Facial and trigeminal nerve reflexes Flashcards
2 tests to evaluate the trigemial nerve
- blink reflex
- trigemino-trigeminal reflex testing
2 tests to evaluate facial nerve
- blink reflex
- Direct facial nerve stimulation
3 clinical usefulness of these tests
- Px for recovery with idiopathic facial paralysis
- Differentiating between central vs peripheral nerve dysfunction
- assessing presence and extent of brainstem Lx in dogs with multifocal CN deficits
What is the blink reflex :)
stimulation of the trigeminal or facial branches –> reflex contraction of the ipsilateral orbicularis oculi muscle
blink reflex
What nerve branches can be stimulated in the blink reflex
Trigemial:
- infraorbital
- supraorbital (frontal)
- ZygomatIic
Facial
- Internal auricular
slide 9
blink reflex
What type of waveform is recorded
Reflex Evoked Muscle Potential (REMP)
(obtained by stimulating the facial or trigeminal branches and record in the orbicularis oculi muscles)
slide 16
Blink reflex
Describe R1
R1:
Trigeminal nerve branch –>
pontine sensory nucleus of V –>
Motor nucleus of VII
Facial nerve branch -> ipsi orbicularis oculi muscles
slide 11
Blink reflex
Describe R2
R2:
Trigeminal nerve branch –>
Spinal tract of V –> nucelus of spinal tract of V –>
to bilateral motor nuclei of VII –> bilateral orbicularis oculi muscles
Essential to distinguish afferent (V) vs efferent (VII) arc involvement (analogy to D+ and C+ PLRs)
slide 12
Describe R3
When specifically stimulating small-diameter, high-threshold afferent unmyelinated fibers
Trigeminal nerve branch (small) -> spinal tract of V -> nucleus of spinal tract of V -> ipsi motor nucleus of VII
slide 13
Blink reflex
understand interpretation based on lesions slide 19-23
Direct facial nerve stimulation