Ch. 19 Pedretti (pt. 1) -- Assessment of Motor Control Flashcards
Motor control
the ability to make dynamic postural adjustments and direct body and limb movement in purposeful activity
Components needed for motor control
Components needed for motor control: normal muscle tone, normal postural tone and postural mechanisms, selective movement, coordination
Collaboration of ____ makes motor control possible
Collaboration of complex neurologic systems (i.e., cerebral cortex, basal ganglia, cerebellum) makes motor control possible
Neuroplasticity
Anatomical and electrophysiological changes in the central nervous system -> explains why recovery is possible after brain injury
How does motor relearning occur?
Motor relearning can occur through the use of existing neural pathways (unmasking) or through the development of new neural connections (sprouting)
Unmasking
In unmasking, seldom-used pathways become more active after the primary pathway has been injured. Adjacent nerves take over the functions of damaged nerves
Sprouting
In sprouting, dendrites from one nerve from a new attachment or synapse with another
Upper motor neurons (UMNs)
UMNS includes any nerve cell body or nerve fiber in the spinal cord
COPM
The COPM helps prioritize the client’s functional activity goals in the areas of self-care, leisure, and productivity
Test d’Évaluation des Membres Supérieurs de Personnes gées (TEMPA)
The Test d’Évaluation des Membres Supérieurs de Personnes gées (TEMPA) is an upper extremity functional activity performance test.
Helps distinguish between normal and pathological aging in UE performance
Test items include: picking up/moving a jar, writing on an envelope, tying a scarf, handling coins etc.
CVA Assessments: Graded Wolf Motor Function Test (GWMFT)
A new assessment developed to measure functional gains after a hemiparetic even from CVA or TBI
Based of the Wolf Motor Function Test. Called “graded” b/c there are 2 levels of difficulty. Level A is more advanced, Level B is easier
Useful on a wide variety of clients w/ hemiparesis with varying degrees of motor recovery.
More research needed to confirm the validity and reliability of GWMFT
CVA Assessments: Wolf Motor Function Test (WMFT)
Wolf Motor Function Test (WMFT): used to quantify the motor abilities of chronic clients from a population with high UE function following CVA or TBI
CVA Assessments: The Functional Test for the Hemiplegic/Paretic Upper Extremity
Assesses client’s ability to use the involved arm for purposeful tasks
Provides objective documentation of functional improvement
Includes tasks ranging from basic stabilization, to more difficult tasks that require fine manipulation and proximal stabilization
Ex: holding a pouch, stabilizing a jar, wringing a rag, zipping a zipper
CVA Assessments: The Fugl-Meyer
Quantitative assessment of motor function following stroke by measuring parameters like ROM, pain, sensation, and balance
Based on the natural progression of neurologic recovery after CVA
Low scores have been closely correlated with the presence of severe spasticity
Scores correlate with ADL performance
CVA Assessments: The Arm Motor Ability Test (AMAT)
Functional assessment of UE function
Example tasks: cutting meat, making a sandwich, putting on a t-shirt
CVA Assessments: Motricity Index (MI)
Test of motor impairment that can be performed quickly
Assesses pinching a cube with the index finger and thumb, elbow flexion, shoulder ABduction, ankle dorsiflexion, knee extension, and hip flexion
The Assessment of Motor and Process Skills (AMPS)
Standardized test created by OTs that assesses motor and process skills in IADLs
Not diagnosis specific, but widely used with CVA
Normal muscle tone
Normal muscle tone is a component of the normal postural mechanism. Also a continuous state of mild contraction, or a state of preparedness in the muscle
Tone is the resistance felt by the OT as they move a client’s limb
Tension between the origin and insertion of a muscle is felt as resistance by the OT when passively manipulating the limb
When passively stretched, normal muscle offers a small amount of involuntary resistance
Normal muscle tone relies on function of _____________.
Normal muscle tone relies on function of cerebellum, motor cortex, basal ganglia, midbrain, vestibular system, spinal cord, neuromuscular system, and normally functioning stretch reflex
Normal muscle tone is characterized by:
Effective coactivation (stabilization) at axial and proximal joints;
Ability to move against gravity and resistance;
Ability to maintain the position of the limb if it is placed passively by the examiner and then released;
Balanced tone between agonistic and antagonistic muscles;
Ease of ability to shift from stability to mobility and to reverse as needed;
Ability to use muscles in groups or selectively with normal timing and coordination;
Resilience or slight resistance in response to passive movement
Hypertonicity
Hypertonicity (increased tone) affects the timing and smoothness of agonist and antagonist muscle groups, which interferes with the performance of normal selective movement
Normalization of muscle tone and amelioration of paresis (slight or incomplete paralysis/weakness) is desirable when striving for selective motor control
Some function can be achieved even though tone may not be normal
Flaccidity
The absence of tone or
absence of deep tendon reflexes and active movement.
Muscles feel soft and have no resistance to passive movement
If flaccid limb is moved passively, it will feel heavy
If moved to a position and released, limb will drop b/c muscles are unable to resist pull of gravity
What can cause flaccidity?
Can result from spinal or cerebral shock immediately after a spinal/cerebral insult
In traumatic cerebral or spinal upper motor neuron lesions, flaccidity usually is present initially and then changes to hypertonicity within a few weeks
Flaccidity can also result from lower motor neuron dysfunction (like peripheral nerve injury or disruption of the reflex arc at the alpha motor neuron level)
Hypotonus
Hypotonus: a decrease in normal muscle tone (i.e., low tone).
Deep tendon reflexes are diminished or absent.
Hypotonus may be an erroneous clinical concept: study shows that if a client’s limb feels hypotonic, it may be a result of weakness, not of long-latency stretch reflexes
Hypertonus
Increased muscle tone. Can occur when a lesion is present in the premotor cortex, basal ganglia, or descending pathways
Damage to upper motor neuron systems increases stimulation of lower motor neurons -> increased alpha motor activity
Any neurologic condition that changes upper motor neuron pathways may result in hypertonicity
Hypertonicity patterns
Hypertonicity often occurs in a synergistic neuromuscular pattern (esp. After CVA or TBI)
Synergies: patterned movement characterized by co-contraction of flexors and extensors
Typical synergy seen in UE after CVA/TBI is a flexion synergy
(Extension synergy is seen in the LE)
Moving against hypertonicity
It takes a lot of effort and energy cost to move against hypertonicity
Antagonist power may be insufficient to overcome spastic agonist muscle groups
Loss of reciprocal inhibition
Loss of reciprocal inhibition is noted between spastic agonist and antagonists -> clients are unable to rapidly turn off their muscles
Clients with an upper motor neuron lesion
- Clients with an upper motor neuron lesion will have dysfunction in spatial and temporal timing of movement
- Makes movements uncoordinated
Initiating movements when you have hypertonicity
- Hypertonicity may make initiating movement difficult, especially rapid movement
- Although hypertonic muscles look like they can take resistance, they do not function as well as normal muscles do
What does painful/noxious stimuli do to hypertonicity?
- Hypertonicity can increase as a result of painful or noxious stimuli (such as pressure sores, ingrown toenails, tight clothing, UTI, constipation etc)
- Other triggering factors: fear, anxiety, environmental temperature extremes, sensory overload
- These factors are true for both cerebral and spinal hypertonia (but more so for spinal)
- Therapeutic interventions should be designed to reduce, eliminate, or cope with these extrinsic factors
Cerebral hypertonia
- Caused by TBI, stroke, anoxia, neoplasms (brain tumor), metabolic disorders, CP, and various brain diseases
- In MS, hypertonia is produced from both spinal and cerebral lesions
- With MS, tone fluctuates continuously in response to extrinsic and intrinsic factors
Cerebral hypertonia patterns
- Cerebral hypertonia usually occurs in patterns of flexion or extension, causing limb to be pulled in one direction
- These patterns typically occur in the antigravity muscles of the UE/LE (i.e. flexors of the UE, extensors of the LE)
Muscle tone in cerebral hypertonia while lying down
- When client is lying supine, muscle tone is less than when client is sitting/standing
- Postural tone is important when splinting/casting. A cast/splint made on a client in supine may not fit when client is sitting up b/c of the influence of gravity and posture on increasing muscle tone
- Tone is highest during ambulation
Spinal hypertonia
- Results from injuries and diseases of the spinal cord
- In traumatic spinal cord injury, spinal shock occurs and is characterized by initial flaccidity. Over time (weeks or months) the flaccidity diminishes and hypertonus develops. The affected extremities first develop flexor and adductor tone. Then extensor tone develops and is predominant in LE
- Can lead to intense muscle spasms
- The degree of tone tends to be more severe in incomplete spinal cord lesions than in complete lesions
Spasticity
- There is debate on the difference between spasticity and hypertonia
- One definition of spasticity: a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks resulting from hyperexcitability of the stretch reflex as one component of the upper motor neuron syndrome
- This definition does not distinguish between the presence of phasic and tonic stretch reflexes
Three characteristics of spasticity
- Hyperactivity of the muscle spindle’s phasic stretch reflex with hyperactive firing of the Ia afferent nerve
- Velocity dependence, aka the stretch reflex is elicited only by the OT’s rapid passive stretch
- The “clasp-knife”: when OT takes the extremity through a quick passive stretch, a sudden catch/resistance is felt, followed by a release of resistance. What is happening is the initial high resistance of spasticity is suddenly inhibited
Main system affected by spasticity
- One of the main systems affected by spasticity is the pyramidal system, consisting of the corticospinal and corticobulbar tracts
- Corticospinal tract: controls goal-directed, voluntary movement by influencing the lower motor neuron
- Corticobulbar tract: voluntary action of the cranial nerves
Although both hypertonia and spasticity both pull the limb into a unilateral direction, they differ in two ways
- Hypertonia typically is not velocity dependent (rapid movement does not evoke it), slow joint movements elicits hypertonia.
- During passive movement, no catch is felt with hypertonia (unlike clasp-knife in spasticity)
Clonus
- Clonus: repetitive contractions in the antagonistic muscles in response to rapid stretch
- Clonus is a type of spasticity often found in clients with moderate to severe spasticity
Clonus is often found in clients with ____.
Clonus is a type of spasticity often found in clients with moderate to severe spasticity
Clonus is seen most commonly in the ___ and the ____.
Seen most commonly in the finger flexors and ankle plantar flexors
What can help to alleviate clonus?
OT needs to educate clients on how to bear weight actively b/c this will usually stop the clonus
How is clonus recorded?
- You record clonus by counting the number of beats
- A 3 beat clonus is mild -> less likely to interfere w/ ADLs (compared to clonus that is 10+ beats)
When can clonus be elicited?
Clonus may be elicited during quick stretch tone eval
If WB doesn’t work, what other steps can be taken for clonus?
If clonus is too great, can refer to a physiatrist or neurologist for medication, botox, myobloc injections, or alcohol/phenol motor point block
Rigidity
- A simultaneous increase in muscle tone of agonist and antagonist muscles (muscles on both sides of the joint).
- Rigidity is NOT velocity dependent
- Both muscles steadily contract -> increased resistance to passive movement in any direction and throughout the ROM
Is rigidity velocity dependent?
Rigidity is NOT velocity dependent
What parts of the brain does rigidity involve?
Rigidity involves the extrapyramidal pathways of the basal ganglia, diencephalon, and brainstem
What types of patients might exhibit rigidity?
- Occurs in Parkinson’s disease, TBI, encephalitis, tumors, and after poisoning of certain toxins
- Also sometimes seen in stroke or TBI patients, combined with spasticity
Four types of rigidity
Lead pipe rigidity, cogwheel rigidity, decorticated rigidity, and decerebrate rigidity
Lead pipe rigidity
Constant resistance is felt throughout the ROM when the part is moved slowly and passively in any direction
Cogwheel rigidity
A rhythmic give in resistance occurs throughout ROM (like turning a cogwheel)
Decorticate rigidity
- Appears as flexion hypertonus in the UE and as extension tone in the LE
- Results from bilateral cortical lesions
Decerebrate rigidity
- Appears as rigid extension posturing of all limbs and the neck
- Results from lesions in the bilateral hemispheres of the diencephalon and midbrain
Rigidity in Parkinson’s
Lead pipe and cogwheel rigidity
Rigidity in TBI
Decorticate and decerebrate rigidity can occur after a TBI with diffuse cerebral damage or anoxia
When to rate spasticity and hypertonia
- Preferable to rate spasticity and hypertonia with the client at the same position, at the same time of day b/c the body and head position influence cerebral hypertonus (and enhance reliability)
- Tone fluctuates from hour to hour, and day to day
Muscle tone assessment for UE - position of client
- Client’s UE muscle tone is usually evaluated with client sitting on a mat table
- Client’s trunk posture will affect the results of the tone eval
Steps for assessment of muscle tone
- Grasp the client’s limb proximal and distal to the joint to be tested and move the joint slowly through its range to determine the free and easy ROM available
(Note the presence and location of pain
If no active movement and limb feels heavy, limb is flaccid or “0” in strength
If limb has some active movement and no increased tone, the muscle may be labeled “paretic” instead of “hypotonic”
The paretic antagonist muscle can then be graded in strength
Usually strength grade falls between 1 and 4-) - Hold the limb on the lateral aspects to avoid giving tactile stim to the muscle belly of the muscle being tested
- Assessing spasticity: hold the muscle (described in the point above) and move it rapidly through its full range when the client is relaxed
(Label tone “mild” “moderate” “severe”) - Assessing rigidity and hypertonia: moving the limb slowly during the range, note locations of first tone/resistance to movement in degrees
(Label tone “mild” “moderate” “severe”)
Manual rating scales for spasticity and hypertonicity: Ashworth Scale, Modified Ashworth Scale (MAS)
- Widely used to manually rate spasticity
- Used to quantify the degree of hypertonus
- Not designed to differentiate between pure spasticity and hypertonic stretch reflexes
- Some controversy over the validity and reliability of the scales
Manual rating scales for spasticity and hypertonicity: Tardieu Scale, Modified Tardieu Scale (MTS)
- Measures spasticity
- Tardieu Scale is in French, not reviewed
- MTS is shown to be more reliable than the MAS
Manual rating scales for spasticity and hypertonicity: Mild-Moderate-Sever Spasticity Scale
To estimate the degree of spasticity, some OTs find it easier to use than the other scales
Manual rating scales for spasticity and hypertonicity: Preston’s Hypertonicity Scale
Guide for estimating the degree of hypertonicity
Mechanical and Computer Rating Systems for Spasticity and Hypertonicity
- Mechanically determining hypertonicity may be reliable than the scales above
- Not widely used b/c of time constraints and difficulty accessing certain muscle groups
ROM Assessment in Evaluation of Tone
- Passive ROM (PROM) assessments often correlates with tone assessments
- PROM assessments can reveal possible signs of joint changes (subluxation, dislocation, contracture)
- Some OTs record PROM measurements from the location of the first tone, or resting position, before and after Botox/Myobloc injections
Other considerations in tone assessment
- Changes in bone or other peripheral structures can lead to ROM limitations
- Ex: a heterotopic ossification (formation of new bone in the soft tissue or joints -> joint ankylosis) can limit joint ROM
- Heterotopic ossification can occur in clients with TBI or spinal cord injury
Assessment of Movement and Control
- OT identifies where and how much the client’s motor control is dominated by synergies, and where selective, isolated movement is present
- Degree to which abnormal tone interferes with selective control, which direction of movement hypertonicity occurs and how it affects functions is also identified
- Manual muscle testing is usually not appropriate for clients who have moderate to severe hypertonicity or rigidity b/c relative tone and strength of the muscles are not normal and movement is not voluntary/selective
(But if hypertonia is mild and selective movements are possible, you can grade the strength of the antagonists to measure progress) - Position change, spinal reflexes, the reticular formation, and supraspinal reflexes influence muscle tone and motor control
Sensation: sensibility tests that are recommended for clients with damage to the CNS
- Kinesthesia
- Proprioception
- Pain
- Static two-point discrimination
- Light touch (Semmes– Weinstein monofilament test)