ROSTRAL MIDBRAIN INFARCTION PRODUCING ISOLATED LATEROPULSION

Dynamic changes of the direction and angle of radiographic ocular lateral deviation in patients with lateropulsion after stroke onset

OBJECTIVE

To examine if radiographic ocular lateral deviation (rOLD) could be provoked in stroke patients with mild-to-moderate lateropulsion according to vertical perception.

METHODS

In this single-center, retrospective study, acute stroke patients with mild-to-moderate lateropulsion assessed by the Scale for Contraversive Pushing were enrolled. Computed tomography or magnetic resonance imaging was performed on all patients on admission and then according to their conditions. The direction and angle of rOLD were compared among three groups according to the responsible lesion: lateral medullary (LM), pontine (P), and hemispheric (H).

RESULTS

Sixty-six patients (male, 47; average age, 67 years) were enrolled and divided into the LM (n = 37), P (n = 8), and H (n = 21) groups. All patients had body tilt. Patients in the LM group showed body tilt to the ipsilesional side during hospitalization, while those in the P and H groups tilted to the contralesional side. All patients had rOLD at the final assessment at an average of 13 days after onset; patients in the P and H groups showed contralateral rOLD, while those in the LM group showed ipsilateral rOLD if they did not have cerebellar or pontine lesions. Significant decreases in the angle and changes in direction of rOLD according to lesion site were observed during hospitalization.

CONCLUSION

Serial changes in rOLD findings after stroke onset are different according to the responsible lesion. The direction of rOLD in most patients is in accordance with vertical perception after the acute stage of stroke.

Body Lateropulsion in Stroke: Case Report and Systematic Review of Stroke Topography and Outcome

INTRODUCTION

Body lateropulsion (BLP) is seen in neurological lesions involving the pathways responsible for body position and verticality. We report a case of isolated body lateropulsion (iBLP) as the presentation of lateral medullary infarction and conducted a systematic literature review.

METHODS

MEDLINE and EMBASE databases were searched up to December 3, 2020.

INCLUSION CRITERIA

age ≥ 18, presence of BLP, confirmed stroke on imaging.

EXCLUSION CRITERIA

age < 18, qualitative reviews, studies with inadequate patient data. Statistical analysis was performed using IBM® SPSS® Statistics 20.

RESULTS

A 64-year-old man presented with acute-onset iBLP. Brain MRI demonstrated acute infarction in the right caudolateral medulla. His symptoms progressed with ipsilateral Horner syndrome over the next 24 hours and contralateral hemisensory loss 10 days later. Repeat MRI showed an increase in infarct size. BLP resolved partially at discharge. Systematic review: 418 abstracts were screened; 59 studies were selected reporting 103 patients. Thirty-three patients had iBLP (32%). BLP was ipsilateral to stroke in 70 (68%) and contralateral in 32 (32%). The most common stroke locations were medulla (n = 63, 59%), pons (n = 16, 15%), and cerebellum (n = 16, 15%). Four strokes were cortical, 3 frontal and 1 temporoparietal (3%). The most common etiology was large-artery atherosclerosis (LAA) in 20 patients (32%), followed by small-vessel occlusion in 12 (19%). Seventeen (27%) had large-vessel occlusion (LVO), 12 involving the vertebral artery. Sixty (98%) had some degree of resolution of BLP; complete in 41 (70%). Median time-to-resolution was 14 days (IQR 10-21). There was no relationship between time-to-resolution and age, sex, side of BLP or side of stroke.

CONCLUSION

BLP was commonly seen with medullary infarction and was the isolated finding in one-third. LAA and LVO were the most common etiologies. Recovery of BLP was early and complete in most cases.

Clinical Characteristics and Clinical Course of Body Lateropulsion in 47 Patients with Brainstem Infarctions

BACKGROUND

In patients with lower lateral medullary infarction (LMI) located under the vestibular nucleus, proprioceptive impairment due to dorsal spinocerebellar tract (DSCT) is considered a pathological condition for body lateropulsion. In patients with brainstem infarction located at or above the level of the vestibular nucleus, other pathways, such as the crossed vestibulothalamic tract (CVTT), are considered responsible.

RESEARCH QUESTION

The clinical course of body lateropulsion between each anatomical level of infarction remains unclear. Further, whether body lateropulsion refers to a static or a dynamic symptom also remains unclear.

METHODS

We examined 47 patients who exhibited body lateropulsion and categorized them into four groups: lower LMI under the vestibular nucleus, LMI at the level of the vestibular nucleus, pontine infarction, and midbrain infarction. The patients' time to acquire static upright standing position and gait in a straight line were statistically analyzed by a log-rank test using the Kaplan-Meier method.

RESULTS

Body lateropulsion in the static upright position was less frequent in the lower LMI group than in the other groups.

SIGNIFICANCE

Lower LMI primarily affected body lateropulsion in gait. DSCT damage could affect ipsilateral hip joint or leg coordination, causing body lateropulsion in dynamic situation.

Tremor

Tremor is a phenomenon observed in a broad spectrum of diseases with different pathophysiologies. While patients with tremor may not complain in the clinic of symptoms of imbalance, gait difficulties, or falls, laboratory research studies using quantitative analysis of gait and posture and neurophysiologic techniques have demonstrated impaired gait and balance across a variety of tremor etiologies. These findings have been supported by careful epidemiologic studies assessing symptoms of imbalance. Imaging and neurophysiologic studies have identified cerebellar networks as important mediators of tremor, and therefore a likely common site of dysfunction to explain the phenomenologic overlap between impaired postural and gait control with tremor. Further understanding of these mechanisms and networks is of crucial importance in the development of new treatments, particularly surgical or minimally invasive lesional therapies.

Body Lateropulsion and Cerebellar Tremor in a Patient with Pontine Infarction

Body lateropulsion is known to be caused commonly by lateral medullary lesions but rarely by pontine lesions. It is also known to be associated with lesions of the dorsal spinothalamic tract or ascending graviceptive pathways. We herein report the case of a 75-year-old woman presenting with contralateral lateropulsion and cerebellar tremor caused by pons infarction. To our knowledge, this is the first case report of pontine infarction causing both lateropulsion and cerebellar tremor. Our case may be helpful in anatomical studies of ascending graviceptive pathways.

Isolated body lateropulsion in a patient with pontine infarction

A 72-year-old man with diabetes mellitus and hypertension was admitted to our hospital with lightheadedness. The patient showed lateropulsion to the right side, but his neurological findings were otherwise normal. Brain magnetic resonance images showed a fresh ischemic infarct in the left dorsal part of the lower pons. Body lateropulsion is characterized by an irresistible falling to one side and has been reported in lesions in several brain regions. However, it has rarely been reported in pontine lesions. We suggest that physicians should be aware that pontine lesions can cause isolated body lateropulsion without other neurological deficits.

[Astasia-abasia: psychogenic and non-psychogenic causes]

Astasia-abasia is defined as the inability to stand and to walk, despite sparing of motor function underlying the required balance and gestures. Initially, astasia-abasia was considered a psychogenic gait disorder, but later on, the description of "high-order" gait disorders mimicking this pure functional deficit led authors to refer to "astasia-abasia" as a pure descriptive term, without a presupposed etiological or anatomical substrate. In this paper, the main clinical characteristics of both psychogenic and non-psychogenic astasia-abasia are presented and discussed.