Citation Information :
Sugantharaj V, Kumar MR, Sekharreddy MR, Sridharan S, Sridhar I. A Rare Case of Eight-and-a-half Syndrome: A Case Report. 2021; 4 (3):71-73.
“Eight-and-a-half syndrome” is a rare entity comprising conjugate horizontal gaze palsy, ipsilateral internuclear ophthalmoplegia (INO), and ipsilateral lower motor neuron type of facial palsy, arising due to a lesion affecting the paramedian pontine reticular formation (PPRF), medial longitudinal fasciculus (MLF), and the ipsilateral facial nerve. Dr. Fischer first described the “one and a half syndrome,” which is much more common in occurrence. It is due to a lesion involving the same side of PPRF, abducent nerve nucleus, and the MLF. Since the motor division of the seventh nerve nucleus winds around the motor nucleus of the sixth nerve at the level of the pons, slightly more extensive lesions in the form of infarct and hemorrhage may involve the seventh nerve also leading to this rare entity called the “eight-and-a-half syndrome.”
Eggenberger E. Eight-and-a-half syndrome: one-and-a-half syndrome plus cranial nerve VII palsy. J Neuro-ophthalmol 1998;18(2):114–116.
Fitzgerald MJT, Gruener G, Mtui E, editors. Clinical neuroanatomy and neuroscience. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012. p. 198–215. DOI: 10.1177/0192623319868160.
Bae YJ, Kim JH, Choi BS, Jung C, Kim E. Brainstem pathways for horizontal eye movement: pathologic correlation with MR imaging. Radiographics 2013;33(1):47–59. DOI: 10.1148/rg.331125033.
Xue F, Zhang L, Zhang L, Ying Z, Sha O, Ding Y. One-and-a-half syndrome with its spectrum disorders. Quant Imaging Med Surg 2017;7(6):691. DOI: 10.21037/qims.2017.12.04.
Bolanos I, Lozano D, Cantu C. Internuclear ophthalmoplegia: causes and long-term follow-up in 65 patients. Acta Neurol Scand 2004;110(3):161–165. DOI: 10.1111/j.1600-0404.2004.00278.x.
Striano S, Luciano R, Meo R, Bilo L, Orefice G, Grasso A. The physiopathology of supranuclear structures in oculomotor disorders. Acta Neurol 1990;12(2):151–171.
Martyn CN, Kean D. The one-and-a-half syndrome. Clinical correlation with a pontine lesion demonstrated by nuclear magnetic resonance imaging in a case of multiple sclerosis. Br J Ophthalmol 1988;72(7):515–517. DOI: 10.1136/bjo.72.7.515.
Fisher CM. Some neuro-ophthalmological observations. J Neurol Neurosurg Psychiatry 1967;30(5):383. DOI: 10.1136/jnnp.30.5.383.
