title: The N3 potential compared to sound and galvanic vestibular evoked myogenic potential in healthy subjects and in multiple sclerosis patients.
abstract: Both sound (s-) and galvanic (g-) vestibular-evoked myogenic potential (VEMP) enable us to study the saccular pathways. However, the VEMP can be abnormal for non-vestibular factors, such as insufficient activation of the sterno-cleido-mastoid (SCM) muscle or a lesion that involves the accessory nucleus and/or nerve or the SCM muscle. These drawbacks do not affect another technique that evaluates the saccular function: the N3 potential. We recorded both the s- and the g-VEMP and the N3 potential in a group of 31 healthy subjects to establish a reference range. The N3 potential and the s-VEMP were recordable bilaterally from all the subjects, whereas the g-VEMP was undetectable uni- or bilaterally in 7 subjects. The latency and amplitude values of the s-VEMP did not differ from those of the g-VEMP. For all three techniques, the latency and amplitude values from the right and from the left recording and/or stimulation side were the same. We suggest using normative latency and amplitude values based on the mean and ratio of the right- and left-side values. The s-VEMP, the N3 potential and the auditory evoked response (ABR) were compared in 15 subjects suffering from multiple sclerosis. The three techniques detected a similar number of abnormalities, but these abnormalities were not correlated. This suggests that these different techniques should be regarded as complementary in evaluating saccular function.
authors.affiliation: Fondazione Istituto Neurologico C.Mondino, IRCCS and Dipartimento Scienze Neurologiche Università di Pavia, Pavia, Italy. mversino@unipv.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Versino
authors.forename: Laura
authors.initials: L
authors.lastname: Ranza
authors.forename: Silvia
authors.initials: S
authors.lastname: Colnaghi
authors.forename: Roberto
authors.initials: R
authors.lastname: Alloni
authors.forename: Roberto
authors.initials: R
authors.lastname: Callieco
authors.forename: Alfredo
authors.initials: A
authors.lastname: Romani
authors.forename: Roberto
authors.initials: R
authors.lastname: Bergamaschi
authors.forename: Anna
authors.initials: A
authors.lastname: Pichiecchio
authors.forename: Stefano
authors.initials: S
authors.lastname: Bastianello
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cosi
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values; D012444:Saccule and Utricle / Q000502:physiology* / Q000503:physiopathology