vHIT: RALP, LARP and Lateral Explained

10 mins
09 February 2022


The video Head Impulse Test (vHIT) produces a rotational stimulus to the head and then assesses the resulting eye movement via the Vestibulo-Ocular Reflex (VOR). The rotation stimulus is applied in the anatomical planes of the respective semi-circular canals hence each stimulus is best detected by one pair of canals; each canal is a coplanar pair with another canal in the other ear.

“Lateral” refers to a head rotation in the horizontal plane, usually with the head bowed forward by approximately 30°. This best stimulates the horizontal canals of each ear (which are a co-planar pair).

“RALP” means Right Anterior, Left Posterior and refers to a head rotation in an orientation which best stimulates this co-planar pair. “LARP” means Left Anterior, Right Posterior and refers to a head rotation in an orientation which best stimulates this co-planar pair. The below figure is a schematic showing a top-down view of the head, which visualises the orientation of the semi-circular canals of each ear.

An image looking down into the anterior canal, lateral canal and posterior canal on each side.


Related course

Best practices in vHIT testing


Michael Maslin
After working for several years as an audiologist in the UK, Michael completed his Ph.D. in 2010 at The University of Manchester. The topic was plasticity of the human binaural auditory system. He then completed a 3-year post-doctoral research program that built directly on the underpinning work carried out during his Ph.D. In 2015, Michael joined the Interacoustics Academy, offering training and education in audiological and vestibular diagnostics worldwide. Michael now works for the University of Canterbury in Christchurch, New Zealand, exploring his research interests which include electrophysiological measurement of the central auditory system, and the development of clinical protocols and clinical techniques applied in areas such as paediatric audiology and vestibular assessment and management.

Popular Academy Advancements

Interacoustics - hearing and balance diagnosis and rehabilitation
Copyright © Interacoustics A/S. All rights reserved.