Does a head tilt help with neurolocalization?
A recent study by Nagendran et al (The value of a head turn in neurolocalization, JVIM 2023) described 4 distinct areas of neuroanatomic lesion localization for head turn, head tilt and neck turn and looked at head and body position in each of these localizations. If you see a patient with their head deviated to one side yet parallel to the floor, that would be a head turn. If a patient has their head deviated to one side NOT parallel to the floor, we would consider this a head tilt. The head tilt can be anything from 1-90% from the x axis! If the neck is turned to one direction it would be called torticollis and may be (and often is) associated with either head tilt, head turn, or both. This recent article looked at these three signs, in reference to the neuroanatomic lesion localization, with the goal of trying to sort out the underlying neuropathology (totally cool but not "light reading" and therefore saved for another conversation).
Key Points:
Forebrain disease – The majority or patients had an ipsilateral head turn, with less than ½ of the dogs demonstrating ipsilateral body/neck turn.
Brainstem disease – All dogs had an ipsilateral head turn, and 5/9 had an ipsilateral head tilt, with a rare dog demonstrating a neck turn.
Cerebellar disease – All dogs had an ipsilateral head turn and the majority had a contralateral head tilt with a rare neck/body turn noted showing a contralateral neck/body turn.
Cervical spinal cord disease – all dogs had a contralateral head turn along with a majority (6/7) showing a ontralateral head tilt.
Summary:
Head turn ONLY – consider forebrain disease
Head turn with neck turn (ipsilateral) – consider forebrain disease, but the neck turn is an inconsistent finding in many dogs with foreain disease.
Head turn, neck turn AND head tilt – most likely cervical spinal cord disease but cannot rule out cerebellar disease.
Head tilt only – likely brainstem disease (or peripheral vestibular disease!)