Test 2 Flashcards
2 functional components of reach and grasp
transportation
- uses proximal muscles
- hand shapes to match object
- under visual control
grasp phase
- distal muscles
-early on, tactile sense to learn how to grasp
- later, grasp anticipated using visual system too
what affects grasp shape
intrinsic properties - object size, shape, etc
extrinsic properties - object orientation, distance from body, location
change in grip size due to finger movement; thumb stays in place
what to look for in grasp at 6 months
should be moving smoothly
should be able to use muscle groups separately (i.e. extend arm while flexing fingers)
look out for stiffness, speed, smoothness of reach
3 components of upper limb control
reaching
object manipualtion- separating fingers out/using independently to move/control object
anticipatory grasp- eyes and hand + arm/ integration of sensory info/ know necessary tension/force needed to grasp
what do you see in the first 2 months vs after 2 months with upper limb control
in the first 2 months of life = when arm is extended, hand does too
after 2 months = arm can extend and fingers can flex; allows for voluntary palmar grasp
what may indicate a problem with grip/upper limb control and possible intervention
holding arm stiff
not disassociating grip and arm movement
interventions = rolling, WBing, putting weight through hand
MSK components that are needed for grasp
joint ROM
spine flexibility
muscle properties
proper biomechanical relationships
Motor aspects needed for proper grasp
appropriate muscle tone
muscle strength
coordination
what combined joint motions are required for successful reach and grasp
scapular RT
movement of humeral head
forearm supination
shoulder/elbow flexion
extension of wrist beyond neutral
mobility of hand to allow grab and release
feedforward vs feedback
feedback
- early on
- allows for motor correction DURING mvmt
- improvement through pressure, touch, etc
- allows kid to become more skilled using sensory system
feedforward
- later in skill acquisition
- plans movement beforehand
sensory systems involved in grasp
visual
- hand eye coordination
auditory
- i.e. have kid use racketball that they can hear when it hits
somatosensory
- knowing where arm is in space
- makes posture/reach more efficient
how does vision help in reach in grasp/how is this info processed in brain
sensory stimulus coded in retina that turns into motor output for controlling reach and grasp
parietal lobe interprets visual space and sends info back to eye muscles
visual feedback given back in regard to final accuracy of reach and grasp
MOST IMPORTANT FOR REFINED MOVEMENTS
When is somatosensory info most important and how does it help with movement/grip force
important for fine regulation; not needed for initiation/execution so long as mvmt is simple
receptors active at extremes of joint motion; not middle
cutaneous afferent info essential for grip forces
role of premotor/primary motor areas in grasp
parietal lobe encodes goals for reach and grasp, intended hand formation, and object orientation
all parietal info sent to premotor and primary motor cortex
premotor = planning
primary = execution
intraparietal neurons code for grasping actions (i.e. precision vs power grip)
how/when does postural control begin to be associated with reach
postural control is critical for reach
initially = use 1 hand to support self and 1 to reach
6-8 months = start using postural control for anticipatory reach
by 10 months = controlled/smooth reach
things to consider if reach is delayed
is it postural? do they do better if PT supports body?
goal/purpose of early hand use
goal = bring hand/object to mouth initially
hands interaction with target is driver of perceptual development; NOT just reach alone
grasp timeline
1-5 months = spontaneous/early grasp behaviors
2-4 months = fisting decreases; pre-precision/precision grasp emerge
4 months = increase in self directed grasping/self exploration
6-8 months = anticipatory reach/grasp/posture/using thumb
** concerning if not grasping and letting loose by 6 months
10 months = pincer grasp using thumb
**if no pincer by 12 months, concerning
9-10 months = can slowly release object; not just drop it
4 grasping patterns used in 1st 5 months
fisted grasp = fisted/grasping clothes
pre-precision (thumb to side of middle or index finger) = bringing thumb in
precision grip of objects = by 10-12 months
self directed grasp of own body or clothing = exploration of objects/body
describe development and timeline of grasp/release
initially = palmer grasp reflex; grasp parent finger
4 months = voluntary hold with involuntary release
4-5 months = fingers flex and thumb adducts
6 months = grasping smaller objects/hold bottle
**should be holding at midline
7-12 months = rapid changes in grasp
12 months = precise release of grasp
stages of object manipulaiton + timeline
rotation (angular displacement) by 2 months
translation of grasped objects by 3 months
vibration (shaking) of held objects by 4 months
bilateral hold/2 handed hold by 4.5 months
hand to hand transfer by 4.5 to 6 months
coordinated action; object in one hand manipulated by the other by 5-6.5 months
coordinated action with 2 objects such as striking 2 blocks together by 6-8.5 months
deformation of objects by 7-8.5 months
instrumental sequential actions by 7.5 to 9.5 months
how does anticipatory control of hand with grasping develop in the first year
hand prepares to grasp based on object characteristics
sensory info guides motor actions
by 5 months = orient had to object
5-8 months = develop vision to anticipate contact with object and orient hand
9-13 months = anticipate size of object by dustance between thumb/index finger
characteristics of later stages of motor learning
adapt movement pattern acquired in initial stages to specific demands of any situation
become consistent in performing skill
movements more efficient/reduced energy cost; “economy of effort”
implicit vs explicit learning
implicit (non-declarative)
- procedural
-associative learning (classic/operant conditioning)
-nonassociative (habituation/sensitization)
explicit (declarative)
- facts
- events
who best benefits from mental practice
more beneficial in adults
crawling infants practice approximately how much
crawling infants practice maintaining balance approximately 5+ hours/day which equates to 300 crawling steps