Monaural caloric test in Whiplash injury: a presentation of prevalent butterfly patterns of vestibulo-ocular nystagmus
Abstract
Patients of whiplash trauma report to a neurootologist with complaints of long standing duration like vertigo, instability, especially on neck movements, vegetative symptoms like nausea, and also auditory symptoms like tinnitus and hearing loss. In addition they complain of neck pain, strain and stiffness.
The mechanism of triggering vertigo from the neck is partly explained by work of Barre´ and Lieou. The trauma causes an over excitation of cervical proprioceptors resulting in hyper tonicity of gamma fibres and sympathetic nerves of the neck triggering thus the vertigo and vegetative symptoms. However there is also intracranial trauma due to movement of brain within the skull thus affecting the brainstem and the supratentorial structures.
In our study we studied the caloric responses in these patients by means of Claussen’s caloric test and the butterfly chart. With respect to the post traumatic vertigo due to whiplash mechanisms, the monaural caloric vestibulo-ocular test by means of butterfly chart could detect 33% of the cases as normal and 67% as pathological.The most frequent types of the 10 pathological butterflies show that the majority of the pathologies are related to brainstem dysfunctions like major and minor brainstem disinhibitions.