Tracts
The _______ corticospinal tract descends from the motor cortex, through the internal capsule, to the medulla, and decussate as pyramids before entering into the spinal cord to the anterior/ventral horns for limb control.
Lateral
Which CN might be damaged if I have a patient with a profound impact to articulation and lingual fasciculations?
Hypoglossal: CN XII
Which is the most common type of CVA?
Ischemic
Describe the impact of a lesion to Broca's area
Nonfluent
Poor Naming
Unable to repeat
Comprehension in tact
Where are UMNs?
Brain
Which tract has more fibers? Anterior or lateral corticospinal tract?
Lateral
Give the name and number of the nerves related to vision/eye movement
II, III, IV, VI
Optic
Oculomotor
Trochlear
Abducens
Which type of ischemia is temporary but a strong predictor of a stroke
a TIA, transient ischemic attack
What is the difference between transcortical motor aphasia and Broca's aphasia?
Repetition is OK in transcortical motor aphasia
Which LMNs are in the midbrain?
CNs 3, 4
What are the exceptions to bilateral innervation in the corticonuclear/corticobulbar tract?
CN VII
CN XII
Which CN is responsible for Taste from the anterior 2/3 of the tongue? The posterior 1/3?
VII, Facial
IX, Glossopharyngeal
aneurysm
In which 3 types of aphasia would comprehension be OK?
Broca's, Transcortical motor, Conduction
Explain the 'safety net' of bilateral innervation for cranial nerves.
For most speech and swallowing cranial nerves (like the Trigeminal, Vagus, and Glossopharyngeal), the "workers" (the LMNs in the brainstem) have 2 managers.
Left Cortex Manager: Sends descending UMN fibers down to the Left LMN and crossing over to the Right LMN.
Right Cortex Manager: Sends descending UMN fibers down to the Right LMN and crossing over to the Left LMN.
Because of this cross-wiring, LMNs receive a stream of motor commands from both hemispheres simultaneously.
Describe the descending pathways discussed in class, name the tracts and details such as what they are involved in.
Corticospinal: ~90% lateral, ~10% anterior
Anterior: trunk, girdle, gross motor control lateral
Lateral: Limbs, fine motor , larger bundle
Corticobulbar:
Face/Jaw, swallowing and tongue
Cranial Nerves
Name 4 areas of MOTOR deficit someone with a lesion to CN X might suffer?
Reduced or absent gag reflex
Swallowing deficit
Cricopharyngeus
Failure to elevate soft palate
Nasal regurgitation: loss of food + liquid through nose
Voice disorders
Define thrombosis and embolism
Blockage due to:
Thrombus: a blood clot in a blood vessel
* Atherosclerotic plaque:
Hardening in the lining of the artery wall due to
deposit + accumulation of fatty substance
* Embolism: thrombus breaks free + lodges elsewhere
Which type of dysarthria would be found in someone with Parkinson's disease and what would their speech sound like?
Hypokinetic:
•Monotone speech (lack of pitch variation)
•Reduced loudness (quiet, muffled voice)
•Rapid speech rate (short rushes of speech)
Difficulty with initiating speech
Describe the innervation of CN VII in terms of Stroke vs. Bell's Palsy.
UMN or Stroke:
Upper face (forehead, eye area) in tact or mild impact
Lower facial droop on opposite side
Is one of the exceptions to bilateral innervation
LMN: Bell’s Palsy
caused by a virus
temporary swelling of CN VII
can cause paralysis of all facial muscles on same side
one side of face droops or becomes stiff
What are the 4 parts of a motor unit?
1. Motor neuron cell body
2. Efferent fibers
3. Motor end plate
4. Innervated muscle fibers
Model testing for 2 motor functions each for CN V and XI.
Motor: Masseter muscle
Palpation of masseter: from cheek/temporal to lower jaw
Strength of jaw closure: open against resistance
Lateralize jaw in chewing
Lateralize jaw against resistance
sternocleidomastoid: turn head to 1 side hold it while examiner tries to push back to center
thrust head forward while examiner resists w hand on forehead
trapezius muscle: Test: shrug shoulders while examiner presses down on them
Describe the different types of CVAs and their subtypes, if any. Also discuss where in the brain they might occur.
Ischemic (Occlusive):
TIA
Ischemic Attack
Hematoma and Hemorrhagic.
Subdural, Epidural, Subarachnoid, Intracranial
Name and describe 2 different types of dysarthria (besides hypokinetic) including cause (s) and speech quality
Spastic
CVA, TBI
•Spasticity (increased muscle tone)
•Hyperreflexia (exaggerated reflexes)
•Slow, effortful speech
•Strained/strangled vocal quality
Hyperkinetic:
Basal ganglia lesion, GABA
•Involuntary movements of the face, tongue, or respiratory muscles
•Variable speech rate (irregular rhythm)
•Sudden interruptions or pauses in speech
•Voice tremors or harsh voice quality
Flaccid : MG, CN damage 5,7,9,10,12
•Weak, imprecise articulation
•Reduced loudness and breath support
•Possible difficulty swallowing (dysphagia)
Mixed, ALS, MS
•Imparied loudness
•Harsh vocal quality
•Breathy voice
•Articulatory difficulty due to weakness
•Hypernasality
•Excess stress
Ataxic: Cerebellar stroke, degenerative disease
•Difficulty controlling speech rate and rhythm
•Sound “drunken” or imprecise
•Voice may sound harsh or breathy
•Irregular speech rhythm (prosody)
•Slurred speech (imprecise articulation)
•Excessive loudness variation or monotone voice
Given the below cases, what will you expect from each case when assessing CN 7 and CN 12? Be specific with WHICH side(s) will show deficit on assessment and why.
Patient A recently suffered a severe stroke in their left primary motor cortex, completely destroying the Upper Motor Neurons (UMNs) originating there.
Patient B has a tumor compressing the right side of their brainstem, which has completely severed the Lower Motor Neurons (LMNs) of Cranial Nerve VII (Facial) and 12.
Patient A: Left UMN Lesion (Stroke)
CN VII (Facial): Right lower facial droop.
Why: The lower face only receives contralateral UMN input. The left hemisphere stroke cuts the signal to the right lower face. The forehead remains totally normal because it has bilateral UMN innervation; the healthy right hemisphere is still sending signals to both sides of the upper face.
CN XII (Hypoglossal): Tongue deviates to the right on protrusion.
Why: The genioglossus muscle of the tongue also relies on contralateral UMN input. The left stroke makes the right side of the tongue weak. When the patient sticks their tongue out, the strong left side pushes ("bulldozes") the tongue over to the weak right side.
Patient B: Right LMN Lesion (Brainstem Tumor)
CN VII (Facial): Total facial paralysis on the right side (both forehead and lower face).
Why: The Lower Motor Neuron is the final common pathway. It originates on the right and goes strictly to the ipsilateral (same) side. Because that final bridge is severed, no signals can reach the right upper or right lower face, resulting in complete right-sided flaccid paralysis (similar to Bell's Palsy).
CN XII (Hypoglossal): Tongue deviates to the right on protrusion (likely with atrophy/fasciculations).
Why: The severed right LMN causes profound ipsilateral flaccid weakness in the right side of the tongue. The mechanical result is exactly the same as Patient A: the healthy left side of the tongue pushes the whole structure over toward the paralyzed right side. (The difference here is that because it's an LMN lesion, you will also expect to see muscle wasting and twitching on that right side).