교뇌병변을 가진 환자에서 보일 수 있는 신경안과 및 신경이과적 이상

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교뇌병변을 가진 환자에서 보일 수 있는 신경안과 및 신경이과적 이상

김재명

전남대학교병원 신경과

Neuro-ophthalmologic and Neuro-otologic Findings in Patients with Pontine Lesions

Jae-Myung Kim, MD

Department of Neurology, Chonnam National University Hospital, Gwangju, Korea

The pontine tegmentum contains essential structures for conjugate horizontal gaze including the paramedian pontine reticular

formation (PPRF), abducens nucleus, nucleus raphe interpositus, and medial longitudinal fasciculus (MLF). Thus, the pontine teg-

mental lesions are commonly associated with horizontal gaze palsy. Localization of the lesions causing horizontal gaze palsy

mostly depends on co-existing neurologic abnormalities such as hemiparesis, sensory loss, and other cranial nerve palsies, even

isolated conjugate horizontal gaze palsy may occur in selective PPRF or abducens nucleus lesions. Moreover, vertical eye move-

ments may also be accompanied by the pontine ocular motor centers are linked to the vertical gaze control centers lying on the

meso-diencephalon through the MLF. Therefore, detailed neuro-ophthalmologic evaluations (e.g., vestibular ocular reflex, gave-

evoked nystagmus, smooth pursuit, and saccades) as well as gaze palsy may be helpful for the differential diagnosis and the iden-

tification of the involved structures.

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Anatomical basis

Leigh & Zee. The neurology of Eye Movements. 2015

Abducens nucleus & its fascicle

Abducens nerve Facial nerve

Abducens nucleus

Facial nucleus

Clinical findings of abducens nucleus lesion

• Ipsilateral horizontal conjugate palsy

horizontal saccade, smooth pursuit, VOR 등 모든 horizontal conjugate gaze 장애를 보임

• Vergence and vertical movements : spared

• Contralesional gaze시 horizontal GEN (+)

• 병변 반대측 시야(intact hemifield)에서 병변측으로 향하 는saccade가 비교적 유지됨 (PPRF병변과 감별점)

• 해부학적 위치상 ipsilateral facial palsy 를 잘 동반

Abducens nucleus lesion

Abducens nerve Facial nerve

Abducens nucleus

Facial nucleus

Courtesy of Seung-Han Lee

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^th

nucleus + ipsilateral facial palsy

Abducens nuclear or fascicular syndromes

Abducens nucleus

Facial nucleus Abducens nerve

Facial nerve

Neuro-ophthalmologic and neuro-otologic findings - Pons

Jae-Myung Kim Department of Neurology Chonnam National University Hospital

Introduction

 Important structures for ocular motor function in pons

• PPRF (Paramedian pontine reticular formation): Horizontal saccadic generator

• MLF (Medial longitudinal fasciculus)

• Abducens nucleus & fascicles

• VTT (Ventral tegmental tract)

• NRTP (Nucleus reticularis tegmenti pontis)

• DLPN (Dorsolateral pontine nucleus)

• RIP (nucleus raphe interpositus): Omnipause neuron (OPN)

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Paramedian pontine reticular formation (PPRF)

 Omnipause neuron (OPN)

• Lying on the RIP

• Saccade가 발생하기 전에 흥분을 멈춘다  PBN이 불필요 하게 흥분하는 것을 막음

• Saccade 직전에만 gain을 증가시킴으로써 안정되게 빠른 운동을 준비할 수 있게 한다

Premotor burst neurons

• 수평 Excitatory burst neuron (EBN): PPRF에 위치

• 수평 Inhibitory burst neuron (IBN): MRF에 위치

Leigh & Zee. The neurology of Eye Movements. 2015

PPRF lesion

Lee SH. et al. J Neuroophthalmol. 2018 Relaxation of the antagonist

muscles, which is mediated by the IBNsin the medullary reticular formation

Internuclear ophthalmoplegia (INO)

Leigh & Zee. The neurology of Eye Movements. 2015 Lee SH, et al. J Neuroophthalmol. 2018

Dissociated torsional-vertical nystagmus in INO Congenital syndrome a/w abducens nerve

Duane retraction syndrome

•

Congenital, non-progressive strabismus

•

Co-contraction of the medial and lateral recti that are supplied by the third nerve (aberrant innervation)

•

Agenesis of abducens nerve

•

Narrowing of the palpebral fissure on adduction secondary to retraction of the eye

•

Head turn toward lesioned side

•

Commonly sporadic, unilateral

•

Combined with other congenital anomalies

• Type I (m/c): abduction limitation

• Type II: adduction limitation

• Type III: Abduction & adduction limitation

Congenital syndrome a/w abducens nerve

 Möbius syndrome

• Congenital facial diplegia + bilateral abduction 장애

• 흔히 systemic 한 congenital anomaly를 동반

• Vertical eye movement는 spared

• Sporadic인 경우가 많다

 Horizontal gaze palsy with progressive scoliosis (HGPPS)

• ROBO3 gene on chromosome11q24

• Split pons sign, butterfly shape medulla

• Uncrossed corticospinal tract

Yang HK, et al. Neurology. 2019

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WEBINO (Wall-eyed bilateral INO)

RH LH

One-and-a-half syndrome

Lee SH, et al. J Neuroophthalmol. 2018

NRTP and DLPN

 NRTP (Nucleus reticularis tegmenti pontis)

• Relay between cortical eye fields/sup. colliculus and cerebellum

• Mediated saccades, smooth pursuit, and vergence

 DLPN (Dorsolateral pontine nucleus)

Relay from the cortical areas concerned with visual motion

Contributes to maintenance of smooth pursuit and saccades

Horizontal GEN + ipsilateral smooth pursuit impairment

Ahn BY, et al. Neurol. 2007

Saccadic oscillation with pontine lesions

 Saccadic oscillation: intersaccadic interval 없이 발생하는 불수의적, 빠른 진폭의 신속보기

 Opsoclonus or Ocular flutter

 Possible mechanisms

 PPRF의 saccadic burst neuron에 대한 억제회로의 장 애

 Burst neuron 및 omnipause neuron으로 가는 feedback 장애

 Fastigial nucleus의 손상으로 인한 억제기능 소실

Dissociated torsional-vertical nystagmus in INO

33 patients with dissociated torsional–vertical nystagmus and INO.

-11 (33%): ipsiversive torsional in both eyes with vertical components in the opposite directions -18 (55%): ipsiversive torsional nystagmus with a larger upbeat component in the contralesional eye - 4 (12%): ipsiversive torsional nystagmus with a greater downbeat component in the ipsilesional eye

The patterns of jerky seesaw nystagmus in INO suggest a disruption of neural pathways from the contralateral vertical semicircular canals with or without concomitant damage to the fibers from the contralateral utricle in or near the medial longitudinal fasciculus.

Oh K, et al. J Neurology. 2005 Jeong SH et al. Ann N Y Acad Sci. 2011

VOR injury in INO

Lee SH, et al. Front Neurol. 2017

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Oculopalatal tremor

경청해 주셔서 감사합니다.