Lecture 21: Brainstem Clinical Conditions

Inferior alternating hemiplegia (medial medulla)

ASA

corticospinal tract: contralateral spastic hemiplegia (UMN)

medial lemniscus: loss of tactile, vibratory sense and proprioception in contralateral body (Romberg sign)

CN XII nucleus/nerve: LMN ipsilateral tongue (dysarthria; deviation to ipsilateral side)

Lateral medullary syndrome/ Wallenberg syndrome

PICA
ALS: contralateral hemianalgesia

Spinal Trigeminal nucleus/tract: ipsilateral facial hemianalgesia

Nucleus Ambiguus: LMN, uvula to contralateral side, diminished gag, dysphagia, hoarse voice

Vestibular Nuclei: contralateral-beating nystagmus, vertigo, nausea

ICP: Ipsilateral ataxia

Hypothalamospinal tract: ipsilateral Horner syndrome

Pure motor hemiparesis

Medial pontine basis, caudal pons

Paramedian Basilar

Corticospinal tract: contralateral spastic hemiplegia (UMN)

Corticonuclear tract: dysarthria, dysphagia (UMN to contralateral tongue, palate)

commonly due to lacunar infarcts

sometimes hand involved to a greater extent than leg (somatotopic organization)

Middle alternating hemiplegia

Medial pontine basis and tegmentum, caudal pons

Paramedian Basilar

Corticospinal tract: contralateral spastic hemiplegia (UMN)

Corticonuclear tract: dysarthria, dysphagia (UMN to contralateral tongue, palate)

Pontine Nucleus/pontocerebellar fibers: contralateral ataxia, dysmetria, dysrhythmia

medial lemniscus: contralateral loss of discriminative touch

Abducens nerve fascicles: ipsilateral abducens nerve- lateral rectus

Medial pontine basis and tegmentum, caudal pons

Paramedian Basilar

Corticospinal tract: contralateral spastic hemiplegia (UMN)

Corticonuclear tract: dysarthria, dysphagia (UMN to contralateral tongue, palate)

Pontine Nucleus/pontocerebellar fibers: contralateral ataxia, dysmetria, dysrhythmia

medial lemniscus: contralateral loss of discriminative touch

PPRF: ipsilateral horizontal gaze palsy, contralateral gaze preference (Wrong way eyes)

Abducens and PPRF

Lateral caudal pons

Bilateral ventral pons

Typically due to basilar artery infarct or thrombosis

Weber syndrome/Superior alternating hemiplegia

Rostral Midbrain

Claude Syndrome

Rostral Medulla

Benedikt Syndrome

Rostral Medulla

Parinaud syndrome

Midbrain-diencephalon junction

one and a half syndrome

lesion involved the MLF in addition to PPRF

horizontal gaze palsy + internuclear ophthalmoplegia

Only possible movement is abduction on side opposite gaze palsy