Clinical significance of the long-loop reflex and giant evoked potentials in genetically proven benign adult familial myoclonic epilepsy

Demura, Ai; Demura, Yutaka; Ota, Megumi; Kondo, Takayuki; Kinoshita, Masako

doi:10.1016/j.clinph.2020.01.005

Cited by 5 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Benign Adult Familial Myoclonic Epilepsy (BAFME): Demura et al evaluated a single family of BAFME, of which three patients had SAMD 12 gene mutation, one of which was found to have C-reflex (correlate of LLR in myoclonus) at 77 ms latency of onset (LLR III). 51 It corroborated with giant flash visual evoked potential (VEP). The longer latency of the C-reflex obtained in these patients could be attributed to the technique used in this study.…”

Section: Llr In Pme Syndromesmentioning

confidence: 77%

Long Latency Reflexes in Clinical Neurology: A Systematic Review

Dhar

Kamble

Pal

2022

Can. J. Neurol. Sci.

View full text Add to dashboard Cite

Background: Long latency reflexes (LLRs) are impaired in a wide array of clinical conditions. We aimed to illustrate the clinical applications and recent advances of LLR in various neurological disorders from a systematic review of published literature. Methods: We reviewed the literature using appropriately chosen MeSH terms on the database platforms of MEDLINE, Web of Sciences, and Google Scholar for all the articles from 1st January 1975 to 2nd February 2021 using the search terms “long loop reflex”, “long latency reflex” and “C-reflex”. The included articles were analyzed and reported using synthesis without meta-analysis (SWiM) guidelines. Results: Based on our selection criteria, 40 articles were selected for the systematic review. The various diseases included parkinsonian syndromes (11 studies, 217 patients), Huntington’s disease (10 studies, 209 patients), myoclonus of varied etiologies (13 studies, 127 patients) including progressive myoclonic epilepsy (5 studies, 63 patients) and multiple sclerosis (6 studies, 200 patients). Patients with parkinsonian syndromes showed large amplitude LLR II response. Enlarged LLR II was also found in myoclonus of various etiologies. LLR II response was delayed or absent in Huntington’s disease. Delayed LLR II response was present in multiple sclerosis. Among the other diseases, LLR response varied according to the location of cerebellar lesions while the results were equivocal in patients with essential tremor. Conclusions: Abnormal LLR is observed in many neurological disorders. However, larger systematic studies are required in many neurological disorders in order to establish its role in diagnosis and management.

show abstract

Section: Llr In Pme Syndromesmentioning

confidence: 77%

Long Latency Reflexes in Clinical Neurology: A Systematic Review

Dhar

Kamble

Pal

2022

Can. J. Neurol. Sci.

View full text Add to dashboard Cite

show abstract

“…This is most likely due to the fact that Fz, the reference electrode on the SSEPs condition, is in uenced by cortical SEPs [12,13]. In addition, a previous report described that the amplitude of the middle latency cortical component after N20 decreases with use of a high bandpass lter and high stimulus rate [11,14].…”

Section: Discussionmentioning

confidence: 99%

“…In the posterior tibial nerve stimulation, the upper limit was set at the mean + 2SD [4] or +3SD [7] of normal subjects. We previously evaluated a diagnostic validity of giant evoked potentials using different upper limits, i.e., the mean + 2SD or the mean +3SD, in familial myoclonic epilepsy [11]. Cumulative data would enable us to determine the optimum reference range in accordance with the purpose of evaluation and the tentative diagnosis.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

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

Demura¹,

Demura

Sato

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The neurophysiological correlate is the significant enlargement of visual evoked potentials (VEPs) 6 . In a recent study on BAFME patients carrying the intronic expansions in the SAMD12 gene, 29 the authors have found giant VEPs as a reliable measure to detect photosensitive myoclonus elicited during flash stimulation 29 . Of interest, in these patients, the authors have observed a clinically overt reflex myoclonus induced by visual stimuli.…”

Section: Visual Evoked Potentialsmentioning

confidence: 99%

Familial adult myoclonus epilepsy: Neurophysiological investigations

et al. 2023

View full text Add to dashboard Cite

Familial adult myoclonus epilepsy (FAME) also described as benign adult familial myoclonus epilepsy (BAFME) is a high‐penetrant autosomal dominant condition featuring cortical myoclonus of varying frequency and occasional/rare convulsive seizures. In this update we provide a detailed overview of the main neurophysiological findings so far reported in patients with FAME/BAFME. After reviewing the diagnostic contribution of each neurophysiological technique, we discuss the possible mechanisms underlying cortical hyperexcitability and suggest the involvement of more complex circuits engaging cortical and subcortical structures, such as the cerebellum. We, thus, propose that FAME/BAFME clinical features should arise from an “abnormal neuronal network activity,” where the cerebellum represents a possible common denominator. In the last part of the article, we suggest that future neurophysiological studies using more advanced transcranial magnetic stimulation (TMS) protocols could be used to evaluate the functional connectivity between the cerebellum and cortical structures. Finally, non‐invasive brain stimulation techniques such as repetitive TMS or transcranial direct current stimulation could be assessed as potential therapeutic tools to ameliorate cortical excitability.

show abstract

Clinical significance of the long-loop reflex and giant evoked potentials in genetically proven benign adult familial myoclonic epilepsy

Cited by 5 publications

References 5 publications

Long Latency Reflexes in Clinical Neurology: A Systematic Review

Long Latency Reflexes in Clinical Neurology: A Systematic Review

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

Familial adult myoclonus epilepsy: Neurophysiological investigations

Contact Info

Product

Resources

About