Brainstem Dysfunction in Alternating Hemiplegia of Childhood

Cephalalgia ◽  
2006 ◽  
Vol 26 (5) ◽  
pp. 511-519 ◽  
Author(s):  
S Rinalduzzi ◽  
M Valeriani ◽  
F Vigevano
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Normal Subjects ◽  
Blink Reflex ◽  
Conduction Time ◽  
System Function ◽  
Alternating Hemiplegia Of Childhood ◽  
Brainstem Dysfunction ◽  
Stimulation Of

Six patients with alternating hemiplegia of childhood (AHC) underwent motor evoked potentials (MEPs), somatosensory evoked potentials (SEPs) and blink reflex recording. No SEP abnormality was found. As for MEP recording, central conduction time did not differ between patients studied during either interictal or ictal phase, and normal subjects, suggesting that the pyramidal system function is spared. In blink reflex recording, the latencies of both the ipsilateral (iR2) and contralateral (cR2) R2 components were significantly longer ( P < 0.01) in patients during the interictal phase than in normal subjects. Moreover, the iR2 and cR2 areas were significantly reduced ( P < 0.01) in patients during the interictal phase, compared with normal subjects. During the ictal phase, the ipsilateral R2 latency was significantly decreased after stimulation of the hemiplegic side, compared with the interictal phase ( P < 0.05). The blink reflex abnormalities suggest a brainstem dysfunction, which may be linked to the pathophysiological mechanisms of the disease.

scholarly journals Amplitude of Somatosensory Evoked Potentials (SEPs) in Short-Latency SEPs Condition is 80% of that in Giant SEPs

2021 ◽  
Author(s):  
Ai Demura ◽  
Yutaka Demura ◽  
Kazuaki Sato ◽  
Masako Kinoshita
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Neurological Disorders ◽  
Bandpass Filter ◽  
Normal Subjects ◽  
Short Latency ◽  
Cortical Hyperexcitability ◽  
Recording Conditions ◽  
The Mean ◽  
Stimulation Of

Abstract The recording conditions of somatosensory evoked potentials (giant SEPs) are different from those of short-latency SEPs (SSEPs). We investigated the waveform characteristics obtained for each condition. Forty-eight upper limbs of 24 adult normal subjects (12 males, age 35.5 ± 9.7 years (mean ± SD)) were investigated. The main differences in recording conditions were reference electrodes (giant SEPs: the earlobe electrode ipsilateral to the stimulated limb, SSEPs: Fz), stimulus rate (1 Hz, 5 Hz), and bandpass filter (1 Hz–1 kHz, 20 Hz–3 kHz). SEPs were elicited by unilateral percutaneous electrical stimulation of the median nerve at the wrist. The amplitudes of N20o–N20 and N20–P25 were significantly larger in the giant SEP condition than in the SSEP condition (p<0.001). The mean + 3SD of N20–P25 amplitude was 10.0 µV in the giant SEP condition and 7.8 µV in the SSEP condition. The N20–P25 amplitude was significantly correlated between the giant SEP and SSEP conditions (R=0.64, p<0.001). Thus, the amplitude of SEPs in the SSEPs condition is equivalent to 80% of that in the giant SEPs condition. The information is useful for detecting cortical hyperexcitability in various neurological disorders including myoclonic epilepsy.

Effects of Stimulus Intensity on Latency and Conduction Time of Short-Latency Somatosensory Evoked Potentials

2001 ◽  
Vol 32 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Y. Shiga ◽  
T. Yamada ◽  
A. Ofuji ◽  
Y. Fujita ◽  
T. Kawamura ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Stimulus Intensity ◽  
Somatosensory Evoked Potentials ◽  
Short Latency ◽  
Conduction Time

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.

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