Paradigm shift in acute dizziness: is caloric testing obsolete?

Abstract

Objective Cold and warm water ear irrigation, also known as bithermal caloric testing, has been considered for over 100 years the ‘Gold Standard’ for the detection of peripheral vestibular hypofunction. Its discovery was awarded a Nobel Prize. We aimed to investigate the diagnostic accuracy of Caloric Testing when compared to the video head impulse test (vHIT) in differentiating between vestibular neuritis and vestibular strokes in acute dizziness. Design Prospective cross-sectional study (convenience sample). Setting All patients presenting with signs of an acute vestibular syndrome at the emergency department of a tertiary referral center. Participants One thousand, six hundred seventy-seven patients were screened between February 2015 and May 2020 for Acute Vestibular Syndrome (AVS), of which 152 met the inclusion criteria and were enrolled. Inclusion criteria consisted of a state of continuous dizziness, associated with nausea or vomiting, head-motion intolerance, new gait or balance disturbance and nystagmus. Patients were excluded if they were younger than 18 years, if symptoms lasted < 24 h or if the index ED visit was > 72 h after symptom onset. Of the 152 included patients 85 completed testing. We assessed 58 vestibular neuritis and 27 stroke patients. Main outcome measures All patients underwent calorics and vHIT followed by a delayed MRI which served as a gold standard for vestibular stroke confirmation. Results The overall sensitivity and specificity for detecting stroke with a caloric asymmetry cut-off of 30.9% was 75% and 86.8%, respectively [negative likelihood ratio (NLR) 0.29] compared to 91.7% and 88.7% for vHIT (NLR 0.094). Best VOR gain cut-off was 0.685. Twenty-five percent of vestibular strokes were misclassified by calorics, 8% by vHIT. Conclusions Caloric testing proved to be less accurate than vHIT in discriminating stroke from vestibular neuritis in acute dizziness. Contrary to classic teaching, asymmetric caloric responses can also occur with vestibular strokes and might put the patient at risk for misdiagnosis. We, therefore, recommend to abandon caloric testing in current practice and to replace it with vHIT in the acute setting. Caloric testing has still its place as a diagnostic tool in an outpatient setting.

Effects of Betahistine on Vestibulo-Ocular Reflex in Normal Healthy Adults: A Randomized Double-Blind, Placebo-Controlled Trial

“…The vHIT is able to evaluate the function of the VOR on high-frequency head thrust. Traditional vestibular tests, such as the caloric test and the rotatory chair, may be rendered obsolete by vHIT, as suggested by Morrison et al (2022) [ 17 ]. Aside from that, the purpose of using healthy people is to monitor the typical changes in a physiological state that are brought on by the administration of drugs.…”

Artificial intelligence for early stroke diagnosis in acute vestibular syndrome

“…Our results of VOR gain accuracy are similar to older studies ( 8 ). The known dissociation between caloric test results and vHIT might affect the overall specificity of this test ( 6 ). A recent study showed a slight worsening of accuracy of AI for stroke classification based on HINTS data ( 14 ).…”

“…A subset of VOR gain data presented here have been published elsewhere (6,(18)(19)(20)(21). A neurootologist with 2 years' experience in the field, performed physical examination, Caloric Testing, and vHIT testing in all enrolled patients.…”

“…Even experts struggle with the assessment of head impulses when hidden (covert) corrective saccades and spontaneous nystagmus occur ( 5 ). In comparison to a clinical assessment, videooculography (VOG) devices enables a quantification of eye- and head movements at the bedside, which can improve the accuracy of HINTS ( 6 , 7 ). The Vestibular-Ocular-Reflex (VOR) gain by video head impulse (vHIT), especially, has already been successfully used to differentiate between central and peripheral causes in patients with an acute vestibular syndrome (AVS) ( 6 , 8 ).…”

The role of vestibular cold caloric tests in the presence of spontaneous nystagmus

“…None of the proposed protocols or algorithms for the evaluation of AVS have included caloric testing, although a unilateral weakness to caloric stimuli could significantly impact differential diagnosis 13 . On the other hand, in the presence of spontaneous nystagmus, classic bithermal tests may be difficult to interpret and may not be recommended 13 , 14 . The main purpose of this study is to evaluate the possibility of detecting a pathological unilateral weakness in the presence of spontaneous nystagmus using only a caloric cold test (ice water test) 15 and to recommend the use of this procedure in the differential diagnosis of APV from central nervous system (CNS) diseases that may present as an isolated vertigo.…”