Head Thrust Test for Vestibular Assessment

The Head Thrust Test is an essential clinical tool designed to assess the integrity of the vestibulo-ocular reflex (VOR). This reflex is crucial for maintaining gaze stability during head movements, enabling clear vision. The test’s primary utility lies in diagnosing vestibular disorders, particularly those affecting the semicircular canals.

The test is very similar to the Head Impulse Test. The only difference is the quick thrust during the movement of rotation.

See Also: Head Impulse Test

How do you perform the Head Thrust Test?

The Head Thrust Test is performed with the patient seated and the examiner standing in front. The patient is asked to focus on a fixed point, typically the examiner’s nose. This initial setup ensures that the patient’s attention is centrally fixed, providing a stable baseline for the assessment. The examiner then gently grips the patient’s head to minimize neck muscle tension, allowing for a more accurate assessment of the VOR without compensatory muscle actions.

The examiner rotates the patient’s head quickly to one side and then decelerates back to the starting position. This sudden movement is intended to stimulate the horizontal semicircular canal on the side toward which the head is thrust. The key observation during this maneuver is the patient’s ability to maintain gaze fixation on a central point (the examiner’s nose) without the need for corrective saccades – quick, jerky eye movements used to re-fixate on a target.

A normal response indicates an intact VOR, where the eyes can adjust to the rapid head movement by moving in the opposite direction at the same speed, thereby maintaining fixation on the target. An abnormal response, indicated by the need for a corrective saccade to regain focus on the fixed point, suggests a deficit in the vestibular system on the side toward which the head was rotated.

The Head Thrust Test is particularly valuable for identifying unilateral vestibular hypofunction. It is a quick, non-invasive test that can be easily administered in a clinical setting without the need for sophisticated equipment. This makes it an accessible diagnostic option for many healthcare professionals, including neurologists, otolaryngologists, and physical therapists specializing in vestibular rehabilitation.

Sensitivity & Specificity

In one study to optimize the sensitivity of the head thrust test for identifying vestibular hypofunction, the sensitivity of the HTT for identifying vestibular hypofunction was 71% for UVH and 84% for BVH. Specificity was 82%.

In another study, its specificity accounts for 100% and the sensitivity for 54%.

Head Thrust Test VS Head Impulse Test

While the Head Thrust Test shares similarities with the Horizontal Impulse Test (HIT), a key distinction is the addition of a quick thrust during head rotation in the Head Thrust Test. This abrupt acceleration is designed to more vigorously stimulate the vestibular system, potentially unmasking subtle abnormalities not elicited by the more uniform speed of the HIT.

Conclusion

The Head Thrust Test is a cornerstone diagnostic procedure in the evaluation of vestibular function. Its simplicity, coupled with its diagnostic utility, makes it an invaluable tool in the clinical assessment of patients with dizziness and balance disorders. By enabling the early detection of vestibular hypofunction, the Head Thrust Test plays a crucial role in facilitating timely and appropriate treatment, ultimately enhancing patient outcomes.

References & More

1. Orthopedic Physical Assessment by David J. Magee, 7th Edition.
2. Schubert MC, Tusa RJ, Grine LE, Herdman SJ. Optimizing the sensitivity of the head thrust test for identifying vestibular hypofunction. Phys Ther. 2004 Feb;84(2):151-8. PMID: 14744205. Pubmed
3. Oliva M, Martín García MA, Bartual J, Ariza A, García Teno M. El test de movimientos cefálicos bruscos (head-thrust test): validación para su uso como prueba diagnóstica clínica [Head-thrust test: its validity as a diagnostic clinical test]. An Otorrinolaringol Ibero Am. 1999;26(4):377-83. Spanish. PMID: 10520277. Pubmed
4. Carey JP, Della Santina CC: Principles of applied vestibular physiology. In Flint PW, Haughey BH, Lund V, et al., eds. Cummings otolaryngology, ed 6, Philadelphia, 2015, Saunders.