Internuclear ophtalmoplegia (INO) results from the damage of the MLF (medial longitudinal fasciculus). The eye on the lesional side can’t adduct during horizontal eye movements. That results in dubble vision when looking contralesionaly. But contruary to III nerve paresis, the eye can adduct during convergence eye movement.
The most frequent cause of INO are stroke and MS.
Here’s an interesting work on INO recording eye movements: LINK
Woman 53yr with symptoms which resembles BPPV history, but not very convincing. Her vertigo started in the morning while she was still in the bed with feeling of sinking. All the time she is dizzy and she can’t move the head neither eyes because it worsens her dizziness; slight instability. She vomited for two times. The same symptoms she had two months ago after yoga exercises and three days after, canalith repositioning maneuver completely resolved her symptoms.
No spont Ny. VHIT is good. But Dix-Hallpike shows downbeating nystagmus which is accompanied with slight vertigo (slightly stronger at the right side).
OK. Let’s check for the central vestibular function.
VNG shows good saccades but smooth pursuit is rather saccadic at both directions more pronounced to the right. But the patient is very drowsy because of Chloropyramine (antihystamine).
I’ve performed Epley (for the right) and demi-Semone.
On the next day she is still dizzy and Dix-Hallpike still shows downbeat nystagmus. Also there’s slight myosis at the right eye.
VNG shows better tracking gains but gain to the right is significantly lower!
Deep-head hanging maneuver and Epley didn’t resolved the downbeat nystagmus (slightly less intense).
Few days later, she is without vertigo and also without any positional nystagmus.
MRI shows arachnoid cyst in the right CPA.
Would you attribute her positional downbeat nystagmus:
– to BPPV (anterior or apogeotropic posterior) or
– to arachnoid cyst in contact with 8th cranial nerve and right cerebellar lobe?
Do you send every positional down-beat nystagmus to MRI?
What’s the significance of asymmetric smooth pursuit gain?
According to Timothy C. Hain asymmetric smooth pursuit gain is because of:
– Acute parietal lobe disorder
– Acute frontal lobe disorder
– Superimposed nystagmus
– Lesion of pontine nuclei
43yr woman noticed few month ago when she listened to the music with earphones that it didn’t sound the same at both sides, she haired worse at the left. In her family hearing problems has father, uncle and aunt. She hasn’t have any balance problems.
Here’s her audiogram: reduced hearing at high frequencies at both sides and little bit worse hearing at law tones on the left. Would you ask for more testing in this patient?
She has gaze evoked nystagmus at both sides (Brun’s nystagmus), and torsional up-beat when fixating up-target.
Reduced VOR gain to the left and 50% paresis of the left labyrinth at caloric test.
Slight dysdiadochokinesia with left hand and finger-to-nose slight dysmetria with first try.
VNG shows saccadic smooth pursuit to the left.
MRI shows big CPA tumor 28x27x35mm
– ipsilesional, large amplitude low frequency, because of geze impairment
– contralesional, small amplitude high frequency, because of vestibular impalance
Progressive Supranuclear Palsy (PSP) or Steele-Richardson-Olszewski Syndrome is neurodegenerative dissorder, characterized by akinetic rigid parkinsonism, dizziness, unsteadiness, slowness, falls, and pseudobulbar dysarthria, and also supranuclear eye movement abnormalities which presented as downward, or upward, or combination gaze palsy.
A discussion of neuropathic disorders encompasses those diseases that affect the neuron’s cell body, or neuronopathies, and those affecting the peripheral process, or peripheral neuropathies. Neuronopathies can be further subdivided into those that affect only the anterior horn cells, or motor neuron disease, and those involving only the sensory neurons, also called sensory neuronopathies or ganglionopathies. Peripheral neuropathies can be broadly subdivided into those that primarily affect myelin, or myelinopathies, and those that affect the axon, or axonopathies.
Here’s a very useful protocol for taking history and exam in 6 key questions: Click on link
Sensory neuronopathies (SNs) are a specific subgroup of peripheral nervous system diseases characterized by primary degeneration of dorsal root ganglia and their projections. Multifocal sensory symptoms often associated to ataxia are the classical features of SN. Several different etiologies have been described for SNs, but immune-mediated damage plays a key role in most cases. SN may herald the onset of some systemic autoimmune diseases, which further emphasizes how important the recognition of SN is in clinical practice. Click on link
Of course BPPV can manifest with DBN also, here’s a review on this topic Link to abstract
Positional nystagmus isn’t always benign; here are some characteristics of Central Paroxysmal Positional Nystagmus (CPPV): CPPN may be ascribed to enhanced responses of the vestibular afferents due to lesions involving the nodulus and uvula. CPPN could be differentiated from benign paroxysmal positional nystagmus by positional nystagmus induced in multiple planes, temporal patterns of nystagmus intensity, and associated neurologic findings suggestive of central pathologies. LINK