a critical literature review. Disability and Rehabilitation: Assistive technology, 11(1), Harris, SR. (2008) Congenital hypotonia: clinical and developmental assessment. Developmental Medicine & Child Neurology, 50: DOI: /j x Hetzel, T. (2013) Posture and Postural Tendencies: What s the Difference? Proceedings of the 29th International Seating Symposium, pp Leyenaar, J, Camfield, P and Camfield, C. A schematic approach to hypotonia in infancy. Paediatr Child Health 2005; 10(7): Pountney, T, Mulcahey, C, Clarke, S, and Green E. (2004) The Chailey Approach to Postural Management. Chailey Heritage Clinical Services. Wilson, P. E. (2012). Seating Evaluation and Wheelchair Prescription. hair_prescription.pdf. Accessed November

10 Questions? Thank you to all the clients and families who have taught me over the years Contact information: For more information on posture and motor disabilities visit: 10