Caloric Test Temperature Recommendations
For standard vestibular caloric testing, use water temperatures of 30°C (cool) and 44°C (warm) for bithermal stimulation, or air temperatures of 21°C (cool) and 51°C (warm) as an equivalent alternative. 1, 2
Standard Temperature Protocols
Water Caloric Testing
- Cool water stimulus: 30°C 1, 2
- Warm water stimulus: 44°C 1, 2
- These temperatures represent the established standard for bithermal caloric testing and have been validated in large population studies involving over 2,500 patients 1
Air Caloric Testing (Alternative Method)
- Cool air stimulus: 21°C (or 30°C in some protocols) 1, 2
- Warm air stimulus: 51°C (or 44°C in some protocols) 1, 2
- Air stimulation at 30°C and 44°C minimizes patient discomfort while producing responses equivalent to water calorics 2
- Air calorics perform comparably to water calorics with sensitivity and specificity values between 0.82 and 0.84 1
Special Circumstances
Ice Water Caloric Testing (Bedside/Screening)
- Temperature: 4°C (ice water) 3
- Volume: 0.5-2 mL for minimal ice water caloric test 3
- This method shows higher sensitivity and specificity for detecting canal paresis compared to 27°C air stimulation 3
- Particularly useful for bedside testing in bedridden patients where standard equipment is unavailable 3
Brain Death Determination (Pediatric Context)
- Ice water irrigation: 10-50 mL per ear 4
- Head elevated to 30 degrees 4
- Each external auditory canal irrigated separately with several minutes interval between sides 4
- Absence of eye movement during 1 minute of observation indicates absent oculovestibular reflexes 4
Key Performance Considerations
Response Characteristics
- Warm water (44°C) produces stronger nystagmus responses than cool water (30°C) 1
- Air stimuli produce more uniform and less variable response distributions compared to water 1
- Combined metrics (combined eye speed and total eye speed) are comparable between properly calibrated water and air stimuli 1
Monothermal Testing Limitations
- Monothermal testing at 30°C shows 84% sensitivity and 80% specificity when compared to bithermal standard 5
- Monothermal testing at 44°C shows 81% sensitivity and 78% specificity 5
- Low sensitivity means abnormal bithermal results may appear normal with monothermal testing 5
- Best reserved as screening tool for patients with low pre-test probability of vestibular disease 5
Important Caveats
- Standard bithermal protocols incorrectly assume equivalent response strength from warm and cool stimuli, but warm stimuli actually provoke substantially stronger responses 1
- All caloric stimuli should be calibrated based on statistical performance rather than arbitrary assumptions about stimulus equivalence 1
- Test-retest variability is similar between air and water protocols 2
- Caloric testing has lower diagnostic accuracy than video head impulse testing (vHIT) for differentiating vestibular neuritis from stroke in acute dizziness (75% vs 91.7% sensitivity) 6