Type of Resources
Prior to administering vestibular evaluations, clinicians often instruct their patients to abstain from several different substances including caffeine. Regarding the video head impulse test (vHIT), research addressing the effect of caffeine is lacking. The purpose of this research was to determine what, if any, effect caffeine had on the results of the vHIT. Participants included 19 healthy adults who were divided into two groups. Group 1 was given caffeinated coffee and group 2 was given decaffeinated coffee. The vHIT was performed on each participant at two points in time—after abstaining from caffeine for 24 hours and then again after consuming a 12-ounce cup of coffee. Vestibulo-ocular reflex (VOR) gain values were measured for both groups before and after coffee consumption. Two independent samples t-tests were performed using the difference values from pre- and post-coffee consumption tests to compare the two groups—one test using the absolute values and one not. While the t-test performed using the absolute values showed a significant difference between groups (t(27.435) = 2.751, p = .01), suggesting a greater amount of variability in VOR gain changes in group 1, the results of the t-test performed without absolute values was not significant (t(25.698) = .028, p = 0.978), indicating these changes in VOR gain values were not consistently either increases or decreases in gain. Despite obtaining significant results in the t-test using absolute values, the differences in VOR gain as well as number of saccades iv observed in each group were not clinically significant, i.e., all participants in both groups would have been classified as having normal test results in a clinical setting regardless of coffee consumption. The results of this study suggested abstaining from caffeine might not be necessary when performing the vHIT clinically. The results of this study might be useful in helping those who perform vHIT clinically to know how to best prepare their patients for this vestibular evaluation.