Eight-and-a-half syndrome: video evidence and updated literature review

Abstract

The eight-and-a-half syndrome (EHS)—defined by the combination of a seventh cranial nerve palsy and an ipsilateral one-and-a-half syndrome—is a rare brainstem syndrome, which localises to the caudal tegmental region of the pons. We present a case of the EHS secondary to an inflammatory lesion on a previously healthy 26-year-old woman, with a literature review emphasising the relevance of aetiological assessment.

An unusual presentation of hemiparesis with complex ophthalmoplegia: A ‘nine’ syndrome

“…The most common etiologies described for the above presentation are brainstem infarction and haemorrhage, multiple sclerosis, and tumours involving the brainstem and fourth ventricle. 5 The majority (70%) are caused by brainstem infarction and multiple sclerosis. When eight-and-a-half syndrome extends to involve the adjacent structure such as corticospinal tract and medial lemniscus, it additionally produces hemiparesis and hemihypesthesia contralaterally.…”

How does a small area cause big syndromes? A case report of a patient with one-and-a-half syndrome and MRI review of the anatomical pathways involved in causing different pontine neuro-ophthalmological syndromes

“…These spectrum syndromes have been categorized arithmetically by summation of the cranial nerves involved. 8 Their diagnosis relies on the distinctive accompanied clinical symptoms, neuroanatomy, and imaging characteristics. 7 …”

“…4 C) was described by Eggenberger in 1998 4 , and it is the most common variant of this spectrum disorder. 7 , 8 , 9 This includes a one-and-a-half-syndrome and ipsilateral peripheral facial paralysis (I ½ and VII = VIII ½). In this entity, the lesion is located in the ipsilateral pontine tegmentum, which includes the ipsilateral PPRF, MLF, VII nerve nucleus or nerve bundle.…”

“…In this entity, the lesion is located in the ipsilateral pontine tegmentum, which includes the ipsilateral PPRF, MLF, VII nerve nucleus or nerve bundle. 7 , 8 , 9 The nine syndrome ( Fig. 4 D) is characterized by an eight-and-a-half syndrome and contralateral hemiparesis and hemihypesthesia (VIII ½ and ½) = IX.…”