Differential Diagnostic Reasoning Method for Benign Paroxysmal Positional Vertigo Based on Dynamic Uncertain Causality Graph

Table 2

Definition of variables for differential diagnosis of BPPV.

Variables	Descriptions
X1–3,201–206, 210–217	Pathophysiology of BPPV: the lesion of the otolithic membrane of utricle macula, the degenerated otolith broken off from utricle macula, misplaced calcium carbonate crystals debris, calcium free-floating particles entering the SCCs, calcium particles adherent to the cupula of SCC, the endolymph movement with free-floating particles that pathologically stimulates the ampulla of canal, and the sensitivity to linear acceleration and gravity induced by the abnormal deflection of cupula
X4,8–11	The description of vertigo: an illusion of movement, the sensation that objects in the environment is moving when the eyes are open, and the sensation that a patient feels as if he or she is moving when the eyes are closed
X11,42,45,46,82	The main accompanying symptoms: spontaneous nystagmus and autonomic nerve symptoms
X20-25	The detailed description of the features of vertigo attacks: attack characteristics, the onset and duration of an attack, causes of disease, frequency, and severity
X26–28,209	Changes in head position relative to gravity: rotation of the head relative to the body while in an upright position
X83–87,130	The feature of spontaneous nystagmus and the Romberg test for vestibular function
X52,49,161,163,238	Other accompanying symptoms: cochlear symptoms, hearing loss, tinnitus, the symptoms of central nervous system, and the manifestations of the primary and underlying disorders
X184,185	Patient’s gender and age
X186,189,198,234	The typical and characteristic medical history: a migraine, hypertension, head trauma, and inner ear pathology
X207–208	More than one semicircular canal is affected simultaneously (obtained statistically during the pretreatment process of medical data)
X218–221,227,228	Positioning test vertigo and nystagmus when the head is moving or rotating
X222–226	Dix–Hallpike test: the feature of evoked nystagmus (latency, duration, direction, amplitude, frequency, fatigability, and reversibility)
X229–233	Supine roll test: the feature of evoked nystagmus (latency, duration, direction, amplitude, frequency, fatigability, and reversibility)
X236	The outcomes of the maneuver treatment
B23–33	PSCC-BPPV (B23); LSCC-BPPV (B24); ASCC-BPPV (B25); MSCC-BPPV (B26); secondary BPPV (B27); idiopathic BPPV (B28); canalithiasis BPPV (B29); cupulolithiasis BPPV (B30); subjective BPPV (B31); persistent BPPV (B32); and recurrent BPPV (B33)