Hypoglossal Nerve Disorder

Question 1

What is it

Answer 1

Dysfunction of the hypoglossal nerve (cranial nerve XII), which controls the muscles of the tongue, leading to weakness, atrophy, and impaired speech/swallowing.

Question 2

Clinical Features

Answer 2

👅 Motor Impairments:

Tongue deviation TOWARD the affected side (due to muscle weakness) ➡️👅
Tongue atrophy & fasciculations (muscle twitching) 🌀
Slurred speech (dysarthria) 🗣️❌
Difficulty swallowing (dysphagia) 🥄❌
Impaired tongue movement affecting speech & eating
🚫 No sensory loss (purely motor nerve)

Question 3

Epidemiology

Answer 3

Rare disorder overall
Most commonly due to stroke, trauma, or tumors
Can be part of neurodegenerative diseases like ALS

Question 4

Age Groups Affected

Answer 4

Any age: Trauma, infections, congenital issues
Middle-aged to older adults: More likely due to stroke, tumors, or neurodegenerative diseases

Question 5

Risk Factors

Answer 5

✅ Modifiable:
Stroke risk factors (hypertension, diabetes, smoking, atherosclerosis) 🩸🚬
Neck trauma or surgery (carotid endarterectomy, tumor resections)
Infections (syphilis, viral infections affecting cranial nerves)

🚫 Non-Modifiable:
Brainstem stroke or tumors (affecting CN XII nucleus)
Neurodegenerative diseases (ALS, MS, Guillain-Barré syndrome)
Congenital CN XII abnormalities (rare)

Question 6

Clinical Presentation

Answer 6

🔹 Unilateral CN XII Palsy:
Tongue deviates TOWARD the affected side 👅➡️
Tongue atrophy & fasciculations (twitching) 🌀
Dysarthria (slurred speech)
Mild difficulty swallowing (dysphagia)

🔹 Bilateral CN XII Palsy (Severe Cases – Rare):
Severe speech impairment 🗣️❌
Difficulty moving food in the mouth → risk of choking 🥄😖

Question 7

Prognosis

Answer 7

🔹 Depends on the cause:
Stroke-related: Recovery varies, may improve with therapy
Trauma or surgical injury: Recovery depends on severity
Neurodegenerative diseases (ALS, MS): Progressive decline
Mild nerve injuries: Can recover with therapy over months

🔹 Prevention:
Control stroke risk factors (BP, diabetes, smoking)
Avoid surgical damage in neck procedures
Early detection of neurodegenerative conditions

Question 8

Test

Answer 8

Resisted tongue movement

Tongue protrusion

Outcomes - tongue deviation, tongue weakness