Reference aids

List of Abbreviations

The 101 acronyms used across the atlas, expanded and glossed, in one alphabetised list — the single source of truth that the chapters draw on.

Inline abbreviations throughout the atlas expand on hover from this same registry. For full definitions of terms, see the Glossary of Terms; to navigate by clinical topic, use the Index.

3D-FLAIR: Three-Dimensional FLAIR — Volumetric FLAIR — used after delayed gadolinium to image endolymphatic hydrops.
ABR: Auditory Brainstem Response — Click-evoked far-field response of cochlear nerve and brainstem auditory pathway.
AC-BPPV: Anterior-Canal BPPV — Rare (~3%) variant; diagnosed by Straight Head Hanging Test, characteristic downbeating-torsional nystagmus.
ADC: Apparent Diffusion Coefficient — Quantitative diffusion map; acute ischaemic tissue shows reduced ADC alongside bright DWI.
ADT: Adaptation Test — CDP test of motor learning across repeated unexpected platform tilts.
AI: Artificial Intelligence
AICA: Anterior Inferior Cerebellar Artery — Infarct typically presents as vertigo + ipsilateral hearing loss + facial paresis; mimics labyrinthitis.
aPVS: acute prolonged vestibular syndrome — Synonym for AVS in some recent literature.
AR: Augmented Reality
AVS: Acute Vestibular Syndrome — Sustained vertigo with nystagmus, nausea, gait unsteadiness lasting hours to days.
BOLD: Blood-Oxygen-Level-Dependent (signal) — The signal contrast read by fMRI.
BPPV: Benign Paroxysmal Positional Vertigo — Brief position-triggered vertigo from displaced otoconia in a semicircular canal.
CBC: Complete Blood Count
CBT: Cognitive Behavioural Therapy
CDP: Computerised Dynamic Posturography — Quantitative balance assessment on a moving platform with sway-referenced visual surround.
CISS: Constructive Interference in Steady State — Vendor-equivalent of FIESTA — same high-resolution T2 contrast.
CNN: Convolutional Neural Network — Deep-learning architecture used for medical image classification and segmentation.
CNS: Central Nervous System
CoP: Centre of Pressure — Point of ground-reaction-force application; the raw sway signal captured by force plates.
CPA: Cerebellopontine Angle — CSF cistern between pons, cerebellum and petrous bone; site of vestibular schwannoma.
CPG: Clinical Practice Guideline
CRM: Canalith Repositioning Manoeuvre — Generic term for Epley, Semont and related repositioning procedures.
CT: Computed Tomography — Cross-sectional X-ray imaging; non-contrast for haemorrhage exclusion.
CTA: Computed Tomography Angiography — Vascular imaging — for vertebrobasilar stenosis, dissection, occlusion.
CTSIB: Clinical Test of Sensory Interaction in Balance — Four-condition test of postural control (eyes open/closed × firm/foam).
cVEMP: cervical VEMP — Sound-evoked SCM EMG inhibition; tests saccule via inferior vestibular nerve.
DHI: Dizziness Handicap Inventory — Standard 25-item patient-reported outcome for dizziness; range 0–100.
DTI: Diffusion Tensor Imaging — MRI technique that quantifies water diffusion directionality along white-matter tracts.
DWI: Diffusion-Weighted Imaging — MR sequence sensitive to acute ischaemia; false-negative rate 12–20% in early posterior-fossa stroke.
ECG: Electrocardiogram
ECochG: Electrocochleography — Recording of cochlear potentials; SP/AP ratio used in endolymphatic hydrops work-up.
ED: Emergency Department
EMG: Electromyography — Recording of muscle electrical activity.
EMR: Electronic Medical Record
ENT: Ear, Nose and Throat (otolaryngology)
EVS: Episodic Vestibular Syndrome — Recurrent episodes of vertigo, normal between attacks.
FCD: Functional Conversion Disorder
FGA: Functional Gait Assessment
FIESTA: Fast Imaging Employing Steady-state Acquisition — Heavily T2-weighted thin-slice MR sequence — gold-standard for IAC nerves and membranous labyrinth.
FLAIR: Fluid-Attenuated Inversion Recovery — T2-weighted MRI sequence with CSF signal nulled; sharpens periventricular and posterior-fossa lesion detection.
fMRI: Functional MRI — MRI of the BOLD signal during task or rest — probes the cortical vestibular network.
GEN: Gaze-Evoked Nystagmus — Nystagmus that appears or worsens on eccentric gaze, often central.
GVS: Galvanic Vestibular Stimulation — Transcutaneous current behind the ears used to activate the vestibular nerve, often as an fMRI stimulus.
HC-BPPV: Horizontal-Canal BPPV — ~10–15% of BPPV; diagnosed by supine roll, treated by Lempert or Gufoni.
HINTS: Head Impulse, Nystagmus, Test of Skew — Three-step bedside oculomotor battery — central pattern more sensitive than early DWI for posterior-fossa stroke.
HIT: Head Impulse Test — Rapid head thrust ~15° while patient fixates a target; catch-up saccade indicates ipsilateral peripheral hypofunction.
HRCT: High-Resolution Computed Tomography — Thin-section CT (≤0.6 mm) of the temporal bone — modality of choice for bony pathology.
IAC: Internal Auditory Canal — Bony canal containing cranial nerves VII and VIII.
IM: intramuscular
IMU: Inertial Measurement Unit — Gyroscope-based sensor used in head-tracking and rehab biofeedback devices.
INFARCT: Impulse Normal, Fast-phase Alternating, Refixation on Cover Test — Mnemonic for the central HINTS pattern.
INO: Internuclear Ophthalmoplegia — Adduction failure with abducting-eye nystagmus from MLF lesion.
IV: intravenous
LoS: Limits of Stability — Voluntary-lean test in eight directions — measures reaction time, excursion and directional control.
MCT: Motor Control Test — CDP test of automatic postural reflexes following sudden platform translations.
MdDS: Mal de Débarquement Syndrome — Persistent rocking sensation after exposure to passive motion (boat, plane, train).
MDT: Multidisciplinary Team — Weekly case review attended by ENT, neurology, audiology and physiotherapy.
ML: Machine Learning
MRA: Magnetic Resonance Angiography — MR-based vascular imaging.
MRI: Magnetic Resonance Imaging — Cross-sectional imaging using magnetic resonance; DWI sequence detects acute infarction.
MS: Multiple Sclerosis — Demyelinating disease with characteristic central oculomotor signs (INO, GEN, downbeat nystagmus).
NIHSS: National Institutes of Health Stroke Scale — Quantitative stroke-severity scale used in the acute setting.
NSAID: Non-Steroidal Anti-Inflammatory Drug
OTR: Ocular Tilt Reaction — Triad of head tilt, skew deviation and ocular counter-roll from utriculo-otolith pathway lesion.
oVEMP: ocular VEMP — Bone-conduction or air-conduction infraorbital EMG response; tests utricle via superior vestibular nerve.
PACS: Picture Archiving and Communication System — Hospital imaging archive system.
PC-BPPV: Posterior-Canal BPPV — ~85% of all BPPV; diagnosed by Dix-Hallpike, treated by Epley.
PCS: Posterior-Circulation Stroke — Ischaemia in vertebrobasilar territory — PICA, AICA, SCA.
PET: Positron Emission Tomography — Nuclear-medicine imaging of metabolic activity; FDG most common radiotracer.
PET-MRI: Hybrid PET-MRI — Simultaneous metabolic + structural/functional imaging in one session.
PICA: Posterior Inferior Cerebellar Artery — Infarct gives Wallenberg (lateral medullary) syndrome.
PIVC: Parieto-Insular Vestibular Cortex — Multisensory cortical region central to vestibular perception; altered in PPPD, VM, MdDS.
PLF: Perilymphatic Fistula — Communication between perilymph and middle ear; HRCT may show pneumolabyrinth.
PO: per os (by mouth)
PPPD: Persistent Postural-Perceptual Dizziness — Chronic functional vestibular disorder by Bárány criteria; ≥3 months of dizziness worse standing or with visual motion.
PTA: Pure-Tone Audiometry — Threshold of hearing across frequencies.
s-EVS: Spontaneous Episodic Vestibular Syndrome — Recurrent episodes without trigger — dominated by vestibular migraine, Ménière's, vertebrobasilar TIA.
SAH: Subarachnoid Haemorrhage — Bleeding into the subarachnoid space; sudden severe headache the cardinal feature.
SCA: Superior Cerebellar Artery — Cerebellar infarct typically affects upper cerebellum.
SCDS: Superior Canal Dehiscence Syndrome — Third-window syndrome with autophony, Tullio, Hennebert and low-threshold cVEMP.
SNHL: Sensorineural Hearing Loss — Hearing loss from cochlear or retrocochlear pathology.
SNRI: Serotonin-Noradrenaline Reuptake Inhibitor
SO STONED: Symptoms, Often, Since When, Triggers, Otology, Neurology, Evolution, Duration — Structured vestibular history mnemonic.
SOT: Sensory Organization Test — Six-condition CDP protocol that probes how the patient weights vestibular, visual and somatosensory inputs.
SSCD: Superior Semicircular Canal Dehiscence — Bony defect over the superior canal causing third-window symptoms; diagnosed on Pöschl-plane HRCT.
SSNHL: Sudden Sensorineural Hearing Loss — ≥30 dB SNHL over ≤72 h. With acute vertigo, an AICA red flag.
SSRI: Selective Serotonin Reuptake Inhibitor — First-line antidepressant class; first-line pharmacotherapy for PPPD.
t-EVS: Triggered Episodic Vestibular Syndrome — Brief episodes provoked by position or sit-to-stand — dominated by BPPV and orthostatic causes.
TBI: Traumatic Brain Injury
TIA: Transient Ischemic Attack — Brief focal neurological deficit from ischaemia, resolved by examination.
TiTrATE: Timing, Triggers, and Targeted Examination — Triage framework for the dizzy patient (Edlow, Gurley, Newman-Toker).
TOF: Time-of-Flight (MRA) — Contrast-free MR angiography sequence using flow-related signal enhancement.
TUG: Timed Up and Go — Mobility screen — >12 s flags fall risk in elderly.
VBI: Vertebrobasilar Insufficiency — Transient posterior-circulation ischaemia; CTA / MRA defines the substrate.
VEMP: Vestibular-Evoked Myogenic Potential — Otolith reflex test — cVEMP (saccule) and oVEMP (utricle).
vHIT: video Head Impulse Test — Goggle-mounted camera quantifies VOR gain for each canal; detects covert saccades the bedside HIT misses.
VN: Vestibular Neuritis — Acute, isolated unilateral peripheral vestibulopathy without hearing loss.
VNG: Videonystagmography — Goggle-recorded vestibular battery — gaze, pursuit, saccade, OKN, positional, calorics.
VOR: Vestibulo-Ocular Reflex — Reflex that drives the eyes equal-and-opposite to head movement to stabilise gaze.
VR: Virtual Reality
VRT: Vestibular Rehabilitation Therapy — Exercise-based therapy: gaze stabilisation, habituation, balance retraining.