Category Archives: Positional Down Beat Nystagmus

Positional DBN central or peripheral

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.
CPA arachnoid cyst

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

Positional DBN – interesting cases

Here’s the case of a patient with assumed vertebral artery compression in some positions inducing positional DBN
link to abstract

And here’s the case of a paraneoplastic DBN
link to abstract

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

AND of course a classic from P. Bertholon from 2002
Positional down beating nystagmus in 50 patients: cerebellar disorders and possible anterior semicircular canalithiasis

Positional Down Beat Nystagmus: Central or Peripheral

Patient 52yr waked up with positional vertigo: when he turned in bed, he felt strong short vertigo. On the next day he leaned forward (fixing washing machine) and then he felt strong vertigo, instability, nausea and vomiting. After that restrictive movements and sleeping on big pillows.

Very standard history for BPPV, isn’t it?

Dix-Hallpike test: Down Beating Nystagmus with very discreate cw torsion component but without vertigo! He felt vertigo when returning to the sitting position.

Deep head hanging maneuver didn’t work. Than Epley from the right side. After that control DH test ok.

Five days later he was still dizzy but positional testing: from standing with head bent to the left, when he quickly raise head to the upright position, he felt short spin and I saw two downbeating Ny.
Calorics, VHIT, SVV, oVEMP and oto-neurological exam normal.

I send him to perform MRI as I do evry time when I see down-beating Ny

MRI demonstrated two lesions at cerebellar peduncles bilaterally
MRI cerebellar peduncle lesion

On that occasion (15 days later) Dix-Hallpike was possitive to the right. Usual upbeating and torsional ccw Ny.

After one Epley meneuver he is without any vestibular complaints.