Reaching & Manipulation Flashcards
What is the major role of the arm & hand?
Arm: Reaching
Hand: Manipulating objects or interacting with the environment
What are the two components of reaching?
- Transportation: Hand moves quickly to region of object
2. Manipulation: Hand slows down & makes final adjustments grasp aperture
What are the important components of reaching?
- Protraction/elevation of shoulder girdle
- Shoulder flexion, abduction, extension
- Shoulder ER
- Elbow flexion/extension
- Wrist extension with radial deviation
- Opening of hand aperture between thumb & fingers
- Pronation/supination appropriate to object orientation
What are the common adaptive behaviours in reaching?
- Using intact arm only
- Excessive hip flexion
- Excessive elevation of shoulder girdle
- Abduction & IR of GH joint
- Trunk side flexion to intact side
- Excessive elbow flexion/pronation
What are the important components of grasping?
- Extension of wrist & fingers
- Conjunct rotation of CMC joint of thumb
- Conjunct rotation of MCP joints of thumb & fingers
- Closure of thumb & fingers around object
What are the important components of holding?
- Flexion/extension of wrist holding object
- Lifting, placing & rotating objects of different sizes & weights
What are the important components of manipulating?
- Flexion/extension of fingers
- Cupping of hand
- Independent finger flexion/extension
What are the common adaptive behaviours in grasping & manipulation?
- Grasps & releases with wrist in excessive flexion
- Excessive aperture between thumb & fingers for grasp/release
- Extension of CMC joint of thumb & pronation of forearm for grasp/release
- Flat hand (lack of cupping)
- Inability to move objects within hand
What evidence is there for the effect of friction & weight in normal reaching & manipulation?
- Examined effect of friction & object weight on grip force
- Increased heaviness & decreased friction increases grip force required
- Clinical implications: Start with objects that are lighter & have more friction (esp if patients are weak)
What evidence is there for muscle activity in normal reaching & manipulation?
- Examined muscle activity during ball catching task when ball was dropped by experimenter compared with subject
- When movements are self initiated, preparatory hand grip movements occur & grip force is less
- Preparatory hand grip movements absent when movements are in response to imposed change in load with vision occluded
- Clinical implications: Train both self- & externally imposed activities, train with eyes open & closed
What evidence is there for the relationship between transport & manipulation components of normal reaching?
- Transport & manipulation components interrelated
- Hand begins to open at start of reach, max hand aperture coincides with deceleration of transport phase
- Transport phase slower when objects are close, but duration of task & grip aperture are unchanged
- Clinical implications: To manipulate speed move objects further away, train both phases together (whole activity training)
What evidence is there for normal grasping?
- Compared grasps used with different tasks
- Different grasps used according to whether object was placed with accuracy or shaken
- Clinical implications: Train specific tasks
What evidence is there for thumb/finger movement in normal grasping?
- When reaching & grasping objects thumb is invariant i.e. already in position at start of reach, doesn’t move
- But hand is opened & closed by MCP & IP movement
- Clinical implications: Don’t allow thumb to move towards fingers - thumb is invariant, fingers move towards object
What evidence is there for objects that are typically handled by healthy adults during a day?
- Observational study, 5 minute intervals between 10am-2pm
- Extensive range of objects
- 50% of time spent performing bimanual tasks, 30% unimanual
- Non-dominant hand used almost as much as dominant
- Subjects most often standing
- Clinical implications: Use a variety of objects, train both hands, train in standing as well as sitting, train bimanual tasks
What evidence is there for uni manual & bimanual reaching & manipulation tasks in stroke patients?
- Compared stroke patients with healthy controls
- Stroke patients took longer to complete bimanual tasks
- Both groups performed uni manual tasks more quickly
- Stroke patients had less synchrony between hands during bimanual tasks
- Clinical implications: Train bimanual tasks, speed
