Cranial Nerves on the Praxis SLP: The 6 You Must Know Cold

Cranial nerves are the single most predictable topic on the Praxis 5331. ETS will ask you which nerve mediates lip seal, which one elevates the velum, and which one a flaccid dysarthria localizes to. There are 12 cranial nerves total — but as an SLP, only six show up on the exam with any frequency. Memorize these cold and you bank easy points across all three content areas.

The 6 cranial nerves SLPs must know

For each nerve, learn three things: name, function relevant to speech/swallowing, and what a lesion looks like clinically.

CN V — Trigeminal

• Type: Mixed (sensory + motor).
• SLP-relevant function: Mastication (motor to muscles of chewing); sensation to face, jaw, anterior 2/3 of tongue.
• Lesion signs: Weak jaw on bite, jaw deviates to weak side, loss of facial sensation. Impacts oral preparatory phase of swallow.

CN VII — Facial

• Type: Mixed.
• SLP-relevant function: Motor to muscles of facial expression (including lip seal, buccal tension); taste to anterior 2/3 of tongue.
• Lesion signs: Bell's palsy = unilateral facial droop, drooling, poor lip seal → bolus loss anteriorly. Stroke can mimic but spares the forehead (UMN vs. LMN distinction — high-yield).

CN IX — Glossopharyngeal

• Type: Mixed.
• SLP-relevant function: Sensation to posterior 1/3 of tongue, oropharynx; triggers swallow reflex; gag reflex (afferent limb).
• Lesion signs: Delayed/absent swallow trigger, reduced gag, dysphagia in the pharyngeal phase.

CN X — Vagus

• Type: Mixed. Longest cranial nerve.
• SLP-relevant function: Motor to soft palate, pharynx, larynx (via recurrent laryngeal nerve); efferent limb of gag and swallow reflex; vocal fold abduction/adduction.
• Lesion signs: Hypernasality (velopharyngeal weakness), wet/breathy vocal quality (vocal fold paralysis), aspiration. Recurrent laryngeal nerve damage after thyroid surgery is a classic vignette.

CN XI — Accessory (Spinal)

• Type: Motor.
• SLP-relevant function: Motor to sternocleidomastoid and trapezius — relevant to head/neck positioning during swallow and to vocal effort.
• Lesion signs: Shoulder droop, head turn weakness. Less commonly tested than the others, but appears in cranial nerve identification items.

CN XII — Hypoglossal

• Type: Motor.
• SLP-relevant function: Motor to all intrinsic and most extrinsic tongue muscles. Drives bolus propulsion in oral transit; critical to articulation of lingual sounds.
• Lesion signs: Tongue deviates toward the weak side on protrusion (mnemonic: "lick your wounds"). Slurred lingual articulation, impaired oral transit.

Quick mnemonic for SLP-relevant nerves

For the swallow specifically: 5, 7, 9, 10, 12. Picture the bolus moving — V chews it, VII keeps it in your mouth, IX triggers the swallow, X powers the pharyngeal phase and protects the airway, XII propels it.

UMN vs. LMN — the distinction ETS loves

• UMN lesion (above the brainstem): contralateral weakness, spares forehead in CN VII, spastic dysarthria, hyperreflexia.
• LMN lesion (cranial nerve nucleus or peripheral nerve): ipsilateral weakness, full facial involvement (forehead included) in CN VII, flaccid dysarthria, atrophy and fasciculations.

Cranial nerves linked to dysarthria types

• Flaccid dysarthria — LMN lesion of CN V, VII, IX, X, or XII.
• Spastic dysarthria — bilateral UMN lesions.
• Unilateral UMN dysarthria — single UMN lesion (often stroke).
• Ataxic dysarthria — cerebellar (not cranial nerve directly).
• Hypokinetic dysarthria — basal ganglia (Parkinson's).
• Hyperkinetic dysarthria — basal ganglia (Huntington's, dystonia).

Praxis-style question pattern

Cranial nerve items usually look like: "A patient presents with breathy vocal quality, hypernasality, and dysphagia after a brainstem stroke. Which cranial nerve is most likely involved?" The answer is CN X (vagus) because it explains all three findings (laryngeal, velopharyngeal, and pharyngeal). The trick is matching the cluster of symptoms to the single best nerve, not to memorize each one in isolation.