Biomaterial Database

Internuclear ophthalmoplegia: pathophysiology and diagnosis. 1992

D S Zee

Johns Hopkins Hospital, Baltimore, MD 21205.

The main findings in unilateral INO are paresis of adduction in the eye on the side of the lesion (for conjugate but not vergence eye movements) and abduction nystagmus in the eye on the side opposite to the lesion. A skew deviation (eye usually higher on the side of the lesion) or a dissociated, mixed vertical-torsional nystagmus, with the eye beating down on the side of the lesion, may also occur. The main findings in bilateral INO are paresis of adduction in both eyes, bilateral abduction nystagmus and, in the vertical plane, impaired gaze-holding, vestibular responses and smooth tracking. Abduction nystagmus in INO may have a number of causes; probably most common are a gaze-evoked nystagmus superimposed on adduction weakness and adaptation to adduction weakness. Most of the findings in INO can be explained by interruption of projections from abducens internuclear neurones, mediating adduction, and from the vestibular nuclei, mediating both canal- and otolith-induced reflexes as well as vertical gaze holding and pursuit. Extension of the lesion to structures near but outside the MLF, or involvement of cell bodies intermixed with MLF fibres, may also be important in the pathogenesis of the abduction nystagmus and the occasional slowing of abducting saccades.

UI	MeSH Term	Description	Entries
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009886	Ophthalmoplegia	Paralysis of one or more of the ocular muscles due to disorders of the eye muscles, neuromuscular junction, supporting soft tissue, tendons, or innervation to the muscles.	Oculomotor Paralysis,External Ophthalmoplegia,Internal Ophthalmoplegia,Ophthalmoparesis,External Ophthalmoplegias,Internal Ophthalmoplegias,Ophthalmopareses,Ophthalmoplegia, External,Ophthalmoplegia, Internal,Ophthalmoplegias,Ophthalmoplegias, External,Ophthalmoplegias, Internal,Paralysis, Oculomotor
D005133	Eye Movements	Voluntary or reflex-controlled movements of the eye.	Eye Movement,Movement, Eye,Movements, Eye
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D016472	Motor Neuron Disease	Diseases characterized by a selective degeneration of the motor neurons of the spinal cord, brainstem, or motor cortex. Clinical subtypes are distinguished by the major site of degeneration. In AMYOTROPHIC LATERAL SCLEROSIS there is involvement of upper, lower, and brainstem motor neurons. In progressive muscular atrophy and related syndromes (see MUSCULAR ATROPHY, SPINAL) the motor neurons in the spinal cord are primarily affected. With progressive bulbar palsy (BULBAR PALSY, PROGRESSIVE), the initial degeneration occurs in the brainstem. In primary lateral sclerosis, the cortical neurons are affected in isolation. (Adams et al., Principles of Neurology, 6th ed, p1089)	Anterior Horn Cell Disease,Familial Motor Neuron Disease,Lateral Sclerosis,Motor Neuron Disease, Lower,Motor Neuron Disease, Upper,Lower Motor Neuron Disease,Motor Neuron Disease, Familial,Motor Neuron Disease, Secondary,Motor System Disease,Primary Lateral Sclerosis,Secondary Motor Neuron Disease,Upper Motor Neuron Disease,Lateral Scleroses,Lateral Scleroses, Primary,Lateral Sclerosis, Primary,Motor Neuron Diseases,Motor System Diseases,Neuron Disease, Motor,Neuron Diseases, Motor,Primary Lateral Scleroses,Scleroses, Lateral,Scleroses, Primary Lateral,Sclerosis, Lateral,Sclerosis, Primary Lateral