The derivation of optimum criteria for use in the monothermal caloric screening test.
OBJECTIVE
The aim of this study was to determine whether it is possible to predict a normal outcome of the bithermal caloric test by testing at a single temperature and if so, what criteria are most appropriate to use.


METHODS
A total of 490 patients were considered candidates for the bithermal test and 414 completed the four necessary components, their nystagmus being measured using videonystagmography.


RESULTS
Clinical decision analysis revealed that the cool monothermal test does not provide an adequate combination of sensitivity and specificity for us to recommend its clinical use. However, the warm monothermal test offers a sensitivity of 95% with 29% of patients with normal bithermal results having to undergo the bithermal test (specificity = 71%) if a combination of three criteria are used: a normal bithermal caloric test outcome can be anticipated and testing curtailed after the first temperature if (a) the warm monothermal caloric asymmetry (MCA) is <15% and (b) the two warm results are each >8 degrees per sec ( degrees /sec), and (c) any spontaneous nystagmus is <4 degrees /sec.


CONCLUSIONS
When appropriate criteria are used, the warm monothermal caloric test offers a performance that is acceptable for routine clinical use, sparing a considerable proportion of patients from unnecessary tests at the cool temperature. We believe that the warm/cool monothermal test difference is probably a consequence of the interrelationship between canal paresis and directional preponderance.
Lightfoot
Guy
G
Department of Clinical Engineering, Royal Liverpool University Hospital, Prescot Street, Liverpool, England. g.lightfoot@liverpool.ac.uk
Barker
Fiona
F
Belcher
Keri
K
Kennedy
Vicki
V
Nassar
Greg
G
Tweedy
Frances
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests / Q000379:methods*; D003080:Cold Temperature; D004584:Electronystagmography; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013696:Temperature; D014741:Video Recording; D055815:Young Adult