Motor Control and Tone

What is motor control?

the ability to maintain and change posture and movement

need an intact nervous system

interaction b/w the environment, the person, and task

Time frame for motor control

happens quickly

efficiently

timely

role of sensation in motor control

reflexive motor response

voluntary motor response

accuracy of movement

Role of feedback from motor control

intrinsic

extrinsic

Sources of sensory feedback

hierarchical theory of motor control

movement progresses as the brain takes over movement and replaces reflexes

reflex theory of motor control

movement begins because of automatic inborne reflexes

primitive reflexes

tonic reflexes

development of postural control

righting reactions

protective reactions

equilibrium reactions

Stages of motor control

stage 1 = mobility

stage 2 = stability

stage 3 = controlled mobility

stage 4 = skill

Tone

resistance of muscle to passive stretch

exam

• observe resting posture and use palpation

  1. flaccid extremity is limp

  2. spastic UE in supine against the body with shoulder add, elbow flexed, forearm supinated with wrist/fingers flexed

  3. spastic LE in supine held in ext, add w/ pf, inv

• PROM

• AROM

Tone varies with:

´Volitional effort and movement

´Anxiety and pain

´Position and interaction of tonic reflexes

´Medications

´General health

´Temperature

´State of CNS arousal or alertness

´Urinary bladder status

´Fever and infection

´Metabolic and/or electrolyte imbalance

Normal tone

light and responsive

cogwheel

rachet-like jerky movement as a constant force is applied to bend the extremity

clasp-knife

increased tension in the extensor of a joint when passively flexed then suddenly giving way

lead pipe rigidity

inc muscle tone causes a sustained resistance to passive movement throughout the entire range

lesions in basal ganglia

decorticate rigidity

sustained contraction and posturing of the UE in flexion and LE in ext

decerebrate rigidity

sustained contraction and posturing of the trunk and limbs in full ext

Hypertonia

spasticity - velocity dependent inc in muscle tone with inc resistance to stretch

stiff and firm

resistant to movement

rigidity = constant resistance throughout ROM and not velocity dependent

clasp-knife

exaggerated DTRs

damage to descending motor pathways from the cortex or brainstem (medial and lateral vestibulospinal tracts, dorsal reticulospinal tract)

UMN syndrome

associated reactions (sneezing, yawning)

clonus

• stretch response

• document hw many beats

• difficult to stretch w/o initiating clonus

Hypotonia

decreased or absent muscular tone (flaccidity)

soft and flabby, dead weight, unresponsive

LMN syndrome from lesions that affect the anterior horn cell and peripheral nerve

UMN lesions can produce temporary hypotonia (CVA, paraplegia) then after a few days or weeks, will develop spasticity and UMN signs

Dystonia

prolonged involuntary movement disorder characterized by twisting or writhing repetitive movements and increase muscular tone

CNS lesion usually in basal ganglia and can be inherited

Documentation of tone

flaccid, hypotonic, spastic, rigid, hypertonic, normal

use descriptive words

Modified Ashworth Scale

´Clinical scale for the assessment of muscle spasticity

´Clinician does PROM to evaluate resistance to passive movement due to spasticity

´Can be subjective

´Need training

´Same person should do the assessment for each session

LOOK AT SLIDE 24

If limb is flaccid or hypotonic, then you need to inc tone by:

using sensory systems:

• visual → certain kinds of lighting; bright colors

• auditory

• gustatory → spicy foods

• olfactory → strong smells

tactile

use of primitive or tonic reflexes

proper positioning and alignment

provide stability at the hips and shoulder

If limb is flaccid or hypotonic, then you need to inc tone by tactile:

´Shaking

´Tapping

´Vibration

´Weight bearing

´Approximation

´Quick stretch

´Quick icing

´Fast varied movements

´Hard resistant surfaces

´Apply firm pressure over mm

´Apply resistance

if limb is spastic or hypertonic, then you need to dec tone by:

using visual systems:

• visual → dull colors

• auditory → soft sounds

• gustatory → bland foods

• olfactory → neutral smells

tactile

start proximally to affect distal segments

once tone is under control, need to do a functional activity to get a carryover effect

if limb is spastic or hypertonic, then you need to dec tone by tactile:

´Slow rhythmic circular or rotational movements

´Weight bearing

´Rocking

´Vibration

´Soft padded surfaces

´Inc warmth

´Prolonged icing on the spastic muscle

´Static stretch with pressure on a tendon

´Abduct the thumb away from the palm and fingers

´Hippotherapy

´Medications

´Surgery

´E-stim