Hypohydration and muscular fatigue of the thumb alter median nerve somatosensory evoked potentials

2010 ◽  
Vol 35 (4) ◽  
pp. 456-463 ◽  
Author(s):  
Scott J. Montain ◽  
William J. Tharion
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Endurance Performance ◽  
Time To Exhaustion ◽  
Neural Processing ◽  
Afferent Signal ◽  
Men 2 ◽  
Fatiguing Exercise ◽  
Voluntary Contractions

The mechanisms by which dehydration impairs endurance performance remain unresolved but may involve alterations in afferent neural processing. The purpose of this study was to determine the effect of hypohydration on somatosensory evoked potentials (SEPs) at rest and during recovery from fatiguing exercise. Fourteen volunteers (12 men, 2 women) performed repetitive isometric thumb contractions (50% maximal voluntary contractions (MVC) and 100% MVC in a 5:1 ratio, each contraction separated by 5 s of rest) until exhaustion when euhydrated (EU) and when hypohydrated by 4% body mass (HY). SEPs were obtained from the median nerve. The results indicated that HY did not produce statistical differences in time to exhaustion (EU = 754 (SD 255); HY = 714 (SD 318) s; p = 0.66) or rate of muscle fatigue. However, HY was associated with greater subjective feelings of fatigue and loss of vigor after exhaustive exercise (p < 0.01). HY affected N20 latency with an interaction effect of hydration by fatigue state (EU-Rest: 18.5 (SD 1.6) ms; EU-Fatigue: 19.0 (SD 1.6) ms; HY-Rest: 18.3 (SD 1.3) ms; HY-Fatigue: 18.4 (SD 1.5) ms; p = 0.034), but N20 and N20-P22 amplitude responses were similar between HY and EU trials. We concluded that moderate water deficits appear to alter afferent signal processing within the cerebral cortex.

Localization of Stereotactic Targets by Microrecording of Thalamic Somatosensory Evoked Potentials

Neurosurgery ◽  
1991 ◽  
Vol 28 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Fumio Shima ◽  
Takato Morioka ◽  
Shozo Tobimatsu ◽  
Omiros Kavaklis ◽  
Motohiro Kato ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Practical Method ◽  
The Other ◽  
Basal Region ◽  
Thalamic Nuclei ◽  
Median Nerve Stimulation ◽  
Lower Amplitude ◽  
Stimulation Of

Abstract To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional “macroclectrode” in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc). situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroclectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.

Median nerve somatosensory evoked potentials in migraine.

2003 ◽  
Vol 43 (4) ◽  
pp. 426-426
Author(s):  
Y Ozkul ◽  
A Uckardes
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials

Lateralization of the P22/N30 precentral cortical component of the median nerve somatosensory evoked potentials is different in patients with a tonic or tremulous form of cervical dystonia

1999 ◽  
Vol 14 (4) ◽  
pp. 642-651 ◽  
Author(s):  
Petr Ka�ovsk� ◽  
Hana Streitov� ◽  
Jaroslav Dufek ◽  
Vladim�r Znojil ◽  
Pavel Daniel ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Cervical Dystonia

Changes of Recovery Function in Median Nerve Somatosensory Evoked Potentials From Awake to Sleep

2009 ◽  
Vol 26 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Hiroo Ichikawa ◽  
Thoru Yamada ◽  
Shinichiro Taniguchi ◽  
Motohiko Hara ◽  
Reiko Fujisawa ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Recovery Function

Effects of Hypothermia on Median Nerve Somatosensory Evoked Potentials During Spontaneous Circulation

2002 ◽  
Vol 14 (2) ◽  
pp. 141-145 ◽  
Author(s):  
Manfred Lang ◽  
Martin Welte ◽  
Rolf Syben ◽  
Diethelm Hansen
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Spontaneous Circulation
Sign in / Sign up

Export Citation Format

Share Document