The test-retest variability of the caloric test: A comparison of a modified air irrigation with the conventional water technique

Abstract

The bithermal caloric test has traditionally been carried out using water but air may also be used. One of the reported disadvantages of air is the high test-retest variability (Coats et al., 1976). A recent study by Moon and Munro (1996) demonstrated that the variability could be reduced by modifying the air irrigator probe to allow greater control of probe placement and direction of air flow within the ear canal. The aim of the present study was to compare the test-retest variability of the modified air technique and the conventional water technique. Twelve normal subjects underwent four full caloric tests: twice with water and twice with air. The results show that it is possible to obtain a similar test-retest variability with the two techniques. The range for canal paresis and directional preponderance are also similar. While further research is required, the modified air technique appears to provide a reliable alternative to the traditional water technique.

Water irrigation versus air insufflation: A comparison of two caloric test protocols

“…Various authors reported similar findings (Benitez et al, 1978;Greven et al, 1979;Zangemeister & Bock, 1980;Karlsen et al, 1992), although others obtained no statistically different responses for water and air SCV values (Capps et al, 1973;O'Neill, 1978;Ford & Stockwell, 1978;Tole, 1979). In concurrence with literature data (Benitez et al, 1978;Munro & Higson, 1996), UW and DP percentages did not differ significantly for water and air. The present study could not demonstrate significant effects due to ear side or temperature for the parameters SCV, frequency, UW, and DP.…”

“…Because of this similarity, the authors also concluded that no order effect was present. In concurrence with Stahle (1957), it is not certain though that Neill (1978) 24; 50 60 6 Á8 15.8 20.5 Benitez et al (1978) 24; 50 60 6 20.9 (7.8) 5.3 Á36.5 21.9 (8.0) 5.9 Á37.9 Ford & Stockwell (1978) 24; 50 60 8 14.9 (2.6) 9.7 Á20.1 19.6 (2.4) 14.8 Á24.4 Greven et al (1979) 20; 50 60 5 10.5 13.8 Karlsen et al (1992) 24; 50 60 17.0 (11.9) (6.8 Á40.8 9.1 (6.1) (3.1 Á21.3 Munro & Higson (1996) 27 Water responses were found to be significantly higher than air responses on the measures of slow component velocity and frequency. Due to an enormous diversity of used test protocols in the literature, it is not always easy to compare results between protocols.…”

“…The 95% confidence intervals were calculated on the basis of two standard deviations. Most authors (Mehra, 1964;Capps et al, 1973;Sills et al, 1977;Benitez et al, 1978;Ford & Stockwell, 1978;O'Neill, 1978;Greven et al, 1979;Press et al, 1979;Jacobson & Henry, 1989;Karlsen et al, 1992;Munro & Higson, 1996;Henry, 1999;Van der Stappen et al, 2000) supply for separate warm and cool normative data for the parameters SCV, and frequency. To be able to compare literature data with the present results, the mean, standard deviation and 95% confidence intervals for both temperatures are also depicted in Table 1.…”

“…Higher SCV values for warm compared to cool water irrigations were demonstrated by Mehra (1964), Bruner & Norris (1971), Sills et al (1977), Ford & Stockwell (1978), O'Neill (1978), and Jacobson & Henry (1989), while Greven et al (1979), Press et al (1979, and Karlsen et al (1992) found higher responses for the cool temperature. For air, Munro & Higson (1996) suggested that insufflation temperatures equidistant from body temperature do not result in a symmetrical SCV response. Coats et al (1976) indicated that for air temperatures below 308C, the cool stimulus has to be approximately 2 Á38C more extreme to produce equal caloric responses, which agrees with the present findings.…”

“…Air stimulation was performed using the Atmos Varioair et al, 1976;Banchi & Beattie, 1991;Munro & Higson, 1996), and were often unpleasant for the subjects (Coats et al, 1976;Moon & Munro, 1996;Munro & Higson, 1996). The same irrigation/ insufflation sequence, interstimulus interval, and fixation suppression as for water were administered.…”