The value of a head turn in neurolocalization

Abstract

Background: A head turn is a clinically relevant abnormality identified on neurological examination and historically has been an isolated or concomitant sign of ipsilateral forebrain dysfunction. Experimental studies in quadrupedal mammals suggest that changes in head posture may be identified as originating in other parts of the central nervous system (CNS).

Objectives: To identify whether other locations within the CNS could give rise to a head turn and whether the head turn identified is isolated or concomitant with other deviations in head and body posture.

Animals: Forty-nine client-owned dogs with a presentation of a head turn, from 6 veterinary referral centers.

Methods: Multicenter observational prospective study including dogs with photographic evidence of a head turn, full neurological examination, and advanced imaging.

Results: Of the population, 15/49 had head turn only, 9/49 had head turn and head tilt only, 12/49 had head turn and body turn only, and 13/49 had head turn, head tilt, and body turn. Nearly all dogs with forebrain disease (23/24), and, all with brainstem and cerebellar disease, had an ipsilateral head turn and body turn (if present). In the cerebellar group, all head tilts were contralateral to the lesion location. In the cervical spinal cord group, all head turns, body turns and head tilts were contralateral to the lesion location.

Conclusion: A head turn, although most likely associated with, is not exclusively seen with forebrain disease. Certain combinations of head turn, head tilt and body turn suggest a neurolocalization other than the forebrain, with appropriate classification needed.

Keywords: body turn; pleurothotonus; postural abnormalities; torticollis.

FIGURE 1

Distribution of etiological diagnosis based on lesion location in the study population.

FIGURE 2

Distribution of postures identified, in association with a head turn, grouped under imaging location.

FIGURE 3

Distribution of the degree of head turns within the study population and whether they had a concurrent body turn, or not; Y = yes, N = no.

FIGURE 4

Representation of the different postures identified in the dogs with forebrain disease; top 2 images show a dog with left head turn and head tilt with left‐sided forebrain disease; middle 2 images show a dog with right‐sided head turn and body turn in a dog with right sided forebrain disease; bottom 2 images show a dog with right‐sided head turn only in a dog with right‐sided forebrain disease.

FIGURE 5

Representative case of the most common (but not exclusive) postural presentation of a dog with brainstem disease; showing a left‐sided head turn and head tilt in a dog with left‐sided brainstem disease.

FIGURE 6

Representative case of the most common (but not exclusive) postural presentation of a dog with cerebellar disease; showing left‐sided head turn and body turn with right‐sided head tilt in a dog with left‐sided cerebellar disease.

FIGURE 7

Representative case of the most common (but not exclusive) postural presentation of a dog with cervical spinal cord disease; showing left‐sided head tilt, head turn and body turn with right‐sided cranial cervical cord disease.