Tone Abnormalities Flashcards
What is muscle tone?
the passive resistance to stretch of a muscle
What is Hypotonicity?
low muscle tone
What is Hypertonicity?
high muscle tone
What is clonus?
multiple rhythmic oscillations of involuntary movement
What is Dyskinesia?
Any type of abnormal movement that is involuntary and has no purpose
What is Dystonia?
involuntary sustained muscle contraction usually resulting in abnormal postures or repetitive twisting movements
What is chorea?
dance-like, sharp, jerky movements
What is ballismus?
ballistic or large throwing-type movements
What is tremor?
low-amplitude, high-frequency oscillating movements
What are athetoid movements?
worm-like writhing movements
When are ATNR and STNR are typically visible?
during infancy and in patients who have neurological deficits
Describe the asymmetrical tonic neck reflex (ATNR)
When the face is turned to one side, the arm and leg on the side to which the face is turned extend and the arm and leg on the opposite side flex
Describe the symmetrical tonic neck reflex (STNR)
when the head and neck are extended infants assume the crawl position by extending the arms and bending the knees
Describe symmetrical tonic labyrinth reflex (STLR)
When the head is tilted back while lying on the back causes the back to stiffen and even arch backwards, the legs to straighten, stiffen, and push together, the toes to point, the arms to bend at the elbows and wrists, and the hands to become fisted or the fingers to curl
What is muscle midrange?
the length at which a muscle can generate the greatest amount of force or tension
A lengthened sarcomere = how much overlap?
No overlap
A shortened sarcomere = how much overlap?
too close for overlap
Neurons transmit signal via what?
Neurotransmitters
Describe muscle spindles
Found inside the muscle, parallel to mm fibers that send action potential through type Ia sensory neurons
Describe GTOs
Detect stretch on the muscle
Protect from over-stretch
Quick, light touch, Manual contact, Brushing, and Quick icing use cutaneous receptors to ____ muscle tone.
increase
Slow stroking, Maintained hold, Neutral warmth, and Prolonged icing use cutaneous receptors to ____ muscle tone.
decrease
Slow, repetitive and maintained nature of the stimuli leads to what?
adaptation by cutaneous receptors
What are propriospinal pathways?
Pathways that receive input from peripheral afferent and help produce synergies (particular patterns of movement)
Volitional movement originates via what?
sensation, an idea, a memory or external stimulus
What is primarily responsible for voluntary contraction, esp. fine motor function?
Corticospinal tract
Volitional movement involves processing through connections where?
In the Basal ganglia
Dysfunction of any of the nuclei of the BG is associated with what?
abnormal tone and disordered movement
What do the Vestibulospinal Tracts (VSTs) do?
Help regulate posture and facilitate antigravity AMNs of the trunk and LEs to keep the body upright
What do the Reticulospinal Tracts (RSTs) do?
- Receive input from vision, auditory, vestibular and somatosensory system, motor cortex, cerebellum, ANS, and hypothalamus
- Regulate responses to reflexes according to the context of current movement
- Produce bilateral synergies in the UEs
The limbic system influences movement via the ____ and _____
Reticulospinal Tracts (RSTs) and the Basal Ganglia
What does hypotonicity result form?
loss of normal AMN input to normal muscles
What is the result of alpha motor neuron damage?
Electrochemical impulses will not reach mm fibers
Flaccid paralysis – no tone, no mm activation
Denervation – removal of neuronal input
Paresis – reduction in activation of motor units
What do strokes, MS, and TBIs alter (hypotonicity)?
Supraspinal Input
What are the consequences of hypotonicity?
- Decreased force output for posture or movement
- Poor posture
What are the consequences of hypertonicity?
- Discomfort/pain from muscle spasm
- Contractures
- Abnormal postures leading to skin breakdown
- Increased assistance required by patient for ADLs
- Stereotypical movement patterns that could inhibit alternative movement solutions
- Possible development of functional limitations
What are the 2 causes of hypertonicity?
1) Supraspinal lesions (CVA, CP, etc.)
2) Parkinson’s Disease
3 examples of peripheral inputs that can lead to hypertonicity
Pain, Cold, Stress
What is rigidity a consequence of?
CNS pathology
2 Patterns of Rigidity
1) Decorticate posture
2) Decerebrate posture
Decorticate posture vs. Decerebrate posture
1) Decorticate posture leads to the flexion posturing of the UEs and extensor posturing of the LEs
2) Decerebrate posture leads to extensor posturing of both the LEs and UEs and usually death
Where is the disinhibtion in decorticate posture and where in decerebrate posture
1) Decorticate posture is disinhibition above the red nuclei in the brain stem (less serious)
2) Decerebrate posture is disinhibition below the red nuclei in the brain stem (more serious)
Decorticate posturing indicates that there may be damage to what?
The cerebral hemispheres, the internal capsule, the thalamus and midbrain
What does decerebrate posturing indicate?
brain stem damage
