To improve the knowledge on the appropriate seating and positioning required for children
using AAC methods
To improve the knowledge on need for assessment of seating and positioning
Children and adults who have severe speech impairments frequently have problems controlling their
posture and extremities, which affect their ability to use augmentative or alternative communication.
Both aided and unaided AAC approaches require sufficiently skilled movement of a hand, an eye, or
other body part, which can be difficult for people who have cerebral palsy, amyotrophic lateral
sclerosis (ALS), traumatic brain injury (TBI), and many other conditions. One factor that can affect
motor performance is body position. Position may also influence person’s communication and
opportunities for interaction.
Successful use of AAC nearly always depends on the quality of the team approach to assessment and
intervention. When an AAC user has problems with motor control, an occupational or physiotherapist
can often provide valuable inputs.
Their contribution includes the following:
To determine whether a person is likely to have the motor control necessary for unaided modes of
communication, such as manual signs or gestures.
To identify body sites and movements to control AAC devices
Determine position and features of position devices to promote optimal neuromusculoskeletal
benefits and use of devices.
Design an AAC system that best matches the motor abilities of the individual.
Designing strategies to promote development of motor control for all components or of the AAC
Candidacy for the assessment of evaluation of seating and positioning:
People who use AAC have many different medical diagnoses; most of which result from congenital
or acquired central nervous system pathology and related physical disabilities. The type and severity
of the motor problems depend on the location and extent of the brain damage or malformation.
Major symptoms are the following:
Muscle tone changes: It involves increased tone which is commonly seen in the extremities and low
muscle tone in the trunk. High muscle tone makes difficulty in producing voluntary movements as in
spasticity and rigidity. Problems related to low muscle tone are inadequate postural control,
inadequate static balance and difficulty applying force.
Primitive reflexes: Neonatal reflexes such as sucking reflex, grasping reflex, automatic stepping
reactions and ATNR disappears at different times of infancy. Reflexes that are persistent and easily
produced after specific developmental ages are a sign of neurological disability. Muscle tone change
and primitive reflexes are considered to be neuromuscular problems
Deformities: It can have many causes and this leads to a tendency to adopt habitual postures of one
part of the body. This result in an inability to move a joint through its full range of motion. A
deformity may partially or totally limit movement in a specific direction. The primary cause of
contractures and positional deformities are muscle imbalance. Deformities and joint contractures are
musculoskeletal problems secondary to neuromuscular impairments. Prevention of this is through
positioning that maintains the body in alignment opposite the pull of more active muscles
Dyscoordination: Lesions in the basal ganglia of the brain can cause movement disorders such as
Athetosis and Dystonia. Movement disorders are characterized by an impairment of postural fixation
of the trunk and by the presence of involuntary movements during muscle activation. These
involuntary movements occur mostly in face and limbs. There is also impairment of balance .
Seating and Positioning
Seating: This refers to all of the seats and their components that assist people to maintain a sitting
position. It includes ordinary seats that people use everyday such as couches and car seats and
specialized seats designed to enhance the function of people with disabilities, such as adapted chairs
and wheelchair seats. With our bodies we experience and learn, we communicate and act. Body
language is often a reflection of a person’s state of mind. For people dependent on wheelchair can be
thought of as a body orthosis, or brace, that creates the physical base for an ever-changing, ever-
growing person. The wheelchair is very important base. Seating positioning not only impacts upon
physical well being but also makes optimal motor function possible and thus affords greater
opportunities for success in daily activities, including communicating with others.
Positioning: This means placing and maintaining a person in sitting, sidelying, standing, prone, or
other postural alignment. A seat is one type of positioning device. Standers, sidelying and prone
positioning are other type of positioning devices.
In good Posture your weight is evenly distributed with
no muscle over working and which enables you to do the
task you want with least fatigue. The classic upright
sitting posture with hips and knees at right angle, feet
flat and trunk more or less vertical. Alternative postures
such as forward leaning, are being proposed for tasks
such as writing and a slightly reclined posture is desired
by many when relaxing.
Goals of optimal seating and positioning
To improve function, comfort, opportunities to participate in a variety of activities and environments
and prevention of musculoskeletal problems.
To improve postural alignment and stability
To improve motor control
Head, trunk and foot control
To prevent or minimize contractures and deformities
To improve sensory and bodily functions
To improve attention and arousal.
An optimal seating and positioning requires vision and head control for balancing. The body always
strives to maintain the eye in horizontal positioning. The eyes are an important part of the control
mechanism for maintaining balance because they provide information about body position in space. If
we move or lose balance, the eyes automatically send signals that initiate a response from muscle
groups in order to maintain or regain balance. The head and neck influence the distribution of muscle
tone throughout the body, and therefore have a strong influence on posture and movement.