Muscle Tone Flashcards
What causes spasticity?
Hyper excitability of stretch reflex
- UMN lesion; descending motor pathways from the cortex (pyramidal tracts) or BS (M and L vestibulospinal tracts, dorsal reticulospinal tract)
- corticospinal tracts- moreso lateral
- lesion produces disinhibition of spinal reflexes with hyperactive tonic stretch reflexes or a failure of reciprocal inhibition
- Hyperexcitability of alpha motor neuron pool
What Dx’s do you most often see spasticity?
- CP
- MS
- SCI (even at same level)
What is chronic spasticity associated with?
- contracture
- abnormal posturing
- deformity
- functional limitations
- disability
during rapid movement, initial high resistance (spastic catch) followed by a sudden inhibition or letting go of the limb (relaxation) in response to a stretch stimulus
Clasp-knife response
cyclical, spasmodic alternation of muscular contraction and relaxation in response to sustained stretch of a spastic muscle
clonus
how do you elicit ankle clonus? how do you stop it?
quick stretch of PF (put into ankle DF)
- leg in slight flexion
- document if any beats are present, if you can count them, how many
- stop = sustained pressure on the foot
Resistance to passive movements involving both agonist and antagonist muscles; both directions whether or not the muscle is on stretch
rigidity
- observed in PD
Indicates Corticospinal lesion in the BS btwn the Superior Colliculus and the Vestibular Nucleus
Decerebrate
- abnormal extensor posturing
Indicates Corticospinal Tract lesion at the level of the diencephalon (above the superior colliculus)
Decorticate
- abnormal flexion posturing
Impaired tone; Hyperkinetic movement disorder characterized by tone and involuntary repetitive twisting movements in large portions of body
Dystonia
What are the causes of dystonia?
- CNS lesion - Usually BG
- Genetic (Primary Idiopathic Dystonia)
- Neurodegenerative Disorders - PD; Wilson’s Disease = if on excessive l-DOPA
- Metabolic Disorders - Amino Acid or Lipid disorders
What are they types of dystonia?
- Focal = spastic torticollis, isolated writer’s cramp
2. Segmental = toritcollis, dystonic posturing of the arm
Diminished resistance to passive movement; Decreased or absent stretch reflexes; Hyperextension of joints common
hypotonia
- LMN lesion and spinal shock
What are the causes of hypotonia?
- lesions of ANT horn cells
- PN Lesions - Peripheral neuropathy, Cauda Equina Lesion. andRadiculopathy
- Cb Lesions = can produce mild decreases in tone and weakness
- UMN Lesions = cause temporary hypotonia = Spinal Shock or Cerebral Shock, depending on lesion location
When there is a problem with tone, what area of the brain is often involved?
BG
What is tone affected by?
- Medication*
- Environmental temperature*
- State of CNS (arousal and alertness)* – esp anxiety – if pt has this then can definitely increase spasticity
- Volitional movement
- Stress and anxiety
- Position
- Health
What is the procedure for assessing tone?
- Palpation of the muscle belly
- Passive motion and speed up as you go
- All limbs/joints
- Compare right and left
- Compare UE’s and LE’s
- Cue your pt to stay relaxed
What are the levels on the modified ashworth scale?
0 = No increase in muscle tone 1 = Slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the range of motion when the affected part(s) is moved in flexion or extension 1+ = Slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM 2 = More marked increase in muscle tone through most of the ROM, but affected part(s) easily moved 3 = Considerable increase in muscle tone, passive movement difficult 4 = Affected part(s) rigid in flexion or extension
What are the grades for DTRs?
0 = absent 1+ = present but depressed 2+ = normal 3+ = brisk 4+ = very brisk, hyperactive, w/clonus
Abnormal obligatory movements that emerge w/spasticity [w/someone w/CNS disorder]; Inability to perform isolated movements at each joint, and will move in a certain pattern
Synergistic pattern
- Ex: Stroke – reach out to grab something, & elbow flexes towards trunk – can’t stop this
- PT records when the patterns occur, under what circumstances, and what variations are observed; Under moments of increased stress, increased fatigue, etc
- decrease in synergy = condition improving
How can you test strength in neuro patients who cannot isolate movements?
observe active movements
- Squats
- Sit/stands
- Heel raises
- Toe raises
- can they do it? how long? how far down can pt go? what does the movement look like?
