Spinal somatosensory evoked potentials following segmental sensory stimulation. A direct measure of dorsal root function

Masud Seyal, G. A. Palma, L. S. Sandhu, Y. P. Mack, J. M. Hannam

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Dorsal root function cannot presently be measured directly. The H-reflex is an indirect measure of dorsal root function but only for the S1 root. Spinal somatosensory evoked potentials (SEPs) following dermatomal stimulation of the legs have the potential of providing direct data reflecting dorsal root function but have not been reliably recorded in normal subjects. We have developed a reliable technique for recording SEPs at the lumbar root entry zone following segmental sensory stimulation of the legs. The saphenous, superficial peroneal, and sural nerves were stimulated representing the L3/L4, L5 and S1 roots respectively. Reproducible responses (N-wave) were recorded over the lumbar spine in all 60 normal limbs examined. The N-wave peak latency was significantly correlated with lower limb length. The conduction velocities from the stimulation sites to the lumbar spine were similar to published values for peripheral conduction velocities in these nerves. The mean inter-limb latency differences for the N-wave peak were: L3/L4 0.61 msec; L5 0.35 msec; and S1 0.57 msec. The mean N-wave amplitudes were: L3/L4 0.11 μV; L5 0.28 μV; and S1 0.23 μV. This technique is a direct measure of dorsal root integrity. Unlike scalp recorded SEPs, the lumbar N-wave is not state-dependent and is unaffected by lesions within the brain and rostral cord.

Original languageEnglish (US)
Pages (from-to)390-393
Number of pages4
JournalElectroencephalography and Clinical Neurophysiology
Volume69
Issue number4
DOIs
StatePublished - 1988

Fingerprint

Somatosensory Evoked Potentials
Spinal Nerve Roots
Leg
Spine
Extremities
H-Reflex
Sural Nerve
Peroneal Nerve
Scalp
Lower Extremity
Brain

Keywords

  • Evoked potentials
  • Leg
  • Segmental
  • Sensory
  • Spinal

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

Cite this

Spinal somatosensory evoked potentials following segmental sensory stimulation. A direct measure of dorsal root function. / Seyal, Masud; Palma, G. A.; Sandhu, L. S.; Mack, Y. P.; Hannam, J. M.

In: Electroencephalography and Clinical Neurophysiology, Vol. 69, No. 4, 1988, p. 390-393.

Research output: Contribution to journalArticle

@article{7a3097d7ec624525ac99f9f49371d89c,
title = "Spinal somatosensory evoked potentials following segmental sensory stimulation. A direct measure of dorsal root function",
abstract = "Dorsal root function cannot presently be measured directly. The H-reflex is an indirect measure of dorsal root function but only for the S1 root. Spinal somatosensory evoked potentials (SEPs) following dermatomal stimulation of the legs have the potential of providing direct data reflecting dorsal root function but have not been reliably recorded in normal subjects. We have developed a reliable technique for recording SEPs at the lumbar root entry zone following segmental sensory stimulation of the legs. The saphenous, superficial peroneal, and sural nerves were stimulated representing the L3/L4, L5 and S1 roots respectively. Reproducible responses (N-wave) were recorded over the lumbar spine in all 60 normal limbs examined. The N-wave peak latency was significantly correlated with lower limb length. The conduction velocities from the stimulation sites to the lumbar spine were similar to published values for peripheral conduction velocities in these nerves. The mean inter-limb latency differences for the N-wave peak were: L3/L4 0.61 msec; L5 0.35 msec; and S1 0.57 msec. The mean N-wave amplitudes were: L3/L4 0.11 μV; L5 0.28 μV; and S1 0.23 μV. This technique is a direct measure of dorsal root integrity. Unlike scalp recorded SEPs, the lumbar N-wave is not state-dependent and is unaffected by lesions within the brain and rostral cord.",
keywords = "Evoked potentials, Leg, Segmental, Sensory, Spinal",
author = "Masud Seyal and Palma, {G. A.} and Sandhu, {L. S.} and Mack, {Y. P.} and Hannam, {J. M.}",
year = "1988",
doi = "10.1016/0013-4694(88)90010-7",
language = "English (US)",
volume = "69",
pages = "390--393",
journal = "Electroencephalography and Clinical Neurophysiology",
issn = "0013-4694",
publisher = "Elsevier BV",
number = "4",

}

TY - JOUR

T1 - Spinal somatosensory evoked potentials following segmental sensory stimulation. A direct measure of dorsal root function

AU - Seyal, Masud

AU - Palma, G. A.

AU - Sandhu, L. S.

AU - Mack, Y. P.

AU - Hannam, J. M.

PY - 1988

Y1 - 1988

N2 - Dorsal root function cannot presently be measured directly. The H-reflex is an indirect measure of dorsal root function but only for the S1 root. Spinal somatosensory evoked potentials (SEPs) following dermatomal stimulation of the legs have the potential of providing direct data reflecting dorsal root function but have not been reliably recorded in normal subjects. We have developed a reliable technique for recording SEPs at the lumbar root entry zone following segmental sensory stimulation of the legs. The saphenous, superficial peroneal, and sural nerves were stimulated representing the L3/L4, L5 and S1 roots respectively. Reproducible responses (N-wave) were recorded over the lumbar spine in all 60 normal limbs examined. The N-wave peak latency was significantly correlated with lower limb length. The conduction velocities from the stimulation sites to the lumbar spine were similar to published values for peripheral conduction velocities in these nerves. The mean inter-limb latency differences for the N-wave peak were: L3/L4 0.61 msec; L5 0.35 msec; and S1 0.57 msec. The mean N-wave amplitudes were: L3/L4 0.11 μV; L5 0.28 μV; and S1 0.23 μV. This technique is a direct measure of dorsal root integrity. Unlike scalp recorded SEPs, the lumbar N-wave is not state-dependent and is unaffected by lesions within the brain and rostral cord.

AB - Dorsal root function cannot presently be measured directly. The H-reflex is an indirect measure of dorsal root function but only for the S1 root. Spinal somatosensory evoked potentials (SEPs) following dermatomal stimulation of the legs have the potential of providing direct data reflecting dorsal root function but have not been reliably recorded in normal subjects. We have developed a reliable technique for recording SEPs at the lumbar root entry zone following segmental sensory stimulation of the legs. The saphenous, superficial peroneal, and sural nerves were stimulated representing the L3/L4, L5 and S1 roots respectively. Reproducible responses (N-wave) were recorded over the lumbar spine in all 60 normal limbs examined. The N-wave peak latency was significantly correlated with lower limb length. The conduction velocities from the stimulation sites to the lumbar spine were similar to published values for peripheral conduction velocities in these nerves. The mean inter-limb latency differences for the N-wave peak were: L3/L4 0.61 msec; L5 0.35 msec; and S1 0.57 msec. The mean N-wave amplitudes were: L3/L4 0.11 μV; L5 0.28 μV; and S1 0.23 μV. This technique is a direct measure of dorsal root integrity. Unlike scalp recorded SEPs, the lumbar N-wave is not state-dependent and is unaffected by lesions within the brain and rostral cord.

KW - Evoked potentials

KW - Leg

KW - Segmental

KW - Sensory

KW - Spinal

UR - http://www.scopus.com/inward/record.url?scp=0023835864&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023835864&partnerID=8YFLogxK

U2 - 10.1016/0013-4694(88)90010-7

DO - 10.1016/0013-4694(88)90010-7

M3 - Article

C2 - 2450737

AN - SCOPUS:0023835864

VL - 69

SP - 390

EP - 393

JO - Electroencephalography and Clinical Neurophysiology

JF - Electroencephalography and Clinical Neurophysiology

SN - 0013-4694

IS - 4

ER -