Artikel
A caloric vestibular test using humidified air in healthy volunteers and in patients with various middle ear conditions – first clinical experiences
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Veröffentlicht: | 8. Juli 2008 |
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Introduction: In previous investigations it could be shown that it is possible to stimulate the vestibular organ thermally using a water vapour saturated tempered air jet without any water condensation in the outer ear canal. There was no significant difference between 40 sec. humidified air calorisation (HAC) and water calorisation using 15 sec. stimuli at 30°C and 44°C (p=0,557).
The aim of this study was to compare HAC with air calorisation at 27°C and 45°C and the more standardised 30 sec. water calorisation (according to the ADANO guidelines) on the basis of the slow phase velocity (SPV) of nystagmus. Additional in patients with defects of the tympanic membrane we searched for paradox nystagmus.
Methods: 30°C and 44°C HAC stimuli of 40 sec. duration were compared to 30 sec. water stimuli and 45 sec. air stimuli using the SPV during culmination phase. For all tests SPV was recorded by videooculography. After investigation all 50 volunteers were asked how they experienced the different tests. In addition we tested 9 patients with a defect of tympanic membrane or with runny ears (middle ear or outer ear canal conditions) with HAC alone.
Results: SPV values with HAC were significantly higher than air calorisation (p<0,05) but did not reach those of standard 30 sec. water stimuli (p<0,05). We found no water condensation in the outer ear canal. All patients with runny ears were successfully tested with HAC without any paradox nystagmus.
Regarding loudness, rotatory vertigo and comfort during the investigation HAC was estimated substantially better than water calorisation (p<0,05).
Hence HAC represents an alternative to air calorisation. In further cases it has to be investigated if it is possible to improve the SPV using a longer HAC stimulus.