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senses

Tactile sensory system

 

THE TACTILE SYSTEM

Definition:

¨       We get tactile information through sensory receptors located in the skin.

¨       The tactile system provides us with information about touch sensations: pressure, vibration, movement, temperature and pain.

¨       The tactile sense is made up of two components: the protective (or defensive) system and the discriminative system.

 

Why is the processing of tactile information important?

¨       The tactile sense or sense of touch is a huge sensory system that gives us information needed for visual perception, motor planning, body awareness, academic learning social skills and emotional security.

¨       The function of the protective / defensive system is to alert us to potentially harmful stimuli. We need it for survival. The receptors for this system are in the skin, particularly the hairy skin on the head and genitals. Light touch is the stimulus that causes the receptors to respond.

¨       The function of the discriminative system is to tell us what we are touching / where on our bodies it is touching us, and the properties of that touch, i.e. size, shape, texture, temperature and whether the touch is light or deep. The receptors for this system are found in the skin, especially of the hands and fingers, soles of the feet and the mouth and tongue.

¨       As an infant develops into childhood, the discriminative system suppresses the protective / defensive system, although not completely. Both systems work together to enable us to interpret tactile information throughout our lives.

¨       Tactile dysfunction is the inefficient processing in the central nervous system of the sensations perceived through the skin.

 

Functional Implications:

Over-responsive to touch: Tactile Defensiveness  /Hypersensitivity:

¨       Child has a tendency to react negatively and emotionally to unexpected, light touch sensations

¨       May dislike having hair washed and brushed and nails cut

¨       May display hostility / or withdraw from situations requiring lots of tactile input: i.e. getting dressed, in the playground

¨       Overreaction to physically painful experiences: make a “big deal” about a minor scrape

¨       Fuss about clothing, such as stiff new clothes, shirt collars, elasticated waists, hats and scarves. May prefer short sleeves and shorts, even in winter to avoid the sensation of clothes rubbing on the skin / OR prefer long sleeves even in summer to avoid having skin exposed

¨       Avoidance of messy play activities i.e. finger painting, clay, sand and water play / fastidious about washing every bit of dirt from hands

¨       Excessive ticklishness / avoidance of kisses preferring hugs

¨       Seeks out deep pressure sensations which are easier to process and can be calming and organising

Under-responsive to touch: Hyposensitivity: (i.e. The child who is not processing enough movement information)

¨       Craves extra stimulation and is constantly touching objects and people

¨       May show no reaction to pain from scrapes, bruises, cuts or injections

¨       May be unaware of messiness around the mouth / nose: may not notice a runny nose

¨       May hurt other children or pets during play, seemingly without remorse but actually not understanding the pain that others feel

¨       May drop things without realising

Poor tactile discrimination (i.e. The child’s brain does not register information about how things feel)

¨       Difficulties using tactile sense for complicated purposes like learning at school

¨       Child may be unable to identify which body parts have been touched without looking

¨       May be afraid of the dark

¨       May be a messy dresser i.e. twisted waistbands, shoes untied etc.

¨       May be a messy eater

¨       Difficulties with tool use: i.e. cutlery, scissors, pencils, paintbrush etc.

¨       May avoid initiating tactile experiences i.e. picking up tools / toys

N.B Remember: your child may be both HYPERSENSITIVE and HYPOSENSITIVE, i.e. s/he may be extremely sensitive to light touch, moving away from a light tap on the shoulder, but indifferent to the deep pain of an injection.

Strategies to Help Improve the processing of Tactile information:

1.     Where possible, avoid surprising your child with unexpected light touch sensations i.e. brushing past them, approaching from behind and touching them.

2.     At school, make sure that your child is not sitting at the end of a the desk next to the main walk way in the classroom, so as to reduce the likelihood of unexpected light touch.

3.     Provide opportunities for your child to experience deep pressure sensations as these help to suppress sensitivity to light touch sensations. Deep pressure can be provided by a bear hug, being rolled up and squashed in a duvet, through rough and tumble play, massage, press-ups etc. Any activity that provides pressure to the joints can be very calming and may help prepare your child for a difficult light touch activity, i.e. hair washing / tooth brushing.

4.     Use sheets on the bed that can be tucked in tightly to make your child feel secure. Some children feel safer sleeping on their beds in a sleeping bag

5.     Brushing with a surgical brush (ask your Occupational Therapist for advice on this technique) can help to reduce your child’s sensitivity.

 

Activities to reduce Tactile Defensiveness:

  • When directing a movement – use firm touch.  Firm pressure can help reduce tone, calm and organise a child’s movements.
  • Avoid light brushing or intermittent light touches.
  • Give verbal cues to prepare a child.
  • Sometimes activities that emphasise joint compression (e.g.. jumping, dangling, pushing, pulling, weight bearing) may help.  Heavy muscle work often reduces sensory defensiveness.
  • Use a variety of texture experiences on the skin.  Start dry and progress – wet materials, e.g. sand, rice, pasta, packaging foam.
  • Small toys hidden in a bucket full of paper / sawdust / material for the child to find.
  • Activities that involve all over body pressure; pretend the child is being painted with a paint roller or get him/her to roll him/herself up in a rug, sheet, etc.
  • Brushes and scourers (not too rough) are useful to have in and out of the bath e.g. nailbrushes, paint, scrubbing and cosmetic brushes.
  • Playdoh – for rolling, patting, poking and modelling.
  • Outdoor play – encourage swinging on a tyre or swing – try on tummy pushing with legs.
  • Play catch and throw with weighted materials, e.g. Beanbags, heavy padded balls.
  • Wet activities – body painting
  • hand lotion / shaving foam on mirror or tray.  Also include cleaning as part of activity
  • When completing puzzles and activities indoors try getting your child to work on their tummies with elbow support
  • Cooking / baking activities involving handling ingredients and experiencing different textures
  • Gardening activities: planting / watering seeds: handling soil etc.
  • Self care activities: Hand washing – Try using liquid soap and a nailbrush.
  • Bath times – Encourage use of different textured bath mitts to wash parts of body.  Afterwards, firmly rub down with a thick terry towel.
  • Encourage the child to rub hands and body with lotion.

 

Vestibular sensory system

THE VESTIBULAR SYSTEM

Definition:

¨       The vestibular system is the most sensitive and one of the most important sense organs. It is stimulated by movement of fluid in the structures of the inner ear, in response to movement by the head.

¨       The vestibular system provides us with information about where our body is in space and whether the movement is up, down, fast, slow or angular.

¨       Even when our eyes are closed we know the position of our head. The vestibular system also allows us to keep our balance with our eyes closed.

 

Why is the processing of vestibular information important?

¨       Input to the vestibular system is important for regulating muscle tone, joint stability, bilateral integration, spatial awareness, eye movements and balance and equilibrium mechanisms. These all affect our ability to maintain good sitting posture i.e. at a desk.

¨       Good postural stability serves as a basis for fine motor control (i.e. handwriting).

¨       The vestibular system sends information to the part of the brain that regulates attention and arousal levels. It also provides a calming effect (i.e. gentle rocking)

¨       The vestibular system ‘talks’ to every other system and is closely linked to the proprioceptive system.

 

Functional Implications:

Over-responsive vestibular system: (i.e. The child who perceives too much movement information)

¨       Gravitational insecurity: excessive fear of falling / of heights / and of feet leaving the ground

¨       Overly frightened by movement / dislikes playground activities

¨       Difficulty mastering environmental obstacles such as stairs or uneven terrain

¨       Intolerance or adverse reactions to movement, motion sickness, nausea, giddiness

Under-responsive vestibular system: (i.e. The child who is not processing enough movement information)

¨       Craves movement, swinging, rocking

¨       Moves excessively, using momentum to compensate for poor balance reactions

¨       Does not get dizzy until they have had an enormous amount of movement

¨       Poor bilateral integration and co-ordination

 

Activity suggestions to Help Improve Vestibular Processing:

1.     Swinging / rolling / rocking / swaying (the best effects are gained when these activities are self activated, i.e. let the child swing / spin him/herself)

2.     Jumping on a trampoline (with supervision)

3.     Balancing on a balance beam or line on the ground

4.     Rolling across the floor, over a variety of textures and objects / in a blanket or towel. Then try with eyes closed

5.     Sledding or rolling down a hill

6.     Spinning around a post / in a chair

7.     Sit ‘n’ spin / pogo stick

8.     Playground activities: see saws, swings, slides, merry go rounds

9.     Bilateral activities: jump rope, swimming, skipping, riding a bike, star jumps, stilts etc.

10.   Movement activities: e.g. Exercises, keep fit, martial arts, dancing

11.   Walking over uneven surfaces

 

WARNING: Encourage the child to choose spinning activities to do independently. Too much swinging / spinning can have a negative effect on the child. Watch carefully for signs of dizziness, nausea, changes in breathing etc. Stop when the child asks to stop the activity. Never swing / spin the child excessively.

 

Beyond our 5 senses.

PROPRIOCEPTION
Definition:
Most people know that we have 5 senses: sight, sound, taste, touch and smell. However, there are other very important senses not included in this list.
Awareness of our body position / movement, or proprioception is one of these.
We do not learn about this sense, so most people are unaware of it. This can be a problem when the proprioceptive sense is not working well. If we are not aware of it, it is hard to understand the problems related to it. (more…)