The vibration test is a recent development in clinical vestibular assessment.
It has been made possible by the wide availability of video Frenzel goggles,
which are devices which allow one to observe a subjects eyes in complete darkness.
It was noted that vibration over the head or neck may elicit a vigorous nystagmus,
and furthermore, the nystagmus is frequently direction specific.
Practical method
Device used for vibration test (cost -- about $25). This is a Sunbeam/Oster shower massager.
A source of vibration, such as a hand-held shower massager (you can use vibrators instead if you prefer) is firmly applied to the mastoid,
anterior or posterior neck of a subject.
Method of vibration test. A shower massager is applied firmly to the lower edge of the sternocleidomastoid. The lower frequency setting is used (60 hz).
Generally we apply vibration to the lower edge of the sternocleidomastoid as we want to avoid the carotid artery area, but the exact location is not at all critical as long as the sternocleidomastoid is located and the pressure is firm. The eyes are observed with a device
such as a video-Frenzel goggle system. No light can be allowed. The subject
is sitting upright, without instruction other than to look straight ahead.
Vibration induced nystagmus. This patient has a 60% left weakness. There is a 3 deg/sec right-beating spontaneous nystagmus, which increases to about 10 deg/sec when vibration is applied to either sternocleidomastoid with a device that produces a 60 cycle pulse (a shower massager).
A positive response is a horizontal nystagmus that beats in the same direction,
for vibration on both sides of the neck. Nystagmus that beats in different directions
according to the side of vibration, as well as nystagmus that is vectored other
than horizontally, is considered either normal or simply of unknown significance.
An example of the vibration test is shown here (movie, 7 meg). This individual has a complete unilateral vestibular loss secondary to removal of an acoustic neuroma on the right side 30 years prior. There is a strong nystagmus beating to the left, for vibration on either side. The subject cannot see because of the goggles which occlude vision. The vibration source is a conventional shower massager as shown above.
Variant vibration tests:
Vibration over the posterior neck -- this method is of unclear utility
Vibration over the anterior neck -- this is the standard location
Vibration over the mastoids. -- this location elicits nystagmus as well as the anterior neck, but due to bone conduction and proximity to the ear, might be less localizing. More study is needed.
Clinical Utility:
There is a suprisingly large literature documenting the utility of neck vibration in diagnosis. There is also a large basic science literature documenting the deleterious effects of vibration on posture.
In essence, vibration of the neck is a moderately reliable method of localizing the side of a unilateral vestibular lesion. In complete darkness, vibration induces a nystagmus that resembles that seen acutely, prior to compensation. Vibration induced nystagmus persists over decades, unlike spontaneous nystagmus.
References:
· Betts GA, Barone M, Karlberg M, MacDougall H and Curthoys IS (2000).
"Neck muscle vibration alters visually-perceived roll after unilateral vestibular
loss." Neuroreport 11(12): 2659-62.
· Biguer B, Donaldson IM, Hein A and Jeannerod M (1988). "Neck muscle
vibration modifies the representation of visual motion and direction in man."
Brain 111 ( Pt 6): 1405-24.
· Bottini G, Karnath HO, Vallar G, Sterzi R, Frith CD, Frackowiak RS and
Paulesu E (2001). "Cerebral representations for egocentric space: Functional-anatomical
evidence from caloric vestibular stimulation and neck vibration." Brain 124(Pt
6): 1182-96.
· Bove M, Diverio M, Pozzo T and Schieppati M (2001). "Neck muscle
vibration disrupts steering of locomotion." J Appl Physiol 91(2): 581-8.
· Gauthier GM, Roll JP, Hugon M and Martin B (1983). "Motor dyscontrol
as a hazard in massive body vibration in man." Adv Neurol 39: 685-97.
· Gauthier GM, Roll JP, Martin B and Harlay F (1981). "Effects of
whole-body vibrations on sensory motor system performance in man." Aviat
Space Environ Med 52(8): 473-9.
· Karlberg M, Aw ST, Black RA, Todd MJ, MacDougall HG and Halmagyi GM (2003).
"Vibration-induced ocular torsion and nystagmus after unilateral vestibular
deafferentation." Brain 126(Pt 4): 956-64.
· Lekhel H, Popov K, Bronstein A and Gresty M (1998). "Postural responses
to vibration of neck muscles in patients with uni- and bilateral vestibular loss."
Gait Posture 7(3): 228-236.
· Michel J, Dumas G, Lavieille JP and Charachon R (2001). "Diagnostic
value of vibration-induced nystagmus obtained by combined vibratory stimulation
applied to the neck muscles and skull of 300 vertiginous patients." Rev Laryngol
Otol Rhinol (Bord) 122(2): 89-94.
· Popov K, Lekhel H, Bronstein A and Gresty M (1996). "Postural responses
to vibration of neck muscles in patients with unilateral vestibular lesions."
Neurosci Lett 214(2-3): 202-4.
· Popov KE, Lekhel H, Faldon M, Bronstein AM and Gresty MA (1999). "Visual
and oculomotor responses induced by neck vibration in normal subjects and labyrinthine-defective
patients." Exp Brain Res 128(3): 343-52.
· Strupp M, Arbusow V, Borges Pereira C, Dieterich M and Brandt T (1999).
"Subjective straight-ahead during neck muscle vibration: effects of ageing."
Neuroreport 10(15): 3191-4.
· Strupp M, Arbusow V, Dieterich M, Sautier W and Brandt T (1998). "Perceptual
and oculomotor effects of neck muscle vibration in vestibular neuritis. Ipsilateral
somatosensory substitution of vestibular function." Brain 121 ( Pt 4): 677-85.
· Yagi T and Ohyama Y (1996). "Three-dimensional analysis of nystagmus
induced by neck vibration." Acta Otolaryngol 116(2): 167-9.
· Yagi T, Yajima H, Sakuma A and Aihara Y (2000). "Influence of vibration
to the neck, trunk and lower extremity muscles on equilibrium in normal subjects
and patients with unilateral labyrinthine dysfunction." Acta Otolaryngol
120(2): 182-6.
Page last modified:
July 5, 2008
