Evaluation of cranial nerve mononeuropathy

Diseases

Summary

Cranial nerve mononeuropathies present with varying signs and symptoms depending on which nerve is affected. The effects of the mononeuropathy also depend on where in its pathway the nerve is affected, and the etiology.

There are 12 paired cranial nerves, named and numbered according to the rostral-caudal order of attachment to the brain. They serve a variety of functions and predominantly provide the motor and sensory innervation to the head.

The 12 cranial nerves and their functional end organs

Adapted from An Introduction to Neurophysiology, Thomy Nilsson (2022). Reproduced under the Creative Commons CC BY-SA 4.0 license (https://creativecommons.org/licenses/by-sa/4.0/)

Olfactory (I)

Anatomy

Olfaction begins with transduction of odorants from the air into the nasal mucosa. These odorants diffuse or are transported to bipolar receptor cells located in the olfactory neuroepithelium in the roof of the nasal chamber. Action potentials are induced in these cells, which synapse with olfactory bulb glomeruli.[1] The receptor cell axons project through the cribriform plate of the ethmoid bone and synapse within the glomerular layer of the olfactory bulb. The paired olfactory bulbs are located at the base of the frontal lobe overlying the cribriform plate.[2] The second-order neurons leave the olfactory bulb to synapse on the primary olfactory cortex. These areas encode characteristics of odor quality, identity, familiarity, and emotion.[3]

Function and disorders

Changes in olfactory function frequently go unnoticed and often do not present to a clinician.[2] Patients may notice altered taste, rather than a loss of sense of smell.[4] Olfaction is critically important for safety, nutritional status, and quality of life. Disorders can manifest as a total loss of smell (anosmia), partial loss of smell (hyposmia), distortions (dysosmias), or spontaneous olfactory hallucinations (phantosmias).[2] Infrequently, olfactory dysfunction can be the presenting sign/symptom of neurodegenerative disorders (such as idiopathic Parkinson disease), or an intracranial mass lesion.

Nerve testing

The diagnosis can usually be made clinically. Commercial odor identification tests are available, which require patients to identify several predefined smells.[5] These may be useful to confirm olfactory dysfunction. Psychophysical tests are useful to validate and classify olfactory dysfunction, but establishing the cause of olfactory loss relies heavily on the history. Olfactory evoked potentials are available in specialist centers.

Optic (II)

Anatomy

Axons making up the optic nerve arise from retinal ganglion cells. These axons run toward the lamina cribrosa and merge in the optic papilla. At this point, they form the optic nerve. In the orbital apex, the nerve passes through the extraocular muscle origins and enters the optic canal. The nerve continues to course upward and inward until it meets with the contralateral nerve to form the optic chiasm superior to the sella and pituitary gland.[6] Action potentials are then carried to the lateral geniculate body. The intraorbital portion is surrounded by the subarachnoid space and dura that extends from the intracranial cavity. The central retinal artery and vein course through the middle of the nerve.

Function and disorders

Humans have a highly developed visual system, which transmits information from the environment. The optic nerve carries millions of fibers from the retina into the central nervous system (CNS).[7] Vision is critical for human function and, as such, optic nerve pathology can severely affect quality of life.[6] Optic nerve lesions typically produce monocular visual loss, which can be sudden or gradual, and may or may not be associated with pain. The potential causes of optic neuropathy are diverse and include vascular, toxic, metabolic, traumatic, compressive, infectious, inflammatory, and idiopathic etiologies.

Nerve testing

Symptoms of optic nerve damage can represent changes in visual acuity, contrast, brightness, or colour.[6] A detailed description of visual dysfunction is essential and can narrow the differential. To define the degree of optic nerve dysfunction, the following tests are frequently performed.

Visual acuity: tested using a Snellen chart.[4] Optic nerve damage may result in central visual loss.
Color vision: assessed with a series of color plates. Patients with unilateral optic nerve impairment have difficulty identifying colors (dyschromatopsia); color perception is more likely to be significantly affected than visual acuity.
Pupillary testing: pupillary light reflex testing for relative afferent pupillary defect (RAPD) is the only bedside test of optic nerve dysfunction that is independent of patient's subjective response.[6]
Visual fields testing: a basic visual field test can be performed at the bedside by comparing the patient's peripheral vision with the clinician.[4] If a defect is identified, formal testing may be required, for example with Goldmann perimetry. The more central part of the visual field may be tested using an Amsler grid.
Direct ophthalmoscopy: visualizing the optic nerve as it enters the back of the eye can reveal pallor (optic atrophy) or disk swelling (papillitis or papilledema).
Electrodiagnostic testing: visual evoked potentials (VEPs) can be performed to objectively assess for conduction slowing at the optic nerve. This potential is recorded from surface electrodes on the scalp while displaying visual patterns or light flashes to either eye. Note that visual pathway lesions posterior to the optic chiasm are technically more challenging to identify with VEP.[8]

Oculomotor (III), trochlear (IV), and abducens (VI)

Anatomy

The oculomotor nerve emerges from the midbrain nucleus that lies ventral to the sylvian aqueduct. One unpaired and 4 paired subnuclei can be distinguished. The most dorsal subnucleus contains the visceral Edinger-Westphal nucleus and the levator palpebrae nucleus. The Edinger-Westphal nucleus mediates pupillary constriction. Laterally the dorsal, intermediate, and ventral subnuclei provide innervation to the ipsilateral inferior rectus, inferior oblique, and medial rectus, respectively. The oculomotor nerve fascicles leave the nucleus and pass ventrally through the red nucleus before exiting just medial to the cerebral peduncles. In the subarachnoid space the third nerve passes between the superior cerebellar and posterior cerebral arteries. The nerve then enters the lateral wall of the cavernous sinus and divides into a superior and inferior branch as it enters the orbit through the superior orbital fissure.[9] The oculomotor nerve contains inner somatic nerve fibers innervating the extraocular muscles, surrounded by outer autonomic nerve fibers mediating pupillary constriction.[10]
The trochlear nucleus is located in the midbrain tegmentum at the level of the inferior colliculus. The nerve fascicles course posteroinferiorly to decussate at the anterior medullary velum before exiting from the dorsal aspect of the midbrain. The trochlear nerve is the only nerve to arise from the dorsal aspect of the brainstem. The fourth nerve traverses the brainstem cisterns close to the undersurface of the tentorial edge and pierces the dura to enter the lateral cavernous sinus. The trochlear nerve enters the orbit through the superior orbital fissure to innervate the superior oblique muscle.[9]
The abducens nucleus contains motor neurons for the lateral rectus and interneurons traveling through the medial longitudinal fasciculus to the contralateral third nerve nucleus (to allow simultaneous movement of the contralateral medial rectus muscle). The nerve fascicles leave the nucleus and travel within the pontine tegmentum to leave the brainstem in the horizontal sulcus between the pons and medulla. The nerve enters the subarachnoid space and courses vertically along the clivus over the petrous apex of the temporal bone, where it is tethered in the Dorello canal. It then enters the cavernous sinus lateral to the internal carotid artery and finally enters the orbit through the superior orbital fissure.[9]

Function and disorders

The third, fourth, and sixth cranial nerves are responsible for eye movements.
The third cranial nerve controls most extraocular muscles, including the superior, inferior, and medial recti, and the inferior oblique muscles. In addition, it innervates the levator palpebrae superioris, which elevates the eyelid, and carries parasympathetic innervation to the pupil. Patients often present with paralysis of adduction, elevation, and depression, and when the pupil is involved a large unreactive pupil is noted. This presentation can suggest serious neurologic disorders, namely subarachnoid hemorrhage, cerebral aneurysms, uncal herniation, or meningitis. Prompt recognition and evaluation is needed.
The fourth cranial nerve innervates the superior oblique muscle, which controls depression, intorsion, and adduction of the eye. It is the most common cause of vertical diplopia. The frequency of fourth nerve palsy is difficult to accurately report, but in one large series it was more common than both oculomotor and abducens palsies.[11] [12] The abducens nerve innervates the lateral rectus muscle and controls abduction. Patients typically present with horizontal double vision. It may be an isolated finding or part of a systemic disease.[9]

Nerve testing

Simple bedside testing of eye movements can be performed to elicit a third, fourth, or sixth nerve palsy. The patient is asked to keep his or her head still and follow the examiner's index finger with the eyes. The examiner slowly moves his or her finger up and down and from side to side at eye level and observes eye movements.[4] The patient should report back any diplopia. Diplopia is maximal in the direction of action of the paralyzed muscle. Of the duplicated images perceived by the patient, the image seen in the periphery is perceived from the paretic (abnormal) eye and should disappear upon occlusion of the eye.[4]

Trigeminal (V)

Anatomy

The trigeminal nerve has 3 main branches: ophthalmic (V1), maxillary (V2), and mandibular (V3).[13] V1 enters the cranial cavity through the superior orbital fissure, V2 through the foramen rotundum, and V3 through the foramen ovale. V1 and V2 traverse the cavernous sinus. The first-order cell bodies carrying modalities of pain, temperature, pressure, and light touch in all 3 branches are located in the trigeminal (gasserian) ganglion in the Meckel cave (near the petrous apex of the temporal bone). Proprioceptive fibers have their first-order cell bodies in the mesencephalic nucleus of the brainstem. From the trigeminal ganglion, the nerve fibers enter the pons and synapse in multiple trigeminal nuclei. From there, second-order neurons carry afferent information to the ventral posteromedial nucleus of the thalamus. Finally, third-order neurons relay to the primary sensory cortex. Efferent motor fibers originate in the motor nucleus of the trigeminal nerve in the midpons and travel with V3 through the foramen ovale to supply the muscles of mastication (masseter, temporalis, mylohyoid, medial and lateral pterygoid, and anterior belly of the digastric), as well as the tensor tympani and tensor veli palatini. The trigeminal nerve and its branches also mediate the afferent limbs of the corneal blink and lacrimal reflexes, and both afferent and efferent limbs of the jaw-jerk reflex.

Function and disorders

The trigeminal nerve is the largest cranial nerve.[4] It carries sensation from the face and mucosal surfaces, cornea, and supratentorial dura, as well as providing motor innervations to the muscles of mastication. The differential diagnosis for trigeminal neuropathy is very broad. Intra-axial pathology, particularly of the pons, can result in trigeminal dysfunction, but only rarely does this result in a mononeuropathy. Extra-axial lesions are more likely to affect the trigeminal nerve or its branches alone. Symptoms of trigeminal neuropathy depend on the location and etiology of the lesion and may include loss of sensation in the distribution of one or more trigeminal nerve branches, neuropathic pain, or weakness of the muscles of mastication.[14]

Nerve testing

Facial sensation can be tested by asking the patient to close his or her eyes and report where a stimulus is felt. Light touch with a cotton wool stick, pinprick with the end of a sterile needle, and warm and cold stimuli can be tested on each side of the face.[4] Contraction of the masseter and temporal muscles can be examined by visual inspection, and palpation of the masseter muscles can be examined when the patient is chewing.
The jaw jerk can be tested as follows: with the patient's mouth slightly open, the mandible is tapped just below the lips in a downward direction. The masseter will move the mandible upward. Normally this reflex is weak, but it may be pronounced with upper motor neuron lesions.[4]
The strength of the pterygoid muscles may be tested by asking the patient to open the jaw against resistance.[4]
The corneal reflex can be tested with cotton wool (afferent-trigeminal, efferent-facial) and elicits an ipsilateral and contralateral blink response in normal individuals.[4]
Electrodiagnostic testing: the afferent component of the trigeminal nerve (V1) may be evaluated via the blink reflex. Needle electromyography of trigeminal nerve-innervated muscles, such as masseter and temporalis, tests for the motor efferent component of the trigeminal nerve (V3). Less common tests of the trigeminal nerve include masseter inhibitory reflex and jaw jerk (the latter is similar to the aforementioned physical exam).[8] [15] [16][17]

Library

The 12 cranial nerves and their functional end organs

Citations

Key Articles

Libreros-Jiménez HM, Manzo J, Rojas-Durán F, et al. On the cranial nerves. NeuroSci. 2024 Mar;5(1):8-38.[Abstract][Full Text]
Erman AB, Kejner AE, Hogikyan ND, et al. Disorders of cranial nerves IX and X. Semin Neurol. 2009;29:85-92.[Abstract]
Gronseth G, Cruccu G, Alksne J, et al. Practice parameter: the diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Neurology. 2008 Oct 7;71(15):1183-90.[Abstract][Full Text]
American College of Radiology. ACR appropriateness criteria: cranial neuropathy. 2022 [internet publication].[Full Text]

Other Online Resources

NCBI: Leber hereditary optic neuropathy

Referenced Articles

1. Moran DT, Rowley JC 3rd, Jafek BW, et al. The fine structure of the olfactory mucosa in man. J Neurocytol. 1982;11:721-746.[Abstract]
2. Doty RL. The olfactory system and its disorders. Semin Neurol. 2009;29:74-81.[Abstract]
3. Gottfried JA, Deichmann R, Winston JS, et al. Functional heterogeneity in human olfactory cortex: an event-related functional magnetic resonance imaging study. J Neurosci. 2002;22:10819-10828.[Abstract][Full Text]
4. Damodaran O, Rizk E, Rodriguez J, et al. Cranial nerve assessment: a concise guide to clinical examination. Clin Anat. 2014 Jan;27(1):25-30.[Abstract][Full Text]
5. Doty RL, Shaman P, Dann M. Development of the University of Pennsylvania Smell Identification Test: a standardized microencapsulated test of olfactory function. Physiol Behav. 1984;32:489-502.[Abstract]
6. Selhorst JB, Chen Y. The optic nerve. Semin Neurol. 2009;29:29-35.[Abstract]
7. Curcio CA, Allen KA. Topography of ganglion cells in human retina. J Comp Neurol. 1990;300:5-25.[Abstract]
8. Rubin DI. Clinical neurophysiology. 5th ed. Oxford: Oxford University Press; 2021.
9. Brazis PW. Isolated palsies of cranial nerves III, IV, and VI. Semin Neurol. 2009;29:14-28.[Abstract]
10. Park HK, Rha HK, Lee KJ, et al. Microsurgical anatomy of the oculomotor nerve. Clin Anat. 2017 Jan;30(1):21-31.[Abstract]
11. Holmes JM, Mutyala S, Maus TL, et al. Pediatric third, fourth, and sixth nerve palsies: a population-based study. Am J Ophthalmol. 1999;127:388-392.[Abstract]
12. Richards BW, Jones FR Jr, Younge BR. Causes and prognosis in 4,278 cases of paralysis of the oculomotor, trochlear, and abducens cranial nerves. Am J Ophthalmol. 1992;113:489-496.[Abstract]
13. Nemzek WR. The trigeminal nerve. Top Magn Reson Imaging. 1996;8:132-154.[Abstract]
14. Hughes MA, Frederickson AM, Branstetter BF, et al. MRI of the trigeminal nerve in patients with trigeminal neuralgia secondary to vascular compression. AJR Am J Roentgenol. 2016 Mar;206(3):595-600.[Abstract][Full Text]
15. Muzyka IM, Estephan B. Electrophysiology of cranial nerve testing: trigeminal and facial nerves. J Clin Neurophysiol. 2018 Jan;35(1):16-24.[Abstract]
16. Kennelly KD. Electrodiagnostic approach to cranial neuropathies. Neurol Clin. 2012 May;30(2):661-84.[Abstract]
17. Perotto AO. Anatomical guide for the electromyographer: the limbs and trunk. 5th ed. Springfield, IL: Charles C Thomas Publisher; 2011.
18. Libreros-Jiménez HM, Manzo J, Rojas-Durán F, et al. On the cranial nerves. NeuroSci. 2024 Mar;5(1):8-38.[Abstract][Full Text]
19. Tawfik EA, Walker FO, Cartwright MS. Neuromuscular ultrasound of cranial nerves. J Clin Neurol. 2015 Apr;11(2):109-21.[Abstract][Full Text]
20. Erman AB, Kejner AE, Hogikyan ND, et al. Disorders of cranial nerves IX and X. Semin Neurol. 2009;29:85-92.[Abstract]
21. Snell RS. Clinical neuroanatomy. Philadelphia, PA: Lippincott Williams & Wilkins; 2001.
22. Remley KB, Harnsberger HR, Smoker WR, et al. CT and MRI in the evaluation of glossopharyngeal, vagal, and spinal accessory neuropathy. Semin Ultrasound CT MR. 1987;8:284-300.
23. Hendelman W. Atlas of functional neuroanatomy. 3rd ed. Boca Raton, FL: CRC Press; 2015.
24. Castillo M, Mukherji SK. Magnetic resonance imaging of cranial nerves IX, X, XI, and XII. Top Magn Reson Imaging. 1996;8:180-186.[Abstract]
25. Parent A. Carpenter's human neuroanatomy. 9th ed. Baltimore, MD: Lippincott Williams & Wilkins; 1996.
26. Smith LJ, Munin MC. Utility of laryngeal electromyography for establishing prognosis and individualized treatment after laryngeal neuropathies. Muscle Nerve. 2024 Jul 30.[Abstract][Full Text]
27. Massey EW. Spinal accessory nerve lesions. Semin Neurol. 2009;29:82-84.[Abstract]
28. Johal J, Iwanaga J, Tubbs K, et al. The accessory nerve: a comprehensive review of its anatomy, development, variations, landmarks and clinical considerations. Anat Rec (Hoboken). 2019 Apr;302(4):620-9.[Abstract][Full Text]
29. Krzesniak-Swinarska M, Caress JB, Cartwright MS. Neuromuscular ultrasound for evaluation of scapular winging. Muscle Nerve. 2017 Jul;56(1):7-14.[Abstract]
30. Standring S. Gray's anatomy: the anatomical basis of clinical practice. 42nd ed. Amsterdam: Elsevier; 2020.
31. Lalwani AK. Current diagnosis and treatment in otolaryngology: head and neck surgery. 4th ed. New York, NY: McGraw-Hill; 2019.
32. Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic-ultrasound correlations. 4th ed. Philadelphia, PA: Elsevier; 2021.
33. Grimm A, Prell T, Décard BF, et al. Muscle ultrasonography as an additional diagnostic tool for the diagnosis of amyotrophic lateral sclerosis. Clin Neurophysiol. 2015 Apr;126(4):820-7.[Abstract]
34. Deutsch PG, Evans C, Wahid NW, et al. Anosmia: an evidence-based approach to diagnosis and management in primary care. Br J Gen Pract. 2021;71(704):135-138.[Abstract][Full Text]
35. Deems DA, Doty RL, Settle RG, et al. Smell and taste disorders, a study of 750 patients from the University of Pennsylvania Smell and Taste Center. Arch Otolaryngol Head Neck Surg. 1991;117:519-528.[Abstract]
36. Doty RL, Yousem DM, Pham LT, et al. Olfactory dysfunction in patients with head trauma. Arch Neurol. 1997 Sep;54(9):1131-40.[Abstract][Full Text]
37. Reden J, Mueller A, Mueller C, et al. Recovery of olfactory function following closed head injury or infections of the upper respiratory tract. Arch Otolaryngol Head Neck Surg. 2006 Mar;132(3):265-9.[Abstract][Full Text]
38. Marin C, Vilas D, Langdon C, et al. Olfactory Dysfunction in Neurodegenerative Diseases. Curr Allergy Asthma Rep. 2018 Jun 15;18(8):42.[Abstract][Full Text]
39. Zou YM, Lu D, Liu LP, et al. Olfactory dysfunction in Alzheimer's disease. Neuropsychiatr Dis Treat. 2016;12:869-75.[Abstract][Full Text]
40. Doty RL, Li C, Mannon LJ, et al. Olfactory dysfunction in multiple sclerosis. N Engl J Med. 1997;336:1918-1919.[Abstract]
41. Schwob JE, Szumowski KE, Leopold DA, et al. Histopathology of olfactory mucosa in Kallmann's syndrome. Ann Otol Rhinol Laryngol. 1993;102:117-122.[Abstract]
42. Lotfipour S, Chiles K, Kahn JA, et al. An unusual presentation of subfrontal meningioma: a case report and literature review for Foster Kennedy syndrome. Intern Emerg Med. 2011 Jun;6(3):267-9.[Abstract][Full Text]
43. Newman NJ, Dickersin K, Kaufman D, et al. Characteristics of patients with nonarteritic anterior ischemic optic neuropathy eligible for the Ischemic Optic Neuropathy Decompression Trial. Arch Ophthalmol. 1996;114:1366-1374.[Abstract]
44. Hayreh SS, Joos KM, Podhajsky PA, et al. Systemic diseases associated with nonarteritic anterior ischemic optic neuropathy. Am J Ophthalmol. 1994;118:766-780.[Abstract]
45. Stiebel-Kalish H, Hasanreisoglu M, Leibovici L. Aspirin following non-arteritic ischaemic optic neuropathy - a systematic review and meta-analysis. Neuro-Ophthalmol. 2010;34:14-19.
46. Repka MX, Savino PJ, Schatz NJ, et al. Clinical profile and long-term implications of anterior ischemic optic neuropathy. Am J Ophthalmol. 1983;96:478-483.[Abstract]
47. Nagel MA, Bennett JL, Khmeleva N, et al. Multifocal VZV vasculopathy with temporal artery infection mimics giant cell arteritis. Neurology. 2013;80:2017-2021.[Abstract][Full Text]
48. Optic Neuritis Study Group. Multiple sclerosis risk after optic neuritis: final Optic Neuritis Treatment Trial follow-up. Arch Neurol. 2008;65:727-732.[Abstract][Full Text]
49. Hassan MB, Stern C, Flanagan EP, et al. Population-based incidence of optic neuritis in the era of aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies. Am J Ophthalmol. 2020 Dec;220:110-4.[Abstract][Full Text]
50. Braithwaite T, Subramanian A, Petzold A, et al. Trends in optic neuritis incidence and prevalence in the UK and association with systemic and neurologic disease. JAMA Neurol. 2020 Dec 1;77(12):1514-23.[Abstract]
51. Beck RW, Gal RL, Bhatti MT, et al. Visual function more than 10 years after optic neuritis: experience of the Optic Neuritis Treatment Trial. Am J Ophthalmol. 2004;137:77-83.[Abstract]
52. Phillips YL, Eggenberger ER. Neuro-ophthalmic sarcoidosis. Curr Opin Ophthalmol. 2010 Nov;21(6):423-9.[Abstract][Full Text]
53. Patterson SL, Goglin SE. Neuromyelitis Optica. Rheum Dis Clin North Am. 2017 Nov;43(4):579-591.[Abstract][Full Text]
54. Sechi E. NMOSD and MOGAD. Continuum (Minneap Minn). 2024 Aug 1;30(4):1052-87.[Abstract]
55. Noble MJ, McFadzean R. Indirect injury to the optic nerves and optic chiasm. Neuroophthalmology. 1987;7:341-348.[Full Text]
56. Borit A, Richardson EP Jr. The biological and clinical behaviour of pilocytic astrocytomas of the optic pathways. Brain. 1982;105:161-187.[Abstract]
57. Chun BY, Rizzo JF 3rd. Dominant Optic Atrophy and Leber's Hereditary Optic Neuropathy: Update on Clinical Features and Current Therapeutic Approaches. Semin Pediatr Neurol. 2017 May;24(2):129-134.[Abstract][Full Text]
58. Newman NJ, Lott MT, Wallace DC. The clinical characteristics of pedigrees of Leber's hereditary optic neuropathy with the 11778 mutation. Am J Ophthalmol. 1991;111:750-762.[Abstract]
59. Lanzillotta M, Mancuso G, Della-Torre E. Advances in the diagnosis and management of IgG4 related disease. BMJ. 2020 Jun 16;369:m1067.[Abstract][Full Text]
60. Marinelli JP, Marvisi C, Vaglio A, et al. Manifestations of Skull Base IgG4-Related Disease: A Multi-Institutional Study. Laryngoscope. 2020 Nov;130(11):2574-2580.[Abstract][Full Text]
61. Grzybowski A, Zülsdorff M, Wilhelm H, et al. Toxic optic neuropathies: an updated review. Acta Ophthalmol. 2015 Aug;93(5):402-10.[Abstract][Full Text]
62. Newman NJ. Optic neuropathy. Neurology. 1996;46:315-22.[Abstract]
63. Renowden SA, Harris KM, Hourihan MD. Isolated atraumatic third nerve palsy: clinical features and imaging techniques. Br J Radiol. 1993;66:1111-7.[Abstract]
64. Lee AG, Onan HW, Brazis PW, et al. An imaging guide to the evaluation of third cranial nerve palsies. Strabismus. 1999;7:153-168.[Abstract]
65. Donahue SP, Taylor RJ. Pupil-sparing third nerve palsy associated with sildenafil citrate (Viagra). Am J Ophthalmol. 1998;126:476-7.[Abstract]
66. Migita DS, Devereaux MW, Tomsak RL. Cocaine and pupillary-sparing oculomotor nerve paresis. Neurology. 1997;49:1466-7.[Abstract]
67. Giraud P, Valade D, Lanteri-Minet M, et al. Is migraine with cranial nerve palsy an ophthalmoplegic migraine? J Headache Pain. 2007 Apr;8(2):119-22.[Abstract][Full Text]
68. Galbraith RS. Incidence of neonatal sixth nerve palsy in relation to mode of delivery. Am J Obstet Gynecol. 1994;170:1158-9.[Abstract]
69. Uberti M, Hasan S, Holmes D, et al. Clinical significance of isolated third cranial nerve palsy in traumatic brain injury: a detailed description of four different mechanisms of injury through the analysis of our case series and review of the literature. Emerg Med Int. 2021 Apr 23:2021:5550371.[Abstract][Full Text]
70. Bijlsma MW, Brouwer MC, Kasanmoentalib ES, et al. Community-acquired bacterial meningitis in adults in the Netherlands, 2006-14: a prospective cohort study. Lancet Infect Dis. 2016;16:339-347.[Abstract]
71. Anwar S, Nalla S, Fernando DJ. Abducens nerve palsy as a complication of lumbar puncture. Eur J Intern Med. 2008;19:636-637.[Abstract]
72. Ayberk G, Özveren MF, Yildirim T, et al. Review of a series with abducens nerve palsy. Turk Neurosurg. 2008;18:366-373.[Abstract][Full Text]
73. Baptista B, Casian A, Gunawardena H, et al. Neurological manifestations of IgG4-related disease. Curr Treat Options Neurol. 2017 Apr;19(4):14.[Abstract][Full Text]
74. Davies GE, Shakir RA. Giant cell arteritis presenting as oculomotor nerve palsy with pupillary dilatation. Postgrad Med J. 1994;70:298-9.[Abstract][Full Text]
75. Rush JA, Younge BR. Paralysis of cranial nerves III, IV, and VI: cause and prognosis in 1,000 cases. Arch Ophthalmol. 1981;99:76-9.[Abstract]
76. Markey KA, Mollan SP, Jensen RH, et al. Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions. Lancet Neurol. 2016 Jan;15(1):78-91.[Abstract][Full Text]
77. Baker RS, Epstein AD. Ocular motor abnormalities from head trauma. Surv Ophthalmol. 1991;35:245-67.[Abstract]
78. Neetens A, Van Aerde F. Extra-ocular muscle palsy from minor head trauma: initial sign of intracranial tumour. Bull Soc Belge Ophtalmol. 1981;193:161-7.[Abstract]
79. Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology. 2016 Jul 12;87(2):220-8.[Abstract][Full Text]
80. Tanrikulu L, Hastreiter P, Bassemir T, et al. New Clinical and Morphologic Aspects in Trigeminal Neuralgia. World Neurosurg. 2016 Aug;92:189-196.[Abstract][Full Text]
81. Gronseth G, Cruccu G, Alksne J, et al. Practice parameter: the diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Neurology. 2008 Oct 7;71(15):1183-90.[Abstract][Full Text]
82. Bennetto L, Patel NK, Fuller G. Trigeminal neuralgia and its management. BMJ. 2007;334:201-205.[Abstract]
83. Krafft RM. Trigeminal neuralgia. Am Fam Physician. 2008;77:1291-1296.[Abstract][Full Text]
84. Prasad S, Galetta SL. The trigeminal nerve. In: Goetz CG, ed. Textbook of clinical neurology. Philadelphia, PA: Saunders; 2007:165-184.
85. Siccoli MM, Bassetti CL, Sandor PS. Facial pain: clinical differential diagnosis. Lancet Neurol. 2006;5:257-267.[Abstract]
86. Feller L, Khammissa RAG, Fourie J, et al. Postherpetic Neuralgia and Trigeminal Neuralgia. Pain Res Treat. 2017;2017:1681765.[Abstract][Full Text]
87. Rosenbaum R. Neuromuscular complications of connective tissue diseases. Muscle Nerve. 2001;24:154-169.[Abstract]
88. Meiling JB, Miller NJ, Gandhi Mehta RK. Sensory-predominant trigeminal neuropathy secondary to a cosmetic liquid nitrogen procedure. J Clin Neuromuscul Dis. 2024 Mar 1;25(3):141-2.
89. Yuliati A, Rajamani K. Tolosa-Hunt Syndrome. Neurohospitalist. 2018 Apr;8(2):104-105.[Abstract][Full Text]
90. Gilchrist JM. Seventh cranial neuropathy. Semin Neurol. 2009;29:5-13.[Abstract]
91. Murakami S, Mizobuchi M, Nakashiro Y, et al. Bell palsy and herpes simplex virus: identification of viral DNA in endoneurial fluid and muscle. Ann Intern Med. 1996;12427-12430.[Abstract]
92. Eviston TJ, Croxson GR, Kennedy PG, et al. Bell's palsy: aetiology, clinical features and multidisciplinary care. J Neurol Neurosurg Psychiatry. 2015 Dec;86(12):1356-61.[Abstract][Full Text]
93. Gagyor I, Madhok VB, Daly F, et al. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2019 Sep 5;9:CD001869.[Abstract][Full Text]
94. Sweeney CJ, Gilden DH. Ramsay Hunt syndrome. J Neurol Neurosurg Psychiatry. 2001;71:149-154.[Abstract][Full Text]
95. Hato N, Kisaki H, Honda N, et al. Ramsay Hunt syndrome in children. Ann Neurol. 2000 Aug;48(2):254-6.[Abstract]
96. Gross GE, Eisert L, Doerr HW, et al. S2k guidelines for the diagnosis and treatment of herpes zoster and postherpetic neuralgia. J Dtsch Dermatol Ges. 2020 Jan;18(1):55-78.[Abstract][Full Text]
97. Kvestad E, Kvaerner KJ, Mair IW. Otologic facial palsy: etiology, onset, and symptom duration. Ann Otol Rhinol Laryngol. 2002;111:598-602.[Abstract]
98. Pachner AR, Steere AC. The triad of neurologic manifestations of Lyme disease: meningitis, cranial neuritis, and radiculoneuritis. Neurology. 1985;35:47-53.[Abstract]
99. Pihlamaa T, Salmi T, Suominen S, et al. Progressive cranial nerve involvement and grading of facial paralysis in gelsolin amyloidosis. Muscle Nerve. 2016;53:762-9.[Abstract]
100. Shambaugh GE Jr, Clemis JD. Facial nerve paralysis. In: Paparella MM, Shumrick DA, eds. Otolaryngology, vol 2. Philadelphia, PA: Saunders; 1973:275.
101. Baloh RW. Clinical practice: vestibular neuritis. N Engl J Med. 2003;348:1027-1032.[Abstract]
102. Flint PW, Haughey BH, Lund VJ, et al. Cummings otolaryngology: head and neck surgery. 7th ed. Amsterdam: Elsevier; 2020.
103. Lanvers-Kaminsky C, Zehnhoff-Dinnesen AA, Parfitt R, et al. Drug-induced ototoxicity: Mechanisms, Pharmacogenetics, and protective strategies. Clin Pharmacol Ther. 2017 Apr;101(4):491-500.[Abstract][Full Text]
104. De Simone R, Ranieri A, Bilo L, et al. Cranial neuralgias: from physiopathology to pharmacological treatment. Neurol Sci. 2008;29(suppl 1):S69-S78.[Abstract]
105. Mulpuru SK, Vasavada BC, Punukollu GK, et al. Cardiovocal syndrome: a systematic review. Heart Lung Circ. 2008;17:1-4.[Abstract]
106. Massey EW, Heyman A, Utley C, et al. Cranial nerve paralysis following carotid endarterectomy. Stroke. 1984;15:157-159.[Abstract][Full Text]
107. Millett PJ, Romero A, Braun S. Spinal accessory nerve injury after rhytidectomy (face lift): a case report. J Shoulder Elbow Surg. 2009 Sep-Oct;18(5):e15-7.
108. de Beer F, Post B. Teaching neuroimages: Villaret syndrome. Neurology. 2010 Aug 31;75(9):e43.[Abstract][Full Text]
109. Węgiel A, Zielinska N, Głowacka M, et al. Hypoglossal nerve neuropathies-analysis of causes and anatomical background. Biomedicines. 2024 Apr 14;12(4):864.[Abstract][Full Text]
110. McGill F, Heyderman RS, Michael BD, et al. The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults. J Infect. 2016 Apr;72(4):405-38.[Abstract][Full Text]
111. Ponte C, Grayson PC, Robson JC, et al. 2022 American College of Rheumatology/EULAR classification criteria for giant cell arteritis. Arthritis Rheumatol. 2022 Dec;74(12):1881-9.[Abstract]
112. Mackie SL, Dejaco C, Appenzeller S, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford). 2020 Mar 1;59(3):e1-e23.[Abstract][Full Text]
113. National Institute for Health and Care Excellence. Subarachnoid haemorrhage caused by a ruptured aneurysm: diagnosis and management. Nov 2022 [internet publication].[Full Text]
114. van Doorn PA, Van den Bergh PYK, Hadden RDM, et al. European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of Guillain-Barré syndrome. Eur J Neurol. 2023 Dec;30(12):3646-74.[Abstract][Full Text]
115. Sardar S, Sasi S, Menik Arachchige S, et al. Isolated facial diplegia: a rare presentation of Guillain-Barre syndrome. Clin Case Rep. 2021 Jul;9(7):e04473.[Abstract][Full Text]
116. Ogura I, Minami Y, Sugawara Y, et al. Odontogenic infection pathway to the parapharyngeal space: CT imaging assessment. J Maxillofac Oral Surg. 2022 Mar;21(1):235-9.[Abstract][Full Text]
117. Whitcroft KL, Altundag A, Balungwe P, et al. Position paper on olfactory dysfunction: 2023. Rhinology. 2023 Oct 1;61(33):1-108.[Abstract][Full Text]
118. Khaku A, Patel V, Zacharia T, et al. Guidelines for radiographic imaging of cranial neuropathies. Ear Nose Throat J. 2017 Oct-Nov;96(10-11):E23-39.[Abstract][Full Text]
119. American College of Radiology. ACR appropriateness criteria: cranial neuropathy. 2022 [internet publication].[Full Text]
120. Expert Panel on Neurologic Imaging: Kennedy TA, Corey AS, et al. ACR Appropriateness Criteria® Orbits Vision and Visual Loss. J Am Coll Radiol. 2018 May;15(5s):S116-S131.[Abstract][Full Text]
121. Wingerchuk DM, Lennon VA, Lucchinetti CF, et al. The spectrum of neuromyelitis optica. Lancet Neurol. 2007;6:805-815.[Abstract]
122. Frisen L, Royt WF, Tengroth BM. Optociliary veins, disc pallor and visual loss: a triad of signs indicating spheno-orbital meningioma. Acta Ophthalmol (Copenh). 1973;51:241-249.[Abstract]
123. Jacobson DM, Trobe JD. The emerging role of magnetic resonance angiography in the management of patients with third cranial nerve palsy. Am J Ophthalmol. 1999;128:94-6.[Abstract]
124. Miller NR. Unequal pupils can be seen in diabetic 3rd nerve palsy. Evid Based Eye Care. 1999;1:40-1.
125. Kim JH, Hwang JM, Hwang YS, et al. Childhood ocular myasthenia gravis. Ophthalmology. 2003;110:1458-62.[Abstract]
126. American Academy of Ophthalmology. Myasthenia gravis. Oct 2024 [internet publication].[Full Text]
127. Balcer LJ, Galetta SL, Bagley LJ, et al. Localization of traumatic oculomotor nerve palsy to the midbrain exit site by magnetic resonance imaging. Am J Ophthalmol. 1996;122:437-439.[Abstract]
128. National Institute for Health and Care Excellence. Headaches in over 12s: diagnosis and management. Dec 2021 [internet publication].[Full Text]
129. Moster ML, Savino PJ, Sergott RC, et al. Isolated sixth-nerve palsies in younger adults. Arch Ophthalmol. 1984;102:1328-1330.[Abstract]
130. Schumacher-Feero LA, Yoo KW, Solari FM, et al. Third cranial nerve palsy in children. Am J Ophthalmol. 1999;128:216-221.[Abstract]
131. Green WR, Hackett ER, Schlezinger NS. Neuro-ophthalmologic evaluation of oculomotor nerve paralysis. Arch Ophthalmol. 1964;72:154-167.[Abstract]
132. Katusic S, Beard CM, Bergstralth E, et al. Incidence and clinical features of trigeminal neuralgia, Rochester, Minnesota, 1945-1984. Ann Neurol. 1990;27:89-95.[Abstract]
133. Olney RK. Neuropathies associated with connective tissue disease. Semin Neurol. 1998;18:63-72.[Abstract]
134. Expert Panel on Neurologic Imaging: Salmela MB, Mortazavi S, et al. ACR Appropriateness Criteria® Cerebrovascular Disease. J Am Coll Radiol. 2017 May;14(5s):S34-S61.[Abstract][Full Text]
135. Keswani R, Perkasa SAH, Nurlita D, et al. Intraoperative monitoring and early recognition of facial nerve root in vestibular schwannoma surgery. Neurosurg Rev. 2024 Oct 15;47(1):798.[Abstract]
136. Liu SW, Jiang W, Zhang HQ, et al. Intraoperative neuromonitoring for removal of large vestibular schwannoma: facial nerve outcome and predictive factors. Clin Neurol Neurosurg. 2015 Jun;133:83-9.[Abstract]
137. Korzec K, Sobol SM, Kubal W, et al. Gadolinium-enhanced magnetic resonance imaging of the facial nerve in herpes zoster oticus and Bell's palsy: clinical implications. Am J Otol. 1991;12:163-168.[Abstract]
138. Gilliatt RW, Taylor JC. Electrical changes following section of the facial nerve. Proc R Soc Med. 1959;52:1080-1083.[Abstract][Full Text]
139. Goldbrunner R, Weller M, Regis J, et al. EANO guideline on the diagnosis and treatment of vestibular schwannoma. Neuro Oncol. 2020 Jan 11;22(1):31-45.[Abstract][Full Text]
140. Zhang Y, Zhou E, Xue X, et al. Intraoperative brainstem auditory evoked potential monitoring during cerebellopontine angle surgery via retrosigmoid approach. Ear Nose Throat J. 2023 Jan 20;:1455613221150574.[Abstract][Full Text]
141. Rapana A, Lamaida E, Bracale C, et al. Glossopharyngeal schwannoma, an uncommon posterior fossa tumor: diagnostical and therapeutical aspects: a case report. Clin Neurol Neurosurg. 1997;99:196-198.[Abstract]
142. Grimm A, Décard BF, Axer H, et al. The ultrasound pattern sum score - UPSS. A new method to differentiate acute and subacute neuropathies using ultrasound of the peripheral nerves. Clin Neurophysiol. 2015 Nov;126(11):2216-25.[Abstract]
143. van Alfen N, van Engelen BG. The clinical spectrum of neuralgic amyotrophy in 246 cases. Brain. 2006 Feb;129(pt 2):438-50.[Abstract]
144. Cignetti NE, Cox RS, Baute V, et al. A standardized ultrasound approach in neuralgic amyotrophy. Muscle Nerve. 2023 Jan;67(1):3-11.[Abstract][Full Text]
145. Aringer M, Brinks R, Dörner T, et al. European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) SLE classification criteria item performance. Ann Rheum Dis. 2021 Feb 10;:.[Abstract][Full Text]
146. Mead P, Petersen J, Hinckley A. Updated CDC Recommendation for Serologic Diagnosis of Lyme Disease. MMWR Morb Mortal Wkly Rep. 2019 Aug 16;68(32):703.[Abstract][Full Text]
147. National Institute for Health and Care Excellence. Lyme disease. Oct 2018 [internet publication].[Full Text]
148. Hellmich B, Agueda A, Monti S, et al. 2018 update of the EULAR recommendations for the management of large vessel vasculitis. Ann Rheum Dis. 2020 Jan;79(1):19-30.[Abstract]
149. Mollan SP, Paemeleire K, Versijpt J, et al. European Headache Federation recommendations for neurologists managing giant cell arteritis. J Headache Pain. 2020 Mar 17;21(1):28.[Abstract][Full Text]
150. Dejaco C, Ramiro S, Bond M, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update. Ann Rheum Dis. 2024 May 15;83(6):741-51.[Abstract]
151. Maz M, Chung SA, Abril A, et al. 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of giant cell arteritis and takayasu arteritis. Arthritis Rheumatol. 2021 Aug;73(8):1349-65.[Abstract][Full Text]