Abstract
Background: Lateral medullary stroke (LMS) results in a characteristic pattern of brainstem signs including ocular motor and vestibular deficits. Thus, an impaired angular vestibulo-ocular reflex (aVOR) may be found if the vestibular nuclei are affected.Objective: We aimed to characterize the frequency and pattern of vestibular and ocular-motor deficits in patients with LMS.Methods: Patients with MR-confirmed acute/subacute unilateral LMS from a stroke registry were included and a bedside neuro-otological examination was performed. Video-oculography and video-based head-impulse testing (vHIT) was obtained and semicircular canal function was determined. The lesion location/extension as seen on MRI was rated and involvement of the vestibular nuclei was judged.Results: Seventeen patients with LMS (age = 59.4 ± 14.3 years) were included. All patients had positive H.I.N.T.S. vHIT showed mild-to-moderate aVOR impairments in three patients (ipsilesional = 1; ipsilesional and contralesional = 1; contralesional = 1). Spontaneous nystagmus (n = 10/15 patients) was more often beating contralesionally than ipsilesionally (6 vs. 3) and was accompanied by upbeat nystagmus in four patients. Head-shaking nystagmus was noted in seven subjects, ipsilesionally beating in six and down-beating in one. On brain MRI, damage of the most caudal parts of the medial and/or inferior vestibular nucleus was noted in 13 patients. Only those two patients with lesions affecting the rostral medulla oblongata demonstrated an ipsilaterally impaired aVOR.Conclusions: While subtle ocular motor signs pointed to damage of the central–vestibular pathways in all 17 patients, aVOR deficits were infrequent, restricted to those patients with rostral medullary lesions and, if present, mild to moderate only. This can be explained by lesions located too far caudally and too far ventrally to substantially affect the vestibular nuclei.
Highlights
The human medulla oblongata is the most caudal brainstem area and is critically involved in various motor, sensory, and autonomic functions
Sensory input originating from the vestibular end organs is forwarded to the brainstem vestibular nuclei (VN) located in the dorsolateral area of the medulla oblongata for further processing and integration [7]
We reviewed the Hospital’s prospective stroke registry for patients with MRI-confirmed lateral medullary stroke (LMS) that either presented to the emergency department or to the outpatient clinic of the Department of Neurology, Chonnam National University Hospital, Gwangju, South Korea
Summary
The human medulla oblongata is the most caudal brainstem area and is critically involved in various motor, sensory, and autonomic functions. Sensory input originating from the vestibular end organs (i.e., the semicircular canals and the otolith organs) is forwarded to the brainstem vestibular nuclei (VN) located in the dorsolateral area of the medulla oblongata for further processing and integration [7]. Subtle ocular motor deficits including spontaneous nystagmus (SN), gaze-evoked nystagmus (GEN), and a deficient angular vestibulo-ocular reflex [aVOR, as assessed by the bedside horizontal head-impulse test [8]] may be observed. While detecting subtle deficits of the brainstem, vestibular circuits may be challenging, and since saccadic lateropulsion may limit significantly the interpretation of the bedside headimpulse test, we asked to which extent the use of quantitative, video-based head-impulse testing (vHIT) may facilitate the detection of a deficient aVOR and further support damage to the most caudal parts of the brainstem. Lateral medullary stroke (LMS) results in a characteristic pattern of brainstem signs including ocular motor and vestibular deficits. An impaired angular vestibulo-ocular reflex (aVOR) may be found if the vestibular nuclei are affected
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
