Nuclear lesion

A bulbar palsy, also called a nuclear lesion, is a bilateral lesion of the motor nucleus of a cranial nerve, its axon, or its NMJ. A bulbar palsy is the "opposite" of pseudobulbar palsy.

Pathophysiology
- Cranial nerves IX, X, XI, and XII are affected
- Equals a “lower motor neuron” lesion, with typical peripheral motor lesion symptoms like atrophy and flaccidity
Clinical features
- Normal facial expressions (because VII is unaffected)
- Nasal speech
- Dysphagia of fluids
- Atrophic and fasciculating tongue
- Absent gag reflex

Supranuclear lesion

A pseudobulbar palsy, also called a supranuclear lesion, refers to a bilateral lesion of the corticobulbar tracts. It's the "opposite" of a bulbar palsy.

Pathophysiology
- Cranial nerves V, VII, IX, X, XI, XII are affected
- Equals an “upper motor neuron” lesion, with typical central motor lesion symptoms like spasticity and hyperreflexia
Clinical features
- Stiff, spastic facial muscles -> no facial expressions
- Spastic dysarthria (Donald Duck voice)
- Dysphagia
- Spastic tongue
- Pseudobulbar affect/emotional incontinence
  - Uncontrollable laughing or crying
  - Think Joaquin Phoenix in the Joker
- CN V palsy -> exaggerated jaw jerk reflex
- Brisk gag reflex