09f
CLINICAL APPLICATIONS OF
YOUR KNOWLEDGE OF THE
MOTOR SYSTEMS
Think: Unilateral damage to upper motor neuron…
and reasons for associated spastic hemiplegia
• At first:
•
Signs present
____________
to site of lesion
See pp. 352-357 in book
– Flaccidity of
distal muscles
– Loss of precise
control
– Positive Babinski
1 to 4 weeks later
– Spasticity of
distal muscles,
esp. for corticospinal system
– Hyperreflexia
– Clasp-knife
rigidity
Spastic hemiplegia,
spastic monoplegia
Which UMNs have been affected?
Think: Bilateral damage to upper motor neuron…
and reasons for associated pseudobulbar palsy
• Signs
Little spasticity in face,
but voice strained
(spastic)
See p. 353-357 in book
– Flaccidity of facial
muscles
– Loss of precise
control of facial
muscles
– hyperreflexia
– Strain-strangled
spasticity of voice
– Voluntary mvmnt
of face poor, but
emotional mvmnt
of face (via limbic
system) present
Pseudobulbar palsy
• Examples of hyper-reflexia, as well as
preservations of normal reflexes, in cases
of severe TBI with associated
pseudobulbar palsy
• Strained-hoarse voice, slow rate,
imprecision of articulation and
hypernasality in Case 13 (pseudobulbar
palsy)
Think: Brainstem stroke, and how it may result in
alternating or “crossed” hemiplegia
• Simultaneous lesion of
•
•
See p. 353-354 in book
– Cranial nerve motor
nuclei and/or nerves,
LMN (motor unit)
– UMN
LMN signs ipsilateral to
lesion
UMN signs contralateral to
lesion
Think: Damage to LMN and its
clinical presentation. Why this association?
• Includes bulbar
•
See p. 353-357 in book
palsy, damage to
nerves, or poor
neuro-muscular
communication
Signs
– Absent reflexes
– Flaccid tone
– Muscle
wasting/atrophy
– Fasciculations
and fibrilations
(activity of
denervated
muscle)
Example of fasciculations and
atrophy with LMN involvement
• Case 14—Fasciculations of tongue
• Case 15---Flaccidity of face and soft palate
Speech motor system complex and
neurologically sensitive
• Over 100 muscles must be controlled and
•
coordinated
Approximately 14 recognizable speech sounds are
uttered per second
“Normal speech production requires the finest motor
control in the body” (W&A, p. 125)
Speech motor system highly sensitive to even small
neurological changes/damage, at any point in the
motor neural pathways
SLP / A----Our role in diagnosis
“Motor speech disorders (and other
communication disorders) often can be
linked to disease location and sometimes
to specific diseases, even when
localization and diagnosis have not yet
otherwise been established.”
(Joseph Duffy, Mayo Clinic, The ASHA
Leader , November 25, 2008)
Dysarthrias (speech motor disorders)
• Dysarthria associated with bilateral upper
motor neuron damage: Spastic dysarthria
(muscles are overly tight, because
inhibition of LMN which would normally be
supplied from cortex through UMN cannot
reach the LMN; hyper-reflexia makes
muscles extra tight)
• Dysarthria associated with lower motor
neuron damage: Flaccid dysarthria
(muscles are floppy because they are not
receiving activation through LMN)
Dysarthrias (speech motor disorders),
cont.
• Dysarthrias associated with basal ganglia
involvement
– Hypokinetic dysarthria (prob. w/ movement
inititation)
• Dysarthria associated with Parkinson’s disease (not
enough dopamine in substantia nigra)
– Hyperkinetic dysarthria (prob. w/ movement
inhibition)
• E.g. Huntington’s chorea
• E.g. myoclonus
• Dysarthria associated with cerebellar
involvement: Ataxic dysarthria
IF DAMAGE/LESION IS
IN….
…THE SPEECH/VOICE/
RESPIRATORY MUSCLES…
…AND THIS IS CALLED
lower motor neuron
are weak and lacking in
muscle tone
flaccid dysarthria
upper motor neuron
(bilaterally)
have too much muscle tone spastic dysarthria
(a “tight feeling”) and move
slowly and with difficulty
cerebellum or cerebellar
pathways
are uncoordinated in their
movements
basal ganglia circuits, for:
--movement initiation
--movement inhibition
language dominant
hemisphere, especially
frontal lobe motor
planning areas
--display excessive, small
movements, not fully
initiated
--display extraneous,
involuntary movement
…are NOT weak, tight,
uncoordinated, or
dyskinetic, BUT the
planning for the correct
movements is poor
ataxic dysarthria
dyskinetic dysarthria
--hypokinetic dysarthria
--hyperkinetic dysarthria
apraxia of speech
Note: Mixed dysarthria
also possible
Additional examples of
dysarthria
• Case 16—Cerebellar degenerative disease
– _______________ articulatory breakdown
• Case 17—Hypokinetic dysarthria of
Parkinson’s disease
• Cases 18, 19, 20—Focal hyperkinetic
dyskinesias affecting speech (facial and
fasciaolingual dyskinesias)