TY - JOUR
T1 - A new measure of dysconjugacy in INO
T2 - The first-pass amplitude
AU - Frohman, Elliot
AU - O'Suilleabhain, Padraig E
AU - Dewey, Richard B
AU - Frohman, Teresa C.
AU - Kramer, Phillip D.
N1 - Funding Information:
This work was supported by the Yellow Rose Foundation (EMF) and the Hawn Foundation (EMF, TCF).
PY - 2003/6/15
Y1 - 2003/6/15
N2 - Background: The ratios of abducting to adducting eye movements (versional dysconjugacy index, VDI) for saccadic velocity and acceleration have been useful measures by which to objectively characterize internuclear ophthalmoparesis (INO). Amplitude measures of dysconjugacy have been less useful, given that many patients maintain the ability to ultimately reach a centrifugal fixation target and that traditional amplitude measures of VDI have focused on this 'final amplitude' (FA) position. Methods: We utilized infrared oculography to define a new amplitude measure of dysconjugacy in 42 multiple sclerosis (MS) patients with INO. The first-pass amplitude (FPA)-VDI is the ratio of abduction/adduction eye movement amplitudes computed at the time when the abducting eye initially achieves the centrifugal horizontal fixation target. Results: FPA-VDI values were significantly more sensitive and specific than FA-VDI values in demonstrating dysconjugacy in INO, and there was a 14-fold increase in dysconjugacy as measured by FPA-VDI Z-scores when compared to FA-VDI Z-scores. Conclusion: Consideration of velocity (pulse) and amplitude (step) components of dysconjugacy in patients with INO can provide a greater understanding of the dynamic aspects of this syndrome. We propose to characterize the relationship between the pathophysiology of INO and neuroradiologic measures of tissue injury in MS.
AB - Background: The ratios of abducting to adducting eye movements (versional dysconjugacy index, VDI) for saccadic velocity and acceleration have been useful measures by which to objectively characterize internuclear ophthalmoparesis (INO). Amplitude measures of dysconjugacy have been less useful, given that many patients maintain the ability to ultimately reach a centrifugal fixation target and that traditional amplitude measures of VDI have focused on this 'final amplitude' (FA) position. Methods: We utilized infrared oculography to define a new amplitude measure of dysconjugacy in 42 multiple sclerosis (MS) patients with INO. The first-pass amplitude (FPA)-VDI is the ratio of abduction/adduction eye movement amplitudes computed at the time when the abducting eye initially achieves the centrifugal horizontal fixation target. Results: FPA-VDI values were significantly more sensitive and specific than FA-VDI values in demonstrating dysconjugacy in INO, and there was a 14-fold increase in dysconjugacy as measured by FPA-VDI Z-scores when compared to FA-VDI Z-scores. Conclusion: Consideration of velocity (pulse) and amplitude (step) components of dysconjugacy in patients with INO can provide a greater understanding of the dynamic aspects of this syndrome. We propose to characterize the relationship between the pathophysiology of INO and neuroradiologic measures of tissue injury in MS.
KW - Dysconjugacy
KW - First-pass amplitude
KW - Internuclear ophthalmoparesis
KW - Z-score
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U2 - 10.1016/S0022-510X(03)00027-3
DO - 10.1016/S0022-510X(03)00027-3
M3 - Article
C2 - 12736091
AN - SCOPUS:0038639009
SN - 0022-510X
VL - 210
SP - 65
EP - 71
JO - Journal of the Neurological Sciences
JF - Journal of the Neurological Sciences
IS - 1-2
ER -