Transcript RHS 332-2

RHS 332: Clinical Neurology
Ahmad Alghadir, M.S. Ph.D. P.T.
Room: 2071
[email protected]
[email protected]
Ahmad Alghadir M.S. Ph.D. P.T.
Recommended texts
• S.B. O’sullivan, T.J. Schmitz, Physical
Rehabilitation: Assessment and
Treatment, F.A. Davis Company. 3rd ed.
1994.
• R.L. Braddom, Physical Medicine &
Rehabilitation, W.B. Saunders Company.
1st ed. 1996.
Ahmad Alghadir M.S. Ph.D. P.T.
Motor Control Assessment
Ahmad Alghadir M.S. Ph.D. P.T.
II. Tone
•
Definition: “resistance of muscle to
passive elongation or stretch.”
---Tonal abnormalities--a) Hypertonia: “state of increased tone
above normal resting levels.” (spasticity
and rigidity)
b) Hypotonia: “state of decreased tone
below normal resting levels.” (flaccidity)
c) Dystonia: “impaired or distorted tonicity.”
Ahmad Alghadir M.S. Ph.D. P.T.
Spasticity
• Definition: velocity-dependent increase in
tone or resistance of muscle to passive
stretch causing stiff movements with
exaggerated tendon jerks.
• Quicker stretch  stronger resistance.
Ahmad Alghadir M.S. Ph.D. P.T.
• Characteristics of spasticity:
1. Clasp-knife reflex: an initial high
resistance followed by a sudden
relaxation or letting go of a spastic
muscle in response to a stretch reflex.
2. Clonus: cyclic hyperactivity of
antagonistic muscles occurring at a
regular frequency in response to
sustained stretch to a spastic muscle.
Ahmad Alghadir M.S. Ph.D. P.T.
• Brainstem lesions: (see figure 7-4).
1. Decerebrate: sustained contraction
(spasticity) of extensor muscles in the
upper and lower limbs as a result of a
brainstem lesion between the red
nucleus and vestibular nuclei
(subthalamus to midpons).
Ahmad Alghadir M.S. Ph.D. P.T.
2. Decorticate: sustained contraction
(spasticity) of extensors in the lower
limbs and flexors in the upper limbs as a
result of a brainstem lesion above the
red nucleus.
Ahmad Alghadir M.S. Ph.D. P.T.
Rigidity
• Definition: stiffness or inability to bend or
be bent.
• “In rigidity, resistance is uniformly
increased in both agonist and antagonist
muscles, rendering body parts stiff and
immoveable.”
• “Independent of the velocity of a stretch
stimulus.”
• Parkinson’s disease.
Ahmad Alghadir M.S. Ph.D. P.T.
• Characteristics of rigidity:
1. Cogwheel rigidity: “ratchetlike response
to passive movement characterized by
an alternate letting go and increasing
resistance to movement.”
2. Leadpipe rigidity: “constant resistance to
movement.”
Ahmad Alghadir M.S. Ph.D. P.T.
Flaccidity
• Definition: “absence of muscle tone.”
• LMNL.
• Spinal or cerebral shock (temporary state
 hypertonic state).
• Hypersensitivity and hyperextensibility.
Ahmad Alghadir M.S. Ph.D. P.T.
Dystonia
• Definition: “hyperkinetic movement
disorder characterized by impaired or
disordered tone, and sustained and
twisting involuntary movements.”
• Inherited (idiopathic), neurodegenerative
disorders (basal ganglia).
Ahmad Alghadir M.S. Ph.D. P.T.
• Characteristics of dystonia:
1. “Muscle contractions may be slow or
rapid, and are repetitive and patterned.”
2. “Tone fluctuate in an unpredictable
manner from low to high.”
Ahmad Alghadir M.S. Ph.D. P.T.
•
---Tonal assessment--Factors affecting tone: position, stress,
anxiety, volitional effort, medications,
temperature, level of arousal and
alertness, bladder state, fever, and
infection.
Ahmad Alghadir M.S. Ph.D. P.T.
1. Initial observation:
• Abnormal posturing (abnormal
synergies)  spasticity or rigidity.
• Complete absence of spontaneous
movements  flaccidity.
• Involuntary movements  dystonia.
Ahmad Alghadir M.S. Ph.D. P.T.
2. PROM:
• Varying the speed of movement 
spasticity (clasp-knife reflex).
• Sudden stretch  spasticity (clonus).
• Side to side comparison in cases of
localized or unilateral dysfunction.
Ahmad Alghadir M.S. Ph.D. P.T.
• General scale to evaluate tone:
0 – no response (flaccidity).
1 – decreased response (hypotonia).
2 – normal response.
3 – exaggerated response (mild to moderate
hypertonia).
4 – sustained response (severe hypertonia).
Ahmad Alghadir M.S. Ph.D. P.T.
• Modified Ashworth scale to evaluate
spasticity: (see table 8-2).
Ahmad Alghadir M.S. Ph.D. P.T.
• Pendulum test: normal and hypotonic limb
swings for several oscillations, hypertonic
limb resists swinging.
• Drop arm test: normal limb falls
momentarily then catches and maintains
the position, hypotonic limb falls abruptly,
hypertonic limb demonstrates delay and
resistance to falling.
Ahmad Alghadir M.S. Ph.D. P.T.
III. Muscle strength
• See table 8-5.
Ahmad Alghadir M.S. Ph.D. P.T.
IV. Reflexes
1. Superficial cutaneous reflexes: (see table
8-3).
2. Deep tendon reflexes: (see table 8-1).
Ahmad Alghadir M.S. Ph.D. P.T.
V. Balance
• Definition: “stability produced on each side
of a vertical axis.”
• “The center of mass (COM) is maintained
over the base of support (BOS).”
• Goals of balance control system: safety
and function.
Ahmad Alghadir M.S. Ph.D. P.T.
•
1.
2.
3.
Components of balance control system:
Sensory elements.
Sensory interaction.
Musculoskeletal elements.
Ahmad Alghadir M.S. Ph.D. P.T.
1. Sensory elements
a) Visual system:
- Function:
“Detects the relative orientation of the body
parts and the orientation of the body with
reference to the environment.” (visual
proprioception)
“Relays information about the organization
of the external environment.”
Visually guided movements.
Ahmad Alghadir M.S. Ph.D. P.T.
- Assessment:
Visual acuity: Snellen eye chart.
Bitemporal hemianopsia: optic chiasm
lesion.
Ahmad Alghadir M.S. Ph.D. P.T.
b) Somatosensory inputs:
- Components:
Cutaneous sensations (touch and pressure)
from body parts in contact with the support
surface.
Joint and muscle proprioceptors.
Ahmad Alghadir M.S. Ph.D. P.T.
- Function:
“Detect the relative orientation and
movement of body parts and orientation of
the support surface.”
- Assessment:
Sensory examination of trunk and
extremities.
Foot and ankle are critical in assessing
somatosensory contribution to balance.
Ahmad Alghadir M.S. Ph.D. P.T.
c) Vestibular system:
- Function:
“Detects angular and linear acceleration and
deceleration forces acting on the head.”
Detects the orientation of the head with
reference to gravity.
Stabilizes gaze during head movements
(vestibulo-ocular reflex).
Ahmad Alghadir M.S. Ph.D. P.T.
- Assessment:
Barany test: nystagmus  vestibular system
lesion. “Nystagmus: rhythmic, oscillatory
movement of the eyes.”
Ahmad Alghadir M.S. Ph.D. P.T.
2. Sensory interaction
• All sensory inputs contribute to the sense
of equilibrium.
• Sense of equilibrium: “sense of the
position of the COM in relation to the
support surface.”
Ahmad Alghadir M.S. Ph.D. P.T.
• “Because these inputs are redundant,
stable balance can be maintained in the
absence of vision, on unstable surfaces, or
in sensory conflict situations.”
• “If more than one sensory system is
deficient however, lack of balance control
will be evident.”
Ahmad Alghadir M.S. Ph.D. P.T.
• Stable support surface, normal vision 
somatosensory inputs.
• Stable support surface, absent vision 
somatosensory inputs.
• Disturbed support surface, normal vision
 visual system.
• Disturbed support surface, absent vision
 vestibular system
Ahmad Alghadir M.S. Ph.D. P.T.
• Assessment:
- Clinical Test for Sensory Interaction in
Balance (CTSIB): (see figure 8-2).
* “Each condition is maintained for 30
seconds.”
* Scoring:
“Changes in the amount and direction of
postural sway” (1=minimal, 2=mild,
3=moderate, 4=fall).
Ahmad Alghadir M.S. Ph.D. P.T.
Time in balance (stopwatch, 30s).
* Nausea and dizziness.
- Dynamic posturography (e.g. balance
master).
Ahmad Alghadir M.S. Ph.D. P.T.
3. Musculoskeletal elements
• Limits of stability (LOS): “maximum angle
from vertical that can be tolerated without
a loss of balance.”
• Nashner: LOS=12° in anteroposterior
direction, LOS=16° in medial-lateral
direction.
Ahmad Alghadir M.S. Ph.D. P.T.
•
Musculoskeletal responses to
disturbance of COM to preserve balance:
a) Monosynaptic reflexes.
b) Postural synergies (functional reflexes).
c) Equilibrium reactions.
• “As the LOS are reached with a COM
disturbance, the magnitude of the
postural response increases.”
Ahmad Alghadir M.S. Ph.D. P.T.
b) Postural synergies
1. Ankle strategy:
• “Involves shifting the COM forward and
back by rotating the body as a relatively
rigid mass about the ankle joints.”
• Muscle activation pattern: distal to
proximal.
• Utilized with small disturbances of COM
within LOS.
Ahmad Alghadir M.S. Ph.D. P.T.
2. Hip strategy:
• “Involves shifts in the COM by flexing or
extending at the hips.”
• Muscle activation pattern: proximal to
distal.
• Utilized with larger disturbances of COM
within LOS.
Ahmad Alghadir M.S. Ph.D. P.T.
3. Stepping strategy:
• “Realigns the BOS under the COM by
using rapid steps in the direction of the
displacing force.”
• “Elicited when the limits of stability are
reached in response to fast, large
postural perturbations.”
• Utilized when “ankle or hip strategies are
no longer sufficient to maintain balance.”
Ahmad Alghadir M.S. Ph.D. P.T.
• “Postural synergies can function in either a
feedback mode (as a reaction to a specific
stimulus) or in a feedforward mode (in
preparation for voluntary movement which
requires a balance adjustment).”
Ahmad Alghadir M.S. Ph.D. P.T.
c) Equilibrium reactions
• “Total compensatory reaction involving
automatic movements of the limbs and
trunk.”
• Initial response elicits postural synergies.
As LOS are reached, compensatory trunk,
arm, and head movements are added.
Ahmad Alghadir M.S. Ph.D. P.T.
•
1.
2.
3.
4.
Factors influencing postural synergies
and equilibrium reactions:
Previous experiences.
Currently available sensory inputs.
Specific parameters of the disturbing
stimulus.
Body position at the time of imbalance.
Ahmad Alghadir M.S. Ph.D. P.T.
•
1.
2.
3.
4.
Assessment of musculoskeletal
elements:
ROM, tone, and strength.
Responses to perturbation.
Assessment of static balance
(maintenance of posture).
Assessment of dynamic balance
(balance during weight shifting or
movement).
Ahmad Alghadir M.S. Ph.D. P.T.
2. Responses to perturbation
• Postural stress test:
-”Measure of motor responses to specified
weight disturbances during standing.”
-”Weights (equal to 1.5%, 3%, and 4% of
body weight) are applied through a pulley
system to a waist belt which is, in turn,
attached to the patient.”
• Expected and unexpected perturbations.
Ahmad Alghadir M.S. Ph.D. P.T.
• Strategies and reactions might be:
a)Present and normal.
b)Present but limited.
c)Present but inappropriate for the particular
situation.
d)Abnormal.
e)Absent.
Ahmad Alghadir M.S. Ph.D. P.T.
3. Assessment of static balance
a) Double limb support.
b) Single limb support.
c) Tandem (heel-toe position).
Ahmad Alghadir M.S. Ph.D. P.T.
4. Assessment of dynamic
balance
a)
b)
c)
d)
e)
Standing up.
Walking.
Turning.
Stopping.
Starting.
Ahmad Alghadir M.S. Ph.D. P.T.
• Scoring:
1. Simple three-point scale: absent,
impaired, and present.
2. Functional balance grades: see table 86.
3. Time in balance (stopwatch, 30s).
Ahmad Alghadir M.S. Ph.D. P.T.
• Dynamic posturography.
• Force platform.
Ahmad Alghadir M.S. Ph.D. P.T.
Factors influencing motor
control assessment
•
•
•
•
•
Cognition.
Perception.
Arousal.
Communication.
Sensation.
Ahmad Alghadir M.S. Ph.D. P.T.