Triple test as predictive screen for unilateral weakness on caloric testing in routine practice

Abstract

Objective: To investigate in vertigo patients in routine practice to what extent a rapid and straightforward triple bedside test (spontaneous nystagmus, head-shaking nystagmus, and the head impulse test) can predict a normal result on caloric testing.

Study design: Prospective, single-blind, diagnostic study.

Setting: Tertiary referral center.

Patients: 151 patients (78 male and 73 female subjects; mean age, 52.5 +/- 16.4 yr) presenting with acute or recent symptoms of vertigo.

Intervention: Diagnostic evaluation.

Main outcome measure: The negative predictive value (NPV) of the triple test in relation to a normal caloric test response.

Results: In unilateral weakness (UW) on caloric testing (UW, >=25%), the triple test had sensitivity of 63.6%, specificity of 85.4%, a positive predictive value (PPV) of 71.4%, and an NPV of 80.4%. In other words, 80.4% of patients with a negative triple test also had a normal response on caloric testing. In pronounced canal paresis (UW, >=50%), the triple test had sensitivity of 81.8%, specificity of 81.4%, a PPV of 55.1%, and an NPV of 94.1%. Significant differences were found between 2 subgroups assessed by examiners with differing levels of experience (p < 0.05).

Conclusion: The triple test represents a good screening tool that quickly and reliably excludes unilateral weakness and in particular pronounced canal paresis on caloric testing.