Table 1.

Overview of the reported signs and symptoms for each condition that may be caused by increased ICP

Affected system	Signs and symptoms	IICH	FM	CFS
Hypothesis		Exacerbation of chronically increased CSP >20–25 cm H2O	Chronic moderate cerebrospinal hypertension (12–20 cm H2O) predominantly affecting the peripheral nervous system	Chronic moderate cerebrospinal hypertension (12–20 cm H2O) predominantly affecting the central nervous system
Increased cranial pressure	Migraine	70.4% of unresponsive migraine patients have IICH25	55.8%99	84%79
	Headaches	• 84% acute101 • 32% chronic104	68% tension headaches51	81% tension headaches79
	Fatigue	Common41	Core symptom20	Core symptom41
	Cognitive impairment	• Deficits in processing speed and reaction time105 • Persists after normalization of ICP103	Impaired processing speed56	Impaired processing speed22
	Loss of gray matter		3.3-fold greater age-associated decrease in gray matter volume57	Regional gray and white matter volume reduction76
Cranial nerve involvement	I Olfactory nerve	• Decreased olfactory bulb volume91 • Impaired olfactory function9	• Decreased olfactory bulb volume90 • Impaired olfactory function3
	II Optic nerve	• Increased optic nerve sheath diameter96 • Visual field constriction27 • Papilledema101	• Retinal nerve fiber thinning35 • Decreased perfusion of the optic nerve75 • 10% loss of peripheral vision102
	III Oculomotor IV Trochlear motor VI Abducens	• 18% double vision101 • Horizontal double vision59	• Eye motility dysfunction87 • 15% double vision102	Eye motility dysfunction6 Binocular vision dysfunction37
	V Trigeminal nerve Motor: muscles of mastication Sensory: face, cornea	Electromyography-proven trigeminal neuropathy4	• 71%–94% masticatory pain68 • Lacrimal nerve: ocular pain syndromes58 • Decreased corneal small fiber density77	21%–32% temporomandibular disorders83
	VII Facial nerve Motor: facial muscles	• 5% with seventh nerve palsy101
	VII Submandibular salivary glands and lacrimal glands	Sicca syndrome94	• > 49 years of age: 80% dry eye syndrome18 • 71% xerostomia81	82% Sicca syndrome89
	VIII Vestibulocochlear	Ménière’s disease21,78,95	• 30% vertigo102	Vestibular dysfunction5,73
		Hearing loss21,78,101	25% hearing loss49,102
	IX Glossopharyngeal X Vagus laryngeal and pharyngeal muscles		• 42% hoarseness102 • 37.3% dysphagia81
	X Vagus visceromotor	Slower gastric emptying associated with increased ICP66	• Belching, reflux, bloating, sour taste, and vomiting74	• Slower gastric emptying12
Olfactory lymphatic pathway	Evacuation of CSF via the lamina cribriformis to the lymphatic vessels of the nasal mucosa	• Sinusitis63 • Spontaneous CFS leak with rhinorrhea62	• 46% nonallergic rhinitis7	• Idiopathic nonallergic rhinitis is highly prevalent in CFS8

Notes: The percentages represent the proportion of patients displaying that sign or symptom, unless indicated otherwise.

Abbreviations: CFS, chronic fatigue syndrome; CSF, cerebrospinal fluid; CSP, cerebrospinal pressure; FM, fibromyalgia; ICP, intracranial pressure; IICH, idiopathic intracranial hypertension.